Document No.
GP 52-20
Applicability
Group
Date
12 December 2005
Guidance on Practice for Passive Fire Protection (PFP)
GP 52-20
BP GROUP ENGINEERING TECHNICAL PRACTICES
12 December 2005
GP 52-20 Guidance on Practice for Passive Fire Protection (PFP)
Foreword This is the first issue of Engineering Technical Practice (ETP) BP GP 52-20. This Guidance on Practice (GP) is based on parts of heritage documents from the merged BP companies as follows:
BP RP 24-1
Fire Protection – Onshore.
Amoco A NM-F-00-E PTA NM-F-00-G PTA NM-F-00-E
Non-metallic Materials—Fireproofing—Engineering Specification. Non-metallic Materials—Fireproofing—Guide. Non-metallic Materials—Fireproofing—Engineering Specification.
Arco Standard 803. Rev 3
Fireproofing.
Copyright © 2005, BP Group. All rights reserved. The information contained in this document is subject to the terms and conditions of the agreement or contract under which the document was supplied to the recipient’s organisation. None of the information contained in this document shall be disclosed outside the recipient’s own organisation without the prior written permission of Director of Engineering, BP Group, unless the terms of such agreement or contract expressly allow.
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GP 52-20 Guidance on Practice for Passive Fire Protection (PFP)
Table of Contents Page 1.
Scope .................................................................................................................................... 4
2.
Normative references............................................................................................................. 4
3.
Symbols and abbreviations .................................................................................................... 4
4.
General.................................................................................................................................. 5
5.
Criteria ................................................................................................................................... 5
6.
Extent of fireproofing.............................................................................................................. 7 6.1. General....................................................................................................................... 7 6.2. Structures ................................................................................................................... 8 6.3. Piping........................................................................................................................ 11 6.4. Equipment, Instrumentation & Control, and Electrical ............................................... 12 6.5. Outside battery limits (OSBL) of processing facility ................................................... 16 6.6. Fireproofing not required........................................................................................... 16
7.
Methods and materials......................................................................................................... 16 7.1. General..................................................................................................................... 16 7.2. Fireproofing materials ............................................................................................... 17 7.3. Dual purpose protective material............................................................................... 20 7.4. Piping and equipment ............................................................................................... 21 7.5. Control systems ........................................................................................................ 21
Bibliography .................................................................................................................................. 26
List of Figures Figure 1 - PFP of fire potential equipment structural support......................................................... 22 Figure 2 - PFP of fire and nonfire potential equipment structural support ...................................... 22 Figure 3 - PFP of nonfire potential equipment structural support................................................... 23 Figure 4 - PFP of pipe racks with fire potential pumps .................................................................. 23 Figure 5 - PFP of pipe racks without fire potential pumps.............................................................. 24 Figure 6 - PFP of air cooler structural support............................................................................... 24 Figure 7 - PFP of transfer line support .......................................................................................... 25
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12 December 2005
1.
2.
GP 52-20 Guidance on Practice for Passive Fire Protection (PFP)
Scope a.
This GP defines minimum technical requirements for selection of materials, methods, and designation of passive fireproofing of structures, piping, equipment, and control systems.
b.
This GP does not cover fireproofing of buildings.
Normative references The following normative documents contain requirements that, through reference in this text, constitute requirements of this technical practice. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this technical practice are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies.
BP GP 06-60 GP 44-80 GIS 52-201
Guidance on Practice for Onshore and Offshore Paints and Coatings Guidance on Practice for Design Guidelines for Relief Disposal Systems Guidance on Industry Standard for Installation of Passive Fire Protection (PFP). GP 52-10 Guidance on Practice for Insulation. BP Group Fire booklet series; Passive fire protection: types and applications (Jan 2004) Link to Booklet
American Petroleum Industry (API) API 2218
Fireproofing Practices in Petroleum and Petrochemical Processing Plants.
British Standards Institute (BSI) BS 5950: Part 8 BS 8110: Part 1
Structural use of steelwork in building: Code of practice for fire resistant design. Structural use of concrete.
National Fire Protection Association (NFPA) NFPA 30
Flammable and Combustible Liquids Code.
Underwriters Laboratories (UL) UL 1709
3.
Fire Resistance Directory Volume 1.
Symbols and abbreviations For the purpose of this GP, the following symbols and abbreviations apply: ESD
Emergency shutdown.
FRA
Fire risk analysis.
MI
Mineral wool insulated.
OSBL
Outside battery limits.
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4.
GP 52-20 Guidance on Practice for Passive Fire Protection (PFP)
P&ID
Piping and instrumentation diagram.
PFP
Passive fire protection.
General a.
Fireproofing shall be used to provide primary protection of: 1.
Structures directly or indirectly supporting significant hydrocarbon inventories or emergency systems.
2.
Structures supporting heavy loads that, if they were to fail, would lead to significant hydrocarbon release, catastrophic failure, or loss or damage to control centre or emergency system.
3.
Class 0 hydrocarbon storage vessels or other plant that could fail catastrophically or lead to further significant releases.
b.
Fireproofing may be applied to critical equipment and structures to protect investment and production.
c.
Fireproofing extent, material type, and configuration shall be specified by:
d.
1.
Defining extent of fireproofing for structural steel and equipment support on fireproofing plans consisting of plot plan and elevation drawings.
2.
Detailing member fireproofing requirements on structural steel design drawings.
3.
Detailing equipment support fireproofing on equipment drawings.
4.
Specifying materials and installation methods within GIS 52-201.
References to flammable or combustible liquids shall comply with NFPA 30. Decision to use fireproofing and what areas to fireproof in facility is made by BP based on full assessment of particular processing facility. Once area to be fireproofed has been defined by BP, designers can complete details based on this GP. API 2218 as recommended practice for fireproofing in petrochemical industry was withdrawn by API in 1995. Commentary in this GP is consistent with API 2218 and is conservative. Lesser degrees of fireproofing may be acceptable depending on relative risks involved and may represent significant savings in fireproofing cost. Recommendations for reasonable reductions in fireproofing are encouraged and will be evaluated by BP.
5.
Criteria a.
Decision to fireproof and extent of fireproofing at facility shall involve assessment of risk to personnel and equipment in case of fire. Intent of fireproofing is to: • • •
Permit emergency shutdown of unit. Restrict addition of fuel to fire. Protect personnel and major equipment from effects of support failure or rupture during fire.
This GP, along with consultation with local facility operations and safety personnel, should be used to: •
Define areas as low, medium, or high fire potential.
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GP 52-20 Guidance on Practice for Passive Fire Protection (PFP)
•
Determine areas to be fireproofed and special consideration of extent.
Other resources for determining fireproofing needs are risk management and insurance personnel. Once decision has been made to fireproof, definition of low, medium, high fire potential areas, special considerations of extent of fireproofing as defined later in this GP, and preference for fireproofing installation materials and methods should be passed on to Vendors performing fireproofing design. b.
The following shall be obtained from BP: 1.
Areas of medium fire potential where structures shall be fireproofed in accordance with this GP. Medium fire potential areas should be defined as areas within facilities in which flammable or combustible liquids are likely to pool and have potential ignition source. Size of pool area should be defined based on source volume, potential leak rate and pressure, surface drainage area and capacity of drainage system, fuel burning rate, and heat of combustion.
2.
Areas of high fire potential where additional equipment shall be fireproofed in accordance with this GP. High fire potential areas should be, but are not limited to, areas within 6 m (20 ft) of equipment defined as follows: •
Fired heaters that charge liquid or mixed phase flammable or combustible liquids under the following conditions: - Operation at temperature and flow rates capable of causing coking within tubes. - Operation at pressures and flow rates high enough to cause large spills before heater can be shut in. - Charging of flammable or combustible liquids that are potentially corrosive. - Incorporation of high level of automation and complex peripheral equipment, such as combustion air preheaters.
•
• • 3.
Pumps operating at high enough pressure or flow rate that upon seal failure may accumulate pool or spray adjacent equipment handling flammable or combustible liquids above their flash (at atmospheric conditions) or auto ignition point. Reactors that operate at high pressure or are likely to produce exothermic reactions. Compressors and seal oil systems with potential prolonged release of flammable materials.
Emergency shutdown equipment or control systems that require fireproofing in accordance with this GP. Control systems should be reviewed in BP approved hazards analysis to identify equipment that would need to operate during emergency shutdown to isolate facility. Such equipment and its control wiring should be identified to fireproofing designer.
4.
Definition of process areas and outside battery limits (OSBL). Low fire potential areas are areas where leakage of significant quantities of pooling hydrocarbons from equipment or piping is unlikely or areas where only nonflammable liquids are handled. These areas need not be fireproofed.
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GP 52-20 Guidance on Practice for Passive Fire Protection (PFP)
In refineries and chemical plants, process facilities that have medium fire potential should have structures fireproofed because these facilities cannot usually be evacuated. Facilities handling gaseous materials only may not require fireproofing. In production sector, decision to fireproof is based on location fire fighting philosophy, ability to evacuate personnel, risk to personnel and public, and evaluation of other fire protection options. Most common fire fighting philosophy is to fight only incipient fires. In event of major fire, facility is shut down and abandoned. Under this philosophy, fireproofing is normally only used on emergency shutdown equipment.
6.
Extent of fireproofing
6.1.
General
6.1.1.
Passive fire protection range
6.1.2.
6.1.3.
a.
Passive fire protection (PFP) may be used to protect plant, equipment, and structures against radiant heat or flame impingement from fires.
b.
BP PFP booklet can be used in conjunction with this GP.
c.
In all cases, guidance may be subject to results of site specific fire scenario analysis.
d.
This GP specifically addresses PFP against effects of pool fires. Jet fires or vapour cloud explosion scenarios have special considerations. In such cases, BP group technology fire advisor should be contacted.
Fireproofing of structures
a.
Fireproofing shall extend 10,7 m (35 ft) above base of potential fire.
b.
Fireproofing of pipe supports, if required, shall: 1.
Extend up to and include first pipe support bank.
2.
Include both columns and pipe support beams.
c.
Spandrel beams need not be fireproofed.
d.
In addition to ground level, horizontal surfaces that can accumulate flammable liquids shall be identified and reviewed for consideration as fire base.
Fireproofing of equipment
a.
Equipment containing flammable or combustible liquids located in upper levels of structures shall be identified and reviewed for consideration as fire base.
b.
Structures for air coolers more than 10,7 m (35 ft) above base of potential fire shall be reviewed for potential fireproofing.
c.
Fireproofing for storage vessels shall ensure that through predicted duration of fire: 1.
2. d.
Carbon steel plate sections in vessel vapour space: a)
Of non-pressurised storage vessels do not exceed 593°C (1100°F).
b)
Of pressurised storage vessels do not exceed 400°C (750°F).
Alloy plate sections in vessel vapour space shall have appropriate maximum temperature established.
Fireproofing for structural columns and beams shall ensure that permitted deflections in BS 5950: Part 8 are not exceeded through predicted duration of fire.
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e.
GP 52-20 Guidance on Practice for Passive Fire Protection (PFP)
Hydrocarbon and non hydrocarbon areas 1.
In hydrocarbon areas, fire resistance ratings for jet or engulfment fires or radiative heat shall be determined by internationally approved high intensity hydrocarbon test.
2.
In non hydrocarbon areas, fire resistance rating may be selected from standard time versus temperature test programme.
6.2.
Structures
6.2.1.
General
a.
Structural members supporting equipment and piping in areas identified as medium or high fire potential shall have fireproofing. Generally, all structures supporting equipment in medium and high fire potential areas designated for fireproofing should be fireproofed. Minor piping supports may not require fireproofing as determined in fireproofing review. Structures not supporting piping and equipment or supporting piping or equipment that would not contribute fuel to fire and contain non toxic material need not be fireproofed, even in high or medium fire potential areas. Before deciding not to fireproof, consequences should be considered of these structures falling on adjacent equipment and causing damage that would contribute to fire or compromise fire fighting efforts. Fireproofing for structures supporting equipment is normally installed to 10,7 m (35 ft) above fire source. Fireproofing for pipe racks is normally installed up to and including first pipe support bank including both columns and beams but not spandrels. Issues that should be considered when deciding extent of fireproofing include: • •
b. 6.2.2.
Extending fireproofing to load bearing level of major pieces of equipment (reactors, vessels, exchanges) in multilevel structures regardless of height. Including pipe rack fireproofing to full load bearing height if such structures support air coolers containing hydrocarbons that are located above medium or high fire potential areas. This is due to induction of fire envelope by fan.
If predicted fire duration in hydrocarbon areas is greater than 10 min, structures and equipment outside flame but exposed to high radiation levels may require PFP.
Concrete structures
a.
Unless specified otherwise, reinforced concrete structures should not normally require fireproofing.
b.
Prestressed concrete structures in fire exposed areas should be fireproofed to prevent relaxation.
c.
Reinforced and pre-stressed concrete members shall be designed in accordance with BS 8110: Part 1 or agreed upon equivalent.
6.2.3.
Steel structures
6.2.3.1.
General
a.
6.2.3.2 through 6.2.3.7 are guidance for application of PFP to steel structures but may be subject to results of fire scenario analysis.
b.
In medium or high fire potential areas, the following equipment shall have fireproofing:
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6.2.3.2.
GP 52-20 Guidance on Practice for Passive Fire Protection (PFP)
1.
Outside of supporting skirts and supporting saddles, lugs, or legs of all vessels and exchangers that contain flammable liquids or gases.
2.
Exception to 1. is that saddles less than 300 mm (12 in) high at centre shall not require fireproofing.
3.
Both sides of supporting skirts and on bottom heads of vertical vessels if: a)
There is flanged joint within skirt.
b)
There are 2 or more skirt openings or single opening exceeding 600 mm (24 in) diameter.
c)
Bottom head is insulated. Fireproofing of head may be hard coat finish instead of stainless steel jacket.
Multilevel structures excluding piperacks
If predictable fire loadings can cause collapse, fireproofing should be applied as follows: a.
Structures that support high or medium fire potential equipment (see API 2218).
b.
Vertical and horizontal primary support members from grade to highest level at which equipment is supported (Figure 2).
c.
Elevated floors and platforms that can accumulate significant quantities of liquid hydrocarbons (Figures 3 and 5).
d.
Structures, collapse of which would result in substantial damage to nearby control centres and/or emergency systems or lead to escalation of incident.
e.
Primary horizontal and vertical support members up to and including level that is nearest to 9 m (30 ft) above grade or if fire loading exceeds 44 kW/m2 (13 950 Btu/hr/ft2) (Figure 4).
f.
Knee and diagonal bracing that contributes to support of vertical loads or to horizontal stability of columns (Figures 1 and 6). Knee and diagonal bracing used only for wind, earthquake, surge, or transportation loading need not be fireproofed. It is advisable to remove bracing that is required only for transportation purposes after equipment is installed.
6.2.3.3.
g.
Brackets, lugs, or skirts of structures supporting reactors, towers, or similar vessels (Figure 4).
h.
Insulating effect of fireproofing materials shall be considered in design of support for vessels that operate at high temperatures.
i.
Beams that support equipment, except for upper surface of top flange.
Support for piperacks and high level air coolers
a.
Piperacks 1.
Primary vertical and horizontal support members up to and including first level of piperacks within fire exposed envelope of sufficient intensity and duration should be considered for fireproofing.
2.
If piping larger than DN 150 (NPS 6) contains hydrocarbons, toxic materials, or corrosive products and is at levels above first horizontal beam or if high fire risk potential hydrocarbon pumps are installed beneath pipe racks, consideration shall be given to fireproofing vertical and horizontal members.
3.
Fireproofing in (2.) should be up to level nearest 9 m (30 ft) or 44 kW/m2 (13 950 Btu/hr/ft2) elevation (Figures 2 and 4).
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GP 52-20 Guidance on Practice for Passive Fire Protection (PFP)
4. b.
Wind, earthquake, transportation, and non load bearing beams that run parallel to piping shall not be fireproofed.
Air coolers 1.
Air coolers that handle flammable fluids and are installed on top of pipe racks or that have high or medium fire potential equipment located beneath them shall have vertical and horizontal support members fireproofed up to base of cooler, regardless of elevation above grade (Figure 6).
2.
Consideration shall be given to providing firewall directly below coolers. To decide on provision of firewall, account must be taken of: • • •
Proximity of air cooled heat exchangers to fire hazards. Whether there is sprinkler system. How quickly exchanger fans can be shut down.
If firewall is not required, it is probably unlikely that fire can be sustained at air cooler level. Additional fire protection may not be required. c.
d.
6.2.3.4.
Bracing 1.
Fireproofing shall be considered for knee and diagonal bracings that contribute to support of vertical loads (Figures 1 and 4).
2.
Knee or diagonal bracing used for wind or earthquake loading need not be fireproofed (Figures 1, 2, 3, and 6).
Auxiliary supports 1.
Auxiliary pipe supports for main pipe rack holding pipe larger than DN 150 (NPS 6) or on essential duties (e.g., flare, relief, blowdown, and pump suction from accumulators or towers) shall be fireproofed if within fire exposed envelope.
2.
Consideration should be given to installing fireproofed catch beam or bracket beneath piping larger than DN 150 (NPS 6) that is supported by exposed steel spring hangers or rods. Sufficient clearance should be provided between pipe and additional structure to permit free movement in normal operation (Figures 6 and 7).
Support for low level air coolers
Support for low level air coolers in hydrocarbon service shall be fireproofed. 6.2.3.5.
Support for vertical towers and vessels
a.
Vessel skirts 1.
Exterior surfaces of skirts supporting towers or vertical vessels containing hydrocarbons and located within fire exposed envelope of sufficient duration and intensity shall be fireproofed.
2.
If there are flanges or valves within skirt or if there are manway openings larger than 600 mm (24 in) in diameter, skirt interior surfaces shall be fireproofed.
3.
Skirts of vessels less than 760 mm (30 in) in diameter need not be fireproofed on inside.
4.
Pipe penetrations and other small openings should be plugged if possible.
5.
Manholes in skirts a)
Manholes in skirts shall be left clear.
b)
If necessary, periphery of manhole should have additional reinforcement.
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GP 52-20 Guidance on Practice for Passive Fire Protection (PFP)
6. b.
6.2.3.6.
Vent holes at or near top of vessel skirts shall be kept clear.
Other supports 1.
Brackets or lugs used to attach vertical re-boilers or heat exchangers to towers or tower skirts should be fireproofed.
2.
Earthing lug should be kept clear of fireproofing.
3.
Unless specified otherwise, anchor bolts shall be fireproofed.
4.
Particular attention shall be paid to detailing around bolts anchored in epoxy resin because there is danger of conducted heat affecting anchorage.
5.
Elevated exposed legs supporting towers or vessels shall be fireproofed to their full load bearing height.
Support for horizontal exchangers, receivers, and accumulators
Steel saddles supporting horizontal exchangers, condensers, drums, receivers, and accumulators shall be fireproofed if saddles: a.
Are within significant fire envelope.
b.
Have diameter of at least 760 mm (30 in).
c.
Have vertical distance between concrete pier and shell greater than 460 mm (18 in). Protection of vessel saddles that have provision for sliding on bedplate should include covering bolts in Denso paste or tape or equivalent and keeping elongated holes free of concrete. It is important to check before commissioning and periodically thereafter that appropriate supports are free to slide.
6.2.3.7.
6.3.
Support for fired heaters
a.
Supports for fired heaters in hydrocarbon service shall have fireproofing up to point where steel supports are attached to steel floor plate of firebox.
b.
If structural support is provided to elevated fired heaters by horizontal beams beneath firebox, beams shall have fireproofing, except where one flange face is in continuous contact with firebox.
c.
If common stacks handle flue gas from several heaters, structural members supporting ducts between heaters and stacks shall be fireproofed.
d.
At furnaces, support columns below floor level, major supports for hydrocarbon process piping, and stack supports shall be fireproofed.
e.
Non process piping supports shall be fireproofed if collapse of supports could allow piping to fall on hydrocarbon bearing piping or equipment.
Piping If piping and equipment are already insulated for heat conservation or other purposes, upgrading insulation to provide fireproofing usually only costs the difference between stainless steel and aluminium jacketing. a.
Prefabricated combination insulation and fireproofing with stainless steel jackets shall be used for small valves and similar equipment if materials meet applicable requirements.
b.
Piping shall be fireproofed using mastic materials as defined for structures and supports, subject to BP approval. Piping generally requires no fireproofing and may be expected to withstand considerable exposure to fire without failure because of normally low stress levels,
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GP 52-20 Guidance on Practice for Passive Fire Protection (PFP)
external insulation, and cooling effects of contents. However, certain flanged lines carrying flammable process materials should be considered for fireproofing. c.
d.
Flare, critical duty (e.g., breathing air), and high hazard toxic material (e.g., ammonia, chlorine, hydrofluoric acid, hydrogen sulphide) pipelines and their supports shall be fireproofed if: 1.
Identified at risk during fire risk analysis (FRA).
2.
They cannot be made safe by location.
In areas identified as high fire potential, the following piping shall have fireproofing: 1.
Relief valve inlet and discharge piping, except relief valve discharge piping that vents directly to atmosphere shall not require fireproofing.
2.
Relief blowdown headers.
3.
Flangeless (wafer type) butterfly, check, block, and control valves in hydrocarbon service. Piping in general does not require fireproofing. Fireproofing hydrocarbon piping that is already insulated usually only requires changing aluminium jacket to steel if insulation material complies with requirements for fireproofing in GP 52-10. Fireproofing should be considered for piping in high fire potential areas if rupture could add significant fuel to fire or if piping will already be insulated. Mastics should be considered if corrosion under insulation or weight is of concern and piping needs to be fireproofed. Mastics can be effective for offshore.
6.4.
Equipment, Instrumentation & Control, and Electrical
6.4.1.
Vessels
a.
Vessel type 1.
Only PFP will provide satisfactory protection against jet and engulfment fires that are characteristic of Class 0 petroleum pressurised storage vessels.
2.
If vessel is to be fireproofed, whole vessel shall be fireproofed.
3.
Pipe work and supports leading from vessel up to first emergency shutdown (ESD) valve shall be fireproofed.
4.
Support legs of spherical storage tanks shall be fireproofed to full load bearing height. Although top of vessel is apparently less at risk in fire, in fact, it is often most vulnerable since it is not cooled by evaporation of liquid contents. There are well known examples of vessels failing during fire, even though pressure relief valves were probably limiting pressure to vessel design pressure because high temperature had reduced material strength below design code safety factors (see Feyzin Refinery disaster in France, 1966).
b.
Sizing credits 1.
If fireproofing sizing credits have been taken for relief system design, pressure containing parts of hydrocarbon service vessels and exchangers shall be fireproofed in accordance with GIS 52-201.
2.
Use of sizing credits shall be obtained from BP. Fireproofing of equipment should be considered and individually justified if rupture is possible and would add significant fuel to fire or if fire case controls capacity of relief system. Vessels already insulated can be converted to fireproofing by
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GP 52-20 Guidance on Practice for Passive Fire Protection (PFP)
changing jacket material to steel and using fireproofing acceptable insulation material in accordance with GIS 52-201. If fire case controls relief system sizing, cost of fireproofing may be offset by reduction in cost of relief system. If sizing credits are taken in sizing relief system, protected equipment shall be fireproofed. Use of fireproofing credits is usually decided by process designer. This information must be given to fireproofing designer. c.
d.
6.4.2.
PFP for vessels 1.
PFP of vessels on process plant is not generally required.
2.
PFP shall be applied to selected vessels to reduce discharge rate and size of any closed relief system (see GP 44-80) if: a)
Economical.
b)
Relief cannot ensure integrity of vessel in fire situation.
c)
Fire conditions result in relief capacity requirements in excess of other emergency conditions.
Pressure relief valve 1.
If pressure relief valve on vessel is sized in accordance with b., PFP shall be specifically designed to resist forces of fire hose streams and maintain insulation properties for extended period, as specified by BP.
2.
Period in (1.) depends on fire fighting facilities available and nature of installation but should not be less than 2 hr.
Instrumentation and Control equipment
a.
Subject to BP definition, emergency instrumentation and control equipment shall be designed to operate for 20 min while exposed to 980°C (1 800°F) fire.
b.
In areas of medium and high fire potential, the following instrumentation and control equipment shall have fireproofing: 1.
Control equipment specified by BP as required for safe and emergency shutdown of the plant or facility. I&C items to fire proof may based on risk assessment include; a)
Instruments that monitor process conditions during shutdown such as key levels, pressures, and temperatures
b)
Instruments that provide protection of equipment
c)
Instrument wiring cabinets (such as DCS marshalling cabinets) that are located within the plant or facility and are in a fire exposed envelope
d)
electrical circuits,
e)
instrument air tubing, instrument air junction boxes, and operators of motor operated valves.
Fireproofing of emergency isolation valves identified by BP approved hazards analysis or other methods should include fire safe packing, seat materials, and high temperature wiring. 2.
Radioactive sources, if source holder (as provided by radioactive source Vendor) is not rated to prevent release of radioactive material if assembly is exposed to 980°C (1 800°F) for 2 hr. API 2218, sections 3.1.8 and 3.1.9 give further guidelines for control system fireproofing.
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6.4.3.
GP 52-20 Guidance on Practice for Passive Fire Protection (PFP)
Electrical power and control cables
a.
Power and control cables associated with critical operating equipment or loss prevention devices located within areas where they may be exposed to flame shall be fireproofed.
b.
Primary methods to avoid early cable failure include:
c.
1.
Burying below grade.
2.
Routing around or high above areas of high fire potential.
3.
Providing water spray protection.
If methods in b. are not available and prolonged cable service is desirable within areas exposed to flame, the following options should be considered: 1.
Cables rated for high temperature.
2.
Fire retardant cable trays.
3.
PFP cable trays.
4.
Wraparound foil backed insulating systems.
5.
Direct application of fireproofing material to exposed cable jacketing.
6.
Preformed pipe insulation rated for service at 650°C (1 200°F).
d.
Instrument cables shall be routed outside of high fire potential areas if possible.
e.
ESD circuits shall be mineral wool insulated (MI) cable, subject to BP definition.
f.
Instrument cable trays in high fire potential areas shall be protected as follows: 1.
50 mm (2 in) of 1035°C (1 900°F) rated insulation block.
2.
Commercially available fireproofing systems as approved by BP.
3.
Top of tray shall be left non-insulated if potential fire source is below tray.
g.
Single conduits without MI cable shall be fireproofed in accordance with GIS 52-201.
h.
Protection system selected should keep cable temperature within acceptable limits for period necessary to perform critical control functions. Fireproofing systems for cables can result in cable operating temperatures that are higher than normal. Cable may need to be derated.
6.4.4.
Pneumatic and hydraulic control lines
a.
Pneumatic and hydraulic control lines associated with double actuating, critical operating equipment, or loss prevention devices sited within areas where they may be exposed to flame shall be fireproofed.
b.
Fireproofing methods described for electrical cable in 6.4.3 are applicable to pneumatic and hydraulic control lines.
c.
Hydraulic systems using type 304, 316, and 321 SS tubing may not require fireproofing if all parts of system have pressure relief.
d.
Other types of control tubing are liable to rapid failure, and fireproofing with preformed pipe insulation should be considered.
e.
Assembly should be weather protected with stainless or galvanised steel sheeting held in place with stainless steel bands and screws. Galvanised steel sheet can cause embrittlement of stainless steel, particularly in intimate contact.
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GP 52-20 Guidance on Practice for Passive Fire Protection (PFP)
Aluminium cladding fails quickly in fire and can generate flaming particles that can travel and cause ignition outside fire envelope.
6.4.5.
f.
PFP applied to control systems shall be compatible with operational and maintenance requirements.
g.
Pneumatic signal tubing shall be non-insulated stainless steel.
h.
Instrument air headers and branches shall be steel.
Emergency valves
a.
If continued power is required to operate valves within significant fire exposed envelope that are critical for safe shutdown, depressurisation, or isolating feed of unit, valve and its associated power supply shall have fireproofing.
b.
Power and signal lines and motor or actuator shall have fireproofing.
c.
Valve body and pipe work 3 m (10 ft) either side of valve may also require protection.
d.
Protection shall be designed such that adequate time is allowed for valve to travel from fully open to fully closed position (or vice versa) if exposed to hydrocarbon jet fire.
e.
Valves that fail to safe position need not be fireproofed.
f.
Power and control cables shall be protected as described in 6.4.3.
g.
Motor actuator may be protected by preformed fire resistant material, specially designed removable fire resistant blanket, or assemblies that use mastic materials.
h.
If specifying emergency valves and protective covers, the following items require special consideration: 1.
Thermal limit switches built into electric motors that may cause motor to fail during fire.
2.
Valve handwheel and engaging lever shall not be fireproofed such that valve is inoperable.
3.
Valve position indicator shall not be covered.
4.
Diaphragm housing on diaphragm operated valves should not be fireproofed if valve is designed to fail to safe position. PFP of valves has in recent years been approached largely by complying with standard fire tests (unwisely often referred to as “fire safe” tests) for soft seated ball valves. This general policy has a number of disadvantages: • •
• • •
For many soft seated valves, behaviour during fire is not significant factor compared with other issues. For certain critical duties it is necessary to distinguish between valves that must remain operable for some period during fire and those required to remain closed. Performance of motor, actuator, and cabling during fire is just as important as that of valve itself. Fire tests of large valves (DN 200 [NPS 8] and above) have required unrealistically long fire durations for test completion. Many valves sold as fire tested to published standard, when checked, have not complied with standard.
GP 62-01 provides general guidance for critical duty valves.
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12 December 2005
i.
j. 6.5.
GP 52-20 Guidance on Practice for Passive Fire Protection (PFP)
Removable and reusable fireproof enclosures shall be specified for emergency control equipment that requires maintenance access (e.g., operators of motor operated valves), as identified in piping and instrumentation diagram (P&ID) reviews with BP, as follows: 1.
Enclosures shall be removable and reusable design consisting of 50 mm (2 in) ceramic fibre insulation encased in weatherproof cover of vinyl coated inorganic fabric.
2.
Enclosures shall be secured by stainless steel lacing and shall have demonstrated ability to protect heat sensitive components for 20 min in 980°C (1 800°F) hydrocarbon fire, such as that used during UL 1709 fireproofing test evaluations.
3.
Alternate fireproofing materials, such as products using endothermic or intumescent materials and providing equivalent fire protection, shall be subject to BP approval.
Emergency isolation or ESD valves shall be certified to have fire safe packing and internals.
Outside battery limits (OSBL) of processing facility The following shall have fireproofing:
6.6.
a.
Supporting columns of spheres in hydrocarbon service.
b.
Outside of supporting skirts and supporting saddles, lugs, or legs of vessels that are: 1.
0,4 m3 (15 ft3) capacity or larger.
2.
In high fire potential areas.
3.
In hydrocarbon service.
Fireproofing not required The following items shall not be fireproofed: a.
Stairways, access platforms, and members used exclusively for their support.
b.
Sliding supports on insulated pipes and exchangers.
c.
Structures supporting auxiliary equipment less than 0,4 m3 (15 ft3) capacity that in event of failure would not add fuel to fire or endanger personnel, unless relief system sizing credits were taken due to fireproofing equipment.
d.
OSBL stanchions, pipe supports, piping, non-bunded vessels, and other equipment. Piping and piping supports OSBL need not be fireproofed. Consideration should be given to fireproofing supports of piping in high fire potential areas.
e.
7. 7.1.
Critical plant receiving less than 44 kW/m2 (13 950 Btu/hr/ft2) for 60 min does not generally need fireproofing.
Methods and materials General a.
Material type shall be based on: 1.
Initial cost to project.
2.
Repair cost: Most intumescents and mastics require reapplication after fire. Concrete can sometimes weather short fire without requiring repair.
3.
Maintenance and total life: Lightweight concrete, mastics, and intumescents are softer and are more susceptible to mechanical damage. Many require surface coatings that have to be maintained.
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GP 52-20 Guidance on Practice for Passive Fire Protection (PFP)
ASTM testing methods pertain to building type fires where temperature rise is over long period of time and final temperature is not as hot as typical hydrocarbon fire. ASTM procedures should not be used for acceptance of fireproofing materials for petrochemical industry. b.
Fireproofing material types shall be subject to BP approval.
c.
Materials for fireproofing austenitic stainless steel shall not contain more than 200 ppm chlorides.
d.
Austenitic stainless steel that is to be fireproofed shall receive protective coating prior to applying fireproofing to prevent stress corrosion cracking in accordance with BP Coatings Spec GP 06-60.
e.
Prefabricated panels shall only be permitted for use on offshore structures or other special applications, subject to BP approval.
7.2.
Fireproofing materials
7.2.1.
General
Concrete is the most common material used for fireproofing structures. Concrete provides good: • • •
Protection from fire. Mechanical integrity. Economics.
Materials for fireproofing structures other than dense concrete shall be tested by UL 1709 methods and approved for 2 1/2 hr rating. Dense concrete materials installed in accordance with GIS 52-201 have proven effective materials for fireproofing. Fireproofing materials for structures may be materials that have received UL 1709 certification by UL. Consideration should be given to performance in durability tests before making material selection. Structures may also be fireproofed using dense concrete mixes. Concrete mixes have been time tested and do not require UL 1709 certification. Fireproofing of structures and supports shall be performed with of one of the following: a.
Dense concrete installed in accordance with GIS 52-201 as follows: 1.
Dense concrete shall not be used on surface temperatures that can be above 120°C (250°F) during operation or maintenance.
2.
Dense concrete shall be used to fireproof lower 2,1 m (7 ft) from grade of structural supports. Dense concrete is normally used below 2,1 m (7 ft) and in any area that might be subject to mechanical damage due to its mechanical integrity. Requirement to use dense concrete below 2,1 m (7 ft) can be waived for areas not subject to mechanical damage as verified by facility maintenance personnel. While lightweight fireproofing material is acceptable above 2,1 m (7 ft) elevation, it may be less costly to continue shop applied column fireproofing full height of shop fireproofed members.
3.
Areas that would require dense concrete due to potential mechanical damage above 2,1 m (7 ft) will be provided by BP. Dense concrete is traditional fireproofing material. Concrete in itself does not promote corrosion due to its alkaline nature. However, pH changes to neutral over period of years. On setting, concrete shrinks and small gap can be left against steel Page 17 of 26
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GP 52-20 Guidance on Practice for Passive Fire Protection (PFP)
that will allow water ingress. In areas subject to acid rain, such ingress can accelerate corrosion and it is important to seal gaps. Dense concrete is liable to spall in hydrocarbon fire, resulting in loss of thickness and lower protection. Concrete fireproofing cast in situ can be expensive. Dense concrete made with calcareous (such as limestone) or dolomitic aggregates is superior for fireproofing purposes to that made with siliceous aggregates because the former contains large amounts of carbonates. In poured concrete, use of siliceous fine aggregate with calcareous or dolomitic coarse aggregates will not materially reduce effectiveness of concrete as fireproofing. b.
Commercial lightweight concrete mix as follows: 1.
Lightweight concrete mix shall be approved by UL using UL 1709 methods in accordance with UL Fire Resistance Directory with 2 1/2 hr exposure rating.
2.
Lightweight commercial concrete mixes, intumescents, or subliming mastics may be used in areas above 2,1 m (7 ft) if not subject to mechanical abuse and if weight must be considered. Use of UL 1709 tested materials should be considered if dead weight of dense concrete will significantly add to size and cost of structures. Mechanical integrity of material should be reviewed for suitability. Some intumescents give off gasses during fire that could be dangerous to fire fighting personnel. All factors should be considered in selecting fireproofing material. Installation should be in accordance with Vendor recommendations. Figures associated with GIS 52-201 relate only to dense concrete materials. UL 1709 is rapid temperature rise fire testing standard for fireproofing materials. This test closely resembles temperature rise conditions found in petrochemical industry fires. UL Fire Resistance Directory documents methods and results of materials that have been successfully UL tested. Section BYBU of UL Fire Resistance Directory documents materials that have passed UL 1709 test.
7.2.2.
c.
Epoxy based intumescent coating approved by UL using UL 1709 test methods with 2 1/2 hr exposure rating.
d.
Subliming mastic approved by UL using UL 1709 test methods with 2 1/2 hr exposure rating.
Asbestos
Spray applied or wraparound asbestos shall not be used. 7.2.3.
Magnesium oxychloride plasters
Magnesium oxychloride plasters shall not be used for fireproofing. Field experience indicates that corrosion of substrate steel occurs as topcoat (over fireproofing) weathers and moisture combines with chloride present in plaster to form hydrochloric acid. Fireproofing flakes and falls off due to moisture entrapment and causes corrosion to steel lathing and wire mesh used for anchoring and reinforcement. 7.2.4.
Preformed/inorganic panels
Preformed/inorganic panels have poor weatherability and are suitable for indoor use only. a.
Panel systems shall pass UL 1709 (P) test or equivalent fire tests.
b.
Pre-cast or compressed fire resistant panels should be attached to substrate by mechanical fasteners designed to withstand fire exposure without appreciable loss of strength. Page 18 of 26
12 December 2005
7.2.5.
GP 52-20 Guidance on Practice for Passive Fire Protection (PFP)
Concrete masonry
Concrete masonry 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. a.
Concrete blocks, if used, shall contain lightweight expanded blast furnace slag as coarse aggregate.
b.
Blocks shall have 1 hr minimum hydrocarbon fire resistance rating or equivalent.
c.
Blocks shall be laid with thin, staggered joints of 6 mm (1/4 in) maximum thickness.
d.
Fire resistant mortar shall be used.
e.
Annular space between blocks and steel member shall be filled with lean cement to prevent moisture or hot gases from reaching steel during fire.
f.
Bead of caulking shall be applied at junction of blocks for weather protection. Before installation of masonry, steel substrate shall be prepared in accordance with GP 06-60.
7.2.6.
Intumescent/subliming coatings
a.
Intumescent/subliming coatings may be used in appropriate applications.
b.
Specific attention should be given to possibility of fume or smoke hazard arising from exposure of intumescent coatings to fire. Subliming materials change phase from solid to gas without going through liquid stage. These agents are incorporated into organic matrices of plastic or elastomeric nature. Intumescence is expansion or foam process whereby insulating char is formed at fire surface. Subliming materials provide high adhesion to steel, protect steel from corrosion, resist impact damage and dislodgement by vibration, and have low absorption rate for liquids. It is important to include mesh reinforcement in these systems for two reasons: • •
Thermal expansion characteristics are thereby modified to come nearer that of steel substrate. Mesh holds coating in place during fire when its bond to primer eventually fails.
To achieve satisfactory protection in jet fires, thickness of coating needs to be increased, and mesh should be carbon or glass fibre. One product used is manufactured as 25% water extended premix and sets due to evaporation. This product is prone to slumping during setting period and is highly porous. c.
Mastic fireproofing materials shall be applied by spraying or by trowel.
d.
Surface preparation for application of paint primer shall comply with Vendor recommendations.
e.
For previously painted and/or fireproofed surfaces, mastic Vendor should be consulted to ensure compatibility.
f.
New galvanised surfaces shall be mechanically abraded to ensure adherence of coating.
g.
If existing structural steel is being fireproofed, preparation shall comply with GP 06-60.
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12 December 2005
GP 52-20 Guidance on Practice for Passive Fire Protection (PFP)
Mastic fireproofing materials have density of approximately 960 kg/m3 to 1 290 kg/m3 (60 lb/ft3 to 80 lb/ft3). h.
Intumescent and subliming mastic coatings shall be sealed in accordance with Vendor recommendations for possible extreme weather conditions.
i.
If there is exposure to high levels of ultraviolet radiation from sunlight, premature ageing should be considered. UV protection can be provided by applying thin top coat of aliphatic polyurethane.
j.
7.2.7.
Spray equipment operators responsible for application of fireproof mastic shall be under direct supervision of trained applicator who is qualified in writing by mastic manufacturer or Vendor.
Special applications
a.
Instances exist where structures or vessels are subject to thermal shock conditions. Examples of these are refrigerated vessels and furnace burner supports where burner is integral with furnace. For these applications, composite arrangements of alternate layers of thermal insulation and PFP would be appropriate.
b.
Irregular shapes, such as flanges, valves, pipes, and cable trays, present difficulties in application techniques and create conflict with access requirements for routine maintenance. Proprietary systems, including preformed and/or sculptured sections or designed boxes, are available. Range of products is expanding as awareness of severity of fires and explosions is increasing. If applications requiring proprietary systems or composite arrangements are identified, advice should be sought from Custodian of this GP.
7.3.
Dual purpose protective material a.
If there is need for thermal insulation of process vessels and/or pipe work and also need for fire protection of this equipment, materials shall be rated for 650°C (1200°F) minimum surface temperature and selected from the following types: 1.
Calcium silicate, block or preformed.
2.
Mineral wool block with minimum density of 192 kg/m3 (12 lb/ft3).
3.
Perlite, block or preformed.
4.
Expanded aluminium silicate fibre blanket with minimum density of 96 kg/m3 (6 lb/ft3).
5.
Foam glass with additives.
6.
Ceramic fibre. All fibrous materials are highly absorbent of water. Silicone treatments will give an element of water shedding. Water uptake can still be high. They are only recommended for indoor use except if adequately clad with metal sheeting and with joints sealed.
b.
If insulation is used on steel that will be at or below ambient temperature, precautions need to be taken to prevent corrosion of steel caused by condensation of water vapour trapped by insulation.
c.
For additional guidance on dual purpose application, refer to GP 52-10. Dual purpose materials will not give protection against sustained jet fire unless specifically designed for this duty.
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GP 52-20 Guidance on Practice for Passive Fire Protection (PFP)
7.4.
Piping and equipment
7.4.1.
Piping
Fireproofing material for piping, if required, shall be selected to provide necessary protection outlined in 6.3. 7.4.2.
Equipment
a.
Fireproofing of equipment supports with insulation shall comply with GIS 52-201. Skirts will normally be fireproofed using concrete, but extending insulation over skirt may be acceptable on vessels and is normal method for fireproofing cold vessels.
b.
Insulation to fireproof equipment surfaces shall only be used if concrete fireproofing is not practical, subject to BP approval. Welding studs, pins, clips, or other attachments to refractory lined equipment may cause spalling of refractory. Welding on pumps and compressors should be carefully evaluated for risk of warping and/or cracking casings and arcing across bearings. Welding on refractory lined or glass lined equipment should be limited.
7.5.
Control systems a.
Emergency control equipment as defined by BP shall be designed to operate for 20 min exposed to 980°C (1 800°F) fire.
b.
Fireproofing of instrumentation and control devices shall be performed using materials to provide necessary protection methods as listed in 6.4.2 through 6.4.5.
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12 December 2005
GP 52-20 Guidance on Practice for Passive Fire Protection (PFP)
Figure 1 - PFP of fire potential equipment structural support
Note: 1 Note: 5
Note: 2
Note: 4 Notes: 1. Fire proofing of load bearing supports regardless of height 2. Fire proofing all levels below fire pote ntial equi pme nt 3. No fire proofing on br acing which is non-load bearing
Note: 3
4. Fire proofing of knee or diagonal bracing which is load bearing 5. Fire proofing of vessel skirt, brackets, or lugs Fire Pote ntial Equi pment Non-fire Potential Equi pment
Fire proofed beam
Figure 2 - PFP of fire and nonfire potential equipment structural support
Note: 1
Fire Exposed Area
Note: 2
Note: 3 Notes: Fire Potenti al Equi pment 1. Fire proofing of load bearing supports regardless of height 2. Fire proofing all levels below Non-fire Potential Equi pment fire potential equi pment. Floor on which li qui ds can pool Fire proofed beam 3. No fire proofing on bracing which is non-load bearing
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12 December 2005
GP 52-20 Guidance on Practice for Passive Fire Protection (PFP)
Figure 3 - PFP of nonfire potential equipment structural support
Note: 2
Note: 1
Fire Exposed Area Note: 3 Notes: 1. Fire proofing of load bearing supports regardless of height in fire exposed area 2. No fire proofing on structures outside of fire exposed area 3. No fire proofing on bracing which is non-load bearing
Fire Potenti al Equi pment Non-fire Potential Equi pment Fire proofed beam
Figure 4 - PFP of pipe racks with fire potential pumps
Note: 1
Fire Exposed Area
Note: 2 Notes: 1. Fire proofing of load bearing supports in fire exposed area reg ardless of height 2. Fire proofing of knee bracing that is load bearing
Fire Potenti al Equi pment Non-fire Potential Equi pment
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12 December 2005
GP 52-20 Guidance on Practice for Passive Fire Protection (PFP)
Figure 5 - PFP of pipe racks without fire potential pumps
Note: 2
Note: 1
Fire Exposed Area Notes: 1. Fire proofing of load bearing supports regar dless of height in fire exposed area 2. No fire proofing on structures outside of fire exposed area
Fire Potenti al Equi pment Non-fire Potential Equi pment Fire proofed beam
Figure 6 - PFP of air cooler structural support
Air Cooler which handles fl ammable liqui ds Note: 1
Fire Exposed Area
Note: 3 Notes: 1. Fire proofing of load be aring suppor ts in fire exposed area reg ardless of height 2. Fire proofing of knee bracing that is load bearing 3. No fire proofing on bracing which is non-load bearing
Note: 2
Fire Potenti al Equi pme nt Non-fire Potential Equi pment Fire proofed beam
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12 December 2005
GP 52-20 Guidance on Practice for Passive Fire Protection (PFP)
Figure 7 - PFP of transfer line support
Fire Exposed Area
Notes: 1. Fire proofing of load bearing supports in fire e xposed area reg ardless of height 2. Fire proofing of knee bracing that is load bearing
Fire Pote nti al Equi pment Non-fire Potential Equi pment Fire proofed beam
Page 25 of 26
12 December 2005
GP 52-20 Guidance on Practice for Passive Fire Protection (PFP)
Bibliography BP [1]
GP 62-01 Guidance on Practice for Valves.
Amoco Corporation (A) [2]
PTA NM-F-00-C, Non-Metallic-Fireproofing-Installation Specification.
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