Passive Fire Protection: Types and Applications Guidance Note
Acknowledgement and pictures credit The cooperation of the following in furnishing data and il
lustrations for this booklet is gratefully acknowledged:
Nick N. Aldis George Wheatman BP Exploration RAK
Resource Protection International was the contractor appointed by the BP HSE Shared Resource for the preparation of this booklet.
Copyright ?2003 First Edition, 2003
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This booklet is intended as a safety supplement to training courses, manuals, and procedures. However, technical advances and other changes made after its publication, while generally not affecting principles, could affect some suggestions made herein. The reader is encouraged to examine such advances and changes when selecting and implementing practices and procedures at his/her facility. While the information in this booklet is intended to increase the store-house of knowledge in safe operations, it is important for the reader to recognize that this material is generic in nature, that it is not specific, and, accordingly, that its contents may not be subject to literal application. Instead, as noted above, it is supplemental information for use in already established training programs; and it should not be treated as a substitute for otherwise applicable training courses, manuals or procedures. This document has been prepared for use by members of the BP Group of Companies and, if it should come into the possession of third parties, the advice contained herein is to be construed by such third parties as a matter of opinion only and not as a representation or statement of any kind as to the effect of following such advice and no responsibility for the use of it can be assumed by BP.
Contents Definitions 3 4 5 6 7 17 23 27 30 40
I. Introduction II. Background III. Passive Protection Overview IV. Types of PFP Available V. Fire Tests, Certifications and Approvals VI. Minimum Design Requirements – All Types of PFP VII. PFP For Buildings VIII. Industry PFP IX. PFP Inspection and Maintenance
Appendices: 1. Examples of Good PFP Installation Practices 2. Case Study – Poor PFP specification / installation 3. UTG Position on the Choice and Specification of Epoxy Intumescent Passive Fire Protection Materials 4. Example of Best Practice -BP Engineering Standard Fireproofing Materials & Application Specification – Onshore Facility
44 47 57 60
The fixing, spraying, coating or other means of covering a structure or vessel with PFP. Term applied for combustible materials including wood, paper, fabrics etc but also including plastics and rubber materials. Commonly referred to as Class A fire events when the materials burn. Term used for materials or structures that can withstand the effects of fire for a given period of time. Term used to describe materials such as steel which are protected from the effects of fire by covering by fire resistant materials. Term used to describe materials or assemblies that have been treated either chemically or otherwise to increase their resistance to fire effects. The oil, gas and petrochemical industries exploration, production, processing storage and distribution facilities and sites. The term Passive Fire Protection (PFP) refers to any fire protection measures such as structural barriers or fixed systems or special coatings or coverings that do not require manual or automatic actuation for them to function to their design intent.
This document is intended for BP project, fire protection, operations and maintenance engineers who will or may have responsibility for the provision of passive fire protection at BP facilities. This guidance document has been developed due to an increase in the number of instances where either poor materials or poor installation techniques have resulted in defects or failure of PFP applications. In at least two serious instances, where claims of “fire tests” were made as rd evidence of compliance, there were, in fact, no required independent 3 party approvals issued for the PFP materials. As an overview, the main points of note for Industry PFP consideration are:
q q q q
A certificate of “fire testing” is meaningless and is not an approval certificate and must not be accepted as proof of PFP performance – there have been instances of suppliers and installers creating “fire test” documents and certificates to read as if the fire test itself means the PFP is certified and approved for use. In other instances, approvals bodies are “referred” to without provision of their approvals certificate; rd An independent 3 party approvals certificate is required for all PFP. Fire tests are controlled events within controlled environments and may not represent actual fire conditions or circumstances on site. Careful study of the fire test methods and results are necessary to assess their relevance to actual conditions; Site specified fire tests may be required to simulate the expected fire event or conditions; PFP installers must be approved by the PFP materials/application supplier. BP representatives must supervise installers at all times; Approved PFP installers should ensure that any sub contractors are supervised and quality control procedures are enforced at all times; PFP must be vi ewed as a fire “system” in the same way as water spray systems or foam systems – they require controlled application as well as inspection and maintenance on a regular basis; Repairs to PFP are not easily carried out, especially offshore. If repairs are necessary, they must only be carried out by approved installers of the suppliers materials/application.
This document provides guidance on passive fire protection material types and applications and also contains information on the fire testing and approvals procedures, which should help eliminate any future doubts over passive products acceptance.
There are two generic applications of PFP – Interior PFP and Process Industry PFP. Interior PFP applies to buildings, ships and offshore living quarters or occupied areas. Industry PFP applies to hydrocarbon fire protection of process equipment or escape routes. Whilst there may be similarities as buildings, ships or offshore installations steel structures can have PFP in the same way as process industry steel structures, increasingly, the industry uses PFP to limit the temperature of a steel structure, whether this steelwork is a supporting structure or a hydrocarbon containing vessel. Carbon steel rapidly loses strength when its temperature increases. For steel structures which are load bearing within normal design limits, collapse o can occur when a temperature in the order of 500-550 C is reached. For a o hydrocarbon pool fire, temperatures of 1000-1200 C are produced. For a o hydrocarbon jet/torch fire the temperature can reach 1600 C. It is obvious that unprotected steelwork can fail in a very short time under such fire conditions and temperatures. Although much depends on the steel thickness and surface area (heat sink), and if liquid is present to absorb heat within the steel as in a vessel, failures have been recorded from 10-15 minutes. Historically, in the oil, gas and petrochemical industry, Passive Fire Protection has been used for the protection of industry process unit plant and equipment including column skirts, vessel saddles, piperack supports etc. Typically, this was referred to as “fireproofing”, rather than the current PFP term used. This fireproofing started out as cement based thermal protection coatings but now includes a variety of materials and applications. The growth of the PFP industry has resulted in an ever-widening range of fire or heat resisting materials, coatings, structures, blocks, tubes, sleeves, blankets and covers. The dramatic increase in PFP options can easily lead to confusion over best selection and fit-for-purpose PFP applications, especially in the key areas of availability and reliability – protection integrity over time. Examples of poor availability and reliability are illustrated in this document.
Within buildings there should always be passive protection employed to prevent propagation of smoke, flame or heat by provision of such measures as fire doors, fire rated wall construction and ceiling void compartmentation. These provisions offer a double benefit – fire containment and protected means of escape for occupants, both for a specified time period. Such measures are appropriate to most occupied commercial buildings, not just those in the oil, gas and petrochemical industry. At the same time, the levels of protection required by statutory authorities for life safety (means of escape) may not be sufficient for protection of critical building facilities such as computer suites from the point of view of disruption to business continuity. It could, therefore, be important not only to review PFP measures in process areas but also in buildings. This is particularly true for Control Buildings in or near to process equipment which might be subject to fire or explosion effects but may also be true where critical control systems or computer data base hardware may be exposed to fire impact within the building.
Passive Protection Overview
In simple terms, PFP is used to perform one or more of the following functions: ? ? ? ? ? ? ? Contain a fire within a compartment or space in a building; Delay fire effects impacting on means of escape; Delay heat transfer to stored or processed flammable liquids and gases; Delay the collapse of load bearing structures or members; Delay the failure of steel used for holding flammable liquids or gases; Assure the closure of critical isolation valves or ESD valves under fire conditions; Delay ignition of cables or control wiring;
Passive protection can not only consist of flame impingement/engulfment or radiant heat protection but also smoke and heat protection and blast/overpressure protection. Typically, for smoke and heat protection, air conditioning and ventilation systems will have passive measures provided at strategic locations within ducting or at fire dampers. For overpressures, buildings may have reinforced steel cladding or concrete or brickwork provided.
The principles of the overpressure protection provisions and materials are generally understood and correctly applied by the use of specialist reference documents. They are therefore not mentioned in depth in this document. Similarly, for building or ships or offshore living quarters, passive fire protection is generally understood and applied, usually because of internationally accepted legislation such as Fire Precautions Acts, IMO Safety of Life at Sea (SOLAS), NFPA 101 Life Safety Code, etc, etc. In the industry, it is the provision of fire hazard specific PFP that is less well understood and it is this application that is mainly explored in this document.
IV. Types of PFP Available
The following section highlights materials available and discusses their use, advantages and disadvantages. Cementitious Materials Cementitious PFP materials use a binder having a hydraulic set when mixed with water and a filler having good insulation properties. Normally the binder is Portland cement although, magnesium oxysulphate and gypsum have been used previously and may still be in use. Fillers may be vermiculite, mica, mineral fibres or ceramic fibres. They are usually spray or trowel applied but may also be cast to preformed shapes or sections. PFP performance relies on a combination of two effects – insulation and dehydration causing cooling.
Cementitious passive protection having been trowelled on to a section of a production facility.
Dense (formed) Concrete Dense concrete is a traditional fire proofing material. Concrete in itself does not promote corrosion due to its alkaline nature. However, the pH changes to neutral over a period of years. On setting, concrete shrinks and a small gap can be left against the steel which will allow water ingress. In areas subject to acid rain, such ingress can accelerate corrosion and it is important to seal gaps using suitable mastics or other sealants rated for the same fire resistance time as the concrete. Dense concrete is liable to spall vi olently in a hydrocarbon fire resulting in loss of thickness and lower protection and also may result in injuries to fire responders. Concrete fire proofing cast in situ can be expensive. If dense formed concrete is to be used, it should conform to ASTM C150 (type 1A) or equivalent.
Lightweight Concrete (Vermiculite) Lightweight concretes do not spall in hydrocarbon fires. However, they have a high porosity and will absorb liquids if unprotected, leading to lower impact resistance, reduced adhesion to steel and potential corrosion. A mesh retaining system is essential for hydrocarbon fire protection systems, offering good protection against pool fire or flame engulfment and jet fires. Certain brands of lightweight concretes have a neutral pH. Cementitious PFP can be applied to all configurations of steelworks although sharp radii items may cause problems. Water pick-up post-fire can re-establish some capability (but structural strength may be affected. Cementitious materials do not normally emit toxic fumes in fire situations (although some topcoats might). There are some disadvantages to be aware of in that oxychloride cements can cause corrosion to the steelwork to which they are attached. Portland cement based cementitious coatings do not normally directly cause corrosion, but may accelerate the process by virtue of water retention unless the substrate is protected. Inspection of the substrate can be difficult. The coatings are porous and should be protected with a topcoat system, which must be carefully maintained over the life cycle of the product. The impact resistance of cementitious coatings tend to be lower than that of the epoxy based materials.
Concrete Masonry This material is not commonly used because of high installation costs and extensive maintenance requirements. Assemblies are prone to cracking and admitting moisture with serious corrosion and spalling problems. Magnesium Oxychloride Plaster Magnesium oxychloride plasters should not be used for PFP. Field experience has indicated that corrosion of the substrate steel occurs as the topcoat (over the fire proofing) weathers and moisture combines with the chloride present in the plaster to form hydrochloric acid. The fire proofing flakes and falls off due to moisture entrapment and causes corrosion to the steel lathing and wire mesh used for anchoring and reinforcement. Fire and Blast Walls and Enclosures Such structures are specialist combinations that can resist the effects of hydrocarbon fires and overpressures. They are used effectively for offshore modules where such dual requirements are identified through hazard assessment. Their specification and installation are of a specialist nature, as are the tests for the overpressure aspects of the wall. Similarly, it is possible to have hydrocarbon fire and blast protected enclosures, or box units, for protection of critical ESD valves and/or their actuators. Careful review of the expected “design case” fire and explosion and careful specification of the fire resistance rating and the overpressure requirements are necessary to ensure fit-for-purpose fire and blast walls or enclosures.
Example of a fire and blast wall showing the bracing and steel plating. Mineral or ceramic or a composite insulation material is placed behind the front steel lining to give thermal resistance according to the rating (H60, H120 etc).
Preformed/Inorganic Panels This material has poor weatherability and is therefore normally for internal use only. Precast or compressed fire resistant panels need to be attached to the substrate by mechanical fasteners designed to withstand fire exposure without appreciable loss of strength.
Asbestos Spray applied or wrap around asbestos or materials containing asbestos must not be used under any circumstances. Where vermiculite is to be used as a material, the material manufacturer should supply a certificate stating that the material is asbestos free, along with a copy of the testing house report that conducted the material analysis. The importance of these checks has been recently highlighted by the discovery of the use of asbestos in a new offshore construction in China.
Intumescent/Subliming Normally epoxy based, these materials swell and convert into carbon when exposed to fire. The carbon based char then forms a low conductivity thermal barrier. In some cases subliming materials which absorb energy in turning from solid to vapour may be included in the product. Below are the typical stages of the charring reaction for an intumescent material, in this case, Chartek Intumescent.
Intumescent materials are most often used as spray coatings but are also available as paints and varnishes, prefabricated panels, mastics for general sealing purposes and in strip form for sealing gaps such as those between doors and door frames.
Example of intumescent strip used to seal the gap between the door and the door frame to prevent passage of flame and heat. It is necessary to place strips completely around the frame to achieve an effective barrier.
Intumescent/subliming coatings may be used in appropriate applications. Specific attention should be given to the possibility of a fume or smoke hazard arising from exposure of intumescent coatings to fire. Subliming materials behave by a phase change from a solid to gas without going through the liquid stage. These agents are incorporated into organic matrices of a plastic or elastomeric nature. Intumescence is an expansion or foam process whereby an insulating char is formed at the fire surface. These materials, if applied correctly, provide high adhesion to steel, prot ect steel from corrosion, resist impact damage and dislodgement by vibration, and have a low absorption rate for liquids. It is important to include mesh reinforcement in these systems for two reasons. Firstly the thermal expansion characteristics are thereby modified to come nearer that of the steel substrate. Secondly the mesh holds the coating in place during a fire when it's bond to the primer eventually fails, To achieve satisfactory protection in jet fires, the thickness of the coating needs to be increased and the mesh should be carbon or glass fibre. Epoxy based spray intumescents can be used for all configurations of steel work. They can exhibit superior physical and mechanical properties leading to a longer life span and lower repair requirements than other spray materials. They are normally extremely weather resistant and less prone to water or oil absorption than other types (although some types may require a top coat). They can provide good corrosion protection to the substrate. For a given fire rating, these materials tend to be the lightest spray type PFP and require thinner coatings but this varies between manufacturers as a function of differing application thickness, product specific gravity and reinforcement structure. There are potential disadvantages in that some intumescents may give off toxic smoke and fumes as they char. Erosion of the char may be caused by jet fire impingement or by use of water jet streams during the fire. Also, products using a water extended premix and setting due to evaporation may be prone to slumping during the setting period, and may also be highly porous. Normally, spray applied intumescent materials require a retention system. Although the epoxy base material itself is inherently water resistant, the intumescent materials may not be. Consequently, weatherproof top coats may be required. Mixing of components in the correct proportion is critical to performance. Considerable safety procedures are often required during application and curing.
Intumescent materials are available in various shapes and forms and applications, including pillows and strips and ventilation grilles. Above shows examples of these.
Fibrous Materials Where there is a need for thermal insulation of process vessels and/or pipework and there is also a need for PFP, the materials should typically be rated for 650 °C minimum surface temperature and selected from the following types:(a) (b) (c) (d) (e) (f) Calcium silicate, block or preformed. Mineral wool block. Perlite, block or preformed. Expanded aluminium silicate fibre blanket. Foam glass with additives. Ceramic fibre.
All fibrous materials are highly absorbent of water. (Silicone treatments will give an element of water shedding but water uptake can still be high.) They are only recommended for internal use, except when adequately clad with metal sheeting and with joints sealed.
Fibrous materials will not give protection against a sustained jet fire unless specifically designed for this duty. When insulation is used on steel that will be at or below ambient temperature, precautions need to be taken to prevent corrosion of the steel caused by condensation of water vapour trapped by the insulation. Fibrous materials will normally be bound together either by weaving or with a chemical binder. (Ceramic fibres tend to have a higher melting point than mineral wool fibres and so can achieve higher fire performance ratings.) The materials can be used either as flexible blankets or as steel or composite material panels. The flexible nature of these materials allows them to be used for relatively complex shaped items. Compared to spray coatings they can be more easily removed for inspection of the protected equipment although great case must be taken to replace them correctly. PFP blankets normally provide a relatively lightweight protection method.
Example of fibrous blankets or wraps used for protection of critical cable runs or ducts. The fastenings must be able to withstand the required fire effects and also weathering conditions.
Ceramic fibre wraps being fastened on a pipe. Again, the fastenings are critical and must be able to withstand the fire effects to the same resistance and duration as the ceramic wrap itself.
The binders used with the fibres may decompose in a fire situation and release toxic fumes. Blankets should be protected against ingress of water which could lead to corrosion of the protected equipment. It is normal practice to provide a barrier – often an aluminium foil – to prevent water ingress and formation of condensation on the substrate. The lower melting point of mineral wool means that it is not normally suitable for PFP application in hydrocarbon fires. Fibres may settle within a barrier with vibration thus reducing effectiveness in some areas. Restrictions on fibre particle size may have to be imposed due to potential health hazards.
In this example, loose mineral wool is used as packing to create fire stopping at cable penetrations. Other options, including preformed transit pieces or intumescent or cement sealing are available.
Vessel Product Insulation It must be noted that some materials such as foam glass blocks or other fibrous materials are used for insulation to maintain vessel, sphere or tank product temperatures. Typical examples are Propylene, Raw C4’s etc. There have been instances where the adhesive used to bind the foam glass blocks has proven to be combustible and the weather protective top coat has also proved to be combustible. For product insulation, care must be taken to check not just the noncombustibility of the fibrous materials but also the other “components” of the system, including adhesives and coverings.
This was a combustion test for a combination of glass blocks held together by adhesive and with an outer (weather) covering of glazed fabric mesh. It clearly illustrates the combustibility of the adhesive and mesh cover. The foam glass block (Insulation) does not burn but the adhesive and glazed mesh cover are burning freely.
Composite Materials The term Composite PFP Materials is used to describe a combination of materials – very often, though not exclusively, a combination of a resin system and a fibre reinforcement – acting together to create a single material with the desired mechanical and fire related performance requirements. Composite materials are available in both flexible and panel form. Composite materials tend to be lightweight and easily adapted for protection of complex structure and shapes. The flexible types available can be relatively easy to install and remove for inspection. Due to the chemical make-up of most composite materials, it is possible that toxic substances may be given off in fire conditions. Composite material is one area in particular where the range of materials available is constantly increasing. Great care must be taken to ensure that any such material being considered has proven availability and reliability, apart from the appropriate and wholly relevant fire tests to the intended application requirement.
Examples of composite material pre-formed blocks for piping or transit pieces etc. In this case, the composite is a mix of fibre and special binding powders.
Fire Retardant Treatments & Coatings/Paints Wood structures and other combustible materials and fabrics can be treated with fire retardant chemicals and applications and there are specialist paints which will also act as a fire retardant surface. In every instance, these applications are only providing a limited time for the combustible material to resist the effects of heat or flame impingement. These treatments offer solutions to special fire risk facilities including prisons and military installations in that fire retardant interior finishing and furniture, bedding, curtains, sheets and other combustibles will reduce the likelihood of accidental or deliberate attempts to ignite such materials. Unlike the PFP materials discussed above, these do not offer good insulation properties and they are prone to decay over time. For instance sheets and curtains laundering will reduce retardancy through wash out of the chemical treatment. Paints and other treatments are subject to weathering and UV rays and will lose some of their retardancy over time. The fire retardant properties of curtains and bedding etc may be considered for offshore living quarters, but the cost may be high when it is remembered that the materials will need re-treated over their useful life span. Initial costs for such items as fire retardant mattresses and pillows are obviously higher than non-treated materials.
V. Fire Tests, Certifications and Approvals
Important Foreword Any fire test, regardless of the methods and procedures, is simply a controlled test with a specific fire type involving a material, assembly or structure. It must always be remembered that if a PFP material or assembly has undergone a “fire test”, this does not mean that the material or assembly has therefore passed the fire test. For any PFP material or assembly or structure to be considered for rd installation at BP sites they must also carry an independent 3 Party Approvals Certificate. Even those materials or assemblies which have been “tested” at reputable testing facilities and carry fire test certificates, regardless of the fire test details, must be accompanied by an Approval Certificate.
Fire Tests The selection of PFP for most fire types and conditions will have been made partly on the basis of standard fire tests on a specimen construction or assembly and over the interpretation of the test results. It is strongly emphasised that the PFP requirement for any given protection scenario may not necessarily match test results. Therefore, careful analysis of the actual test and its results will always be necessary to ensure that the PFP material, when applied, will provide the necessary protection against the identified fire event, in terms of fire type and duration. Only those PFP materials or assemblies or structures which have been fire tested to a recognised standard and have subsequently been given an Approvals Certificate and Number should be considered for use. Fire rd ratings achieved during recognised standard tests are given by 3 party, independent certifying authorities such as Lloyds, Underwriters Laboratories (UL) or DNV etc. However, it must be noted that the standard test fires may not represent the exact conditions which will be encountered on an installation and therefore careful study should be made of the test results to ensure that performance matches the site requirements. If it is obvious that the particular test is not site or facility specific, it may be necessary to develop more precise tests specifications for the PFP and to carry out one or more live fire tests and have the tests certified by an approvals body. It is vital that the selection of PFP is based on test data that will be wholly relevant to the actual site and fire condition or situation requirements. Standard fire tests are available to assess PFP applications or materials capability to retain its integrity and limit heat transfer to the protected structure or vessel. The tests are used to rate PFP performance according to its ability to provide 3 key elements as follows:(i) (ii) (iii) Integrity – the ability to prevent the passage of smoke, flame or toxic gases. Stability – the ability to maintain its structure. Insulation – the ability to limit spot or area temperature on the “nonfire” or cool side of the PFP.
Different fire tests are available and the engineer should check which is appropriate to their operating region. For Cellulosic and Hydrocarbon Pool fires, there is no single “internationally recognised” standard test. Although many countries may have their own tests, the more widely used tests are: Cellulosic ASTM E-119 BS 476 Parts 20-24: 1987 DIN 4102 ISO 834
Hydrocarbon Pool Fire BS 476 Part 20: 1987 UL 1709 FM Approval Standard High Rise Fire Test of Protection Materials for Structural Steel. Rapid Rise Fire Test of Protection Materials for Structural Steel. Fire Protective Coatings for LP Gas Steel Storage Vessels and Process Structures. Hydrocarbon Pool Fire Test “H” Class Fire Test (Accepted widely for Offshore Industry)
Mobil Oil Co. NPD
Fire Rating Terminology A and B ratings refer to cellulosic material fires and are, therefore, relevant to most building or ship or offshore accommodation applications. H ratings refer to hydrocarbon pool fires – not hydrocarbon jet fires. (Hydrocarbon pool fire tests simulate the more rapid temperature rise and higher end temperature that occurs with hydrocarbon fires compared to cellulosic fires.) J (or JF) ratings refer to jet fires.
Rating Examples –
RATING TEST TEMP CURVE STABILITY/ INTEGRITY (Mins) TEMP. LIMIT (°C)
B A H J/JF Cellulosic Cellulosic Hydrocarbon 30 60 120 Refer to specific test details for jet fire ratings 139 + A* 139 + A* 139 + A*
225 + A 180 + A 180 + A
* Ambient. Examples: H60 ? Hydrocarbon ? 120 minutes integrity/stability ? 60 minutes temp test limit HO ? Hydrocarbon ? 120 minutes integrity/stability ? No insulation
Comparison of Typical ‘cellulosic’ and ‘hydrocarbon pool fire’ temperature time curves. 1 is typical hydrocarbon curve. 2 is BS 476 cellulosic curve and 3 is ASTM E-119 curve. 20
Jet Fires Hydrocarbon jet (or torch) fires pose particular problems due to extremely and rapid high heat flux levels, their erosive effect and their “heat shock” loading, all of which can vary considerably according to actual fire conditions. Like the Cellulosic and Hydrocarbon pool fire tests, there is no single internationally accepted jet fire test. Various jet fire “tests” have been carried out since 1990, mostly by oil companies including Shell, Exxon, British Gas and UKOOA. A working group consisting of these companies and SINTEF, NBL and HSL (Health & Safety Laboratories) carried out large scale testing involving natural gas at a 2 pressure of 59 barg and rate of 3 kg/second with a heat flux of 300 kW/m . This evolved into the current standard OTI 95 634 – Jet Fire Resistance Test of Passive Fire Protection Materials. This lays out the test procedure for jet fires and is accepted in the UK and elsewhere as an assessment method for passive fire protection under jet fire conditions. However, it is perfectly possible and acceptable to set out specific test parameters that simulate expected jet fire sizes and conditions at a site, and organise a fire test based on these requirements to give confidence that the PFP shall be fit-for-purpose. Various organisations and facilities can carry out these tests. European examples include SINTEF (Trondheim, Norway), Advantica (Formerly BG Technology) Spadeadam (Cumbria, UK), CTICM, (France) and South West Research (USA). It must be remembered, always, that if jet fire protection is to be provided, the “size” of the jet fire used during the fire test conditions (and thereby as the basis for an “approval” certificate) must be studied closely in relation to the expected or credible jet fire size impacting on the structure or vessel to be protected. Thus, if a 13mm gas jet orifice with a flow rate of 2 kg/second is the test fire, it will not be anywhere near realistic if the credible scenario is a 50mm hole size with a flow rate of 40 kg/second. Higher pressures will mean greater erosive effects and higher hole sizes will mean greater area flame impingement.
Full scale jet fire test, Spadeadam. (Photo: Leigh paints/ Firetex )
The jet fire example right shows the force and erosive characteristics of a jet fire event. Jet fire tests must be representative of the jet fire fuel, fire size and release pressure if they are to equate to the site expeted fire event.
PFP as a Fire Protection System Passive fire protection, regardless of its construction or application, must be treated as a fire protection system insofar as application, inspection and maintenance requirements are concerned. Unlike other fire systems such as water, foam, gaseous protection, PFP cannot be “tested” in place, whereas water or foam is discharge tested. It is obvious that since it is not possible to test PFP in place, the areas of specification, followed by testing or approval certification, followed by installation and then inspection and maintenance are critical to the PFP system performance under fire conditions. It is therefore necessary to view PFP, in any form, as a fire system and ensure that it receives the same importance on site as, for example, fire and gas detection or fire pumps or fire systems.
VI. Minimum Design Requirements – All Types of PFP
PFP should always be suitable for the fire type or types that may impact the particular structure or vessel to be protected. Fire types to be considered are cellulosic, hydrocarbon pool and hydrocarbon jet. Another consideration is that whilst a formal fire assessment may identify no flame impingement on a structure or vessel, there may still be a requirement to apply PFP due to high levels of radiant heat. Whilst cellulosic will typically involve buildings and commercial facilities, it is important not to confuse the applicable cellulosic fire tests for PFP with hydrocarbon fire tests as these use different test conditions.
Regardless of which type of PFP is being considered, there are practical availability and reliability factors that must be remembered. These are:o The PFP must provide its functional role by limiting the protected structure or vessel to the desired temperature over the specified time for the design fire type or types. The PFP application must not fail rapidly or catastrophically immediately or shortly after the time of “heat resistance”. The PFP application must remain in place under the design fire conditions. The PFP should not present hazards additional to the fire such as toxic by-products or spalling etc. The PFP must not lose any integrity over the design lifespan in situ.
o o o
Additional factors for consideration, depending on the design objectives, may include:
Able to withstand thermal shock – where cooling or firefighting water streams may be used directly or indirectly on the PFP. Non-corrosive requirement where applied to metal structures or vessels etc.
Where the selected PFP may be subjected fire fighting operations, a hose stream test may be required as part of the fire tests to confirm its ability to withstand hydraulic jet stream erosion and thermal shock.
Where a fire proofing material is located outdoors and is water absorbent it should be sealed to prevent moisture from reaching the fire proofed surface. Seals at junction points between the fireproofing and exposed steel structure should be inspected regularly. In cases of high vibration levels, inspection should be every two years.
Mastics may be used to seal gaps and prevent moisture build up or penetration. The mastics must themselves be rated for the same fire resistance and duration as the PFP they are sealing.
Design Considerations A check list for design and fire performance considerations may consist of the following: Fire type (e.g. cellulosic, hydrocarbon liquid spill, jet fire, etc.) Time for which protection must be effective in controlling heat transfer or other fire products. Resistance to thermal shock. Resistance to blast overpressures. Resistance to projectiles/missile debris during fire. Resistance to the effects of other fire protection measures such as deluge systems or sprinklers. Toxicity of decomposition products. Smoke from product causing obscuration. Retained protection capability post-fire. Failure mode – (e.g. Is loss of protection sudden after given time ?)
As well as fire performance the following features/requirements of PFP may require consideration prior to selection according to the PFP type and application: ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? Corrosion (of the PFP itself and of the protected substrate). Adhesion to substrate. Vibration resistance. Resistance to flexure of substrate. Mechanical and chemical stability. Ageing characteristics and weather resistance. Abrasion and erosion resistance. Resistance to hosing, cleaning agents and process fluids. Impact resistance (including non-fire/explosion situations). Acoustic absorption/damping. Thermal insulation. Low level heat resistance (e.g. from long exposure to flare). Removability for inspection of the substrate or protected item. Ease of correct replacement after removal for inspection Repair methods and effectiveness.
Installation considerations ? ? ? ? ? ? ? ? ? ? ? Weight. Suitability of surface preparation and retention system. Compatibility with substrate. Need for specialist application equipment and/or trained manpower. Expertise/experience of installers. Presence of health hazards during application and curing time. Environmental conditioning requirements (e.g. special curing requirements.) Topcoat or seal requirements. Sealing requirements (at joints and penetrations). Method of application and whether mechanical reinforcement of required. Material manufacture support to installer.
The example below shows a typical outcome of ‘getting the design wrong’: a refinery propane vessel in Propane Deasphalting unit was to be PFPed: during a turnaround, the old insulation was took off, the vessel inspected and the coat of primer paint applied. The rest of the PFP was to be put after start-up. For start-up, the operator steam-purged the vessel to take the air off. As this vessel was supposed to work at ambient temperature, the paint specification didn't include any heat resistance... look at the picture...
Water Shedding For all PFP the issue of water ingress is particularly important since this can delaminate the coating or application and cause corrosion. The top surfaces of encased beams and all flat surfaces of the finished PFP coatings should be suitably sloped to provide an adequate water shed. This is particularly important at the top of the PFP on columns. Where a steel section, nozzle or support emerges from the casing or an exposed steel surface is flush with the casing, the junction of the fireproofing and the section should be pointed and sealed with an approved fire resistant mastic or flashed to prevent the ingress of water. Frost Precaution In low temperature environments where frost may occur, to avoid water freezing during wet PFP mixing applications, work should be suspended when the temperature is falling, typically, when the temperature has dropped o to +4 C and should be recommenced only when the temperature has risen to this level.
Final selection of the PFP type should be based on the above considerations but also for the PFP as an installed system. That is to say, the performance of the PFP material alone should not be the only consideration but rather the performance of the total PFP “system” including bonding methods, retention systems, top coats, sealants, joints, weatherproofing, installation techniques and installer capability as a total package.
VII. PFP For Buildings
The stability of a building involved in a fire event depends mostly on the fire resistance of the load bearing members. Vertical members may be load bearing walls or reinforced concrete columns or steel beams. Under fire conditions, unprotected steel beams or columns expand and distort and finally, as they lose their tensile strength, collapse. The steel expansion on its own can cause building collapse before the beams fail. The prime objective in building PFP is therefore to protect such beams and columns. The methods of protection are similar to that for the industry in terms of cementitious, intumescent, panels or other PFP materials. There are other aspects of building PFP that involve protection of escape routes (means of escape) and fire enclosures (compartmentation) to check fire in its area of origin for a specific period of time.
The basic purpose of passive fire protection in buildings is to try to contain any fire in i t’s “compartment” of origin. The term compartment varies with the building type and layout, number of floors, etc. The principles of compartment wall integrity are shown right.
Cavity Barriers or Full Wall Height Installed in line with compartment walls or floors
Not necessary to locate ‘too often’ As long as max void dimensions not exceeded Cavity barrier (max 20m Spacing)
Compartment Wall Extends to underside Of floor or roof.
There is no single internationally recognised standard or industry standard for building fire safety. There are national regulations and standards that establish the requirements for protection and means of escape but usually these will not provide the technical detail or give guidance on appropriate PFP materials. Guidance is often provided by fire research establishments, insurance organisations or fire protection approval authorities. For example, in the UK, the Loss Prevention Council (LPC) issues guidance booklets for specific protection considerations.
Apart from the structural and compartmentation aspects of buildings, the most important PFP issues are fire ratings of enclosures (time of fire resistance) used as means of escape. An enclosure considers floors, walls and ceiling or roof and any fire rated enclosure must also have fire rated closures (doors, windows, HVAC ducting etc) to the same rating as the enclosure. Additionally, any service penetrations for piping or conduits must be sealed (fire stopped) at enclosures to the same enclosure rating.
Example of HVAC ducting constructed of PFP materials to prevent ingress and transfer of heat/smoke. Fire dampers at compartment walls will further prevent heat smoke migrati on to other areas.
An example of very poor fire stopping of penetrations through a fire wall. Mineral wool or transit pieces or cements could have been used to effectively seal the cables and ducting.
Example shown left of how effective fire stopping of penetrations should be provided. This applies to vertical or horizontal penetrations.
Fire doors in means of escape should be self-closing to ensure enclosure integrity. HVAC ducting should have fire dampers at the enclosure. Means of escape (protected routes) should be free from fire hazards. Fire enclosure walls should rise from floor to floor (unless a fire rated false ceiling is provided).
The fire door shown left has been modified and is now useless as a fire resistant door. The vision panel in the centre is plain non-fire resistant glass, the glass panel above the door is non- fire resistant glass and the ventilation louvre in the door bottom third allows free passage of heat and smoke. The door fire resistance has been severely compromised and it will not serve as a barrier at all.
Example right of special foam strips with intumescent facings to seal gaps between steel structures and brickwork to contain fire in compartment of origin.
The Association for Specialist Fire Protection (ASFP) has recently (2003) published a guidance document for buildings PFP. This document should be used for reference – Ensuring Best Practice for Passive Fire Protection in Buildings. ASFP. The document is issued through a partnership of the Office of the Deputy Prime Minister, ASFP, FRS (Fire Division of BRE), Warrington Fire Research and PFPF (Passive Fire Protection Federation). ASFP website is www.asfp.org.uk
VIII. Industry PFP
Industry Fire Hazards for PFP Considerations In the industry, PFP will typically be considered in order to prevent escalation through fire spread or explosion. This will primarily consider life safety especially where catastrophic failure may lead to high loss of life on site, or where there is an off-site impact on neighbouring facilities or public areas with resultant losses. PFP may also be applied to critical equipment and structures in order to protect investment and production and may also be considered where there are inadequate water supplies such as in a desert environment, provided the fire event duration can be designed for, otherwise it becomes expensive protection that will be lost and escalation will still occur. The following should be viewed as a generic list of typical PFP considerations for particular industry facilities and is intended only as a guide. Offshore Living Quarters Typically, USCG, SOLAS or other recognised standards requirements cover the anticipated fire hazards within living quarters. Where fire hazard assessment requires protection against external incidents, the PFP should be appropriate to the fire type and anticipated duration of the incident or the duration required to ensure life safety.
Offshore living quarters may need to have PFP provided on the external walls according to the type and duration of the identified external fire hazard. This may require Hydrocarbon pool or jet fire protection and in some cases may also require blast protection .
Living quarters, control rooms, service enclosures etc are similar to onshore buildings in that the intention is to limit fire, heat and smoke impact to the compartment of origin for a period of time to permit personnel to escape. This is often referred to as “compartmentation”. SOLAS Barrier Definitions The International Maritime Organisation (IMO) publishes standards for offshore and marine fire protection under Safety of Life at Sea (SOLAS). A brief review of SOLAS highlights their classification of fire division barriers as follows: “A” Class Divisions Shall be those formed by bulkheads and decks which comply with the following:
q q q
They shall be constructed of steel or other equivalent material; They shall be suitably stiffened; They shall be constructed as to be capable of preventing the passage of smoke and flame to the end of the one hour standard fire test; They shall be insulated with approved non-combustible materials such that the average temperature of the unexposed o side will not rise more than 139 C above the original temperature, nor will the temperature, at any one point, o including any joint, rise more than 180 C above the original temperature, within the time listed below: Class A-60 60 minutes Class A-30 30 minutes Class A-15 15 minutes Class A-0 0 minutes.
Example of an “A” fire wall with steel panels on both sides and mineral or ceramic or other fibre backing on one side of the wall.
“B” Class Divisions Shall be those formed by bulkheads, decks, ceilings or linings which comply with the following:
They shall be so constructed as to be capable of preventing the passage of flame to the end of the first half hour of the standard fire test; They shall have an insulation value such that the average temperature of the unexposed side will not rise more than o 139 C above the original temperature, nor will the temperature, at any one point, including any joint, rise more o than 225 C above the original temperature, within the time listed below: Class B-15 15 minutes Class B-0 0 minutes They shall be constructed of approved non-combustible materials (with certain exceptions as specified in SOLAS).
A test construction with a full A-60 rating will have been passed as suitable for exposure to fire from either side of the panel/division but it must be remembered that the test panels have been tested without load and under Cellulosic test fire conditions. Consideration also has to be given to openings in class A or B walls. In many cases, sliding or suspended doors need to be provided to the same rating as the wall, operated by fusible link or in some cases, by smoke or fire detection.
Example of a drop door over a fire wall opening. When the fusible link separates due to heat, the counterweight on the right falls, allowing the door to drop and seal the opening. The door has to be the same rating and duration as the wall.
Example of a roller shutter door, in this case, in a galley. The door is held open by a fusible bulb. When the bulb breaks, the door drops into position.
Production Platform Facilities Production facilities offshore are similar to onshore, with the main difference being the limited space available offshore. The fireproofing of vessels and tankage in the E&P industry is not a common consideration. However, PFP can be used to reduce vapour relief load and pressure build-up, thus allowing longer depressurising times under fire conditions. Unlike onshore, where spacing can act as passive protection, offshore has to consider PFP for divisions where a fire may occur and escalate to hydrocarbon processing areas or to occupied sections. PFP may therefore be considered between, for instance, wellhead areas and process areas or between decks and between process areas and occupied areas. The potential for sea surface fires also needs to be considered and the appropriate PFP applied on the undersides of structures and decks for the period of exposure.
Care has to be exercised when selecting the PFP for such duty offshore. Whereas repair to, for instance, a living quarters fire wall will not cause too much disruption, repairs to supporting structures or decks PFP coatings or applications close to the water line may cause major logistical problems with consequent high cost factors. The repair or re-application of PFP in a hostile marine environment is obviously problematic and since most of the supporting structure PFP will have been applied onshore (See Appendix 1), it will not be possible to create the same controlled climate for PFP application. Only tried and tested PFP materials, and their application by approved installers must be used for offshore facilities. The selection of offshore structure PFP also needs to consider the marine environment, potential collision damage from marine traffic, saline weathering etc, etc. Factors that will influence the selection of appropriate PFP for an offshore production platform environment will include, but no be limited to : Weight. Suitability of surface preparation and retention system. Compatibility with substrate. Environmental conditioning requirements (e.g. special curing requirements.) PFP proven reliability/availability offshore Vessel/container inspection Vessel/container operational access.
Given the weight factor, the use of intumescent PFP can sometimes be more favoured offshore although cementitious coatings are also used. As an example of weight, (which will also apply to onshore facilities) densities of various products to achieve a two hour hydrocarbon pool fire protection rating for steel structures will vary but can be in the order of :Dense Concrete 2225 - 2400 kg/m3 Light Concrete 560 - 1200 kg/m3 (35 - 75 lb/ft 3) Intumescent/Subliming Coatings 960 - 1290 kg/m3 (60 - 80 lb/ft 3 )
The table below highlights PFP requirements for one particular offshore installation. It is stressed that this table was produced as a res ult of study of the installation fire hazards assessment and should not therefore be used as PFP requirements for any particular facility. Adjacent Area to Be Protected
Fire Areas LQ Living Quarters 2 hr HC Utility Area 1 hr CF Well Head No adjacent allowed 1 hr CF 1 hr JF 1 hr JF Process Area No adjacent allowed 1 hr CF 1 hr JF 1 hr JF Control Rooms 2 hr CF
UA WH PA
2 hr HC No adjacent allowed No adjacent allowed 1 hr CF
1 hr CF 2 hr JF 2 hr JF
2 hr HF No adjacent allowed 2 hr JF
1 hr CF
No adjacent allowed
1 hr CF
1 hr CF
1 hr or 2 hr is the specified minimum fire resistance duration. HF Hydrocarbon pool fire CF Cellulosic fire JF Hydrocarbon jet fire
For BP offshore PFP application a draft document is in circulation – BP Exploration Passive Fire Protection Specification – 1998. This document offers further detail on the above PFP issues. Onshore PFP should be applied to the following process or process related plant and equipment. (1) structures directly or indirectly supporting significant hydrocarbon inventories or emergency systems. structures supporting heavy loads which, if they were to fail, would lead to a significant hydrocarbon release, or catastrophic failure, loss or damage to a control centre or emergency system. hydrocarbon storage vessels or other plant that catastrophically or lead to further significant releases. could fail
Although fire hazard assessments will provide a more accurate time frame, as a guide, where the predicted fire duration in hydrocarbon areas is greater than 10 minutes, structures and equipment outside the flame but exposed to high radiation levels may also require passive protection. Typical Process Areas PFP The following are typical process areas that will normally have PFP.
q q q q q q
Multi-level Structures (Excluding Piperacks) Supports for Piperacks and High Level Air Coolers Supports for Low Level Air Coolers Supports (Base Skirts) for Vertical Towers/Columns And Vessels Supports (Saddles) for Horizontal Exchangers, Receivers and Accumulators Supports for Fired Heaters
In addition to the above, specific vessel or sphere or drum protection may be required according to the fire hazard assessment.
The example left shows multilevel structures PFP (right foreground) and elevated receiver vessel with support saddle fireproofing in the middle right.
Vertical vessel skirts fireproofed to prevent collapse under pool fire conditions. Horizontal vessel to the right has fireproofed saddles.
Process Vessels Passive fire protection of vessels on process plant is not generally required. Where relief cannot ensure integrity of the vessel in a fire situation or, where fire conditions result in relief capacity requirements in excess of that from any other emergency condition, passive fire protection of selected vessels should be applied, where economical, to reduce the discharge rate and the size of any closed relief system. Where fire hazard assessment or unacceptable consequences identifies a need for vessel PFP, the whole vessel should be insulated. Pipework and its supports leading from the vessel up to the first ESD valve should be protected. The support legs of spherical storage tanks should have PFP to the full load bearing height. Although the top of a vessel is apparently less at risk in a fire, in fact it is often the most vulnerable, since it is not cooled by evaporation of any liquid contents and there are well known examples of vessels failing during a fire, even though pressure relief valves were probably limiting the pressure to the vessel design pressure, because high temperature had reduced the material strength below the design code safety factors.
One example of PFP applied to a vessel. A stainless steel covering in sections has a mineral fibre block system fastened underneath. Using this method allows for sections to be removed for inspection and maintenance but great care must be taken when replacing sections to ensure full integrity.
LPG Spheres/Vessels LPG spheres and vessels are often the focus of PFP, especially where they are near public areas or neighbouring facilities. The application of PFP to spheres has to consider the weight, inspection access and corrosion potential under the PFP.
The spheres and vessels above are fully coated with a cementitious application. The support legs or saddles/supports are also fully coated. Rating is for 2 hours hydrocarbon jet and pool fire. Piping in the bund and ESDV’s in bund or on bund edge (within fire or high radiant heat envelope) are also rated 2 hours jet and pool fire. Of particular note is the stairway and relief valves/safety valves on sphere tops are unprotected. This may require water-cooling streams for cooling these under fire conditions. Therefore, the PFP coating will be subjected to thermal shock/pressure wash from water jets. It is of interest to note that the original industry concept of applying PFP to spheres was to exclude the need for fire responders to apply cooling water. Stairways were overlooked as was top valving. Steel stairways can conduct heat to the sphere shell and distort, placing stresses on welds at the sphere shell, hence they may require cooling.
Pipelines Will not normally need PFP unless the fire incident assessment identifies a need. However, flare lines, critical duty (e.g. breathing air) and high hazard toxic material (e.g. ammonia, chlorine, hydrofluoric acid, hydrogen sulphide) pipelines, and supports, may need PFP if they have been identified as potentially affected areas from fire incidents. Electrical Power and Control Cables Power and control cables associated with critical operating equipment or loss prevention devices located within an area where they may be exposed to flame may be considered for PFP. Methods may include:
q q q q q q
Cables rated for high temperature. Fire retardant cable trays. Passively fire protected cable trays. Wrap around, foil-backed insulating systems. Direct application of fire proofing material to exposed cable jacketing. Preformed pipe insulation
The wrap around fibrous blankets shown above need to be fit- for-purpose in that apart from the fire resistance of the blanket, the binding must not unravel, degrade or destruct under the design fire conditions. There is also the issue of product being trapped or seeping into or under the blanket. These are features that need to be studied closely.
Emergency Valves Where continued power is required to operate valves which are critical for safe shutdown, depressurisation or isolating the feed of a unit, the valve and its associated power supply may need to be provided with PFP if within a significant fire exposed envelope. Protection should be provided to power and signal lines and the motor or actuator. The valve body and pipework either side of the valve may also require protection. Valves that fail to a safe position need not normally have PFP.
Example of an unprotected motorized valve is shown above. The valve actuator and the valve itself may both need PFP plus the flanges and piping at either end may need PFP depending on the identified fire event type and duration.
Example of PFP applied to a valve actuator. In this case, mineral/ceramic fibre wraps are used. Other means are also possible.
PFP box for protection of valve actuator or valve itself. The box can be made to the size required and the opening door on the side allows for inspection. This has advantages over the wrap type PFP for ease of access and assurance of replacement integrity.
IX. PFP Inspection And Maintenance
It is strongly suggested that apart from the correct PFP for the anticipated fire event and its duration, any selection of PFP should also consider only those materials, structures, systems or coatings which have clear evidence of integrity maintenance over time elsewhere. This may be at a BP facility or other industry company. Unproven materials, even with certification or approvals, should be viewed as doubtful unless there is clear evidence of prolonged (years) durability via samples or other evidence. The ability of PFP to provide long-term performance needs to be checked regularly. To do this it may be necessary to have samples provided of the actual installation and install these near to it. Checks on the PFP sample condition can then be made after specific time periods to give confidence in the integrity and stability of the original installation. Cracks Minor surface cracks in PFP coatings, particularly cementitious coatings, may not necessarily mean loss of fire integrity but any cracks appearing in PFP coatings or applications need to be checked for cause, and for depth and an assessment made of remaining integrity/performance. Where any doubts exist, the manufacturer should be consulted. Repair fillings to cracks can be made provided correct materials and techniques are used to return the system to its full integrity. Only approved suppliers and installers for such repairs should carry out this work.
Delamination Top coat or finishing/weather coat or other layer delamination needs to be investigated and remedied. Delamination of the finishing coat is not unusual in cementitious coatings, but deeper delamination especially for intumescent coatings could indicate poor installation techniques, which may reduce the PFP performance under fire conditions. Top coatings or weather coatings can be re-applied provided correct techniques and materials are used. Only approved suppliers and installers should carry out this work. Bubbling/Blistering Depending on the materials and finishing coatings used, there may be evidence of blistering or bubbles under or on the surface. For external PFP, this may indicate water ingress into porous materials, in turn indicating a failure of the weather coating. Worst case may find separation of the coating from the protected steelwork. Repairs for blisters or bubbles may not be straightforward since water ingress may have contaminated materials under the overall coating/surface and extensive remedial work may be necessary. Worst case may require complete replacement and if so, a more resilient/robust system provided. Rust Coloured Trails These may be noticed under PFP joints or coatings and will probably indicate that PFP sealants or interfaces have failed, the materials are causing corrosion on the steelwork or water ingress has occurred and seeped through to the steel. Slumping/Bulging This is where coatings have drooping bulges, similar to a heavy sludge build-up on the lower ends of steel or structure. To achieve the PFP fire rating and duration, the applied coatings need to be uniform to the depth required for resistance time. Slumping can indicate thin coatings at the upper areas and thinker coatings where the bulges are. This would indicate poor installation techniques, poor materials mixing, poor fixings or porous materials absorbing water or a combination of all of these factors. Simple repairs will not be possible for such problems.
Corrosion One of the major concerns with some of the cementitious or intumescent PFP coatings is the potential for corrosion below the application. Corrosion inspection at regular intervals will be necessary to check the steelwork condition. This may involve cut outs of the coating for inspection but replacement needs to be carried out by approved installers using the original manufacturers materials and techniques.
The sphere left, a 20-year old, 12,580 bbls (2,000 m3) sphere, was taken out of service for internal inspection and hydrotest. It was approximately 75% full of water in preparation for hydrotest when the legs collapsed. One death and one injury occurred due to the structural failure. The legs of the sphere were coated with fireproof concrete and salt water was used in the water deluge fire system on the sphere. Water sprays were tested at periodic intervals.The legs had suffered severe corrosion underneath the fireproofing. The same incident occurred at another refinery in the 1970s.
Overview of PFP Materials and Their Applications The following table highlights typical materials and their applications. This is not an exclusive list and is not exhaustive. New PFP materials and innovations are constantly being introduced as are new companies providing and installing such materials. Care has to be exercised always in the specification and selection of the PFP for any site or facility.
TABLE 1 Summary of Passive Fire Protection Measures
Category Spray or Trowelled materials Commonly used materials Intumescent coatings Cementitious coatings Typical Applications Structural members bulkheads process vessels/piping HVAC trunking Firewalls/Fire doors HVAC trunking Valves/Actuators Fire dampers Pipe/Cable transit sleeves Valves/Actuators Expansion joint Cable transits Door gaps Cable sheathing
Panels/preformed units of enclosures
Prefabricated steel panels Composite materials Ceramic and mineral wool fibres Intumescent materials Cementitious materials Ceramic and mineral fibres Composite materials Intumescent materials
Flexible cover/blankets Seals and Sealants
Composite materials Low frame propagation plastics Low flame propagation plastics Flame retardant/intumescent Paints or varnishes
Appendix 1 Examples of Good PFP Installation Practice
The following illustrates the qualities required for good PFP installation - a good combination of quality materials, quality installation techniques and overall quality control.
Offshore module under construction. Steelwork ready for PFP application.
Retaining mesh being cut to fit.
Retaining pins for the mesh being fitted to structure. Manufacturers installation procedures and methods must be followed exactly.
Mesh laid ready for application.
Cementitious materials readied. Materials must be as per manufacturers requirement and be from the same test materials approved for use.
Mixing materials before the application. The installers must be approved by the manufacturer if necessary, by the site. Quality Control procedures are critical.
This application i s being trowelled on to the steelwork mesh system. Spray applications are also used.
Smooth and even application is essential. Particular attention is paid to corners, joints and irregular shapes to ensure uniform protection
The finished application should be to the specified depth and uniform over the structure. Thinner areas must be corrected.
The completed PFP over the whole structure. The key areas are the retaining system, the materials mixing, the depth and uniformity of the application and the coverage of joints and seams.
Appendix 2 Case Study – Poor PFP Specification / Installation
The following is a recent case study where a combination of poor quality PFP materials and improper installation practices resulted in costly repair work and insufficient guarantees that the PFP will perform as intended. NB: This information is provided on the basis that it will be used for the purpose of benefiting BP in decisions relating to the specification, installation and maintenance of PFP systems. As a case study, those reading the information contained herein will realise that the situation is an ongoing one, and as such, circumstances are evolving. However, the study represents important current knowledge relating to the above. The Case Study is broken down into several key areas: ? Background and Facts ? Extent of Defects / Damage ? Possible Causes ? Extent of Repair Task and Problems Encountered ? Lessons Learnt Background and Facts as of June 2003 ? THERMOLAG 2000 is a product manufactured by NU-CHEM, purchased and used by HHI in Korea as Subcontractor to MPG to coat the relevant steel structures in the framework of the Passive Fire Protection (PFP) implemented on the FPSO Girassol. The facility is operated by Total and BP have a 16% share.
During the application process, the MPG Quality Control team identified several non-conformances and issued relevant notices to HHI. Several areas were repaired.
At the time of departure, a number of small defects were still known and marked for repair. These repairs were performed during the FPSO towing between Korea and Angola.
Nonetheless, upon arrival in Angola, and in the following weeks, MPG noticed that defects were still developing. These defects were surveyed and mapped in September 2001 then in January 2002 showing definitely that the phenomenon was evolving (see photo). MPG and TFEA decided to commit NU-CHEM to conduct an inspection of the FPSO Girassol to better define the scope of damages and find out whether the evolution process had reached an end or not.
After inspection, repair trials managed by Nu-Chem were performed on FPSO in May 2002. In July, a new inspection was made. It became obvious that the repair trials, specially implemented by NU-CHEM (following their procedures and recommendations), were not successful and were therefore deemed not satisfactory/acceptable to TFEA and MPG. As a first consequence, the repairs were not validated and could not be qualified. An independent review and assessment of Passive Fire Protection (PFP) provision on the Girassol FPSO was performed. Pilot furnace tests at SINTEF have been performed to evaluate the fire resistance of damaged PFP collected on the FPSO
Tests consisting of drilling soft blisters were performed and appeared to be a success. Removal of topcoat does not allow soft blisters to dry. Further inspections are needed to confirm the results.
Extent of Defects / Damage – Facts and Figures ? ? FPSO total surface covered by THERMOLAG : Breakdown of the whole coated area 37,250 m2
Structures between elevation 100 to 107
Bottom + top beams Columns + bracings Ceilings elevation 107 and above
2 12,340 m
2 16,900 m
Approximately 8% of the total area coated with THERMOLAG 2000 was inspected : 3,100 m2 out of 37,250 m2
Three types of distinct defects were encountered : Hard cured blisters, Soft blisters with soft material extending down into the coating or down through the wire mesh reinforcement, Soft blisters with delamination between two or more layers within the coating.
? ? ? ? The soft defects represented approximately 80% of the blisters. The hard defects represented approximately 20% of the blisters. The damages were uniformly distributed with no blister concentration.
Assumption of the rates of the damaged areas Structures between elevation 100 to 107 Bottom + top beams 80% Columns + bracings 10% Ceilings 65%
Structures at elevation 107 and above ?
Breakdown of the estimated coated area requiring repairs Structures between elevation 100 to 107 Bottom + top beams 9,872 m2
Columns + bracings
730 m2 4,225 m2 15,289 m2 12,231 m2 3,058 m2
462 m2 Structures at elevation 107 and above
Estimation of the total surface to be repaired : Estimation of repairs on soft blisters : Estimation of repairs on hard blisters :
The following photographs illustrate the above defects ?
This photograph shows ‘hard’ blistering which is evident by the raised areas. The markers indicate how the blistering has propagated in the space of four months, and where new areas of blistering have appeared.
Photos showing ‘soft’ blistering. The top coat of PFP can clearly be removed very easily by hand. A pen is used to demonstrate the extent of air gaps existing under the coating
Possible Causes ? Possible causes of damages are as follows :
Improper application techniques, Improper solvents (which would retard or stop the curing process and leave areas exposed to the elements without being properly top coated for extended periods of time), Improper mixture of THERMOLAG part A and part B components, Extended exposure/application to/over moisture, rain ice, etc., Delayed application of topcoat, Surface contamination by dirt, oil, grease, etc.
Extent of Repair Task and Problems Encountered Following realisation of the extent of the problem, repair procedures and trials were instigated. To appreciate the extent of this task, the following is a breakdown of the repair trial procedure with conclusions. ? Repairing the soft defects with THERMOLAG 95% solids: Removal of outer layer of THERMOLAG 2000 to good material or bare steel of structure (the wire mesh might be replaced in some cases) Reactivation of THERMOLAG 2000 by abrading the old surface and cleaning it with solvent (TOLUENE), Preparation of new THERMOLAG 2000 by mixing the part A and part B components, Application: spraying the new product (pump unit) + trowelling and levelling the new layer (manually), Sealing of the area repaired with an epoxy topcoat.
The following photos illustrate this process.
Photos showing surface preparation prior to repair (left), preparation of Thermolag 2000 (centre) and reactivation of old layer (right).
Trowelling (above left) and levelling (right). Below – Surface recharged and top-coated.
Repairing the hard defects with THERMOLAG 100% solids : preparation of repair by drilling fill and weep holes in the hard blister, preparation of new THERMOLAG 2000 by mixing the part A and part B components, application : injection of new product to fill the cavities (pump unit), sealing the injection and weep holes with an epoxy topcoat.
The following photos illustrate this process.
Above – Surface prepared (fill and weep holes drilled) and injection. Below – Injecting Thermolag 2000. Hard blister repair and topcoating.
8 repair trials held o/b the FPSO from 05/07/02 to 05/23/02 (5 soft and 3 hard blisters)
The tests performed on board the FPSO under the expertise of NUCHEM led to the following conclusions: Validation of the procedures for each type of repair, Determination of the conditions for implementation of each repair procedure, Determination of the material and human resources necessary for the repair campaign. 60,000 man-hours estimated for repairs
From the field: Repairs on soft defects (application) => at least one repair out of three presents defaults (repairs at the ceilings only inspected visually); Repair on hard defects (injection) => many areas feature hard blisters disbonding (sounding hollow) with solvent trapped inside as well as cracks (THERMOLAG envelope bursting under pressure of solvent vapours).
It is obvious that the repair trials, specially implemented by NU-CHEM (following their procedures and recommendations), were not successful and are therefore deemed not satisfactory/acceptable to TFEA / MPG. As a first consequence, the repairs are not validated and cannot be qualified. ? A new analysis of the problem should be quickly implemented by NUCHEM. Based on a technical point of view, it seems that several parameters related to the solvent are not mastered and might constitute the key of the problem : Is the solvent the most appropriate considering the FPSO environment ?
Is the topcoat not applied too quickly (only 24 hours after the repair is done) with regard to the THERMOLAG thickness applied/injected ?
Is the THERMOLAG thickness well adapted for the repairs (thickness not measured/mastered) : too much THERMOLAG would retard the topcoat application for drying out reasons, exposing therefore the uncovered THERMOLAG to absorb/receive moisture and other contamination if not well protected while curing ?
Fire Testing of Damaged Areas Ad hoc fire tests with a Hydrocarbon Fire exposure curve were performed on samples of representative damaged areas taken from FPSO. Test results are compared to undamaged reference test sample. The reference sample was a 1.2 x 1.2 m steel bulkhead made of 10 mm plating and protected with 10 mm Thermolag 2000. The test samples were sheets of Thermolag 2000 stripped from the steel substrate from the FPSO. Three samples were chosen for fire testing and fixed to 10 mm steel plating and installed in a purpose made insulated steel bulkhead. A total of four fire tests were carried out, each with a bulkhead insulated with a sample of Thermolag 2000. Unexposed side steel temperatures were measured and compared. The results of the samples were more or less the same as the specimen. SINTEF is studying the impact of the blisters on the FPSO protection regarding H rating and Jet fire rating areas. Review of PFP Provision Simultaneously to the repair procedures, the FPSO has commissioned a review of PFP provision, and, given the unsuccessful nature of the repairs, a revised repair procedure has had to be requested. In addition, other PFP manufacturers have been contacted to study the possibilities of using another system for the repairs.
The review work entails a detailed review of the relevant design documentation, including risk assessments etc to validate input assumptions and methodology, as well as the extent of PFP surface area requirements.
Engineering documents and analyses which have been used in justifying the initial provision of PFP are being reviewed. The review also includes an assessment of the need for PFP in various areas according to the QRA throughout the integrated deck where up to 53% of the Thermolag PFP is provided. The assessment includes a study of the extent of PFP by considering a number of areas broken down longitudinally and transversally to identify areas where PFP reduction is possible. Lessons Learnt The above case study illustrates clearly how a PFP system can ‘go wrong’ if insufficient attention is given to the specification, installation and repair. The very fact that extensive repairs were necessary can be said to be testament to the fact that the PFP system failed ‘early on’ in it’s design life. Broadly speaking, this can be attributed to two main issues, although the causal factors are complex:? Poor suitability of PFP materials – the PFP ‘system’ lacked key environmental and fire performance characteristics to the extent that the product effectively ‘fell apart’ on installation. Subsequent repairs on systems that fail in this way may hold well, but there can be no guarantee that the system will achieve the required degree of fire resistance, and fire tests cannot usually be carried out ‘in situ’. Improper / difficult application and installation – the PFP system could only be applied during a 6 hour ‘window’ each day whilst humidity remained low. Improper curing may have contributed to the system’s failure.
Appendix 3 UTG Position on the Choice and Specification of Epoxy Intumescent Passive Fire Protection Materials
UTG Position on the Choice and Specification of Epoxy Intumescent Passive Fire Protection Materials These are the recommendations of the UTG technical authorities on Fire Hazard Management, Fire Protection and Coatings; Background Intumescent epoxy passive protection systems have been commercially available for over 20 years and their progressive development has responded to industry needs such as jet fire resistance, longevity in harsh environments, ease of application and weight. Standards have been developed to address the environmental resistance and jet fire loadings. The market has become increasingly competitive in recent years. Third and fourth generation materials have been developed which achieve the minimum test standards with thinner, lighter and commercially more competitive systems, as opposed to earlier generation products which were designed to meet the most intense loadings that test sites could devise. There is concern that the lighter and thinner products may be more susceptible to failure from the intense effects of a jet fire. These materials are used for the protection of structures, blast walls, risers and safety equipment against severe fire hazards and are safety critical. As such, they are required to be suitable and sufficient for the hazards to which they will be exposed. As operators, we are obliged to do everything reasonably practical to meet this aim, starting with minimum standards and thereafter applying good practice and engineering judgement. There have also been a number of instances, including one on a BP facility where the applied materials have failed in service, with material softening, delaminating and falling off. The exact reasons have been difficult to ascertain because of the number of parties involved from material supply to final top coating. However, they would appear to be a combination of inherent material properties, weather conditions during application, surface preparation and application methods. The underlying causes appear to be associated with the inherent material properties, quality control, vendor support and relationships between them, applicators and the construction yards.
It is an almost impossible task to make significant repairs or replace systems on site, particularly on an offshore facility. This is a highly disruptive, prolonged and labour intensive activity involving scaffolding, surface preparation and application within hydrocarbon production and processing modules. This activity multiplies the risks in these areas, bringing new causes of release, restricting ventilation, increasing explosion overpressures and exposing all of the repair crew to those hazards. As a consequence, the choice of material and vendor is absolutely critical. There must be confidence that the system will last for the life of the facility and fulfil its role.
Recommended Suppliers and Materials: Following the failures mentioned above, at least two vendors have shown consistent historical performance of their material in service, inferring that their products and support are sufficient to provide a material which will achieve and maintain its long term integrity in a range of application conditions and environmental exposure. These vendors are AKZO Nobel (International Paints) and Leigh Paints. In view of reported and actual failures, consultation with the BP technical authorities and a higher level of assurance and guarantee is recommended from other vendors before they are to be considered. As a minimum standard for environmental exposure of overcoated passive fire protection materials, the prequalification test in Norsok standard M-501 Rev 4 1999 is taken as the minimum but materials should be inherently capable of passing this test without overly depending on high quality topcoats. Continuous exposure to water wetting has resulted in severe softening of certain passive fire protection materials which has necessitated costly offshore repairs.
On suitability for fire performance, two types of exposure may be encountered; pool fires and jet fires. The former does not have turbulent abrasive exposure and is adequately simulated by an electric or gas powered furnace test – the classic H rated fire test and temperature profile. The jet fire testing covers a range of potential scenarios from low pressure flare leaks at a few bars to reinjection compressors at 3 -400 bar. The original development testing for jet fire resistance was carried out at the British Gas Spadeadam site, with up to 60 bar, 3 kg/sec, 120 Megawatt methane fires. It was impractical to use this as a test standard due to the scale, pressures and fuel supplies, typically LNG.
A smaller more easily undertaken jet fire test was developed using propane at a 2.5 – 7 bar pressure, 0.3 kg/sec and 12 megawatt. It is practical for test organisations to replicate this test and it is the only accepted international standard, OTO 95634, for jet resistance. This only represents the minimum acceptable standard for any jet rated application on a BP facility. In selecting materials for severe gas fire duty (i.e. intense large high pressure jet fires), those which have been voluntarily exposed to the Spadeadam high pressure; 40 - 60 bar tests and performed well should be preferentially considered. The larger test is closer to the actual conditions that the material may be exposed to in a typical hydrocarbon producing facility. The preferred materials for severe jet fire exposure, which have survived this test, are the Leigh’s Firetex M90 and International’s Chartek 4. Where the only exposure is a pool fire, then International’s Chartek 7 shows fully acceptable performance, as do Chartek 4 and Firetex M90. Websites:http://www.chartek.com (Includes application guides, approved primer list, checklist for specifiers and information on epoxy intumescents).
Example of Best Practise BP Engineering Standard Fireproofing Materials & Application Specification – Onshore Facility
1.0 FOREWORD 2.0 SCOPE 3.0 TYPE OF FIREPROOFING 4.0 EXTENT OF APPLICATION 5.0 SUPPLY OF MATERIAL 6.0 MATERIALS 7.0 SURFACE PREPARATION 8.0 GENERAL APPLICATION 9.0 VERMICULITE FIREPROOFING 10.0 PARTICULAR APPLICATION 11.0 WATER SHEDDING 12.0 MISCELLANEOUS REQUIREMENTS 13.0 QUALITY ASSURANCE
Appendix A Approved Materials.
Fireproofing Materials & Application Specification 1.0 1.1 Foreword User Feedback
The value of this Grangemouth Engineering Manual Standard (GEMS) to its users will be significantly enhanced by their regular participation in its improvement and updating. Users are urged to inform the GEMS Administrator of their experience in all aspects of its application. 1.2 Use of language
Throughout GEM Standards, the words "will ", "may", "should", " shall", and "must", when used in the context of actions by BP or others, have specific meanings as follows: ? ? ? ? ? "will" is used normally in connection with an action by BP, rather than by a contractor or supplier. "may" is used where alternatives are equally acceptable. "should" is used where a provision is preferred. "shall" is used where a provision is mandatory. "must" is used only where a provision is a statutory requirement.
This paragraph (1.2) shall be included in the Foreword of each GEMS 1.3 Documents Replaced
This document replaces: GES/ES120-16/1 Fireproofing EM/POL/24-01 Policy - Fire Protection EM/PRAC/24-02 Practice - Guidelines for Fire Protection 1.4 Reference Documents
BS 476 Part 20; 1987 Appendix D High Rise Fire Test Of Protection Materials for Structural Steel. BS 476 Part 21; 1987 Employing the Hydrocarbon Heating Curve OTI 95 – 634 Offshore Technology Report. RP 24-1 Fire Protection – Onshore April 1994 Section 18 Passive Fire Protection. BS EN 197-1:2000 Standard for Portland Cement
This specification covers the requirements for the selection and application of fireproofing to steel structures, vessels, spheres and supports with concrete, lightweight vermiculite cementitious factory mixes, intumescent epoxies, and man made mineral fibre insulating materials. This specification does not cover engineering design issues with regard to process plant layout, or designation of which type of fire hazard may exist in a particular process area. This latter will be notified to the passive fire protection applicator by BP Grangemouth representative. This GEM complements BP RP 24-1, and should be used in conjunction with the RP, which does address many of the engineering design issues, for passive fire protection requirements, with guidance on plant layout, definition of the different types of fire risk and explanation on h ow these risks are to be mitigated, and assessed. This GEM also acknowledges the fire resistance requirements of various regulatory bodies, e.g. the HSE, C.O.M.A.H. Regulations etc. The requirements have been incorporated into the performance criteria and the material selection as well as the applicators ability to correctly apply the selected materials to meet the laid down criteria. 3.0 3.1 Type of Fireproofing Resistance
Fireproofing shall furnish 2 hour hydrocarbon pool fire rating in accordance with BS 476 Part 20, and BS 476 Part 21: 1987, plus hydrocarbon accelerated time/temperature curve. It shall also furnish 2 hour jet fire rating in accordance with OTI 95-634 Offshore Technology Report unless otherwise specified. Passive fire protection shall be engineered to give the two hour rating for jet and pool hydrocarbon fire resistance as stated above by preventing the protected substrate from reaching the following temperatures; Pressure o containing surfaces shall not exceed 400 Celsius, non pressure containing o support structures shall not exceed 550 Celsius.
Type of Fireproofing
Fireproofing shall be of 3 types as follows:a) Vermiculite - Vermiculite/Portland Cement of an approved factory controlled pre-mix, of 40mm minimum net thickness measured from the protected surface.
Intumescent Two Pack Epoxy of an approved manufacturer, with thickness to be calculated from the relevant manufacturers Hp/A ratio tables, according to the surface being protected. All thicknesses so derived shall be minimum thicknesses and measured from the protected surface upon complete through curing of the intumescent epoxy. Man Made Mineral Fibre or Body Soluble Ceramic Fibre ( ‘Superwool’) of an approved type from an approved manufacturer may be used, with prior approval of BP Grangemouth representative, where process equipment operates at elevated temperature or requires thermal insulation for process reasons as well as fireproofing. This to be covered with a well sealed and well fitted metal cladding of an approved type. Thickness to be calculated according to thermal insulation and fire resistance requirements. Extent of Application
The extent of application of fireproofing shall be detailed on drawings that will be provided with the Works Order by the BP Representative. The type of fire hazard to be protected against will also be notified either on the drawings, or in writing within the Works Order. (e.g. pool and/or jet fire resistance required) 5.0 Supply of Material
All materials shall be supplied by the application contractor, including clips or rods to attach reinforcing mesh to structural members in accordance with the manufacturers instructions. Vessel skirts will be supplied complete with attachments for fixing reinforcing mesh in place. All materials shall be new quality, shall conform to the requirements given below, and shall be to the approval of the BP Representative. During transportation, off-loading and storage at site, all materials shall be adequately protected against damage, and from the weather. Materials shall not be set directly on the ground and shall be kept under covered storage.
Cement shall conform to BS EN 197-1 : 2000 Ordinary Portland Cement. 6.2 Vermiculite Filled Cementitious Mixes
Vermiculite filled cementitious mixes shall be supplied as a pre-mixed factory controlled material. The mix shall be certified material approved by the BP representative. Fendolite MII or Fendolite TG (trowel grade) as supplied b y Cafco UK Ltd are currently approved grades. (Herein after described as ‘vermiculite’) The dry density of the materials shall be in the range 3 670-800 Kg/m and they should have a compressive strength of 3000 psig minimum after 28 days. Alternative materials, which are considered to be "equivalent" to the proprietary materials specified in this section, shall not be used unless approved by the BP Representative. All such material proposals shall be accompanied with full documentation including fully auditable independent third party certification that is current and valid. Independent third party bodies recognised for this purpose are DNV, Lloyds, or UL. ) A testing house facility report does not in itself constitute ‘Certification’. In addition to the fire performance certification, the material manufacturer shall issue a certificate stating that the material is asbestos free, including the vermiculite, along with a copy of the testing house report that conducted the material analysis. Particular attention should to be paid to the vermiculite for asbestos content.
Reinforcing Fabric For vermiculite/cement, reinforcing mesh should be 50 x 50 x 1.6 mm plastic coated hexagonal mesh or 75mm x 75mm x 2mm plastic coated hexagonal. Expanded metal lath shall be by Expanded Metal Co. Ltd., BB Ref. BB264 galvanised, for large surfaces "Expamet" or Rib-lath. Reinforcing fabric for use with intumescent epoxy mastics shall be as the material manufacturers recommendations.
Alternative expanded metal lath may be submitted for BP Representative approval, such submittal shall be accompanied by relevant certification stating that the proposed material has achieved British Board of Agrement approval, and is in accordance with the standard BB264.
Attachments For structural steelwork and vessel skirts attachment shall be by 3mm diameter x 11mm long stainless steel pins with stainless steel bridge clips 20 mm x 10 mm x 7 mm high. The pins shall be Type 304 stainless steel. Fireproofing must not be applied until the surfaces of attachment welds and heat affected zones have been prepared and painted as per section 7. For vessels, attachments shall be shop welded studs or edge mounted nuts. See 11.2. Bands
Galvanised mild steel bands shall not be less than 0.6 mm thick by 13 mm wide with matching seals. 6.6 Tie Wire
Tie wire for securing mesh joins/overlaps shall be galvanised soft iron wire 1.6 mm diameter. 6.7 Mastic Caulking
Mastic for caulking shall be silicone rubber or polysulphide type that is suitable for application on material with pH 12.5
Surface Preparation Steelwork to be fireproofed with vermiculite / cement, unless it is galvanised, shall be prepared and painted in accordance with GEMS/06-001 Specification Number A.1.9 after the fixing attachments for reinforcement have been welded in position. Steelwork to be fireproofed with intumescent two pack epoxy shall be prepared and primed in accordance with the manufacturers recommendations. Particular attention shall be paid to the film thickness of the priming coat, it shall in no case exceed the maximum thickness as laid down by the manufacturer of the intumescent epoxy. Where steelwork, vessels or pipework are to be fireproofed using man made mineral f ibre, the substrate shall be prepared and painted in accordance with GEMS 06-001.
The protective coating system shall be selected for use under insulation and by reference to the operating temperature of the surface to be fireproofed. Paint shall be allowed to dry thoroughly before any fireproofing is applied. 8.0 General Application
The application of the fireproofing shall not commence without the approval of the BP Representative, who shall ensure that the steelwork or vessels have been plumbed, levelled and fully bolted. 9.0 a) Vermiculite Filled Fireproofing Vermiculite filled fireproofing may be spray or trowel applied. Before being applied by hand however, spray grade materials shall be passed through a spray gun. Trowel grade materials can be mixed and trowel applied without the need to be passed through a spray gun. Care must be taken to avoid excessive working of the material or polishing the finish because this tends to bring cement to the surface and makes it susceptible to frost damage. Steelwork, which is to receive spray -applied fireproofing, shall be given a bond coat. The bond coat shall be produced by a styrene/butadiene additive in the normal spray applied mix. The surrounding plant and steelwork shall be protected from droppings, over-spray and re-bound material. Re-bound material shall not be reused. Vermiculite filled fireproofing shall be mixed and applied in accordance with the material manufacturers technical data recommendations. The use of expanded metal lathe as an additional substrate is not considered necessary when application to steel backgrounds is required . Expanded metal lath would require to be to be pre-formed to suit steel section sizes and shapes . Reinforcing fabric shall be fixed after application of the base coat. Junctions in the reinforcing mesh shall overlap 50 mm minimum and shall be tied at approximately 150 mm centres. All overlaps shall be staggered so that no more than 3 layers of mesh are present at any point. The reinforcing mesh shall be positioned so as to lie substantially in the mid third of the applied thickness. Please note previous comments on vermiculite thicknesses. ( Ref. Section 3.2.b) All corners shall be finished straight and true lined with no reduction in thickness.
When it is impossible to complete a whole section in one day an overlap of at least 150mm of uncompleted work shall be left to avoid a straight through joint.
10.0 Particular Application 10.1 a) Structural Steelwork The fireproofing shall follow the contour of columns and beams where the depth of member is over 203 mm. Steel sections up to and including 203 mm shall be protected by the "solid fill" method. Helical CD weld pins shall be spaced sufficiently close together to hold the metal lath or mesh firmly in position. A spacing of approximately 400 mm centres in a diamond position shall be used, being welded close to the edges or in a staggered pattern. Where the fire protection follows the contour of the beam or column, the rods shall be welded to the steel section with sufficient clearance to allow the fixing of the securing clips. Welding will necessitate the local removal of the priming system and fireproofing shall not be applied until the surfaces of attachment welds and heat affected zones have been prepared and painted as per section 7. c) Where intumescent epoxy mastics are to be used, they will follow the contours of the structural steel element. Solid fill method shall not be used. Thickness shall be in accordance with manufacturers recommendations or by use of the Hp/A ratio calculation of that particular steel element. 10.1 c) Structural Steelwork cont. Where welding is not permitted, patent metal clips may be suitable, but shall be used only with the prior agreement of t he BP representative. A 10 mm deep x 10 mm wide rebate shall be formed at all fireproofing/steel interfaces to receive sealant. The rebate shall be dry, wire brushed and air blown clean prior to application. The sealant shall be bonded to both sides of the rebate but debonded from the base of the rebate by a strip of non-adhesive waterproof membrane. Application shall be after the top coat paint system.
Vessels and Vessel Skirts Where possible fixings for securing the expanded metal lath firmly against the surface shall be shop welded to the vessel by the vessel fabricator. The fixings shall be Helical CD pins, or stainless steel studs welded to the vessel. They shall be fixed at approximately 400 mm staggered centres, except at manholes etc. where closer spacing may be necessary. Where welding of fixings is not permitted or when particularly specified, expanded metal lath shall be firmly held in place by stainless steel bands at 450 to 600 mm centres, but care must be taken to ensure that the mesh is correctly positioned (Section 9 (f)). Bands used to retain expanded metal lath to the bottom heads of vertical vessels shall be spaced at not greater than 450 mm centres at the circumference. On vertical vessels without a skirt, the bands shall be tied to the bottom band on the vessel which shall also be of stainless steel. On vessels with a skirt, the bands shall be tied to rods or lugs previously welded to the top of the inside of the skirt. On large skirts a ribbed expanded metal may be used to give greater rigidity. Manholes in skirts shall be left clear. Vent holes at or near the top of vessel skirts for ventilating the inside shall be kept clear. For this purpose a light gauge galvanised steel tube shall be inserted in the hole and held in position by the vermiculite. The tube shall finish flush with the outer face of the fireproofing.
Holding-down bolts of skirts shall be fully covered with fireproofing unless otherwise directed. Before bolts are covered they shall be coated with a suitable protective material such as Denso tape. Where bolts are in the plane of the skirt the cut-out shall be protected, unless otherwise called for.
g) On Vessel skirts over 1 metre in diameter there is a requirement to fireproof the internal of the vessel skirt. When the vessel skirt is under 1.8 meters in diameter and has more than one opening, fire proofed removable covers may be substituted in lieu of fire proofing the interior of the vessel skirt.
This will be at the discretion of the BP Representative. The applicator will be notified accordingly. h) Where vessel skirts reach operating temperatures in excess of 40 Celsius, they shall be insulated down to grade, or base mounting, prior to application of fireproofing. This shall be carried out in accordance with GEMS 06-002, insulation thickness as per the thickness tables for the relevant operating temperature. Severe Cracking and adhesion failure can occur if this is not taken into consideration, past experience has shown that the heat can be conducted downwards quite a considerable distance. It is for this reason that the insulation shall continue down to the base mounting. 10.3 Special Requirements for Insulated Cold Vessels
The specification for skirts of insulated cold vessels shall have the following additional requirements:a) The outer fire protection shall be carried over the insulation and 75mm above the junction of the skirt and the vessel, or as otherwise specified. The vermiculite inside the skirt shall be taken over the insulation and finish against the underside of the insulation applied to the bottom of the vessel. When vermiculite/cement laps over the insulation, the latter shall be wrapped with coarse weave glass cloth. Care shall be taken not to damage the vapour seal. The top of the protection shall be sloped off and the junction of the protection and the insulation sealed with an approved mastic (see 5.10). Vessel Saddle Supports The fireproofing shall follow the contour of the support where the depth is 600mm or greater. Unless otherwise specified, forked metal clips shall be spot welded to the surface to hold the expanded metal lath. The clips shall be spaced at approximately 300 mm, being welded close to the edges and in staggered pattern. For supports less than 600 mm they shall be boxed around, the expanded mesh being fixed to 6 mm diameter rod welded to the saddle at approximately 300 mm centres.
In the case of vessel saddles which have provision for sliding on a support, the bolts shall be covered in “Denso” paste or tape and the elongated holes kept free from the vermiculite/cement so that the supports are left free to slide. Support Legs for Storage Spheres The fireproofing shall be terminated below the junction of the leg with the sphere to enable satisfactory sealing to be provided. This shall consist of a bolted-on or welded flashing cap. The expanded metal lath shall be held against the circular legs by stainless steel bands at 450 to 600 mm centres. Body of Storage Spheres. The fireproofing shall be applied over the entire surface of the sphere as a continuous coating, and shall include all of the associated pipework up to the first isolation valve, or to the bund wall, if the first isolation valve is well outside the fire zone area. This will be indicated on a drawing, or indicated by the BP Grangemouth representative. When lightweight vermiculite cementitious fireproofing is to be used for protection of spheres, it shall be retained in situ with a reinforcing mesh, as listed below.
The reinforcing mesh shall be either stainless steel, or plastic coated galvanised welded mesh of 76 x 76 x 2.5 mm – 3.0 mm diameter. The 2 tensile strength of the wire must be a minimum of 350 N/mm . The mesh shall be overlapped by 2 meshes minimum and secured with galvanised hog rings or stainless steel wire ties. Sufficient rings or wire ties shall be used to ensure that the overall tensile strength is maintained to not less than 50% of the tensile strength of the mesh. In order to aid installation of the mesh on spheres support rings shall be used, these may be constructed of either single strand or multistrand galvanised wire, to support the weight of the mesh plus any applied tensioning forces. The support rings shall be 4 in number, 2 off at 0.3 diameters of the sphere, and 2 off, at 0.5 diameters of the sphere. These are referred to as the ‘Floating Rings’ and shall be supplied by the fireproofing/application contractor.
The tensile strength of the wire used for the fabrication of the floating rings shall be at least 2 tonnes. The mesh shall be supported off the sphere surface in such a way as to keep it in the middle third of the overall thickness of the lightweight vermiculite fireproofing. If the fireproofing to be applied to the sphere body is of the intumescent epoxy type, then the manufacturers recommendations for reinforcing using a scrim or mesh type reinforcing shall be strictly adhered to.
The top surfaces of encased beams and all flat surfaces of the finished fire protection shall be suitably sloped to provide an adequate water shed. This is particularly important at the top of the fire protection on columns. Where a steel section, nozzle or support emerges from the casing or an exposed steel surface is flush with the casing, the junction of the fireproofing and the section shall be pointed and sealed with an approved fire resistant mastic or flashed to prevent the ingress of water. A weatherproof topcoat is required at Grangemouth and it should be used on all areas that are fireproofed with lightweight vermiculite cementitious materials. Special topcoats may be required, for example where exceptionally wet conditions occur due to regular use of water spray systems etc. 12.0 12.1 Miscellaneous Requirements Frost Precaution
To avoid water freezing in the wet fireproofing, work shall be suspended when the temperature is falling and has reached +4C and shall not be recommenced until the temperature is rising and has reached +2C. Any work completed shall be protected against damage by frost. 12.2 Patching of Fireproofed Surfaces
Patching of the fireproofing shall be equal in all respects to the originally applied material, in particular joints between new and old material shall be truly flush.
Spheres and other equipment, fireproofed with lightweight vermiculite and when subject to continuous contact with water from spray cooling systems, shall receive one coat of Liquid Plastics Limited Bonding Primer followed by two coats of Liquid Plastics Limited Fire Check paint. The Liquid Plastics Limited Fire Check coating serves as an effective weatherproofing that is more resistant to the conditions experienced by equipment that is in continuous contact with running water from spray cooling equipment. It is more resistant to the erosion effects of the running water directed against the surface under pressure. 12.4 Environmental Conditions.
Application of passive fire protection shall not take place if the following conditions prevail. Relative humidity is greater than 85% Steel temperature is less than 3 Celsius above the dew point. Where surfaces are unprotected during rain or snow. Where surfaces are subject to standing or running water. Where surfaces are below 4 Celsius.
12.5 Repair Procedure. Prior to commencement of the works, the Applicator shall submit to BP Grangemouth representative a copy of a repair procedure for passive fire protection for approval. This repair procedure shall be supported by the material manufacturers recommendations and data sheets, and shall be approved by the material manufacturer prior to submittal to BP Representative. The applicator and the material manufacturer shall ensure that all such repairs carried out in accordance with the approved procedure give an equal performance to that of the original fireproofing, and shall be guaranteed as such, by the two parties. The applicator shall be approved for carrying out such repairs, by the manufacturer.
13.1.1 Quality Assurance Management System. The application contractor and its personnel shall be experienced in the particular application method chosen to apply the selected fireproofing materials for the works in hand. They shall also have an auditable track record and be able to demonstrate proof of this to BP Grangemouth prior to commencing the works. This auditable proof shall be submitted with their tender documents. All application contractors shall be subject to a technical review and selection process to assess their technical ability prior to being accepted to carry out the works. 13.1.2 Quality Assurance Management System.
The application contractor shall operate an ISO 9000 compatible quality management system. This should be audited and approved by BP Grangemouth or their appointed representative prior to the order being placed. A comprehensive inspection test plan or quality plan that is job specific shall be submitted with the bid tender documents. This plan will be approved and annotated with any relevant hold or witness points etc. by BP Grangemouth prior to commencement of the works. During the period of the works, BP Grangemouth or their appointed representative will conduct quality audits at their discretion. Prior to the commencement of the actual works, a test piece shall be carried out by the applicator. This test piece shall be representative of the works to be carried out and shall be of sufficient size and geometry to give a realistic assessment of the capabilities of the applicators workforce, and of the materials suitability for the particular application in the chosen location. The test sample shall be truly representative of the level of workmanship that is to be used in the actual application. It shall be retained as a reference sample and marked as such for the duration of the works. The purpose of the reference sample is to ensure that the quality of the works matches that of the reference sample for finish, thickness and bonding to the surface. Full quality assurance records shall be kept for the carrying out of the test sample. During the period of the works, a Crush Test cube sample shall be taken from each days production. This shall be cured as per the manufacturers recommendations, and subjected to a crush test at 28 Days. The minimum crush shall be 3000 psig. Any cubes which fail the test shall be traced back to the area of that days production by use of the Daily Inspection Record.
Such area shall be removed at the applicators/material manufacturers expense and replaced with material which conforms to the Crush Test requirements. It may be possible to incorporate the test sample into the actual works, however such area as used for the test sample shall be clearly defined and agreed by the BP representative that this may be allowed. Such an area 2 shall be clearly marked as the reference standard area. It shall be 6m if on a flat surface, or it shall be at least 2 metres long and incorporate one connection or joint on typical beams or columns.
13.1.3 Quality Assurance Records During the period of the works the application contractor shall retain a full and accurate set of site records. These shall be available at all times for BP Grangemouth representative to inspect. This documentation to be kept up to date at all times. 13.2 Quality Control. The application contractor shall nominate a competent person to carry out Q.C. inspection duties, such person’s C.V. to be submitted to BP Grangemouth for approval prior to commencement of the works. Such nominated person shall be approved for this function by the material manufacturer. The nominated and approved competent person shall carry out all inspection duties, collect and record results of such inspections on a daily basis. BP Grangemouth may appoint an inspection representative of their own, who shall be granted access to the works at all times. This representative may be a third party inspection person. The nominated and approved Q.C. inspector utilised by the application contractor shall produce a weekly inspection report that is to be based upon the daily inspection reports. Copies of all reports shall be retained on site at all times. The weekly report shall be submitted to the BP Grangemouth representative no later than midday Monday of the week immediately following the period covered by the report. The daily and weekly reports shall clearly state the environmental conditions for the period of the works covered by such report. Each report shall also state the batch numbers of the materials applied during the periods covered by the report and the location of where each batch was applied. The reports shall also list and record any defects found during the works carried out
during the period covered by the report, or any such defects that subsequently appear after drying out or curing of the materials applied. The application contractor shall furnish a full set of instruments required for the inspection activities to be carried out during the period of the works. These instruments shall be made available for use by BP Grangemouth representative. The instruments must be calibrated and certified as such by a UKAS Approved body, or the equipment manufacturer. Copies of all calibration certificates shall be available at all times, on site. Certificates will be current and valid at all times. The instruments shall be kept in good working order, if in the opinion of the BP Grangemouth representative any of the instruments are not in good working order they shall be changed immediately, this to be at the application contractors own cost. It shall be the responsibility of the application contractor to ensure that the inspection instruments are maintained in good working order, and that sufficient instrumentation is available at all times in order that delays in the works are avoided. Inspection instrumentation, as a minimum, shall comprise of: 1. Whirling Hygrometer 2. Dew Point/Humidity Calculator. 3. Steel Temperature Gauge. 4. Metal Wet Film Comb Gauge ( For Paint and Intumescent Epoxy) 5. Dry Film Gauge. (Range suitable for Intumescent Epoxy.) 6. Depth Gauge (Lightweight Cementitious, Vermiculite Filled.) 7. Scales. ( For Density Checks on Lightweight Cementitious) 8. Slip Tube (For Density and Slump Testing.) 9. Pin Bending Tool. (For use on Welded Helical Pins.) 10. Crush Cube Moulds. Environmental condition monitoring shall take place at least 4 times per work shift, once prior to starting work, once mid morning, once immediately after the mid day lunch break prior to starting the afternoon works, and once in the mid afternoon. The BP Grangemouth representative may require additional testing if in their opinion the environmental conditions are near to or approaching unacceptable limits. No works shall be allowed to progress if such weather conditions prevail that could be detrimental to the passive fire protection. If work proceeds in out of specification conditions or fireproofing becomes damaged due to poor weather conditions immediately after application, then such affected areas shall be stripped off and fresh materials applied when
environmental/weather conditions allow. The cost of this shall be held to the application contractors’ account. Ensuring the correct environmental controls are in place to protect the works shall be the responsibility of the application contractor. Density and slump checks shall also take place 4 times per working shift. These checks may also be required at the discretion of the BP representative should there be any doubt about the density or consistency of the mixed material. These additional tests shall be carried out at the request of the BP representative and shall incur no additional costs to BP Grangemouth. Any mix of material found to be outside the manufacturers recommended range as per data sheets shall be dumped and fresh material mixed in the quantities stated in the data sheets, this will be observed by the BP representative. Should this fail to meet the manufacturers stated range, the whole batch of material that is marked with the same batch number shall be quarantined and the manufacturers technical department consulted. The material manufacturer shall approve the application contractor, prior to commencement of the works. The material manufacturer shall also approve or certify the competence of the p ersonnel who are actually carrying out the works. This approval shall be for the application of the materials and the techniques to be used during the application of the passive fire protection at BP Grangemouth. This approval shall be recorded and a copy of the approvals shall be submitted to BP representative prior to the commencement of the works. Such approval/certification shall be kept up to date by periodical re-assessment of the personnel. No unapproved or uncertified personnel will be allowed to apply passive fire protection at BP Grangemouth, at any time. The application contractor shall also have the material manufacturer pay regular inspection visits to the worksite to assure that the materials are being correctly applied in accordance with their own technical data sheets, or procedures. This shall then be included in the performance guarantee required by BP Grangemouth. The material manufacturers representative shall provide copies of all inspection visit reports to the BP representative, as soon as they become available, but in any case within 1 week of the date of the inspection visit.
APPENDIX A. Approved Materials for Passive Fire Protection. This appendix lists all of the suppliers/manufacturers of passive fire protection that have current approval for use at BP Grangemouth complex. Included in the list are summarised details of the materials certification along with the name of the Certifying Body. As materials are tested and certified by a recognised Certifying Body, their details will be added to this list. Manufacturer Product Name Cafco Ltd. Fendolite M 11 Fendolite M 11 TG Firetex M90 Certifying Body Certificate No. Lloyds Lloyds Lloyds SASF000190 SASF010001 SVG/F94/282 SVG/F94/284 SVG/F94/285 F-12846
W & J Leigh
DNV International Akzo Nobel PPG Chartek 4.
Lloyds DNV DNV
Protective Concepts Inc.
Onshore Fire Protection.
BP Exploration Passive Fire Protection Specification – Draft Issue 1998. OTI 95 634 Materials. Jet Fire Resistance Test of Passive Fire Protection
HSE Offshore Technology Report OTO 2000 051 - Review of the Response of Pressurised Process Vessels and Equipment to Fire Attack'. BP Exploration Passive Fire Protection Specification. Ensuring Best Practice for Passive Fire Protection in Buildings – ASFP 2003. API 2218 – Fireproofing Practices in Petroleum and Petrochemical Processing Plants. GESIP Report 93.6 – Utilisation of fire proofing coatings for the protection of pressurized tanks containing liquefied flammable gas GESIP Report 93.11 – Methodologie d’essais de vieillissement accelere (English Version) GESIP Report 93.12 Version) Methodologie d’essais au four (English
GESIP Report 93.17 – Fire protection study on fire proofing tanks containing pressurized combustible liquefied gases – Final Test Report. GESIP Report 96.09 – Thermal behaviour and corrosion resistance test after accelerated ageing on passive protection products for tanks containing pressurized flammable gases. NFPA BLEVE video
The Process Safety Booklet Series: (grey books) Hazards of water (2003) Hazards of air and oxygen (2003) Safe furnace and boiler firing (2003) Safe ups and down (2003) Hazards of electricity Hazards of steam (2003) Safe handling of lights ends Safe operation of refinery steam generators and water treating facilities 9. Engineering for safe operation 10. Hazards of Nitrogen, safe handling of catalysts (2002) 11. Hazards of trapped pressure / vacuum (2003) 12. Tank farm and (un)loading safe operations 0. Hazards of Ammonium Nitrate 1. 2. 3. 4. 5. 6. 7. 8.
The Fire Booklet Series: (blue books) * Liquid hydrocarbon storage tanks: prevention and firefighting
** Hotel Fire Safety (2003) *** Passive Fire Protection (2003)