PTS 20160G

PETRONAS TECHNICAL STANDARDS DESIGN AND ENGINEERING PRACTICE

MANUAL

SHELL MARKETING SAFETY CODE - PART 7

PTS 20.160G OCTOBER 1993

PREFACE

PETRONAS Technical Standards (PTS) publications reflect the views, at the time of publication, of PETRONAS OPUs/Divisions. OPUs/Divisions. They are based on the experience acquired during the involvement with the design, construction, operation and maintenance of processing units and facilities. Where appropriate they are based on, or reference is made to, national and international standards and codes of practice. The objective is to set the recommended standard for good technical practice to be applied by PETRONAS' OPUs in oil and gas production facilities, refineries, gas processing plants, chemical plants, marketing facilities or any other such facility, and thereby to achieve maximum technical and economic benefit from standardisation. The information set forth in these publications is provided to users for their consideration and decision to implement. This is of particular importance importance where PTS PTS may not cover every requirement or diversity diversity of condition condition at each locality. The system of PTS is expected to be sufficiently flexible to allow individual operating units to adapt the information set forth in PTS to their own environment and requirements. When Contractors or Manufacturers/Suppliers use PTS they shall be solely responsible for the quality of work work and and the attainment of the the required design and engineering engineering standards. In particular, for those requirements not specifically covered, the Principal will expect them to follow those design and engineering practices which will achieve the same level of integrity as reflected in the PTS. If in doubt, the Contractor or Manufacturer/Supplier shall, without detracting from his own responsibility, consult the Principal or its technical advisor. The right to use PTS rests with three categories of users : 1) 2) 3)

PETRONAS and its affiliates. Othe Otherr part partie ies s who who are are auth author oris ised ed to to use use PTS PTS subj subjec ectt to app appro ropr pria iate te con contr trac actu tual al arrangements. Cont Contra ract ctor ors/ s/su subc bcon ontr trac acto tors rs and and Manuf Manufac actu ture rers rs/S /Sup uppl plie iers rs unde underr a cont contra ract ct with with users referred to under 1) and 2) which requires that tenders for projects, materials supplied or - generally - work performed on behalf of the said users comply with the relevant standards.

Subject to any particular terms and conditions as may be set forth in specific agreements with users, PETRONAS disclaims any liability of whatsoever nature for any damage (including injury or death) suffered by any company or person whomsoever as a result of or in connection with the use, application or implementation implementation of any PTS, PTS, combination of PTS or any part thereof. The benefit of this disclaimer shall inure in all respects to PETRONAS and/or any company affiliated to PETRONAS that may issue PTS or require the use of PTS. Without prejudice to any specific terms in respect of confidentiality under relevant contractual arrangements, PTS shall not, without the prior written consent of PETRONAS, be disclosed by users to any company or person whomsoever and the PTS shall be used exclusively for the purpose they have been provided to the the user. They shall be returned after after use, including any copies which shall only be made by users with the express prior written consent of PETRONAS. The copyright of PTS vests vests in PETRONAS. PETRONAS. Users shall arrange for for PTS to be held in safe safe custody and PETRONAS may at any time require information satisfactory to PETRONAS in order  to ascertain how users implement this requirement.

LIST OF SECTIONS

PART 1 00.00.00

INTRODUCTION

01.00.00

SAFETY MANAGEMENT AND ORGANISATION

PART 2 02.00.00

GENERAL SAFETY PRACTICES

03.00.00

HEALTH AND PROTECTION

PART 3 04.0 04.00. 0.00 00

ELEC ELECTR TRIC ICAL AL HAZA HAZARD RDS, S, HAZA HAZARD RDOU OUS S ARE AREAS AS AND AND STA STATI TIC C ELE ELECT CTRI RICI CITY TY

05.00.00

LAYOUT AND DESIGN FEATURES

PART 4 06.00.00

INSTALLATION AN AND DE DEPOT OP OPERATIONS

PART 5 07.0 07.00. 0.00 00

MAIN MAINTE TENA NANC NCE E AND AND REPA REPAIR IR (INC (INCLU LUDI DING NG TANK TANK CLEA CLEANI NING NG PROC PROCED EDUR URES ES  AND EQUIPMENT)

PART 6 08.00.00

SAFE PRA PRAC CTICE ICE IN IN SP SPECIALISED OP OPERATIONS

09.0 09.00. 0.00 00

SAFE SAFE PRAC PRACTI TICE CE FOR FOR RETA RETAIL IL OUTL OUTLET ETS S AND AND CONS CONSUM UMER ER FACI FACILI LITI TIES ES

PART 7 10.00.00

FIRE PROTECTION AND FIRE FIGHTING

PART 8 11.00.00

LIQUEFIED PETROLEUM GASES

12.00.00

SAFETY AUDITS AND INSPECTIONS

13.00.00

BIBLIOGRAPHY INDEX

CONTENTS OF SECTION

10.00.00

FIRE PROTECTION AND FIRE FIGHTING

10.01.00

GENERAL PRINCIPLES OF FIRE PROTECTION

10.01.01

Fire Prevention

10.01.02

Design Philosophy

10.02.00

FIRE EMERGENCY PLANNING

10.02.01

Emergency Plans, Drill and Training

10.03.00

FIRE FIGHTING SYSTEMS AND EQUIPMENT

10.03.01

Summary

10.03.02

Hand and Mobile Extinguishers

10.03.03

Water Supply, Fire Mains and Hydrant Systems

10.03.04

Fire Hoses and Accessories

10.03.05

Road and Rail Loading Facilities

10.03.06

Wharves and Jetties

10.03.07

Fires involving Electrical Equipment

10.03.08

Protection of Computer Facilities

10.03.09

Fires Involving Chemical Products

10.03.10

Fires Involving Class III Products

10.03.11

Fire Alarms and Emergency Calls

10.03.12

Foam and Water Monitors

10.03.13

Floating Roof Tanks

10.03.14

Distinctive Colouring

10.03.15

Base Injection of Foam for Storage Tanks  Appendix 10.03.01

Recommended Scale of Fire Fighting Equipment

 Appendix 10.03.02

Recommended 'First aid' Fire Extinguishers

 Appendix 10.03.03

Inspection and Testing of Fire Extinguishers

Figure 10.03.04

Chubb Mobile PD 150 Dry Chemical Powder Extinguisher 

Figure 10.03.05

Chubb Mobile Foam Units

Figure 10.03.06

Flow Rates from Fire Hose Nozzles

Figure 10.03.07

Pressure Loss in Fire Hoses

Figure 10.03.08

Hydrant-fed Fire Fighting Equipment

Figure 10.03.09

Typical Foam-generating Fire Fighting Equipment

Figure 10.03.10

Typical Foam Compound Induction

Figure 10.03.11

Typical Mechanical Foam Generators

Figure 10.03.12

Foam Chute with Staggered Openings inside Tank

Figure 10.03.13

Base Injection of Foam (Folded Hose System)

Figure 10.03.14

Chubb 'Jetmaster' Portable Mechanical Foam/Water Monitor 

Figure 10.03.15

Distribution of Foam and Circulation of Tank Contents for  Foam Base Injection Systems

Figure 10.03.16

Fixed Base Injection System - Inductors and Generators near pump discharge - Single Tank near to foam station

Figure 10.03.17

Fixed Base Injection System - Inductors and Generators near pump discharge - Multiple Tanks near to foam station

Figure 10.03.18

Fixed Base Injection System – Generators separated from Inductors - Single Tank

Figure 10.03.19

Fixed Base Injection System – Generators separated from Inductors - Multiple Tanks - separate foam lines to each tank

Figure 10.03.20

Fixed Base Injection System – Generators separated from Inductors - Multiple Tanks - Single Foam line to Generator  Manifold

Figure 10.03.21

Semi-fixed Base Injection System

Figure 10.03.22

Angus Fire Armour High-Back-Pressure Generators

Figure 10.03.23

Chubb Big 10, 20 and 30 Base Injection Foam Generators

Figure 10.03.24

Chubb 'Jetmaster' Mechanical Foam Monitor with Adaptor  for Base Injection

Figure 10.03.25

Angus Variable Foam Inductors

Figure 10.03.26

Tank Inlet for Base Injection of Foam Base

 Appendix 10.03.27

Base Injection - Design and Equipment

Figure 10.03.28

Alternative Tank Inlet arrangements using single inlet and Multiple Foam Outlet points

10.04.00

FIRE FIGHTING AGENTS

10.04.01

Types of Fire

10.04.02

Water 

10.04.03

Foams

10.04.04

Carbon Dioxide

10.04.05

Dry Chemical Powders

10.04.06

Halogen Compounds (Halons)  Appendix 10.04.01

Storage of Protein and Fluoroprotein Fire Fighting Foam Compound

 Appendix 10.04.02

Simple Field Test for Evaluating Protein/Fluoroprotein Foam Compound

10.00.00

FIRE PROTECTION AND FIRE FIGHTING

10.01.00

GENERAL PRINCIPLES OF FIRE PROTECTION

10.01.01

Fire Prevention The protection of personnel, equipment and product by the prevention of fires is the responsibility of the Manager of any plant. Effective fire prevention depends on the design and operation of a plant so as to minimise the risk of a fire starting. This entails ensuring by regular review that facilities and equipment meet appropriate standards of design and operation, and that personnel are taught enough about the properties of flammable products that they understand and use the correct procedures for handling them safely. Notwithstanding the above, the possibility of a fire occurring must be recognised. This necessitates preparing and rehearsing effective emergency fire plans, ensuring that the appropriate scale and type of fire fighting equipment is available and maintained in satisfactory working order, and training all personnel (including office staff) in the correct use of the fire fighting equipment provided. Fire escape routes must be provided and prominently signposted. Wherever possible the co-operation should be sought of any outside support such as the local fire brigade, nearby refinery or airfield brigade, and other  oil companies, both with respect to the type and quantity of equipment to be held and the use of available manpower to be trained for fire fighting duties. Details of fire fighting procedures, types of fire, extinguishing methods and techniques, use and care of fire fighting equipment are given in 'Plant Operating Manual', Volume 1, 07.00.00.

10.01.02

Design Philosophy Installations and depots are designed and operated in such a manner that the risk of fire is remote. Fire fighting equipment is provided on a scale suitable for these proven design and operational standards. As the size of installations and depots as well as the tanks within them grow, so too must the scale of fire fighting effort required to protect them. The scale of equipment described below generally refers to the total capacity that should be available to protect the various facilities. However, every opportunity should be taken to share this load and reduce the individual burden by combining men and material with those of neighbouring installations/depots/refineries and local fire brigades.  A distinction can be drawn between the scale and standards of fire protection appropriate to an installation or depot as defined in 02.01.00. Size is not the only criteria on which to base a decision, since while an installation is usually an important strategic part of a company's product distribution system, the same status may also apply to a depot if it occupies and indispensable position in its location.  An installation fire protection system would normally be based on a water main and hydrant system routed and equipped so as to be able to apply foam and water to all main fire targets such as loading and jetties, buildings, etc. Water supply should preferably be from a harbour, river or similar unlimited source, but if such are not available an installation should have its own stock of water in a reservoir or tank. Furthermore, pumping capacity would also be installed unless the local fire brigade or similar pumps are always readily available, and their participation in the installation fire plan is organised and rehearsed. The incorporation of base foam injection for tank protection would be decided upon in accordance with considerations given in 10.03.15 below. The provision of more sophisticated fire protection equipment such as self-propelled motorised fire engines, continuously pressurised water mains, automatic or remote pump starting and control, automatic foam generating or deluge systems, though not normally appropriate for other  than the largest installations, should nevertheless be considered in the light of the size (physical as well as throughput), complexity and accessibility to effective outside help.

Depots, which cannot be readily by-passed or duplicated because of their strategic position, hazard to and from the surrounding environment, unique product stockholding, or any other factors, should be treated as if they are installations and be provided with a fire main and related facilities (e.g. base foam injection) to an appropriate scale. Depots which are not of strategic importance should be judged according to their hazard to and from the outside environment, the class and volume of products handled, degree of  outside fire fighting support and other local factors. Fire protection based on mobile and hand extinguishers may be appropriate for non-critical depots. Nevertheless, the possibility of installing a branch off a municipal water main for supplying a small number  of hydrants and/or hose reels, should always be considered since a water supply, however small, is always an asset. The requirements of local legislation must always be met. If these are excessive, every effort should be made to persuade the authorites to bring them into line with the recommendations made in this code. Reference can also be made to the UK Institute of  Petroleum Marketing Safety Code and the European Model Code Part II, Design, Layout and Construction. The recommendations in the following sections are considered appropriate preparations for fighting a single major centre of fire at one time.

10.02.00

FIRE EMERGENCY PLANNING

10.02.01

Emergency Plans, Drill and Training Intelligent pre-planning and practice can reduce the amount of confusion and time wasted between the moment a fire starts and the initiation of an effective fire fighting response to it. The development of a fire emergency plan carries with it the need to practise the plan so that everyone knows what to do and so that the inevitable snags can be identified and removed in advance. Training in the use of extinguishers and general fire fighting equipment is an important but distinctive need to give men the confidence and skills necessary to fight or contain a fire. Existence and knowledge of escape routes, particularly in buildings and other congested areas, is an important aspect of personal survival. (i) Immediate Reaction  All personnel need to be trained in the use of those extinguishers which have been selected as suitable for the type of fire that may occur in their workplace, and have been put in readily accessible positions. (ii) Hose attack Generally this will be a team effort in which members have been allocated specific duties to mount a water cooling or foam attack by hose. This stage takes somewhat longer but should be carried out to completion whether or not it appears the fire has been put out by extinguishers. The exercise under live conditions is good practice for  the hose team! When developing this part of the fire plan the following matters must be dealt with:

-

-

-

Team composition including selection of a leader: Teams should be selected in accordance with the manpower available on the site at any time. Consideration must be given to shift patterns, night time activities, weekends and other periods outside normal working hours. Specific duties: Each team member should be allocated specific tasks and be trained in their execution in the correct sequence. After completion of their duties they should gather together with any other spare manpower assembly point and wait for further orders. Logistics: The initial movement and subsequent replenishment of fire fighting equipment, foam compound and any other items required at the fire site must be planned for, including provision of necessary transport and/or manpower.

-

-

-

Direction and control: The most senior man on the site should take charge. Provision should be made for setting up an easily recognisable control point at which he will remain and from which he will direct the fire fighting. The policy and manner of handing over control to more senior staff as they arrive should be agreed including how and whether to pass control to outside authorities, the fire brigade, etc. It is useful if the man in control can be clearly identified by distinctive clothing e.g. yellow jacket or helmet. Evacuation procedures: It may not always be necessary or advisable for all bulk vehicles or personnel to leave the site. It is more important to get them away from the fire without obstructing incoming fire appliances. In this respect the local traffic police should be brought in on any procedures to be established. Evacuation of personnel from offices, warehouses and other work sites must also be organised which necessitates planned and prominently signposted escape routes. Relief and refreshment: Fire fighters require food, drink and rest and their  provision must be planned for in advance. Liaison and outside contact: All aspects of the plan must be agreed in advance with the local fire brigade, police must be agreed in advance with the local fire brigade, police and similar emergency bodies. Contact during the fire may well be needed with hospital and ambulance services, neighbouring oil industry sites, suppliers of fire fighting equipment and foam, press and TV, as well as members of the public. It can save a lot of stress on the leader of the fire fighting effort, if a specific contact point and person are established for such purposes.

(b) Training (i)

Basic use of equipment: All members of the fire fighting team must be trained in the use of all items of fire fighting equipment in addition to being rehearsed in their allocated duties under the fire plan. This will provide a totally flexible force of men who can swap duties as necessary during an emergency. Activities that should be covered by such basic training include starting up and operating the fire pump; operating fire main and sprinkler  valves and being thoroughly familiar with their location; running out and connecting fire hoses; fitting and handling nozzles, foam-making branch pipes, foam monitors, and the system for foam compound induction; base injection systems; and methods of directing cooling water or foam onto the correct target. It is suggested that foam compound should be treated as a consumable stock and up to 20% of stocks should be used in practices in any one year.

(ii)

Rehearsal of fire plan: Fire plans must be rehearsed in order to train and test the fire fighters and to test the equipment. Both these aspects are important for a successful fire fighting capability - men may well be trained but they must be provided with up-to-date equipment, in good repair, and foam compound which has not deteriorated. Rehearsals should be fully planned in the early stages of training until the teams become familiar with what is expected of them. The next stage could be to hold planned rehearsals or exercises but without warning of the locations in the plant where they are to be held. The final stage would be to hold unexpected exercises without any previous warning of time or location.

Two important principles should govern fire plan exercises for rehearsals. These are: •

All exercises or rehearsals must be led by line management - i.e. the persons who should take charge in a real emergency directing the supervisors who will actually run the on-the-ground fire fighting. Safety personnel can run basic training sessions and assist in the development of fire plans, but they are not necessarily the correct people to take charge of the total fire fighting effort and therefore should not lead training exercises.

•

The fire plan and the subsequent exercises must take place in all the different locations in the plan where a fire could occur, and at different times -e.g. outside normal working hours and at night, for instance during tanker discharge operations.

(iii)

Joint exercises: Joint exercises should be held with the local fire brigade or  neighbouring installations in order to ensure a smooth combination of effort and to make sure that equipment is compatible. These aspects should not be underestimated. Outside help is nearly always required in an emergency and pre-planning and practice are the only way to eliminate some of the problems that are bound to arise.

(iv)

Post-mortem: Soon after any exercise or rehearsal no matter how big or  small, a meeting of all responsible parties should be held to discuss every aspect so as to: •

Take note of all mistakes, failures and unforeseen problems.

•

Identify areas where more training is required.

•

Develop and agree modifications to the plan.

The findings of the post-mortem should be communicated to all fire fighters and other persons concerned, and the modified plan should be practised and any written copies revised without delay.

10.03.00

FIRE FIGHTING SYSTEMS AND EQUIPMENT

10.03.01

Summary The purpose of an installation or depot fire fighting system is to provide two stages of fire fighting capability. Firstly, there must be an immediate action response based on own resources, using hand or mobile extinguishers by the people working at or those first to arrive at the scene of  the fire. Secondly, there must be a back-up either from one's own resources or by or in conjunction with outside assistance to undertake the larger scale and more prolonged fire fighting effort to extinguish or contain the fire, in the event that the immediate action is unsuccessful. The scale and type of protection provided depends not simply on whether the plant is an installation or a depot, but rather on the number, scale and type of the various activities that comprise the total operation, any of which may present unique problems, and all of  which must be appropriately protected. By virtue of its size and importance in the distribution network, an installation would normally be expected either to have its own fixed facilities comprising water supply, pumping capacity, and fire main and hydrants system, or to have sufficient facilities (e.g. a dry main and hydrants system with access to water) for a nearby local fire brigade to use with its own manpower and equipment.

By definition, depots (distribution and airfield) present smaller, less potent targets and therefore a reduced scale of fire protection may be adequate. On the other hand, depots are often located in remote areas where outside help may be non-existent or of  unreliable quality. If such a depot cannot be by-passed or duplicated, for instance if it occupies an indispensable position in its area, then the results of a loss or lengthy period out of service have to be judged against both commercial and political repercussions. An additional factor to be taken into consideration is whether a fire (for example a tank fire) could pose a serious threat to adjacent property, particularly domestic. If such special factors indicate that a particular risk exists or in order to comply with local requirements, depots may in certain instances have to be treated as small installations, and their fire fighting system must be designed and built accordingly.

10.03.02

Hand and Mobile Extinguishers  At every workplace in installations or depots where a fire could possibly start, a supply of  portable and/or mobile extinguishers should be readily accessible to enable the nearest person to mount an immediate first attack on an incipient fire. The value of being able to put out a fire in its early stages should not be underestimated. Efforts to ensure such units are plentiful, easily seen, kept in good condition, appropriate for the type of fire that might occur, and that people working in that vicinity are properly trained in their use, will be repaid many times over if just one fire is caught before serious injury or damage can occur.  A scale of one 90/150-litre foam trolley or one 70kg dry powder extinguisher unit at each main potential hazard such as pump manifold, double bay vehicle loading gantry, drum filling shed, etc., would normally be sufficient. Where a unit with rather longer fire fighting capability is thought necessary, a trolley unit carrying concentrated foam compound to which water is supplied by hose may be appropriate as these give up to 15 minutes foam application. For special hazards such as at vehicle loading bays, a 90-litre aqueous-film-forming foam (AFFF) mobile unit is an effective means of covering and sealing a spill caused by overfilling, or rapidly extinguishing any fire that may result.  A supply of smaller hand extinguishers should be provided as supplementary to the larger units as well as for all other locations where minor fires can be expected. The distribution and location of these units should be such that every potential fire target has not less than two units readily accessible. Th is is particularly important where little or  no back-up fire fighting support is available. See Figures 10.03.04 and 05 for examples of the many typical mobile units available. Extinguishers should be positioned in the most conspicuous and accessible position (e.g. near entrances and exits, on staircase landings, etc.,) with painted background if  necessary to attract attention. They should be mounted on brackets at convenient height, and not be left standing on the ground where they are subject to damage, splashing or  rain and dirt, and are less obvious. An empty bracket is a convenient signal that a unit is missing. When mounted outside, extinguishers should be kept in or under weather  protection in order to reduce deterioration. Two important factors influencing the selection of extinguishers are: (i)

The type and size of fire for which they are likely to be used. There are hand or  mobile extinguishers which can apply to any of the known fire fighting agents. Section 10.04.00 gives information on the characteristics of different agents to assist in selection of the best choice of extinguisher.  Appendices 10.03.01 and 10.03.02 give data on different types of extinguishers and on the recommended scale to be held at different locations.

(ii)

Requirement and availability of service and repair facilities. All extinguishers deteriorate with time and under the influence of atmospheric conditions. It is essential that they be regularly inspected and maintained. This can either be done by PETRONAS mechanics or else contracted out to local agents or  suppliers, provided they are competent, hold a good stock of spare parts and refills, and that their work is spot checked by company staff on a random basis

so as to keep them up to standard. Makes of extinguisher with poor back-up supply of spares and refills should not be used and should be replaced by better  serviced makes. In addition to the programme of formal inspections it should be part of the regular duty of supervisors and/or operators visually to check extinguishers at least monthly to make sure they are in their proper position, have not been discharged or lost pressure, suffered visible damage or deterioration, and are being regularly inspected. For this purpose the dates of inspection and refilling should be indelibly recorded on the extinguisher or on a firmly attached label. For  details of inspection and testing of extinguishers see Appendix 10.03.03.

10.03.03

Water Supply, Fire Mains and Hydrant Systems The backbone of most fire protection systems is a properly designed water main, hydrant and pumping system. The recommended level of fire fighting equipment is based on the assumption that only one major fire may have to be fought at a time. The first step therefore must be to assess what might be the worst incident. Normally this has been regarded as the largest diameter tank containing Class I or II products in an installation or depot, but this decision should be taken only after assessing all other major fire possibilities, such as tank bunds, vehicle or rail loading gantries, jetties, warehouses, etc., as well as the simultaneous cooling requirements. It should be realised that the biggest tank fire might not be related to the highest cooling demand for surrounding tanks. Depending on tank farm layout a somewhat smaller tank fire might be in a situation requiring the highest cooling water for  surrounding tanks, such that the combination of the two was the maximum and so to be used for the overall design basis.  Any system must be designed to be adequate in three related aspects if it is to be effective: (i)

Adequate supply of water (m³, gallons) in the right places to provide foam making and/or cooling capacity for the necessary period of time.

(ii)

Sufficient water flow rate (m³/hour, gallons/minute) to overcome the burning of a fire by foam application and/or provide adequate cooling of exposed facilities to overcome effect of heat from an adjacent fire.

(iii)

Sufficient water pressure (bar, lb/sq inch) at all hydrant outlets to operate foam making equipment and to reach high or distant fire targets.

Deficiency in any one of the above may well result in failure to extinguish or contain a fire. The highest combination of foam making and cooling water must be used for the design basis. (a) Water supply  A supply of either fresh or salt water is required at a minimum main pressure at distant hydrants of 10 bar. (Higher pressures may be required for base injection systems, refer 10.03.15.)  Except where water supply is unlimited, e.g. from sea, harbour, rivers or other open sources, provision of a reservoir, tank or other water  storage must be considered. This will necessitate carefully estimating what water  stocks are necessary and practicable to hold. Methods for estimating the quantity needed for foam making are given under  (c). For  cooling purposes it is suggested a supply to permit at least 2 hours cooling be held, but every practicable means of supplementing this should be sought; too much water  will never be an embarrassment during a real fire! Note: During tank maintenance a back-up water supply must be arranged.

The water volume depends upon the scope of the facilities to be protected and must be adequate for the highest combination of both the foam making requirements and the cooling of adjacent tanks or other structures. Water is also used for fires not involving petroleum products (i.e. offices, dry vegetation, etc.), however, quantities provided for fighting oil fires will normally be more than adequate for these other  purposes. Provision for future expansion should be made where applicable. The routing and extent of the fire main system plus the number and location of  hydrants must be carefully chosen so as to provide water for foam making and cooling of adjacent tanks or facilities at all significant potential fire targets. Water hydrants, each with two outlets, should be sited strategically throughout the installation, at distances of between 30 to 50m from the items to be protected allowing for the possibility that access to any fire may be restricted by prevailing winds and/or the fire situation itself being limited to only one predictable avenue of  attack. The aim should be to restrict hose strings to two or three standard lengths in order to minimise pressure losses and the time taken to connect hoses. Block valves should be incorporated in the ring main where it may be considered useful to be able to isolate sections of the main, s hould it become damaged. (b) Water flow rate - cooling (Appendix 10.03.01) Cooling is required for fixed roof tanks holding Class I, II (2) or III (2) products and, in addition, for tanks holding Class II (1) and III (1) products where these might become endangered by adjacent fires. Class I, II (2) and III (2) tanks should be fitted with water sprinklers to provide immediate all-over cooling, whereas Class II (1) and III (1) tanks can be cooled using water hoses or monitors from the ground on the exposed sides only. The design of a tank farm cooling system requires careful consideration of the several variables such as different combinations of tanks to be cooled, variation in size and type of fire, products involved, wind conditions, presence of possible fire in the bund, and changes that take place during a fire. No single water application rate will cater exactly for all fires but proper design and operation can approach the ideal.  A final point is that the total water supply has to be shared simultaneously with the demands of the foam making system used for fire fighting, see  Appendix 10.03.27 Base Injection Design and Equipment.  A fixed cooling water system with an application rate of 1 litre/min/m² of exposed surface (shell plus roof for tanks) is recommended as providing a heat barrier and cooling effect that can normally be turned on almost immediately thus leaving personnel free to carry out other fire fighting duties. (For LPG requirements see 11.00.00.). Depending on the development of a fire it may become a tactical requirement to supplement this basic level for a particularly exposed surface by reducing application to a less exposed surface during an actual fire. Such application would not necessarily require the total design cooling water rate to exceed 1 litre/min/m² . It would be applied by utilising hoses and/or monitors wherever the amount of sprinkler water is inadequate, for example, on any part of a tank shell. This would be evident if all cooling water on exposed shell or roof turns into steam, some parts of the shell are not receiving water, the shell metal is discolouring from the effect of heat, vapour and/or flames are seen issuing from roof pressure/vacuum valves, or total water flow and pressure are judged to be inadequate. It takes careful design and operation to produce a tank farm sprinkler system that gives close to 1 litre/min/m² on all possible combinations of tanks. One solution for  setting and controlling sprinkler flow rates is to fit pressure gauges downstream of  each sprinkler line control valve. The pressure gauge sight glass can be marked with the pressure reading known by previous trials to give the desired water flow rate to that particular tank. As flow and pressure conditions vary during a fire, the sprinkler  line control valves can be adjusted so as to maintain as closely as possible the various design flow rates. Such valves should of course be fitted outside bunds in

positions least likely to be engulfed by fire. Recommendations for water sprinklers are given in the PETRONAS 'Standard Tanks' manual.  A cooling water system designed for storage tank protection will normally have more than sufficient capacity for handling cooling requirements for any other installation or  depot facilities, for which hoses, nozzles and monitors would be used. LPG facilities are likely exceptions to this - refer 11.00.00. (c) Water flow rate - foam making (Appendix 10.03.01) For foam making, the rate of application is related to the time taken to cover the entire burning surface with a blanket of foam. Because a proportion of the foam which reaches the burning surface is continually being destroyed or consumed by the fire, there is a minimum application rate which must be achieved to extinguish the fire at all. The rate depends upon the surface area and depth of the fire, the class of  product which is burning, and the method of application of the foam. Using foam branch pipes or monitors*, the minimum foam compound solution (i.e. foam compound plus water but not yet aerated) flow rate that should be provided to produce foam to extinguish a fire are:

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Class I products - shallow surface fire (e.g. spills): 4.9 litres/min/m² of product surface applied for 30 minutes.

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Class I products - deep product fire (e.g. storage tanks, bunds, etc.): 7.4 litres/min/m² of product surface, applied for 30 minutes.

-

Class II and II products - all types: 4.9 litres/min/m² of products surface, applied for 30 minutes.

* For base injection application rates see Appendix 10.03.27. The above assume that all the foam reaches the burning surface, which is very difficult to achieve in practice, particularly in storage tanks, due to the effects of  winds, fire up-draughts or obstructions. For this reason the application rates and foam concentrate stocks needed to maintain them should be regarded as an absolute minimum and may be increased where outside assistance is not available. The necessary stock of foam concentrates and water required can be calculated from the mix percentage specified which varies from 1-6% foam concentrate depending upon the type used. For example: Tank:

20 m diameter 

Product:

Gasoline

Product Surface Area:

314 m²

Flow rate:

Foam solution – 7.4 litres/min/m² = 2324 litres/min

Volume of foam solution in 30 min:

69720 litres

Volume of 3% foam concentrate:

3% x 69720 = 2090 litres

Flow rate of water:

97% x 2324 litres/min = 2250 litres/min (135m³/hour)

The same basic foam solution flow rates are needed when foam is applied for tank fires by base injection. In this case virtually all the foam reaches the burning surface - which illustrates the main advantage of the base injection system (see 10.03.15 f or  details). The amount of foam making equipment and foam concentrates to be held depends upon the scope and degree of assistance available from the local fire brigade and/or  other oil companies. Unless legislation requirements exceed this amount, the guidelines outlined should be followed when determining minimum requirements.

(d) Water pressure Pressure is needed to throw water or foam high enough to reach the tops of tanks or  far enough to reach targets too hot or inaccessible to approach. Foam making equipment (inductors, generators and mobile units) require minimum water pressures (specified by manufacturers) to operate effectively. Whether the water is taken direct from a city supply main or from own pump output, the design calculations must allow for pressure losses in all branches of the fire main, hydrants, hoses, etc., which are downstream of the outlet for the fire pumps. Figures 10.03.06 to 10.03.11, inclusive, give data on pressure losses as well as the flow and pressure requirements of  various units of fire fighting equipment. As a guide the aim should be for a mains pressure of 10 bar at the hydrant furthest from the pump discharge. This would give adequate pressure to operate normal fire fighting equipment. However, as it would create rather higher pressures at the hydrant outlets nearer to the pump discharge, care must be taken with the use and handling of hoses under such high pressures.  Alternatively, the pump discharge pressure can be reduced if only hydrants close to the pump are in use. Pressure gauges installed at suitable hydrants will facilitate this and avoid lowering pressures below that required. Pumpsets for fire service should preferably be separated from each other and driven by independent suctions. Use of electrically-driven fire pumps which are quick starting, easy to operate and can be provided with remote starting may be considered, but in such cases the wiring and switch gear should be independent of all other electrical circuits so that the fire pumps remain unaffected in any emergency necessitating the isolation of normal circuits. Detailed and clearly printed instructions for starting and operating each fire pump should be displayed at the pump site.  As many of the installation staff as may be required for an emergency should receive training in the use of equipment. The site chosen for fire pumps should be strategic (NB prevailing wind) and safe from vandalism, sabotage and any foreseeable source of fire (e.g. drainage outlets). Particular care must be taken to provide pump suction intakes of adequate size for the design maximum flow rate, positioned so as to be always below lowest water/tide level and protected from damage or clogging with vegetation or other matter by a screen and, ideally a means to back-flush particularly in rivers or harbours. Where a fire pump is also used for the supply of water for tank testing and other installation purposes, this must not prejudice its use for fire fighting.

10.03.04

Fire Hoses and Accessories Fire hoses and accessories such as stand pipes, branch pipes, water and foam monitors, water inductors, generators, nozzles and couplings should be provided as necessary, see Figures 10.03.08 to 11 inclusive. Fire equipment boxes (hydrant boxes) should be distributed round the installation and should each contain sufficient equipment to enable an immediate initial hose attack to be mounted from the hydrants nearest to potential fire sites. Hose couplings should conform to local national standards. If such standards do not exist it is recommended use be made of the 2½ inch instantaneous couplings described in MESC 96.22.10 and Figure 10.03.08. In any case, equipment should be compatible with that used by local fire brigades and other oil companies, otherwise enough adaptors must be provided to enable inter-connection between their equipment and PETRONAS facilities.

10.03.05

Road and Rail Loading Facilities For loading bays handling Class I, II (2) or III (2) products, in addition to hand and mobile extinguishers, the fire main and hydrants system should run close enough to permit application of water and/or foam from at least two directions. This is to facilitate access in the event of obstruction by abandoned vehicles/rail cars as well as difficulties caused by wind direction. Since small spills are not infrequent in or around loading bays the ability to cover the product with a blanket of foam should be provided. Fixed foam or water deluge systems (manual or automatic) are not generally recommended for oil product loading bays at marketing plants. The risk and consequence of overfill fires at loading bays designed in accordance with the PETRONAS 'Loading and Discharging -Road' manual are considered to be small enough not to warrant fixed systems. Furthermore, fixed deluge systems may hinder escape or  rescue of personnel; are limited to immediate loading area; are unnecessary if there is manpower available to use the more flexible traditional fire fighting equipment; require careful and perhaps complex design and operation with respect to coverage above and beneath vehicles, total loading area coverage versus the bay(s) actually involved, means of initiating and reliability particularly if automatic. Where gantry is sub-standard, improved design will most likely be more cost-effective in the long term. For a small number of loading bays or filling points handling only Class II (1) or III (1) products, mobile wheeled units may give sufficient protection (see 10.03.02).

10.03.06

Wharves and Jetties (See International Safety Guide for Oil Tankers and Terminals ISGOTT) The type and quantity of fire fighting equipment should be based on an assessment of  the total risk situation and be related to the size and location of the berth; the layout of  the installation, 'the types and throughputs of product handled', and the hazard to and from adjacent or jointly operated facilities. The aim is to provide adequate protection for  the jetty in the event of a shore or tanker fire, in particular the loading and unloading arms and hoses, and related pipework. Such a system should also be capable of  providing assistance to a berthed tanker particularly in the area of its manifold. Fire on a berthed tanker can usually be fought more easily if the tanker is kept alongside the wharf  or jetty, and at larger ports the harbour authorities should preferably provide sufficient floating fire fighting equipment to tackle a ship fire and/or supplement shore fire fighting efforts. For this, easily accessible hose connections should be provided to enable tugs' fire pumps to charge the installation fire main if necessary.  At installations which have jetty/wharf berths handling Class I and II cargoes and accommodating ships of 18 000 tonnes and over, or receiving more than 60 ships/year  with a throughput exceeding a half million tonnes per year, fire fighting facilities should be provided as follows: (a) Fire mains  A fire water main to each wharf or jetty head, together with hoses and equipment. Water mains should terminate in double hydrants. There should be one double hydrant for each 60m length of the largest ship which the jetty can accommodate. Hydrants and fire equipment must be sited to permit the main concentration of fire fighting to be aimed at the shore/ship manifold area, but at the same time providing some cover throughout the length of the berth.  Accessibility and protection from exposure to fire must also be considered.

Based on the maximum size of tanker acceptable at the berth, the water main should be capable of supplying 50m³/hour for each 30m length of ship at a minimum pressure of 10 bars under full flow conditions at the most unfavourably sited hydrants, up to a maximum total flow rate of 250m³/hour.. This will permit the use of  mechanical foam generators (see Figure 10.03.11) or high-pressure spray nozzles, see MESC 96.28.20. Fire towers are not recommended for marketing installations. Where fire towers have been erected, one or more branch lines should be installed to supply water to fixed monitors, installed on top of the tower. The monitors should preferably be dual controlled (local and remote) and should be able to throw jets of water for a distance equal to the beam of the largest tanker likely to use the berth, and should be capable of delivering water, fog or spray as required. The direction of any prevailing wind should be borne in mind when siting towers. The total quantity of water required should be increased accordingly. Water jets are intended for dealing with fires on ship's superstructures until close range fire fighting can be carried out. Fog or spray jets are particularly useful for  cooling purposes and to provide a protective curtain of water to assist personnel in gaining access to the ship. Water supplies may be from the harbour or other open source, or from an extension to the installation fire water main. Where jetties or berths are remote from installations it may be necessary to install separate pumps or connections for the local fire brigade (shore or harbour) to connect their pumps. Where the jetty or berth is either shared or operated by third parties (other oil companies, harbour authorities) specific arrangements must be made to ensure a viable fire protection system, properly maintained and manned when required. (b) Stocks of foam compound Foam compounds should be readily available either in bulk or on a mobile trailer for  quick delivery to the fire site. The quantity should be 0.5m³/30m length of ship. For  berths where chemical products are handled, consideration should be given to the different types of fire fighting equipment that may be required as well as various types of foam compound. (c) International shore fire connection The purpose of the International Shore Fire connection is to connect the fire water  supply from shore to ship's fire main or to interconnect the fire mains of two ships. Reference should be made to Appendix E of the International Safety Guide for Oil Tankers and Terminals. (d) Portable fire fighting equipment In addition to the above, sufficient hand and mobile fire extinguishers should be provided at all berths or jetties to enable an immediate attack to be mounted on any small fire that may occur on or near the berth, see Appendix 10.03.01. (e) Fire fighting equipment for small wharves or those handling a few small vessels and/or barges, or those handling only Class III products.  At small wharves handling ships of less than 18 000 tonnes and at a frequency of  less than 60 ships/year, or wharves handling only Class III products, at least two 275kg or four 150kg dry chemical or equivalent foam units should be provided unless equivalent or better protection is already available on the wharf. For bulk barge traffic only, carrying Class I, II or III products, the number and size of  mobile units may be reduced to a minimum of two 70kg dry chemical (or equipvalent foam) units provided such movements are infrequent and the risk of a fire spreading to neighbouring faciliftes is insignificant.

(f) Escape routes Some types of berths and jetties can be particularly difficult to escape from in the event of fire or other emergency and careful thought must go into providing more than one means of escape. A selection of the following should be considered:

-

access ways to and from and between off-shore berths/ dolphins; personnel must not be left unattended on isolated dolphins

-

small boat with both motor and paddles in case oil spillage makes use of motor  unsafe.

-

fire protection blankets to enable men to escape to shore perhaps by running through flames

-

life belts in prominent and accessible positions

-

steel steps or ladders between berth deck and water level

Clear notice detailing actions to be taken in an emergency as well as indicating escape routes should be prominently displayed.

10.03.07

Fires Involving Electrical Equipment Because of the risk of electrocution, water or foam are not safe to use on electrical equipment. Halon or carbon dioxide extinguishers are preferred. Dry powder is also effective but should be used only when halon or carbon dioxide units are not available since dry powder tends to corrode electrical switch gear, instruments, etc. For the protection of computer facilities see 10.03.08 below.

10.03.08

Protection of Computer Facilities While an ideal fire extinguishing agent for computer installations does not exist, Halon 1301 (BTM) and 1211 (BCF) are the most commonly used and possess the fewest disadvantages with respect to toxicity and damage to delicate electronic equipment. The importance of not using carbon dioxide or dry powder is that carbon dioxide can be more toxic in enclosed spaces and both are more likely to cause corrosion and cleaning problems particularly to delicate electronic equipment.  Although Halon 1301 is less toxic, Halon 1211 (having a higher boiling point than Halon 1301) leaves the extinguisher nozzle as a liquid so that it is thereby easier to aim at a fire. It is therefore most appropriate for hand-held application to protect individual computer units, since not only can the operator aim the jet more accurately but he can also stand at a safer distance from the fire and the resulting vapour. For atmospheric flooding of larger computer installations, Halon 1301 (which vaporises immediately) is more suitable, and can safely be operated while personnel are evacuating the premises. When considering the hazard to personnel one should not lose sight of the fact that the construction materials of the facilities generally produce far more hazardous vapours of  combustion than the halon extinguishing agents and that prompt evacuation followed by thorough ventilation after the fire are important aspects of the fire emergency plan for  any computer installation. Smoke detectors and/or automatic alarm and extinguishing systems can be used but the design and operation of automatically released systems into occupied areas must be subject to certain conditions designed to protect personnel. (Refer BS 5306 Code of  Practice for Fire Extinguishing Installations and Equipment in Buildings).

10.03.09

Fires Involving Chemical Products  At installations and depots where chemical products are stored, recommendations on fire fighting are as follows: (a) Hydrocarbon solvents Fires involving solvents such as SBPs, benzene, toluene, xylene, white spirit, etc., can be extinguished using dry powder or fluoroprotein foams. The latter can be applied in the same manner and at the same application rates as for fires involving petroleum  products (see 10.03.03c)  including by base injection methods (see 10.03.15 below). (b) Chemical solvents Fires involving chemical solvents such as ketones, alcohols, IPA, etc., can be extinguished by the use of:

-

Special 'all purpose' or 'alcohol-resistant' type foams, or, Fluoroprotein foams applied at three times the application rate needed for  fighting oil product fires (i.e. 22 litres/min/m² unless flashpoint above 21°C in which case 15 litres/min/m²).

For fires involving blends of gasoline with not more than 20% alcohol (ethanol or  methanol) fluoroprotein foam can be used at an application rate of 7.4 litres/min/m²; note that application must be smooth and gentle. Spillages of alcohols can be rendered less flammable by flooding with water, e.g. alcohol mixed with more than 20% water becomes equivalent to a Class II product; with more than 92% is equivalent to a Class III product. Care must nevertheless be taken with run-off since very small percentages of alcohol in water are toxic to human/animal/plant life and normal oil/water interceptors will not separate solutions of alcohol in water. It is generally recommended that where the quantities of chemical solvents stored are small relative to oil products, fire fighting should be based on fluoroprotein foam rather than the special all purpose/alcohol resistant types. This avoids the complications of holding two types of foam compound and of organising fire fighting procedures to ensure the correct foam is used in the event of a fire. In addition, although chemical solvent tanks require three times the application rate, in most cases this will amount to a smaller flow than that provided for the larger oil product tanks. Where all purpose/alcohol resistant type foams are nevertheless considered necessary, they are obtainable from most foam suppliers, and can be applied using standard foam-making equipment. As these foam compounds tend to be slightly acidic, all equipment must be thoroughly washed after use and any bulk compound containers must be specially lined. Gentle application of all purpose/alcohol resistant foams to the burning surface of  alcohols is essential to obtain control and extinction of a fire. This is because, to prevent foam breakdown, when the initial foam contacts the surface of the product, a polymer film is formed on the surface. This film acts as a physical barrier to prevent the breakdown of any further foam applied to the product surface and thus allows the foam layer to build up until extinction is achieved. If the foam is applied forcefully, the polymer film disintegrates and a foam layer cannot build up. The recommended technique is to direct the foam against any vertical or sloping surface and so allow it to run down onto the fire, or to bounce it off an adjacent flat surface. For tank fires, over the top application by monitor or branch pipe is unlikely to give the required gentle application, nor will the use of standard fixed top pourers unless the level of product happened to be high enough that the foam does not have far to fall. A device to overcome this weakness of fixed top pourers is illustrated in Figure 10.03.12.  Fixed to the inside of the tank shell and extending from the point where the foam enters the tank at the top of the shell to the tank bottom, a vertical conduit or chute contains staggered openings provided at intervals. The delivered

foam piles up inside the chute and emerges through the first opening immediately above the product surface. Discharge of foam through the higher openings is prevented by baffles and by ensuring the openings are large enough to accommodate full foam flow. The maximum drop of foam is regulated by the vertical spacing of the overflow outlets which should be at maximum of 1.5m apart.  Application by base injection is obviously not possible because of the intimate mixing of the foam with product as it rises through the product. An alternative may be a system of base injection which employs a flexible hose fitted in the foam inlet line outside the tank. As foam is pumped into the tank the hose unfolds, floats to the surface of the product and discharges the foam at the product surface thus keeping foam and product separated from each other until the foam reaches the surface, see Figure 10.03.13. PETRONAS experience with this device is limited particularly with respect to its use in water miscible products. (c) Other chemical products If fire protection has to be provided for chemical products outside the above two categories, advice may be found in the Handling and Safety manuals, the Depot manual and the Safety Guide for Pesticides. (d) General Many agricultural products and some industrial and plastic products produce toxic vapours in a fire. Fire fighting personnel may therefore require breathing apparatus and protective clothing. Only personnel properly trained and experienced in the use of breathing apparatus should be so employed since inexperienced users may put themselves at considerable risk if they are not fully aware of the hazards and the means to overcome them. Water used for fire fighting may become contaminated by toxic products and must be prevented from escaping into public drainage systems or waterways by using segregated bund/drainage systems. Solutions of toxic chemicals in water are not trapped by standard oil-water interceptors. Other precautions are to segregate different types of fire by storing toxic/non-toxic and flammable/non-flammable chemicals separately and to minimise the use of  water by basing the fire protection on dry powder or foam as far as possible. Refer  manual, 'Warehousing for Packed Chemicals and Other Products'.

10.03.10

Fires Involving Class III Products Because of the extremely low fire risk from tanks containing Class III products, it is generally unnecessary to provide foam protection for them. However, where high viscosity products are stored or handled at temperatures approaching their flash-points (e.g. bitumens) foam provides a means of applying water in the finely divided state necessary, particularly in the event of bitumen tank fires, to minimise the risk of  boil-over. Even in tanks of unheated black oils, after the surface has been burning for as little as 10 minutes a hot zone is formed in the product at a temperature above the boiling point of water. Here again foam offers a means of applying water in a state which will minimise the risk of boil-over. Where storage tanks are not insulated, application of cooling water to the shell of a tank on fire can be most effective in reducing the intensity of the fire and can even lead to total extinguishment. The use of base injection into black-oil tanks is not possible because of the above-mentioned hot zone effect, however the folded hose base injection system may offer a solution.

10.03.11

Fire Alarms and Emergency Calls Suitable audible alarms must be provided with actuating points (switches) located and clearly marked in strategic positions, e.g. loading gantries, jetties and berths, pump stations, dispatch office, etc. Such alarms must, of course, be audible (or visible) at all locations - particularly remote ones such as berths and jetties. There should be no restriction as to who may sound an alarm since delays in calling for help can be critical. A notice on which the telephone numbers of the fire and emergency services are clearly recorded should be displayed near the telephone at the gate house or other control centres.  All personnel, including contractors, must know what to do in the event of a fire alarm (see 10.02.01) and fire alarms should be regularly tested, e.g. at monthly fire practices, to ensure they can work and can be heard at all working locations.

10.03.12

Foam and Water Monitors These units (see Figure 10.03.14 f or example) are normally chosen according to the desired capacity required. Most models are dual purpose - i.e. they can be used to throw water for cooling purposes or foam for fire-fighting or blanketing product spillages. Smaller, portable units are usually more appropriate for marketing installations and depots as they can be manhandled by one or two men, and are relatively easy to set-up in most locations. larger units usually have to be mounted on wheeled trolleys which require some form of transport and therefore better means of access to fire targets.

10.03.13

Floating Roof Tanks The most common fire in a floating roof tank is a seal or rim fire. Automatic halon systems are effective. As an alternative or a back-up if the halon system fails, a dry riser  installed up the tank shell with top pourers to supply foam to the seal space can be used.

10.03.14

Distinctive Colouring Fire fighting equipment should be painted distinctively. Red is the accepted basic colour  (Shell standard colour No 11), but each type of extinguisher may be painted wholly or  partly in other colours for the purpose of ready identification, and a suggested arrangement is as follows: Water

Red

Foam

Cream

Carbon dioxide

Black

Dry chemical powder

Blue

Vaporising liquid (Halon)

Green

Instruction labelling with black letters on a yellow background is generally more clearly visible than other colour combinations. Notices indicating the location of equipment should have white letters on a red background. Fire boxes containing hoses, branch pipes and other equipment should be painted red. Fire precaution notices should have red letters on a white background, e.g. No smoking, etc.

10.03.15

Base Injection of Foam for Storage Tanks (a) General description: In the base injection system, fire fighting foam is injected through one or more inlets in the shell near the base of the tank. The injected foam then rises freely to the surface to form a stable fire-resistant blanket and in the process sets up circulation currents in the product which remove heat from the burning surface, see Figure 10.03.15. Unlike foam applied from the outside of the tank by branch pipe or  monitors, which can be blown away by the wind or the hot up-draught of the fire or  can be obstructed by a damaged roof structure, base injected foam suffers hardly any wastage and practically all of it reaches the product surface. A further advantage is that the inlets being at the bottom of the tank are relatively safe from damage. Direct base injection is not feasible for tanks containing: (i)

Black oils - because, if they burn for more than 5 to 10 minutes before injection of foam starts, hot zones with temperatures exceeding 100°C are formed which are likely to convert the foam to steam and cause dangerous frothing or boil-over; for white oils the hot zones stay far enough below 100°C for this not to occur.

(ii)

Water soluble chemical products - since water-based foam is destroyed as it bubbles through such products, and in addition the need for gentle application of alcohol resistant foams precludes application by base injection.

One possible solution to both these obstacles is a recent development in which foam is injected through a sealed container which is attached to the outside of the tank shell and which contains a folded hose (see Figure 10.03.13). The hose is forced out of the container by the foam/air pressure breaking the seal, and is pushed up through the product to the burning surface where it expels the foam to extinguish the fire. Thus the foam does not come into contact with the product until it reaches the product surface. PETRONAS experience with this device, available from two different suppliers, is at present limited. (b) Recommendations Base injection is generally regarded as one of the most effective means of  extinguishing white product petroleum fires in fixed roof tanks. Nevertheless, a decision whether or not to install base injection on one or more tanks in a tank farm should take account of the following: (i)

It is more difficult to extinguish fires by conventional means in large-diameter  and high tanks than in small and low tanks. To extinguish a fire in a large-diameter tank requires a higher foam flow rate owing to the greater  product surface area, and with high tanks there is the difficulty of throwing the foam sufficiently high. Base injection therefore offers greatest improvement over conventional methods of fire fighting for large-diameter, high tanks which are more difficult to tackle using hoses, branch pipes and monitors.

(ii)

Irrespective of tank diameter or height, base injection has the advantage that it is relatively safe from damage or obstruction should an explosion distort the roof or tank shell.

(iii)

For tanks with properly fitted and maintained floating roofs or screens, which, provided the ullage spaces are effectively ventilated to remove product vapour, are themselves an important means of reducing the risk of fires, base injection offers little benefit and is not normally recommended. Where base injection already exists, or where no increased ventilation is provided, the installing of floating screens should not seriously interfere with its operation, however the fitting of two foam inlets would increase the likelihood that one still works should the other be obstructed by a1screen sinking inside the tank.

(iv)

A fixed base injection system and to a lesser degree a semi-fixed system [see (c) below] require less manpower and time to start up and operate than conventional hose systems. This is a particular advantage in areas where municipal fire brigade support is either slow or inadequate.

(v)

Either fluoroprotein foam (not normal protein foam) or aqueous film forming foam (e.g. light water) can be used, though the latter may be expensive, requires higher water pressures, can be less stable and more difficult to control, and is likely to leave small rim fires (caused by the effect of the hot steel shell) which may have to be extinguished using hand extinguishers or  hoses.

(vi)

Where outside developments exist or have approached installation/depot boundaries such that, in spite of safety distances, there is an increased risk and consequence of fire both to the installation/depot and to the outside environment, base injection may offer a practical and economic means to improve both the speed and effectiveness of response.

(vii)

In spite of the foregoing, there are locations where the risk of a fire starting and/or of consequential damage or operational disruption may be judged too small to warrant the cause of conversion of all or any tanks to base injection, e.g. some up country depots in isolated areas and at small storage points.

Careful appraisal of the above factors in relation to local circumstances is therefore recommended. If base injection is being seriously considered, money can be saved initially be fitting the necessary foam inlets and valves when constructing new tanks of emptying/cleaning existing ones with a view to ultimate conversion at a later date. Design of base injection systems, even for initial cost estimates, requires careful thought by competent engineers. (c) Type of system Base foam injection facilities can be installed either as a fixed system in which all equipment is permanently in place or as a semi-fixed system necessitating the use of  portable or mobile foam generating equipment and hoses brought and connected up at the time of the fire. With either system the foam can be injected either direct into the tank through dedicated foam inlets or via existing product lines. The choice of  which system to use should be based on a cost versus benefit analysis of the alternatives taking into account the advantages and disadvantages given in the following descriptions. (i)

Semi-fixed system The fixed part of the system consists of the foam line which runs from outside the tank bund to the tank inlet and is fitted with suitable valves and an inlet manifold to which the foam generators can be connected when needed. Since the tank valve has to be open to permit foam to enter, it must either be remotely operated or be left permanently open, in which case it is necessary to fit a second steel tank valve and/or bursting disc Just outside the bund to contain the tank contents. If manually operated this valve must be located and protected such that an operator can get to it quickly and open it even when the tank and/or the bund is on fire. A possible arrangement is shown in Figure 10.03.21.  The foam compound, inductors, and generators can be carried in a van or trailer and brought to a fire when required, for  connection by hoses between the water supply hydrants and the foam lines. Foam generation is initiated by opening the water supply and foam line valves and maintaining adequate supplies of water and foam compound. The main advantage of the semi-fixed system is that only one set of  generators, inductors and foam compound is needed to cover perhaps several tanks or different groups of tanks. This however carries with it the main disadvantage of the system which is that it obviously takes time to connect and start foam injection, and in addition a means to transport the foam injection, and in addition a means to transport the foam and equipment

to the appropriate foam line manifold must be provided and kept in constant readiness. Furthermore, suitable and protected access to every foam line or  manifold connecting point must be provided. (ii)

Fixed system The foam line and valve requirements within the bund are much the same as for the semi-fixed system, but outside the bund all foam inductors and generators plus a foam compound tank are installed as fixed parts of the system (see Figures 10.03.16 to 20 inclusive). An obvious advantage of the fixed system is the speed with which it can be operated, since there is no delay while bringing up foam and equipment, connecting hoses, etc. A disadvantage is the cost of the greater number of generators, inductors and foam compound tanks that are required. However, judicious layout design can minimise this by grouping tanks so that each battery of generators and related equipment will serve several different tanks. One, two or at the most three such batteries will normally be sufficient to cover most marketing tank farms. Generally, therefore, the fixed system is to be preferred since the additional cost is not large compared with the longer delay and lower reliability of the semi-fixed system which requires more manpower and the need to maintain equipment in constant readiness. Furthermore, for Class I product tanks, a fixed system that can be started up within 10 minutes can be designed for a lower foam application rate with obvious cost benefit (see Appendix 10.03.27).

(iii)

Separate foam line or product line For either fixed or semi-fixed systems the choice lies between injecting foam through dedicated foam lines connected direct to the tank or via existing product (inlet) lines (see Figure 10.03.16). Use of the product outlet line is less attractive as it is more likely to be complicated with branches, pumpsets, etc., and better kept free for possible use to empty a tank in the event of a fire. Provided that the product inlet line is of large enough diameter  (see Appendix 10.03.27, Velocity Restrictions) its use will usually be simpler  and cheaper since the necessary pipeline modifications can be made without emptying and gas-freeing the tank. However, careful thought must be given to the location of the connection to the product line since the finished installation must allow for the tank valve being kept open or being operated in the event of a fire, and there must also be a valve upstream of the connecting point to prevent back-flow of foam in the wrong direction. Where the inlet line is not large enough to accommodate the full foam flow without exceeding design velocity limits, then an additional or alternative foam inlet line will be necessary. If it is decided to use separate foam inlet lines then again the tank valves must either be kept open or remotely operated in the event of a fire.

(iv)

General arrangement Deciding on the disposition of the various system components (pumps, inductors, generators, foam solution lines, finished foam lines, valves/bursting discs, etc.,) requires careful consideration of a number of  factors. These relate primarily to the distance from the water supply pump to the tanks to be protected; the high back pressures on the system caused by the product heads in high tanks; the need for the foam inlet valves being open at the time of starting base injection; the inability for men to operate valves or replenish foam compound within intolerable heat radiation levels of  tanks or bunds on fire, etc. To illustrate one typical problem area the simplest system may be to group pump, foam compound indicators and foam generators together so that foam can be directed via a manifold to any one of a group of tanks. This necessitates pumping finished foam all the way from the pump outlet to the tank inlet. However, if the tank is high and

relatively distant the pumping pressure to achieve this may be excessive. One answer would be to locate the generators further downstream, i.e. closer  to the tanks since foam solution pressure losses are lower than those of  finished foam. Then the problem becomes one of opening valves closer to the tanks without exposing men to intolerable heat radiation. Alternatively, instead of valves one may choose to design a system using bursting discs which will blow open when foam pressure builds up behind them. Some suggested layouts are discussed in  Appendix 10.03.27 (under B) Design Factors. Operating companies who have problems with this aspect that are not covered here should consult SIPC, (MKDD/21) for further  advice. (d) Operating factors To extinguish a fire successfully by base injection, three operational factors are particularly important: (i)

Foam solution must be supplied to the generators at or above the specified minimum flow rate continuously until the fire is extinguished. Application at a lower rate for a longer duration of time will not generally extinguish a fire.  Additionally, if (perhaps through lack of foam compound), injection has to be stopped before the fire is totally extinguished, this will allow the flames to spread back across the product surface thus losing all that one has gained up to that requirement of foam compound is assembled or immediately available before base injection operations start. (See Appendix 10.03.27.)

(ii)

The inlet pressure specified for the high back-pressure generators used (normally 7 bars but for some makes as high as 10 bars) must be maintained continuously otherwise inferior quality foam may be produced leading to extended extinction time or even failure to extinguish the fire. It is important therefore that, during the actual base injection operation, significant changes in demand on the water supply, (which could upset the flow/pressure supply to the base injection system) do not occur.

(iii)

If variable foam inductors are considered necessary to permit the use of  different concentrations of foam compound, they should preferably be set and sealed at the correct percentage. Alternatively, a clear sign should be posted directing the fire fighters to set the inductors at the correct percentage induction rate for the foam compound in use. If foam compound is induced too slowly, poor foam will result; if induced too fast stocks will be consumed wastefully and too little foam will be produced.

(e) Design and equipment Guidance on the design of base-injection systems is given in  Appendix together with a calculated example, and some design features. Examples foam generators and foam inductors are shown in Figures 10. 03.22 to 25  A sketch showing the recommended tank inlet for base injection is Figure 10.03.26.

10.03.27, of typical inclusive. given in

 A computer programme has been developed to carry out design calculations - given the necessary details of tank dimensions, layout, products stored, etc.

APPENDIX 10.03.01 – RECOMMENDED SCALE OF FIRE FIGHTING EQUIPMENT INSTALLATIONS (INCLUDING LOBP - Note (7), AND CHEMICALS - Note (5), BUT EXCLUDING LPG PLANTS – SEE SECTION 11)

APPENDIX 10.03.02 – RECOMMEDDED ‘FIRST AID’ FIRE EXTINGUISHERS

APPENDIX 10.03.03 - INSPECTION AND TESTING OF EXTINGUISHERS

Extinguishers, spare gas cartridges and replacement charges should be visually inspected at least monthly by a responsible person to make sure that appliances are in their proper  positions and have not been discharged, or lost pressure (in the case of extinguishers fitted with a pressure indicator), or suffered obvious damage. The provision of brackets, shelves or  base blocks will help to show if any appliance is missing.  A more thorough inspection should be carried out at least twice a year by a competent person, e.g. a properly trained member of staff, or a service man from the extinguisher  suppliers, or from a firm specialising in this type of work. The recommendations below are intended as a guide. Faulty, damaged or corroded parts should be replaced only by the correct component supplied or recommended by the extinguisher manufacturer. Before opening any extinguisher it is important to check the vent holes or other venting device. Any blocked vent should be cleared before the extinguisher is opened, and then the extinguisher should be opened slowly in order to allow any gas present to escape in a controlled manner. The dates of inspection and refilling should be indelibly recorded on a label securely attached to the extinguisher or painted on the body (it should not be stamped into the body of the extinguisher). Extinguishers should be recharged in accordance with the supplier's instructions immediately after they have been completely or partly discharged. Sufficient refills for this purpose should always be kept available. The date of refilling should be recorded as above. Periodic pressure testing of extinguishers other than carbon dioxide and halon extinguishers is not considered necessary.

Water (gas cartridge  At least twice a year see that: 1.

Corrosion is not visible externally.

2.

On emptying the liquid into a clean container and examining the body with an illuminating probe, corrosion is not visible internally.

3.

The gas cartridge is weighed to detect any loss, and if this loss exceeds 10 per cent of  the weight marked on the cartridge (or the percentage recommended by the manufacturer, if less than 10 per cent) then the cartridge should be replaced.

4.

The nozzle, strainer, vent holes in the cap and (where fitted) the internal discharge tube and breather valve are not clogged; clean if necessary.

5.

The operating mechanism and discharge valve (where fitted) move freely. Rectify or  replace if necessary.

6.

The sealing washers and hose (if fitted) are in good condition.

7.

After returning the original charge to the extinguisher, it is filled to the correct level. More water should be added if necessary except in the case of special solutions (such as anti-freeze or corrosion inhibitor) when the manufacturer's instruction should be followed.

8.

The extinguisher is correctly re-assembled and safety device fitted.

Every extinguisher should be test discharged at least once every five years.

Water (stored pressure)  At least twice a year see that: (a)

The correct pressure is shown on the indicating device or tell-tale indicator. Where possible the extinguisher pressure should also be checked using an independent pressure-measuring device.

(b)

Corrosion is not visible externally.

(c)

The weight of the extinguisher is correct.

The extinguisher should be test discharged at least once every two years.  After discharge see that: 1.

The pressure-indicating device or tell-tale indicator is functioning correctly and showing zero pressure.

2.

On opening the extinguisher and examining the body internally using an illuminating probe, corrosion is not visible.

3.

The nozzle, strainer, venting device and (where fitted) the internal discharge tube are not clogged. Clean if necessary.

4.

The operating mechanism moves freely. Rectify or replace if necessary.

5.

The sealing washers and hose (if fitted) are in good condition.

6.

The extinguisher is refilled with water, or with special solution in accordance with the manufacturer's instructions.

7.

The extinguisher is re-assembled and repressurised in accordance with the manufacturer's instructions. Effective means should be provided to ensure that extinguisher bodies are not over-pressurised.

8.

The safety device is fitted.

Water (soda/acid)  At least twice a year see that: 1.

After carefully removing the acid bottle, the extinguisher is filled to the correct level.

2.

On pouring the main liquid charge into a clean container and examining the body internally with an illuminating probe, corrosion is not visible. The body should also be examined externally for corrosion.

3.

There has not been acid leakage, which can be caused by seepage past the lead stopper in the case of some turn-over models, or which may result from a cracked bottle. (Cracked bottles should be replaced.)

4.

The nozzle, strainer, vent holes in the cap and (where fitted) the internal discharge tube and breather valve are not clogged. Clean if necessary.

5.

The operating mechanism moves freely. Rectify or replace if necessary.

6.

The sealing washer and hose (if fitted) are in good condition.

7.

If there has not been a leakage of acid, the original main liquid is returned to the extinguisher. Any slight loss should be made up with water. If leakage of acid or a large loss of water has occurred the extinguisher should be recharged according to the manufacturer's instructions.

8.

The extinguisher is correctly re-assembled and the safety device fitted. Each extinguisher should be test discharged at least once every five years. Turn-over  models (loose stopper acid bottle), however, should be discharged every two years.  After discharge, extinguishers should be thoroughly washed out with clean water and any pieces of glass or solid matter removed.

Foam (chemical)  At least twice a year see that: 1.

The extinguisher and inner container are filled to the correct levels.

2.

On pouring the liquids into separate clean containers and examining the extinguisher  body internally with an illuminating probe, corrosion is not visible. The body should also be examined externally for corrosion.

3.

The nozzle, vent holes in the side of the cap, and breather valve (if fitted) are not clogged. Clean if necessary.

4.

The operating mechanism and discharge valve (if fitted) move freely. Rectify or  replace if necessary.

5.

All washers and hose (if fitted) are in good condition.

6.

The original liquid charges, including any undissolved powder, are returned to the appropriate containers. Any slight losses should be made good with water. If large losses have occurred, new charges supplied by the extinguisher manufacturer should be used.

7.

The extinguisher is correctly re-assembled and the safety device fitted. It is not necessary to stir the contents of this type of extinguisher and stirring may, in fact, cause damage.

Every extinguisher should be test discharged at least once every two years.

Foam (mechanical, gas cartridge)  At least twice a year see that: 1.

The extinguisher is filled to the correct level.

2.

On pouring the main liquid charge into a clean container and examining the extinguisher body internally with an illuminating probe, corrosion is not visible. The body should also be examined externally for corrosion.

3.

The gas cartridge is weighed to detect any loss and if this exceeds 10 per cent of the contents (or more than the percentage recommended by the manufacturers, (if less than 10 per cent) the cartridge should be replaced. The sealing washer should also be checked to ensure that it is in good condition.

4.

The nozzle, strainer, branch pipe, internal discharge tube, breather valve and vent holes in the cap are not clogged. Clean if necessary.

5.

The operating mechanism and discharge valve (if fitted) move freely. Rectify or  replace if necessary.

6.

The washers and hose are in good condition.

7.

Where the foam compound is in a separate container, leakage of foam compound has not occurred.

8.

The extinguisher is refilled with the original main liquid charge. Any loss should be made up with water. If the charge is a pre-mixed foam solution and there has been a loss of more than 5 per cent by volume, then a new charge should be used.

9.

The extinguisher is correctly re-assembled and the safety device fitted.

Every extinguisher should be discharged at least once every four years.

Foam (mechanical, stored pressure)  At least twice a year see that: (a)

The correct pressure is shown on the indicating device or tell-tale indicator. Where possible the extinguisher pressure should also be checked using an independent pressure measuring device.

(b)

Corrosion is not visible externally.

(c)

The weight of the extinguisher is correct.

Every extinguisher should be test discharged at least once every four years.  After discharge see that: 1.

The pressure indicating device or tell-tale indicator is functioning correctly and showing zero pressure.

2.

On opening the extinguisher and examining the body internally using an illuminating probe, corrosion is not visible.

3.

The nozzle, strainer, branch pipe, venting device and (where fitted) the internal discharge tube are not clogged. Clean if necessary.

4.

The operating mechanism moves freely. Rectify or replace if necessary.

5.

The sealing washers and hose (if fitted) are in good condition.

6.

The extinguisher is refilled with manufacturer's instructions.

7.

The extinguisher is re-assembled and repressurised in accordance with the manufacturer's instruction. Effective means should be provided to ensure that extinguisher bodies are not over-pressurised.

8.

The safety device is fitted.

special solution in

accordance with

the

 After discharge, foam extinguishers should be thoroughly washed out with clean water and any solid matter should be removed.

Dry powder (gas cartridge) Powder extinguishers should be opened only in a dry room and for the minimum time possible in order to minimise the effect of atmospheric moisture on the powder. Only extinguishers containing the same type of extinguishing powder should be opened and examined at any one time in order to avoid t he danger of cross-contamination. Where a discharge control is fitted on the nozzle at the end of the hose, this should be operated before opening the extinguisher in order to relieve immediately any pressure which may be present in the extinguisher. The following checks should then be made at least twice a year: 1.

The extinguisher contains the correct weight of powder.

2.

On emptying the powder into a clean dry container, it is free-f lowing and does not contain lumps or foreign bodies. If only small, soft lumps occur these can be removed by sieving the powder. Otherwise powder should be replaced.

3.

On examining the body internally using an illuminating probe, corrosion is not visible. The body should also be examined externally for corrosion.

4.

The gas cartridge is weighed to detect any loss and if this exceeds 10 per cent of the contents (or more than the percentage recommended by the manufacturers if less than 10 per cent) the cartridge should be replaced.

5.

The nozzle, hose, vent holes in the cap and internal discharge tube are not clogged. Clean if necessary.

6.

The washers and hose are in good condition.

7.

The operating mechanism and discharge control (where fitted) operate freely. Rectify or replace if necessary. (Do not use grease or oil on these parts.)

8.

The original charge, or a new one if necessary, is returned to the extinguisher.

9.

The extinguisher is correctly re-assembled and the safety device fitted.

Every extinguisher should be discharged at least once every five years.

Dry powder (stored pressure)  At least twice a year see that: 1.

The correct pressure is shown on the indicating device or tell-tale indicator. Where possible the extinguisher pressure should also be checked using an independent pressure measuring device.

2.

Corrosion is not visible externally.

3.

The weight of the extinguisher is correct.

4.

The nozzle and hose are not clogged. Clean if necessary.

5.

The hose is in good condition.

6.

Where extinguishers are designed to have the operating mechanism removed, the operating mechanism and discharge control (where fitted) move freely. Rectify or  replace if necessary. (Grease or oil should not be used on these parts.)

7.

The safety device is replaced.

Every extinguisher of the field refillable type should be discharged at least once every five years.  After discharge see that: (i)

The pressure indicating device or tell-tale indicator is functioning correctly and showing zero pressure.

(ii)

On opening the extinguisher and examining the body internally using an illuminating probe, corrosion is not visible.

(iii)

The nozzle, hose, venting device and internal discharge tube are not clogged. Clean if necessary.

(iv)

The operating mechanism and discharge valve (if fitted) move freely. Rectify or  replace if necessary. (Grease or oil should not be used on these parts.)

(v)

The sealing washers and hose are in good condition.

(vi)

The extinguisher is refilled and repressurised in accordance with the manufacturer's instructions. Effective means should be provided to ensure that extinguisher bodies are not over-pressurised.

(vii)

The safety device is fitted.

 All dry powder extinguishers should be kept perfectly dry after discharged and not washed out.

Carbon dioxide  At least once a year see that: 1.

Corrosion is not visible externally.

2.

The weight of the extinguisher is correct. If a loss in weight of more than 10 per cent of the contents (or more than the percentage recommended by the manufacturer, if  less than the percentage recommended by the manufacturer, if less than 10 per  cent) has occurred, then the extinguisher should be taken out of service and replaced.

3.

The horn, and valve assembly are in good condition.

4.

Where extinguishers are designed to have the operating mechanism removed, the operating mechanism and discharge control (where fitted) move freely. Rectify or  replace if necessary.

5.

The safety device is replaced.

Every carbon dioxide extinguisher should be discharged at least once every ten years.

Halon (stored pressure)  At least once a year see that: 1.

Corrosion is not visible externally.

2.

The weight of the extinguisher is correct.

3.

The correct pressure is shown on the indicating device (if fitted). Where possible the extinguisher pressure should also be checked using an independent measuring device. Extinguishers showing a significant loss of pressure (as defined in the manufacturer's recommendations) should be taken out of service and replaced.

4.

Where extinguishers are designed to have the operating mechanism removed, the operating mechanism and discharge control (where fitted) move freely. Rectify or  replace if necessary.

5.

The safety device is replaced.

Every halon (stored pressure) extinguisher should be discharged once every ten years. Extinguishers containing carbon tetrachloride should not be used.

FIGURE 10.03.04 – CHUBB MOBILE PD150 DRY CHEMICAL POWDER EXTINGUISHER

CAPACITY: PRESSURE CHARGE: OPERATING PRESSURE: DURATION OF DISCHARGE:

70kg (150lb) Chubb standard dry powder   One 3.6kg (8lb) CO2 gas cylinder  7 bars 45-55 seconds

Note: 90-litre AFFF (model SF 20 FN) and fluoroprotein foam (model PF 20 and SF20) mobile units of  similar design to this extinguisher are also available

APPENDIX 10.03.05 – CHUBB MOBILE FOAM UNITS

CAPACITY : 11 litres (2.5 UK gal) foam compound (6% only) OPERATING PRESSURE: 2 – 10.5 bars  At operating pressure of 3.5 bars it produces about 1400 litres foam during operating time of  4 minutes CHUBB FL 2.5 HOSE REEL FOAM UNIT

CAPACITY : WATER SUPPLY REQUIRED: OPERATING PRESSURE: OPERATING TIME:

100 litres (22 UK gal) foam compound (3% or 6% only) 225 litres/min 3 – 10 bars 3% compound – 14 minute 6% compound – 7 minute CHUBB FL 22 MOBILE FOAM LIQUID PROPORTIONER UNIT

FIGURE 10.03.06 – FLOW RATES FROM FIRE HOSE NOZZLES

FIGURE 10.03.07 – PRESSURE LOSS IN FIRE HOSES

FIGURE 10.03.08 – HYDRANT-FED FIRE FIGHTING EQUIPMENT

FIGURE 10.03.09 – TYPICAL FOAM-GENERATING FIRE-FIGHTING EQUIPMENT

FIGURE 10.03.10 – TYPICAL FOAM COMPOUND INDUCTION

FIGURE 10.03.11 – TYPICAL MECHANICAL FOAM GENERATORS

FIGURE 10.03.12 – FOAM CHUTE WITH STAGGERED OPENINGS INSIDE TANK

FIGURE 10.03.13 – BASE INJECTION OF FOAM (folded hose system)

FIGURE 10.03.14 – CHUBB ‘JET-MASTER’ PORTABLE MECHANICAL FOAM/WATER MONITOR

Foam improver/nozzle section in which foam of correct consistency is formed and expelled as high-velocity rope  jet. For water spray only, this section is removed

Total weight 34 kg (74.5 lb)

Foam generator  section which combines water, foam liquid and air 

Main body comprises two sections joined by quick action thread

Two legs, independently adjusted and lockable, support monitor at elevations between 40° to 70° Easily observed pressure gauge, recessed for  protection

Carrying handle

Connection for  aluminium foam compound pick-up tube/hose assembly or for 1½-inch hose from wheeled foam liquid tank Swept-elbow connector fitted with two 2½-inch instantaneous male couplings. (Other  couplings can be fitted) Swivelling base plate allows alteration of  elevation while the unit is operating

JET LENGTH JET HEIGHT - FOAM  WATER FLOW : FOAM COMPOUND

1600 litres/min at 10.5 bars 3% or 6% by calibration

: 40m at 10.5 bars : : 12m at 6.7 bars 23m at 10.5 bars - WATER : 30m

FIGURE 10.03.15 – DISTRIBUTION OF FOAM AND CIRCULATION OF TANK CONTENTS IN FOAM BASE INJECTION SYSTEMS

FIGURE 10.03.16 –

FIXED BASE INJECTION Inductors and generator near pump discharge – single tank near to foam station

FIGURE 10.03.17 –

FIXED BASE INJECTION SYSTEM Inductors and generators near pump discharge – multiple tanks short distance to foam station

FIGURE 10.03.18 –

FIXED BASE INJECTION SYSTEM Generators separated from inductors – single tank

FIGURE 10.03.19 – GENERATORS SEPARATED FROM PROPORTIONER – MULTIPLE TANKS – SEPARATE FOAM LINES TO EACH TANK

FIGURE 10.03.20 –

GENERATORS SEPARATED FROM PROPORTIONER – MULTPLE TANKS – SINGLE FOAM SOLUTION LINE TO GENERATOR MANIFOLD

FIGURE 10.03.21 – SEMI-FIXED BASE INJECTION SYSTEM

FIGURE 10.03.22 – ANGUS FIRE ARMOUR HIGH-BACK-PRESSURE FOAM GENERATORS

MODEL HBPG 450

MODEL HBPG 2250 Performance Data Model Design Flow Rate

Design Inlet Pressure Max design Back Pressure Expansion

HBPG 225

HBPG 450

HBPG 900

HBPG 2250

225 litres/min

450 litres/min

900 litres/min

(50 lmp GPM)

(100 lmp GPM)

(200 lmp GPM)

2250 litres/min (500 lmp GPM)

2

7 bars (100 lb/in ) 25% of inlet Pressure 3–4:1

FIGURE 10.03.23 – CHUBB BIG 10, 20 AND 30 BASE INJECTION FOAM GENERATORS

MODEL

BIG 10

20

30

FOAM SOLUTION FLOW RATE:

litres/min

455

910

1365

FOAM OUTPUT:

litres/min

1800

3600

5400

DESIGN INLET PRESSURE:

Bars

7

7

7

Note : Maximum back pressure 25% of inlet pressure

FIGURE 10.03.24 –

CHUBB ‘JET-MASTER’ MECHANICAL FOAM MONITOR WITH ADAPTOR FOR BASE INJECTION

FOAM SOLUTION FLOW RATE : 1600 litres/min (350 UK gal/min) FOAM OUTPUT: 6300 litres/min (1400 UK gal/min) DESIGN OPERATING PRESSURE: 10 bars Maximum Design Back Pressure – 25% of Inlet Pressure

FIGURE 10.03.25 – ANGUS VARIABLE FOAM INDUCTOR

FIGURE 10.03.26 – TANK INLET FOR BASE INJECTION OF FOAM

APPENDIX 10.03.27 -

BASE INJECTION - DESIGN AND EQUIPMENT

 A. General Description The capacity of a base injection system for fixed roof tanks is based on the minimum foam solution (water plus foam compound but not aerated) flow rate required to extinguish a storage tank fire. The Recommended minimum rates are as follows: Class I products -

2

7.4 litres/minute/m² (0.15 UK gallon/minute/ ft ) of product surface to be protected. Note: If a fixed system is to be installed which can be started within 10 minutes of the onset of tank fire, then a foam solution flow rate of  2 2 4.9 litres/minute/m  (0.10 UK Gallon/minute/ ft ) can be used.

Class II products -

2

2

4.9 litres/minute/m  (0.10 UK gallon/minute/ft ) of product surface to be protected. 2

2

Class III products - white oils - 4.9 litres/minute/m  (0.10 UK gallon/minute/ft ) of product surface to be protected. - black oils - base injection not suitable. Sufficient foam compound and water should be available to permit operation at the above application rates for a period of 30 minutes. The design of a base injection system involves a sequence of steps as follows: (i)

Calculating the minimum acceptable foam solution flow rate. When more than one tank is to be protected by the same system, the design flow rate is determined by the tank requiring the highest flow rate.

(ii)

Selecting the number, size and distribution of foam generators plus the general layout of water, foam solution and finished foam pipelines. Depending on the tank farm layout as well as the location and orientation of water supply, the combination and grouping of generators (and their related inductors) may vary from: (a) a single battery of generators to supply all needs via a foam distribution manifold, to: (b) a number of separate batteries of generators strategically located to serve different groups of tanks. The decision between semi-fixed and fixed systems will also have to be made at this point in the calculation.

(iii)

Selecting the number of foam inlets for each storage tank, which is governed primarily by the diameter of the tank in accordance with the 'Number of Inlets' table shown in C5.  An alternative ar rangement using  a single tank inlet and multiple foam outlet points is shown in Figure 10.03.28.

(iv)

Estimating the foam inlet diameters. Foam inlets must be sized so that the velocity of foam entering the tank is not greater than 3.0m/second (10ft/second) for volatile products (flash-point less than 21°C) or 6.0m/second (20ft/second) for  non-volatile products (flash-point equal to or greater than 21 0C). The correct attitude of the inlets is horizontal (not upwards or downwards); a 45° chamfer is acceptable, see Figure 10.03.26. Foam velocities may be greater in the pipelines further upstream (which permits the use of smaller pipelines) but pipelines must be increased to the correct inlet diameter at a distance of not less than 20 times the pipe diameter from the inlet to the tank. At no point should the foam velocity exceed 9.15m/second (30ft/second).

The inlet diameters estimated at this stage will have to be checked at a later  stage in the design depending on the ultimate hydraulics of the system (see D(c) below). (v)

Calculating system pressure losses so as to derive the finished foam supply pipeline diameters downstream of the foam generators. This part of the design is governed by a number of parameters:

-

-

-

The design of foam generators is normally such that the maximum back pressure downstream of the generator outlets (caused by pipeline losses plus static head of product in the tank) must not exceed 25% of the inlet pressure to the foam generators. This then is the starting point of the hydraulics design and in situations with high tanks (i.e. high static head of product) and high foam flow rate requirements, can result in substantial pressure requirements. For this reason since pipeline pressure losses for water or  foam solution are much lower than for finished foam, a guiding principle is to minimise the lengths of finished foam lines by positioning the foam generators as far downstream as practically possible so as to limit the distance finished foam has to be pumped before it enters the storage tank. Foam generator inlet pressure requirements vary from 7 to 10 bars depending on make. Higher pressures can be used to give higher  throughputs and/or to meet high downstream back pressures. To allow full development of finished foam properties a foam line length of  preferably 20m is required before entering the tank, but 5m is an absolute minimum without significant foam deterioration.

(vi)

Estimating the inlet pressures to the foam generators (i.e. 4 times the outlet back pressures derived from (v) above): thence calculating the foam solution pipeline sizes between the pump discharge and the generator inlets (including the pressure losses sustained through the foam compound inductors).

(vii)

Estimating the volume of foam compound as well as the water flow rate and water volume needed to provide base injection operation at the recommended application rate for a period of 30 minutes.

From the above the base injection system for one or more tanks can be calculated in isolation from the requirements for the rest of the fire fighting system. Section D below describes the points to be considered to produce an overall tank farm fire fighting protection system. B. Design Factors (i)

Foam pipelines should, whenever possible, run outside the bund area so as to be less exposed to fire. This may lead to longer lines which will add to pipeline friction losses. Where a foam line has to run inside the bund area flanges should be eliminated or minimised. Wrapping and burying lines will provide additional fire protection.

(ii)

Testing - once a base injection system has been installed it has to be tested in order to prove the equipment as well as train personnel in its operation. This is straightforward if the tank is still empty and the injected foam can be removed from the tank. If however, the tank contains product, a perfectly adequate test can be carried out if a foam outlet/sample point is installed in the foam line upstream of the tank valve. The sample points do not have to be close to the storage tanks but may be more conveniently located near the foam generators (subject only to the 20m minimum distance necessary to permit full development of the foam properties or even in the foam solution lines in which case a generator would have to be attached at the time of sampling. This will minimise consumption of foam compound during tests and fire practices, and will also facilitate flushing out the lines after such tests. A minimum slope of 1/240 with suitable drainage outlets will facilitate flushing and draining foam lines after testing or usage.

(iii)

Quick-action valves - all valves at the tank selection manifold should be quick-action (ball) valves. Particularly for aviation products a double seal valve, bursting disc, or two valve separation is required to prevent water contamination of the aviation product. The size of the ball valves can be reduced to limit cost but to no less than 50% of the pipeline cross-sectional area. In such a case however, the additional pressure lost through the valve must be allowed for in the back pressure calculations.

(iv)

The non-return valves should preferably be soft seated (but not spring-loaded).  Accepted materials for the soft seat are nitrile rubber, Viton and Buna-N but not Neoprene. In the event that product passes the non-return valve and fills the line from the tank to the generator manifold, the aerated foam is able to push the product back to the tank without significant deterioration. If soft seated non-return valves are not available, conventional non-return valves can be installed.

(v)

As mentioned in 10.03.15(d) sufficient foam compound must be available or  immediately accessible before base injection operations begin. One way to minimise total stocks of foam compound held at any plant, is to keep part of the total requirement in a small bulk tank suitably located for base injection purposes. The balance can then be stored in easily movable containers ready to be carried to any part of the site when needed. For example, if the base injection requirement is 2.5m³ of compound, and this is estimated to be more than enough for any other possible fire, then 1.5m³ could be stored in a small tank or trailer  ready for immediate use in the base injection system, and the remaining 1m³ kept in containers at the most strategic location for any other fire. The emergency fire plan should then be arranged so that should a tank fire occur, previously detailed personnel would take the foam containers to the bulk foam tank ready for decanting as the initial compound in the tank is consumed. If a fire occurs elsewhere, the portable containers can be taken to the site of the fire for  use with the normal hoses and foam making equipment, and if necessary further  stocks of foam compound can be drawn from the compound tank. To minimise foam compound deterioration, the tank should be fitted with an expansion dome on top and the level of compound maintained within the dome. To protect the tank against internal corrosion the tank should be lined with bitumen or an 'EPIKOTE' resin based paint.

(vi)

The principle mentioned in A(v) above of converting foam solution into aerated (finished) foam at the latest possible moment will help limit pressure losses/reduce pipe diameters. Against this saving will have to be offset the possible need for additional generators because rather than a single battery of  generators to cover all needs, locating generators further downstream in the system may mean having to install more than one small battery of generators resulting perhaps in a greater total number of generators required. The relative economics of this must, of course, be estimated. Such a situation would probably not occur with a semi-fixed system which depends on a common store of  generators which are taken to whichever is the appropriate foam inlet point.

(vii)

Foam/foam solution distribution systems Depending on the number of tanks, as well as the size and layout of the site, various designs of distribution systems can be employed as shown in Figures 10.03.16 to 10.03.21 inclusive, and described below.

1.

2.

Fixed base injection system where tanks are only a short distance from fire pump/water supply permitting the foam station [foam compound tank, inductor(s), generator(s), etc.] to be positioned together near the pump discharge. (a)

This layout (see Figure 10.03.16) is appropriate for single tank protection, and show how the product inlet may be used as one of  the foam inlets. As the tank valves (VO) must be kept open, a second valve (VT) or bursting disc with gate valve to protect it when sampling foam acts to contain any product that may pass the non-return valve in the foam lines. Valve (V P ) is to prevent backflow of foam in product line and wily normally be closed.

(b)

This layout (see Figure 10.03.17) is for multiple tank protection, where the foam station is only a short distance to the tank farm but pressure drops are nevertheless low enough to permit foam generation at the foam station close to the pump. As tank valves V O remain open, valves V T  outside the bund must either be quickly accessible (fire screen plus rapid access) or be remotely operable (reliable power) by a protected system. Bursting discs are not appropriate since one can not select which disc to burst.

Fixed base injection system where for distance and/or pressure drop reasons the foam generators are separated from the inductor/proportioner units. (a)

This layout (see Figure 10.03.18) is appropriate for single tank protection. As the tank valve (V O) is kept open, a bursting disc is all that is required outside the bund. A manual valve would not be suitable because of the time taken for someone to get to it and open it, but a remotely-operated valve could be used provided that there is a reliable power supply. Foam sampling is best done by connecting a generator at the solution outlets shown. To sample downstream of the generators entails filling the whole pipeline with solution which is both costly and would necessitate a laborious draining and flushing operation afterwards.

3.

(b)

This layout (see Figure 10.03.19) is for multiple tank protection with separate lines to each tank. A foam proportioner may be considered here since it will automatically induce the correct rate of foam compound depending on which foam control valve (V C) is opened, and in addition has a much lower pressure drop compared with inductors. As this system permits manual control it is ideal where power supply (for remote valve operation) is unreliable. For foam sampling see the comment given in 2(a) above.

(c)

An alternative layout (see Figure 10.03.20) is to run a single foam solution line from the discharge side of the proportioner to a manifold positioned immediately upstream of the generators. In this case the control valves (VC) would have to be remotely operated, which means a reliable and protected power supply is essential. Bursting discs are necessary to contain product as tank valves (VO) are kept open. The same comment as in 2(a) above covers foam sampling.

Semi-fixed base injection system. A typical layout is shown (Figure 10.03.21) in which the foam inductor and generator are brought to the foam inlet point outside the tank bund and connected to the water supply by hoses. Foam sampling can be done in either way (1 or 2 above) depending on pipe lengths, layout, etc.

(viii)

Equipment - all pipelines, valves and other standard fittings should be in accordance with the specification for normal installation operations given in the 'Installations and Depots' manual, 05.00.00. In addition, the following items of  equipment have been developed especially for base injection: (a) High back-pressure generators - these are required to produce foam with suitable properties for base injection; expansion 2 to 4 and a 25% drainage time of 90-180 seconds. Models are available from different manufacturers for a range of foam solution flow rates of between about 50 and 2 250 litres/ minute (10 and 500 UK gallons/minute) and which operate at inlet pressures ranging from 7 to 10 bars; examples are shown in Figures 10.03.22 to 10.03.24 inclusive. One supplier has produced an adaptor, see Figure 10.03.24, for use with the existing foam monitor shown in Figure 10.03.14. (b) Foam compound inductors and proportioners - most in-line inductors working on the venturi principle with a minimum induction rate of 3% can be used. One of the models available is illustrated in Figure 10.03.25. This type of unit suffers one major drawback in that pressure lost through it equals one-third of its inlet pressure. Thus to feed high back-pressure generators which require minimum inlet pressures of 7.0 bar, the inlet pressures to the inductor  must be 10.5 bar. These pressure levels may be tolerable for relatively small or simple applications where back-pressures downstream of the generators can be kept to reasonable levels (or for non-base injection applications) but for larger systems at higher pressure levels generally an alternative such as a variable-flow proportioner may be considered as it has a considerably lower pressure drop and inducts foam compound at a rate directly proportional to the water flow rate through it. However, the relative economics must be assessed before the choice is made.

C. Design Example for Base Injection of Foam into Single Tank (see Fig 1) 1.

2.

Tank Details Product

:

Gasoline

Tank size

:

34.0 m dia. x 22m height

Product inlet (existing)

:

10" (250mm)

Distance from fire pump

:

150m

=

907.5m²

Minimum solution flow rate

=

7.4 litres/min/m²

(see ‘A’ General Description)

=

7.4 x 907.5

=

6716 litres/min

 Assuming design is a fixed system, startable within 10 min, then solution flow rate can be = reduced to =

4.9 x 907.5 4447 litres/min

Product surface area π

4

x 34 2

3. Foam Solution Flow Rate :

4.

Generator Requirements (based on Angus Range) Generators - 2 x 2250 litres/min = Note:

5.

4500 litres/min

While these two large units are ideal for this particular single tank size, were it intended to use the same set-up to supply foam to a number of tanks of  which this was the largest, a combination of say 1 x 2250 plus 2 x 900 and 1 x 450 litres/min generators would permit using various combinations to match the different tank sizes.

Number of Inlets The number of tank inlets required depends upon the diameter of the tank:

Minimum No of Inlets Tank Diameter in Metres

Volatile products (Flash-point21.0°C)

18.5

1

1

18.5 - 35.5

2

1

35.5 - 42.5

3

2

42.5 - 48.5

4

2

48.5 - 55.0

5

2

55.0 - 61.0

6

3

 Above 61m add one inlet for  each additional:

465m²

695m²

In the example, two inlets are required. 6.

Inlet Diameters [see A(iv)] Each takes half the flow rate

=

0.5 x 4500 = 2250 litres/min

Maximum design flow rate

=

3.0m/second (flash-point