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IS I 6382 - 1984

Indian Standard CODE OF PRACTICE FOR DESIGN

AND IN-STALLATION OF FIXED CARBON DIOXIDE FIRE EXTINGUISHING SYSTEM

( First Revision )

Fire Fighting Sectional Committee, BDC 22

Chairman Representing

, SERI G. B. MENON Gujarat Electricity Board, Vadodara

Members

SHRI A. N. AHLUWALIA The Institution New Delhi

of Fire Engineers ( India ),

SHRI B. R. MEHTA ( Alternate ) SHRI S. R. BANSAL Steel Authority of India ( Bokaro Steel Plant),

Bokaro Steel City CH~EB FIRE OFFICER Municipal Corporation of Delhi (Delhi Fire

Service ), Delhi SHRI R. K. BHARDWAJ ( Alternate )

SHRI K. K. DAS GUPTA West Bengal Fire Services, Government of West Bengal, Calcutta

DEPUTY INSPECTOR G E N E R A L Ministry of Railways ( RPSF )

ASSISTANT SECURITY OFFICER ( FIRE ), NORTHERN RAILWAY ( Alternate )

SRRI V. P. DEWAN Ministry of Defence ( DGI ) LT-COL V. R. BANAHATI ( Alternate )

SHRI R. R. DHOBLEY Bhabha Atomic Research Centre, Bombay DIRECTOR Home Department ( Fire Service ), Government of

Tamil Nadu, Madras DEPUTY DIRECTOR ( Alternate )

DIRECTOR GENERAL o F F I R E Home ( Police ) Department, Government of SERVICES Andhra Pradesh, Hyderabad

DE P u T Y DIRECTOR ( FIRE SERVICES ) ( Alternate )

( Continued on page 2 )

Q CopVrigkr 1986

INDIAN STANDARDS INSTITUTION

This publication is protected under the Indian Coprright Act ( XIV of 1957 ) and reproduction in whole or in part by any means except with written permission of the publisher shall be deemed to be 9 infringement of copyright under the said Act.

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IS : 6382 - i984

( Continued from pag8 1 )

Members

FIRE ADVISER SHRI A. K. GUPTA

SHRI J. S. JAMSHEDJI

SHRI C. GRANARAJ (Alternate)

SHRI P. KHANNA SERI V. V. KIMMATKAR

Representing

Ministry of Home Affairs Central Building Research Institute ( CSIR ),

Roorkee Steelage Industries Limited ( Minimax Division ),

Bombay

SHRI S. N. KUNDU MANAQIN~ DIRECTOR

Jaya Shree Textiles & Industries, Rishra Oil & Natural Gas Commission, Dehra Dun Fire and Safety Appliances Co, Calcutta Avon Services ( Production & Agencies ) Pvt Ltd,

Bombay TECHNICAL EXECUTIVE ( Alternate J

COL S. A. MOEILE Ministry of Defence ( R & D ) SERI A. K. SURI ( Alternate )

SERI M. MIJEHERJI Steel Authority of India Ltd (Rourkela Steel Plant ), Rourkela

SHRI C. D. SHARMA (Alternate 1

SHRI V. B. NIKAM Municipal Corporation of Greater Bombay * ( Bombay Fire Brigade ), Bombay

SHRI P. N. PANORAL Central Industrial Security Force (Ministry of Home Affairs ), New Delhi

SHRI D. N. PANDIT Directorate General of Supplies & Disposals, New Delhi

SHRI P. H. SETHNA Kooverji Devshi & Co (P) Ltd, Bombay SERI N. T. PA~J~ANI (Alternate )

SHRI D. K. SIRK&R Synthetics & Chemicals Ltd, Bareilly SHRI CHANDRAKANT M. S~AE Zenith Fire Services, Bombay

SHRI M. H. SHAH ( Alternate )

SHRI J. V. SHAH Newage Industries, Surendranagar ( Gujarat) SHRI B. J. SHAH ( Alteraatc )

SRRI TARIT SUR Surex Production & Sales Pvt Ltd, Calcutta SERI SUSHIL KUXAR Directorate General of Technical Development,

New Delhi SHRI J. N. VARIL Tariff Advisory Committee, Bombay

SHRI K. RAVI ( AIternatc ) SHRI S. VENEASWAMY Directorate General of Civil .4viation, New Delhi SERI B. V. WAGLE Urban Development, Public Health & Housing

~

Department, Government of Maharashtra, Bombay

SRRI V. H. MADKAIIKAR ( A&C&s ) SHRI G. RAMAN, Director General, IS1 ( Ex-o&o Member)

Director ( Civ Engg )

Secretary

SEIRI K. M. MATHOR, Joint Director ( Civ Engg ), IS1

( Continued on page 32 )

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IS : 6382 - 1984

Indian Standard CODE OF PRACTICE FOR DESIGN

AND INSTALLATION OF FIXED CARBON ’ DIOXIDE FIRE EXTINGUISHING SYSTEM

( First Revision)

0. FOREWORD

0.1 This Indian Standard ( First Revision) was adopted by the Indian Standards Institution on 10 December 1984, after the draft finalized by the Fire Fighting Sectional Committee had been approved by the Civil Engineering Division Council.

0.2 Fixed fire extinguishing installations are usually employed for protecting public buildings and industrial premises where it is desired to keep fire losses to the minimum by automatic discharge of fire extinguishing media immediately upon an outbreak of fire particularly when the permises are unoccupied, as at night and during week ends and holidays, or in particular parts of the premises which are at times unattended. Such installations are also usually employed for fire protection in premises or risks where it is not possible to fight the fire manually.

0.3 There are various types of fixed fire extinguishing installations, like the ‘Fixed Foam Fire Extinguishing Installation’, the ‘Sprinkler Installation’, the ‘Drencher System’ and the ‘Fixed Carbon Dioxide Fire Extinguishing Installation’. This standard covers the requirements of ‘Fixed carbon dioxide fire extinguishing installations’. c

0.4 Fixed carbon dioxide fire extinguishing installation is usually provided -on premises where water or foam cannot be used for fire extinguishment because of special nature of the contents of the building/ area to be protected. This type of installation is also useful for extinguishing fires in specific hazards or equipment, and in occupancies where an inert electrically non-conductive medium is essential or desirable, or where cleaning-up after fire -extinguishment present problems, or where this type of installation is more economical, although equally suitable, in comparison with other types of fire extinguishing

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installations. For the premises which contain the following such installations wiI1 be suitable:

a) Alternators,

b) Bonded warehouses,

c) Carding machines,

d) Chemical works and stores,

e> Drawing office plan safes, .

f) Diesel and diesel electric locomotives,

g) Driers,

h) Electric movers,

3 Flammable liquids,

k) Kitchen equipment,

ml Oil-circuit breaker,

4 Paint dip tanks and drain boards,

P) Printing presses,

9) Record safes/rooms,

r ) Signal cabins,

s) Transformers,

t ) Solvent stores,

u) Spray booths, and

v) Engine test beds.

NOTE - The above list is not exhaustive.

0.4.1 This standard does not cover the fixed carbon dioxide fire extinguishing installations for aircraft engines.

0.4.2 Carbon dioxide should not be used to extinguish fires involving the following:

a) Chemicals containing their own oxygen supply, such as cellulose nitrate;

b) Reactive metals, such as sodium, potassium, magnesium, titanium, zirconium, and aluminium; and

c) Metal hydrides.

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0.5 Carbon dioxide is most effective as a fire extinguishing medium in confined spaces. The provisions of the standard do not apply for protection of hazards in open spaces. Due allowance should, therefore be given to the size and capacity of the fixed installation if it is to be used where some loss of gas is possible because of open doors, windows and ventilators.

0.6 The discharge of this gas in large amounts, for the extinguishing of fire, may create hazards to personnel, such as oxygen deficiency and reduced visibility. The dilution of the oxygen contents of the effected space by carbon dioxide concentrations necessary to extinguish the fire may create an atmosphere that will not sustain life specially in the case of ‘total flood installation’ ( see 1.1 ), where similar atmosphere may also be produced in adjacent low places, such as cellars and pits, because of large volumes of gas drifting and settling there. Persons rendered unconscious in these atmospheres without any permanent ill-effects,

can, however, be usually revived it resuced promptly and removed to

fresh air.

0.6.1 Because of these reasons, it is necessary to provide suitable safeguards to ensure prompt evacuation from and prevention of entry into spaces where there is a possibility that men may get trapped in or enter into atmospheres renderded hazardous because of discharge of carbon dioxide.

0.6.2 When men are required to enter into atmospheres rendered unsafe by the discharge of carbon dioxide, for any purpose whatsoever, they should wear breathing apparatus. This should be particulary borne in mind while entering the effected space immediately after fire extinguishment to ensure that it is complete and to remove any material involved in fire, or for the purpose of ventilating the premises after fire extinguishment.

0.7 This standard was first published in 1971. This revision has been prepared so as to align this standard with latest international standards on this subject.

0.8 For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance with IS : T-1960*. The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard.

*Rules for rounding off numerical values ( revised).

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IS : 6382 - 1984

1. SCOPE

1.1 This standard lays down the requirements for design, materials and testing of ‘fixed carbon dioxide fire extinguishing installation’ of the following types:

a) Total flood installation, and

b) Local application installation.

1.1.1 The two types of installations may also be combined, if required. When this is done, the requirements of’ both types shall be taken into consideration while designing the installation.

2. TERMINOLOGY

2.0 For the purpose of this standard, the following definitions shall apply.

2.1 Automatic System or Circuit - A system or circuit which operates under predetermined and pre-set conditions without manual intervention.

2.2 Battery -Two or more gas cylinders connected to a common manifold into which one or more could discharge the gas.

2.3 Clearance --Clearance shall mean air distance between equipment, including piping and nozzles and unenclosed or uninsulated live electrical components at other than ground potential.

2.4 Coated SurFace - Coated surface are defined as those designed for drainage which are constructed and maintained so that no pools of liquid will accumulate over a total area greater than 10 percent of protected surface.

2.5 Directon Valve -A valve which permits the flow of gas in the * desired direction.

2.6 Discharge Head - A fittings on the mouth of the gas cylinder, which may also incorporate the mechanism for releasing the gas from the cylinder, through which gas is discharged.

27 Discharge Horn -_A horn type fitting through which carbon dioxide is discharged on the fire.

2.8 Emergency Manual Operation - Operation of the system by human means where the device used to cause operation is fully

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mechanical in nature and is located at or near the device being controlled. ~Fully mechanical may incorporate the use of system pressure to complete operation of the device.

2.9 Gas Pressure Trip-A device designed to operate by the pressure of gas discharging from a gas cylinder and which may arranged to trip the weighted mechanisms for closing down doors, windows, etc.

2.10 Local Application Installation - It consists of a fixed supply of carbon dioxide, normally connected to a fixed network of pipes, nozzles and discharge horns arranged to discharge the gas directly on the surface or object on which fire is anticipated.

2.11 Manifold - A common pipe or chamber into which one or more gas cylinders may discharge the gas for distribution to the fire zone(s).

2.12 Normal Manual Operation - Operation of the system requiring human action where the device used to cause operation is located so as to be easily accessible at all time to the hazard. Operation of one control shall be all that is required to bring about the full operation of the system.

2.13 Total Flood Installation - It consists of fixed supply of CO2 normally connected to a fixed network of pipes, nozzles and discharge horns arranged to evenly distribute sufficient quantity of the gas throughout the entire enclosure(s) and capable of extinguishing fire within the enclosure(s) regardless of location of fire.

3. DESIGN CONSIDERATIONS

3.0 Types- The fire extinguishing part of the installation should be designed to perform any of the following functions:

a) Total jlooding of the space or spaces, a$cted by fire, by carbon dioxide - the total flood installation;

b) For local application of carbon dioxide to a sfiecijic hazard - ‘Ihe local application installation; and

c) A combination of (a) and (b).

3.1 General Requirements

3.1.1 The installation shall be designed to provide instant means of combating a fire that may break out, even when the premises are unoccupied or unattended. It shall also be capable of sounding an alarm to prevent loss of life by warning occupants to evacuate the

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affected premises quickly and to secure the immediate attention of the fire fighting staff or the fire brigade or both, This shall be maximum 60 s before release of extinguishment.

3.1.2 For the purpose of satisfying the requirements given in 3.1.1 the installation shall be fully automatic in action. But means shall also be provided to operate the installation manually in case of any defect in the autmomatic system, or while carrying out maintenance, etc.

3.1.3 Detector must be sensitive enough to the fuel in question to give rapid response to fire at an early stage, at the same time not far too sensitive to produce false actuation. A simple way to combine success- fully both sensitivity and reliability is by utilising multiple detectors connected in a double circuit, or a cross-zoned mode of operation. An operation of one detector provides an alarm, but only when a second detector in the same area operates the extinguishing media discharge ( that is, operation of single detector zone triggers the alarm sequence, whilst operation of second detector zone triggers extinguishment release ). Cabling from control panel to electrical actuating units shall be preferably monitored for open circuit and short circuit conditions. An alarm shall alert ‘fault conditions’. The gas discharge panel shall have provision for relay contacts to indicate the following:

a) Zone 1 alarm,

b) Zone 2 alarm,

C) System alarm, and

d) System trouble.

3.1.4 The carbon dioxide supply shall be of the high pressure type, in which the gas is stored in rechargeable containers designed to store liquified carbon dioxide at atmospheric temperature corresponding to a nominal pressure of 6 MN/m2 ( 60 kgf/cm’ ) at 27°C. High pressure cylinder shall hold pressurised CO2 in liquid form at ambient temperature corresponding to a nominal pressure of 6 MN/m2 ( 60 kgf/cm2 ) at 27°C.

3.1.5 The complete equipment design shall be reliable in operation. All components of the installation should be located, installed or suitably protected to ensure that no mechanical, chemical or other damage is possible which may render these inoperative.

3.1.6 All devices used in the installation shall be capable of functioning satisfactorily between - 29% and 65°C. Where the devices do not satisfy this condition, the temperature range within which these are capable of correct operation should be suitably marked.

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3.2 Capacity

3.2.1 The capacity of the installation shall be the total amount of liquid carbon dioxide stored in the main battery of carbon dioxide cylinders by weight. factors:

a)

b)

c)

d)

e)

f)

g)

\

It shall be determined taking into consideration the following

Nature of flammable material;

Type of fire to be extinguished, that is, surface fires involving flammable liquids, gases and solids or deep seated fires involving solids subject to smouldering;

Type of installation, that is, total flood or local application type;

Volume of the space or spaces to be protected;

Where normal temperature of enclosures is below -18”C, one percent increase in calculated total quantity for each degree below - 18’C;

If temperature of enclosures is greater than 93’C, one percent increase in calculated total quantity of CO, for each additional degree above 93%;

The question on limitation of unclosable opening is frequently encountered and does not afford a precise solution. Since surface fires are normally of the type that can be extinguished with local application methods, a choice between total flooding or local application can be made on the basis of quantity of CO2 required. These forced ventilation is not a consideration leakage of CO2 - air mixture from an enclosed space which will depend upon one or more of the following parameters:

i) Temperature of the enclosureS - CO, will not expand as much at low temperature and would be more dense, thus a greater amount would leak out if the openings were in the lower portion of the enclosure.

ii) Volume of enclosure - ?he percent of total volume of CO, lost to any given opening in a small enclosure would be greater than that from the same opening in the large enclosures.

iii) Venting - An opening at or near the ceiling is usually desirable to permit exhausting the lighter gas from the room during discharge.

iv) Locating of opening - Since CO, is heavier than air, there ma) be little or no loss of CO, from openings near the ceiling, while the loss at floor level may be substantial. Thus any openings

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that cannot be closed at the time of extinguishment shall be compensated for by addition of CO2 through the regular distribution syseem. The leakage rate from an enclosure in the absence of forced ventilation depends mainly on the difference in density between the atmosphere within the enclosure and the air surrounding the enclosure. The following equation can be used to calculate the rate of CO, loss assuming that there is sufficient leakage in the upper part of the enclosure to allow free ingross of air.

&I *Pm (Pm1 - Pmz ) hm P ml

where

Rm = rate of CO, loss in kglmin.

C = CO, concentration fraction,

pm = density of CO, vapour in kg/ms,

*A, = area of opening in ms (iflow coefficient included),

gm = gravitation of constant 9.81 m/sets,

pm1 = density of atmosphere in enclosure in kg/ms,

pm2 = density of surrounding air in kg/m3, and

h, = static head between opening and top of enclosure in metres.

If the quantity of CO, required for compensation exceeds the basic quantities required for flooding without leakage, the system may be designed for local application.

For forced ventilating systems, which cannot be shut down, additional CO, shall be added to the space through the regular L distribution system in an amount computed by:

Volume move during the liquid discharge period Flooding factor

The above quantity shall be multiplied by material conversion factor if the design concentration is greater than 34 percent.

‘If there are openings in the walls only, the area of the wall opening can be divided by 2 for calculations since it is assumed thatfresh air can enter through one-half of the openings and protective gas will exit through the other half.

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h) Phase change (for local application increase nominal cylinder capacity ~by 40 percent of account for vapour portion of CO, ); and

j) While computing net cubic capacity to be protected in case of total flooding system, allowance may be made for permanent non-removable impermeable structures permanently reducing

volume.

NOTE - Tightness of enclosure is more important with deep seated fires because CO, concentration must be greater and must be maintained for a longer time to ensure complete extinguishing. or actually in coiling.

The openings shall be restricted to those bordering

3.2.2 Data given in Tables 1 to 4 may be used as a guide for ~determining the total capacity of the installation.

3.2.3 Where more than one space is protected by a single installation, the capacity of the installation shall be calculated on the basis of the largest space w~hich it is to protect. But, where there are openings between two protected spaces, and such openings cannot be shut down, the calculations shall be based on the combined volume of such spaces provided that this volume is greater than the volume of the largest protected space.

3.2.4 Enclosed electrical equipment, for example, generators, rotary frequency converters provided with or without recirculating ventilation shall be adequately tight with automatically closing dampers to maintain required carbon dioxide concentration.

3.2.4.1 Open rotating electrial apparatuses may be protected by the volume of carbon dioxide under total flooding method provided the con- centration of carbon dioxide is maintained throughout the deceleration period or for 20 minutes as minimum. For both the types of risks, the extinguishing concentration of carbon dioxide shall be attained within one minute, with a prolonged discharge sufficient to maintain the carbon dioxide concentration during the deceleration. The quantity of carbon dioxide for initial discharge shall be sufficient to provide quantities on volume factors given in Table 5.

3.2.4.2 For enclosed tight electrical equipment, the quantity of carbon dioxide for extended discharge shall be sufficient to maintain carbon dioxide concentration of at least 30 percent throughout the deceleration period or for a minimum of 20 minutes as in Table 6.

3.2.4.3 Where a concentration test is not required, the size of the extended discharge orifices shall be such that the discharge of the extended gas requirements shall continue for a minimum of 30 minutes or

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MATERuL

(1) Acetylene Acetone Benzol, benzene Butadiene Butane Carbon disulphide Carbon monoxide Coal or natural gas Cyclopropane Dowtherm Ethane Ethyl ether Ethyl alcohol Ethylene Ethylene dichloride Ethylene oxide Gasoline Hexane Hydrogen Isobutane Kerosene Methane Methyl alcohol Pentane Propane Propylene Quench, lube oils

(Clause 3.2.2 )

IS : 6382 - 1984

throughout at least two-thirds of the deceleration period of the equip- ment, but not beyond the deceleration period. Where a concentration test is provided for, the extended discharge period will not be necessary if a 30-percent gas concentration is maintained throughout the deceleration period, or for a minimum of 20 minutes. ~discharge nozzles shall be as in Table 7.

The discharge rates of extended

TABLE 1 MINIMUM CARBON DIOXIDE CONCENTRATIONS FOR EXTINGUISHING SURFACE FIRES IN SOME COMMON

LIQUIDS AND GASES

THE~RETIOAL CO, DESIQN COs CONCENTRATION,

Min ( PERCENTAQE CONCENTRATION,

Min ( PERCENTAGE BY VOLUME ) BY VOLUME )

(2) (3)

55 66

:7 !I 34 41 28 55 :: 53

it $

38 33 ::

46 2 41 :i 21 44 z:

2 ;: 62 74 30

z: 30 31 35 36 36 34

NOTE - The values for minimum theoretical carbon dioxide concentrations for materials not given above in co1 (2) shall be determined by test. The theoretical carbon dioxide concentration values may be calculated by the formula given below if residual oxygen values are available:

Percentage 0f~COs = (21-0,) x l()() 21

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TABLE 2 VOLUME FACTOR USED TO DETERMINE THE BASIC QUANTITY OF CARBON DIOXIDE FOR A TOTAL FLOOD INSTALLATION

INVOLVING MATERIALS REQUIRING A DESIGN CONCENTRATION OF UP TO 34 PERCENT ( see also TABLE 1)

( Ctausc 3.2.2 )

SPACE/VOLUME VOLUME FAOTOB CALCULATED r__*_-----) QUANTITIES

ma/kg of kg of kg (NOT CO* co,/m* LESS THAN)

(1) (2) (3) (4)

Upto 0.87 1.15 -

Above 4 up to and including 14 0.93 1’07 4.5

Above 14 up to and including 45 0.99 1’01 15.0

Above 45 up to and including 127 Pll 0.90 45’5

Above 127 up to and including 1416 1’25 0’80 114.0

Above 1416 1.35 0.74 1 135.0

NOTE 1 -While calculating the volume of space to be protected, due allowance may be made for the following:

4

b)

Permanent non-removable impenetrable rtructurcs which may reduce the volume materially; and

Loss of gas expected during discharge because of doors, windows or other openings which cannot be closed or effectively sealed off. It shall be ensured that sufficient gas shall remain in the protected space after the initial loss because of leakage. Additional gas required for this purpose may be calculated at 5 kg of carbon dioxide per square metre of flow space. This shall further be increased for ventilation systems which cannot be shut down and this calculation shall be basrd upon the volume of air moved in one minute, using the volume factor given above in co1 (2) and (3), multiplied by the conversion factor (see Note 3 ) if the design concentration is greater than 34.

NOTE 2 -For materials requiring a design concentration of over 34 percent, the basic quantity of carbon dioxide calculated from the data given in this table shall be increased by multiplying this quantity by the appropriate conversion factor given in Fig. 1.

NOTE 3-- For each additional 3°C rise in temperature of the protected space above 93”C, the total calculated quantity of carbon dioxide should be increased by one percent.

NOTE 4 -For each degree below - 18’C for the reduce expansion of gas at low temperature, the total calculated quantity of carbon dioxide should be increased by one percent.

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w-5

4

3

2

1 70 34 40 50 60 70 80

MlNlMUM DESIGN OF CO2 CONCENTRATION -‘is

FIG. 1 MATERIAL CONVERSION FACTORS

(1)

9

ii)

iii)

iv)

TABLE 3 FLOODING FACTORS FOR DEEP SEATED FIRES IN SPECIFIC HAZARDS

( Clause 3.2.2 )

SPECIFIC HAZARD FLOODING FACTOR p--_--*_--_-_l

m’/kg of CO*

kg of COs/ms

(2) Dry electrical wiring insulation hazards in

general

(3) (4)

0’75 1933

Small electric machines, wire enclosures, 0.62 1.60 under 57 ms

Record ( bulk paper ) storage 0’50 2’00

Fur storage vaults, dust collectors 0.38 2’66

NOTE 1 - Flooding factor for deep seated fires in other materials shall be

c

calculated keeping in view the mass of the material to be protected, because the rate of cooling ir reduced by the thermal insulating effects.

NOTE 2 -Notes 1 to 4 under Table 2 also apply to this table.

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TABLE 4 CARBON DIOXIDE REQUIREMENTS PER UNIT AREA FOR LOC-AL APPLICATION INSTALLATIONS

( Clause 3.2.2 ) SL TYPE OF Cms/g OF Co,

No. INSTALLATION g OF CO,/cm*

(1) (2) ’ (3) (4) i) Liquid surfaces 0.82 1.22

ii) Coated surfaces 1.20 o-83 iii) Vapour exits 1.02 0.98

NATE 1 --The figures listed indicate the minimum quantity which is permissible subject to a minimum of 5 kg of carbon dioxide. While designing the installation, factors such as wind currents, nature and placements of coated surfaces shall also be taken into consideration. These figures do not apply to special cases involving three dimensional objects, such as oil filled electric transformers.

NOTE 2 -While considering the effect of wind currents, no increase in the basic amount of carbon dioxide is necessary for winds or droughts up to 24 km/h. The basic amount of carbon dioxide shall be increased by 10 percent for each additional 8 km/h above the first 24 km/h.

NOTE 3 - If coated stock is hanging more than 600 mm above a liquid or coated surface or is of such a nature as to hold substantial amounts of flammable liquids, the protection shall be extended to include those parts, and additional carbon dioxide shall be added. When coated rollers or lengths of coated materials are involved, the calculations shall be based on the developed method area regardless of possible duplication by contacting or close proximity surfaces. A minimum dimension of 600 mm shall be used in calculating the area of a given hazard even though its actual dimensions may be less.

NOTE 4-Where it is possible that metal or other material shall become heated above the ignition temperature of the fuel or fuels involved before the carbon dioxide is applied to the fire, additional carbon dioxide will be needed for cooling. The amount of carbon dioxide needed for cooling shall be increased, if necessary, to maintain the rate of discharge for the time necessary to cool heated materials to a point where re-ignition shall not occur.

TABLE 5 QUANTITY OF CARBON DIOXIDE FOR INITIAL DISCHARGE ( OPEN ROTATING ELECTRICAL APPARATUSES )

SL VOLTJ~~E OF ELEOTILICAL VOLVME FACTOR No. EQUIPMENT ma/kg OF CO,

(1) (2) (3) i) Electrical equipment and wiring over 57 ma 0’75 ii) Electrical equipmrnt and wiring under 57 ma 0’62

NOTE 1 - The piping for the initial discharge is equal to that required for total flooding system for surface burning materials.

NOTE '2. -The ratio of the nozzle orifice area to cylinder outlet area shall not be more than 55 percent nor less than 35 percent of the initial discharge.

NOTE 3 -For rotating electrical machinery protection by differential relays, the relays being connected to the release mechanism of the system shall be arranged to discharge the gas in the case of a fault in the equipment.

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TABLE 6 CO, REQUIREMENTS FOR ROTATING ELECTRICAL EQUIPMENT

(Clause 3.2.4.2 )

DECELERATION TIME IN MINUTES c__~-_----_-_-_-- h_-_------_----~

5 10 15 20 30 40 50 60 *Maximum volume protected, ma

c-------- ----*___-__--_---~

3”; zi

130

ii! 55 69 68

17 28 37 47 57

11 17

iii 37

173 218 262

%

116 85 153 108 193 139 229 173 269 210

ti!i 7”: 113 88 142 110 173 139

47 57

iii 119

394

z1 524 570

309 244 204 348 279 235 385 314 266 420 350 297 464 385 328

170 200

;:: 289

147 127 110 272 176 156 136 295 204 181 159 318 232 207 !84 340 262 232 207 363

609 503 421 360 320 289 -651 541 456 391 350 217 697 580 491 422 379 345 739 620 527 453 411 374 782 660 564 484 442 402

% 912 954

1000

697 736 773 813 852

596 631 667 702 738

515 547 578 609 641

470 500

z:; 592

430 459 487 515 544

1042 889 1 087 929 1 130 968 1 172 1008

773 808 844 878

673 623 572 521 471 704 654 600 548 496 736 685 629 575 520 767 715 657 600 544

34 45 59 79

102

258

$7: 337 364

s;; 442 467 494

co* REQUIRED

kg

:z 91

113 136

159 181

‘2;; 249

229 386 255 408 278 431 303 454 326 476

351 499 374 522 399 544 422 567 447 590

612 635 658

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*Maximum volume protected includes all the air space within the-machine and ducts, For dampered non-recirculating type machines, add 30 percent to the gas requirement determined from this table.

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TABLE 7 DISCHARGE RATES OF EXTENDED DISCHARGE NOZZLES

( Clause 3.2.4.3 )

ORIFICE DIAMETER AREA mm mm%

(1) (2) (3)

0’57 0.26 0.48 0’66 0.34 0.64 0’71 0’40 0.73 0’83 0.54 1.00 o-97 0.74 1.36 1’07 0.90 1.67 I.18 1’09 2’04 1.40 1.54 2.86 1.59 1.99 3‘67 1.78 2’49 4-63 1’93 2.91 5.44 1.98 3’08 5’75 2.06 3’33 6.17 2.18 3’73 6.94 2‘38 4.28 7.96

DEXBAROE RATE OF

COO kg/min

NOTE - Nozzle discharge rate for other sizes may be computed on the basis of 186 kg/min/cm*.

3.2.4.4 Freezing and consequent plugging of the nozzles and a separate piping system shall be provided for the lower extended discharge rates and -the extended discharge shall be continuous. Intermittent extended discharge shall not be permitted. For smaller diameter outlets, piping shall be provided with strainers. Piping sizes and extended discharge rates shall be as given in Table 8.

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TABLE 8 LOWER EXTENDED DISCHARGE RATE

PIPIN 0 SIZE mm

(1)

12’7 19.05 25‘4

DISCHARGE RATE kg/min

(2)

up to 45 up to 102 Over 102

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3.3 Carbon Dioxide Supply

3.3.1 The total amount of carbon dioxide, calculated according to 3.2 shall be stored in a main battery of carbon dioxide cylinders conforming to IS : 7285-1974*. The carbon dioxide shall conform to IS : 307-19116t.

3.3.1.1 The total number of carbon dioxide cylinders in the battery shall be determined depending upon the capacity of the installation and the capacity of individual cylinders. The sizes of cylinders recommended are 20 kg, 40 kg and 50 kg. For very small installations, however, cylinders of smaller capacity may be used.

3.3.1.2 All cylinders in the battery shall be interchangeable.

3.3.1.3 Each cylinder shall be provided with its own valve with a dip tube extending to the bottom inside the cylinder, and valve discharge head which shall be connected to a common manifold through high pressure connecting pipes or tubes.

3.3.1.4 All carbon dioxide cylinders in the battery and the common manifold shall be mounted and suitably supported in a rack provided for the purpose. The rack shall be designed in such a manner that servicing and checking of contents of individual cylinders shall be convenient, and the cylinders are rigidly held in position.

3.3.1.5 Means shall be provided to automatically prevent the loss of carbon dioxide from the manifold if the installation is actuated, when any cylinder is removed during maintenance of the installation. Flexible connectors shall be used between each cylinder and the common manifold. All manifolded systems that are not ~open ended, that are normally closed, must preferably have a vent plug in the manifold. This device releases slow accumulations of pressure in the manifold caused by a leak in one of the cylinder valves and prevents the discharge of the system caused by a leaky cylinder.

Ir Flexible hoses used for discharge bend shall preferably be double

wire braided ( perforated ) rubber covered hose suitable to withstand a minimum bursting pressure of 420 kgf/cmz at 54°C.

3.3.1.6 The battery of carbon dioxide cylinders shall be located in a room which shall satisfy the requirements of and where the ambient temperature shall not exceed 54°C or below 0°C.

*Sprcification for seamless manganese steel cylinders for permanent and high pressure liquefiable gases ( first revision ).

tspecification for carbon dioxide ( second rcuirion ).

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3.3.2 A reserve battery of carbon dioxide cyljnders shall be provided in addition to the main battery.

3.3.2.1 The reserve battery shall be duplicate of the main battery and it shall be arranged for a quick and easy change-over so that it may:

a) be ready to discharge the gas into any space or spaces adjoining the one ‘on fire’, and

b) stand guard while the main battery is being re-charged.

NOTE -The reserve quantity may be more depending upon the time needed in refilling.

3.4 Distribution System

3.4.1 Discharge Heads and Values

3.4.1.1 All discharge heads and valves shall be designed taking into consideration the fact that liquefied carbon dioxide expands very rapidly ( 1 to 450 ) when discharged. The requirements of minimum flow of gas and the temperatures at which these are required to operate shall also be taken into consideration. These shall conform to IS : 3224-1979*.

3.4..1.2 All valves under constant high pressure shall have a minimum bursting pressure of not less than 42 MN/m” ( 420 kgfjcm” ) and those not under constant pressure shall have a bursting pressure of not less than 35 MN/m2 ( 350 kgf/cm” ).

3.4.1.3 Discharge heads and valves shall be designed to permit a minimum discharge of 85 percent of the carbon dioxide in the cylinder in not more than 30 s at a temperature of 27 f 1°C. The discharge rate of carbon dioxide shall be not less than O-68 kg/s for the first 85 percent of the cylinder’s contents.

3.4.1.4 All discharge heads and valves shall be so arranged that these shall not be susceptible to mechanical, chemical or other damage.

3.4.1.5 Nozzles shall be sufficient in a number and so located that the gas discharge pattern shall completely cover the enclosure ( not more than 20 mm’! ). To extend the discharge period the ratio nozzle-orifice area to cylinder outlet area shall be between 27.5 and 37.5 percent. Design nozzle pressures shall be preferably not less than 20.6 kgf:cm2 at 27°C.

*Specification for valve fittings for compressed gas cylinders excluding liquefied petroleunl gas ( LPG ) cylinders ( second rtvi~ion ).

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3.4.2 Direction Valves

3.4.2.1 If a single battery of carbon dioxide cylinders serves more than one space, direction valves shall be fitted to the manifold. These valves shall be designed to conform to the requirements given in 3.4.1.1 to 3.4.1.4.

3.4.2.2 The direction valves shall permit automatic selection -of discharge pipe leading from the manifold to the affected space in case of a fire.

3.4.2.3 The linkage between the selectors on the direction valves and the tripping mechanism at the cylinder position shall be arranged so that the direction valve is selected and opened before the gas is discharged into the manifold.

3.4.2.4 The design shall also provide for the manual selection of the direction valve in addition to the automatic device.

3.4.3 Connecting Pipes and Tubes-The connections between the discharge heads and the manifold may be made by rigid pipes.

3.4.4 Pipes and Fittings - The pipes and fittings used in the distribution system may be made out of any of the following:

a) Galvanized steel [see IS : 1239 ( Part 1 )-1979* ) 1,

b) Copper ( see IS : 2501-19727 ), and

c) Brass ( see IS : 407-1981 )$.

3.4.4.1 All pipes and fittings, including the manifold, shall have a minimum bursting pressure of 35 MN/m” ( 350 kgf/cm” ).

3.4.4.2 Pipes shall be laid in such a manner that friction losses shall be reduced to a reasonable minimum, and any possible constrictions due to foreign matter or faulty fabrication shall be avoided. Care shall be taken to ensure that the number of bends and sharp angles is kept to the minimum to achieve this.

3.4.4.3 Pipes shall be securely supported with due allowance for expansion and contraction and shall not be subject to mechanical, chemical or other damage. In premises where an explosion is likely, the pipes shall be hung from supports that are least likely to be displaced.

*Specification for mild steel tubes, tubulars and other wrought steel fittings : Part 1 Mild steel tubes (fourth revision ).

fSpecification for copper tubes for general engineering purposes (Jirst revision 1. $.Specification for brass tubes for general purposes ( third reuision ).

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3.4.4.4 All pipes shall be reamed and cleaned before being laid out in position and, after fitting the entire distribution system, shall be blown through before the nozzles and discharge horns are fitted. .::* V_

3.4.4.5 The sizes of pipes used in the distribution system depends on the maximum desired flow of carbon dioxide through these pipes. Table 9 gives the data on which these calculations may be based.

TABLE 9 SIZES OF PiPES IN THE DISTRIBUTION SYSTEM (FOR PIPE RUNS UP TO 75 m )

SURFACE FIRES CO, REQUIRED

kg

(1)

50

112

150

300

500

1225

1250

2 225 3 550

5 225

7 500

10 450

16 800

NOMINAL PIPE SIZE mm

(2)

12’5

20

25 Extra heavy

30 ,, I,

37 ,, $3

50 ,, ,s

62 3, ,,

75 ,, ,) 87 3, ,,

108 1, ,,

112 1, X>

125 ,, 3,

150 I, ;,

DEEP SEATED COs REQUIRED

kg

(3)

900

1600

2 175

3 875

5 375 - - - - - -

-

NOTE I- For surface fires requiring over 16 800 kg carbon dioxide the size of pipe may be calculated at 0%09 8 cm* pipe area per kg CO,. For deep seated fires requiring over 5375 kg carbon dioxide, the size of pipe may be determined at the rate of .002 cm’ pipe area per kg Cop.

NoTE'L- Several small pipes may be used in place of one large pipe, provided the aggregate cross-sectional area of such pipes is equal to the calculated cross- sectional area. Pipe size of any length of branch piping shall not be larger than that of the preceding length. The total length of pipe from the cylinder manifold to the most distant nozzle shall not exceed 75 m.

NOTE 3- The number of nozzles that may be fed by any branch line of the pipe is determined by the total orifice area of the nozzles supplied by it. The total orifice area of the nozzles supplied by any branch line of the pipe shall not exceed the cross-sectional area of the branch line pipe multiplied by the nozzle orifice or ratio of the system.

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3.4.4.6 The complete distribution system shall be free from leakage when tested at a pneumatic pressure of 14 MN/m? ( 140 kgf/cm2) with all nozzle outlets closed.

3.4.4.7 All sections of pipe having dead, ends shall be fitted with suitable pressure relief devices designed to operate between 16.8 MN/m” ( 168 kgf/cm’ ) and 21 MN/m2 ( 210 kgf/cm” ). Alternatively, the valves in the system shall be designed to prevent entrapment of liquid carbon dioxide.

3.4.4.8 In installations employing pressure operated cylinder discharge heads, it shall be ensured that any gas leaking from the cylinders into the manifold shall be vented to atmosphere. Any devices used for this purpose shall be capable of preventing loss of gas when the installation is operated. Each cylinder valve shall be fitted with a safety device to release excess pressure safety below cylinder test pressure. Frangible disc that bursts to release pressure in excess of 184 bars f 10 percent will be deemed to satisfy above.

3.4.4.9 It shall be ensured that the discharge of carbon dioxide through any pressure relief device shall not cause any personal hazard.

3.4.5 Nozzle

3.4.5.1 The nozzles shall be designed and located in such a manner that an even distribution of gas will be achieved throughout the protected space and, at the same time, the discharge from the nozzles shall not cause undue splashing of flammable liquids or creation of dust clouds that might aid spread of fire, cause explosion or otherwise adversely affect the contents of the protected space. When installed in duct work spacing and sizing of nozzles is dependent upon the following factors:

a) Velocity in duct;

b) Location and effectiveness of dampers;

c) Possible loading of duct walls with combustible deposits; and L

d) Duct length and cro+zs-section dimensions.

NOTE -No allowance is needed for inlet and outlet duct openings. CO, fire extinguishing system protecting areas where rxplosive atmospheres could exist -shall utilise metal nozzles and shall be properly grounded. ( Since discharge of liquid CO, is known to produce electrostatic charges which under certain conditions could create a spark ).

3.4.5.2 For systems protecting quick burning materials, the total area of all discharge outlets for the system or for individual hazards where the system is to protect multiple hazards simultaneously, shall be

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within 6.5 to 85 percent of the cylinder outlet area or of the area of supply pipe, whichever is smaller. The system protecting materials subject to glow or smouldering ( see hazards in Table 3 ) the total area of all discharge outlets shall be within the range of 3 to 10 percent of cylinder outlet area, except that the total area of all discharge outlets shall not exceed 85 percent of the supply pipe area.

3.4.5.3 Nozzles vary in design and discharge characteristics and shall be selected to suit the intended purpose.

3.4.5.4 For installations intended for surface fire protection, the aggregate cross-sectional area of nozzle outlet shall not exceed 85 percent or be less than 35 percent of the aggregate release outlet area of the system, or minimum cross-sectional area of the pipe, as determined from Table 9, whichever is smaller.

3.4.5.5 For installations intended for deep seated fire protection, the aggregate cross-sectional area of nozzle shall not exceed 85 percent of the cross-sectional area of the pipe as determined from Table 9; nor be less than three percent of the aggregate release outlet area of the system.

3.4.5.6 Nozzles shall be capable of withstanding pressures up to 14 MN/m2 ( 140 kgf/cm” ) and shall be of Leaded tin bronze ( see

IS : 318-1981* ).

3.4.5.7 Nozzles used in the local application installations shall be so connected and supported that these may not be readily put out of adjustment.

3.4.5.8 Irrespective of the number of orifice or the shape of the nozzle, it shall be marked, permanently and indelibly, to show its equivalent single orifice diameter. All nozzles having an equivalent single orifice diameter of 2’38 mm and more shall also be marked with a code number as given in Table 10.

3.4.5.9 The limitations for nozzle spacing and coverage as well as minimum and maximum distance above flammable liquid surfaces ( in t depth ) shall be determined for each type and size of nozzle and checked and verified by a testing laboratory. Where this information is not provided, the limitations for spacing and location of nozzles shall be governed by the following:

a) Nozzles shall not be spaced more than one metre apart. A single row of nozzles may be satisfactory for area, up to 1.25 m width;

b) One additional row of nozzles shall be provided for each additional 1.25 m width of hazard area, or fraction thereof; and

*Specification for Leaded tin bronze ingots and castings (second revision).

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c) Where low-velocity nozzlespoint directly at liquid surfaces, the distance of the nozzle from such surfaces shall be indicated by a table giving nozzle number, diameter, area, minimum and maximum distance from liquid surface, as given in Table 11.

TABLE 10 CODE NUMBERS OF CARBON DIOXIDE DISCHARGE NOZZLES ( Clause 3.4.5.8 )

NOZZLECUDE EQUIVALENT SINGLE EQUIVALENT SINQLE NUMBER OUTLET DIAMETER OUTLET AREA

mm mm*

(1) (2) (3)

- 0’66 0’342 - 1.59 1.986 - 1’99 3.109 3 2.38 4.448 3+ 2.78 6’067 4 3.17 7.918 4+ 3.57 10’010 5 3.97 12.380 5+ 4.37 15.000

6 4.76 17’79 6+ 5.16 20.90 7 5.56 24.28 7-b 5.95 27.80 8 6.35 31.66 8+ 6.75 35.78

9 7.14 40.03 9+ 7.54 44.65

10 7.94 49.50 11 a.73 59.84 12 9.52 71.15 13 10.32 83.60 14 11.11 96.91 15 11’91 111.40 16 12.70 126.70 18 14.29 160.30 20 15.87 197’90 22 17.46 / 239.30 24 19.05 284.90 32 25.40 506.50 48 38’ 10 1 140.00 64 50.80 2 027.00

NOTE - The nozzle code number indicates the equivalent single orifice diameter in 0’79 mm increments. A plus sign following the code number indicates equivalent diameter O-4 mm greater than the one indicated by the number system.

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TABLE 11 LIMITING DISTANCES OF LOW VELOCITY NOZZLES FROM FLAMMABLE LIQUID SURFACES

[ Clause 3.4.5.9 (c)

NOZZLE NUMBER

(1) (2)

3 2.38

3+ 2.78

4 3’17

4+ 3’57

5 3.97

5+ 4’37

6 4.76

6+ 5’16

7 5.56

7+ 5’95

8 6.35

8-t- 6.75

9 7.14

9+ 7’54

IO 7.94

10 f 8’33

11 8.73

11 + 9.13

12 9.52

13 10.32

14 11.11

15 11’91

16 12’50

DIAMETER mm

AREA mms

(3) (4) 0)

4.448 0.46 O’G9

4.067 0.46 0.69

7’918 0’53 0.79

10-010 0’53 0.79

12’380 o-30 0.91

15*000 0.61 0’91

17.790 O-69 l-02 20.900 0.69 1.02 24.280 0.76 1’14 27,800 0.76 1’14 31.660 0.84 1.24 35.780 0.84 1.24 40.030 0.91 1.37

44.650 0.91 1.37 49.500 0.99 1.47 55.260 O-99 1.47 59.840 1.07 1.6 65.290 l-07 1.6 71’150 1.14 1.7 83.600 1.22 1.83 96.910 1.30 1.93

111.400 1.37 2.06 126*700 1’45 2’16

MINIXUM DISTANCE

RBOM FLAMMABLE

LIQUID SURFACE*

m

MAXIMUM DISTKNCE

FROM FLAMXABLE

LIQIXD SURFACE

m

NOTE - The nozzle code number indicates the equivalent single orifice diameter in @19 mm increments. A plus sign following the code number indicates equivalent diameter @4 mm greater than the one indicated by the number system.

*Twice the distances shown are permitted for a special diffuser nozzle with higher discharge velocity.

3.4.5.10 Where nozzles are likely to get clogged by foreign materials these shall be provided with frangible discs which shall automatically rupture by the pressure of the discharging gas.

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IS 16382 - 1984

3.4.6 Discharge Horns

3.4.6.1 Each discharge nozzle shall be fitted with a removable discharge horn designed to prevent solidification of carbon dioxide while discharging from the nozzle outlet.

3.4.6.2 Discharge horns shall be made out of non-conducting and non-corrosive material which shall not deform or fail under normal temperature ranges to which these shall be exposed and shall conform to IS : 2878-1976*.

3.5 Actuating Mechanism

3.5.1 The actuating mechanism for discharging the gas from the cylinder battery into the distribution system shall be designed for instant operation upon an outbreak of fire or upon dangerous temperature being reached in any of the protected spaces. This may be achieved either through electrical relays, operating through an independent fire alarm system tripping the weighted actuating mechanism or through fusible links, suitably distributed in the protected spaces, performing a similar function.

3.5.2 If all carbon dioxide cylinders in the battery do not discharge simultaneously, the cylinders arranged to discharge initially shall provide adequate pressure and flow in the system to maintain the required discharge rate of the gas in the largest space protected by the installation. Subsequent cylinders shall be arranged to operate automatically through gas pressure trips or switches designed to operate by the pressure of the gas discharging from the gas cylinders. Where the supply of gas consists of more than two cylinders, not less than two cylinders shall be used for such operation.

3.5.3 The total contents of the cylinder battery or the minimum amount of gas required for a particular space shall be discharged into the space within 60 s maximum. Ir

3.5.4 In addition to the automatic actuating mechanism, a well designed manual control shall also be provided for actuating the installation.

3.5.4.1 The manual control shall be arranged to enable the installation to be operated in the normal manner manually, both from the cylinder position and from a position cl-e by to the protected space or spaces. Cables used for manual pull shall, be of phosphor bronze and wired through conduit*. Maximum number of cylinders that can be

*Specification for portable fire extinguishers, carbon dioxide type (Jirst revision ).

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gauged together and operated by one weight release unit shall not exceed 16. The pulley used for gauge release shall be heavy duty type.

3.5.4.2 Manual controls shall not require a pull of more than 18 kgf nor a movement of more than 350 mm to secure operation.

3.6 Lock-Off Arrangements

3.6.1 Where factory personnel or maintenance staff have access to a space protected by the installation, lock-off arrangements shall be incorporated in the installation design to permit the automatic devices being rendered inoperative before the personnel enter the protected space.

3.6.2 The lock-off arrangement may be incorporated in the direction valve trip mechanism.

3.6.3 The installarion shall still be capable of manual operation, as specified in 3.6.4 after the automatic devices have been locked-off.

3.6.4 Indication lights shall be provided iear the remote control position, control point and in the fire station control room to indicate whether the installation is on automatic or manual control and also to indicate if the system has operated. The following colour shall be used:

Red Automatic control

Green Manual control

Amber System operated

3.7 Shutting Down of Openings in the Space on F’ the total flood installation only, all doors, windows, ventilatio- other openings in walls, floor or roof shall be fitted with we+ operated by gas pressure trips on the carbon dioxide cylinder batte., close the openings. All other openings/crevices, not required for normal use, shall be effectively sealed.

3.8 Gas Pressure Switches -Gas pressure switches shall be incorporated in the installation design to shut down electric fans, electric motors, etc, and to operate alarm lights on a control panel to indicate that gas has discharged.

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NOTE-Gas pressure switches may also be used for sounding electric alarm bells or a siren in casz of installations not having an independent alarm circuit.

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3.9 Control Point

3.9.1 The control point shall comprise the carbon dioxide battery or batteries, indication lights and alarm signals. It shall be so located and arranged that inspection, testing, recharging and maintenance of cylinders may be carried out conveniently and without interruption to the protection afforded by the installation.

3.9.2 The control point shall be located, as near as possible, to the protected hazard or hazards, but shall not be located where it will be exposed to a fire or explosion that might occur in the protected hazards.

3.9.3 Suitable guards or enclosures shall be provided where excessive climatic or mechanical exposures are expected.

3.10 Venting

3.10.1 The venting of flammable vapour and pressure built-up because of discharge of large volumes of carbon dioxide .gas into closed spaces shall also be considered while designing the intallation so as to prevent their spreading to adjacent fire hazards or work areas.

3.10.2 Where safe venting of flammable gases and vapours is not feasible, such as in the case of process and storage tanks, the use of external local application systems shall also be considered in conjunction with the total flood system.

3AO.3 The pressure venting consideration involves such variables as enclosure strength and rate of irrjection of carbon dioxide.

3.11 Pressure Relief Venting

a Il.1 The area necessary for free venting in case of fairly light may be calculated from the following formula, assuming the

r carbon dioxide to be 0.5 m3;kg :

where

X = free venting area in cm!,

R = rate of injection in kg/min/cm: of orifice area,

A = total nozzle orifice area in cm’, and

P = allowable strength of enclosure in kg/cm?.

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For average discharge systems, a rate of 42 kg of CO”/min/cm” may be obtained; while for special high rate systems, a maximum of 18.5 MN/m” ( 185 kgf/cm” ), minimum may be obtained.

3.11.2 In many instances, particularly when hazardous materials are involved, relief openings are already provided for explosion venting. These and other available openings often provide adequate venting.

3.11.3 The normal strength and allowable pressures of average enclosures may be taken as given in Table 12.

TABLE 12 STRENGTH AND ALLOWABLE PRESSURES FOR AVERAGE ENCLOSURES

TYPE OF CONSTRUCTION

(1)

Light building

Normal building

Vault building

SINDAQE

(2)

160 km/h

225 km/h

320 km/h

PRESSURE r__--A____7

MN/m* kg/cm*

(3) (4)

12-5 (125) 25 (250) 50 (500)

HEAD OF WATER

COLUMN

cm

(5)

12.5

25

50

3.12 Electrical Clearance - All components of the installation shall be so located that electrical clearances are maintained from live electric wiring and equipment as given below:

Clearance from CO, equipment to live uninsulated electrical components:

Nominal Line Voltage (kV)

r 0’6

/ 2.5

To ( 5’o 1 15.0

\ 23’0

134.5

Minimum Clearance (cm)

2’5

5.0

7.5

15.00

20’00

30.00

4. TESTS

4.1 Tests shall be carried out to check fulfilment of conditions and specifications given under in respect of the fire extinguishing system.

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These shall include a test for the actual operation of the complete system.

4.1.1 A discharge test shall be made to ensure actuation of all operated trips and interlocked controls time delay devices, alarms and other components. The test shall be generally made with one pilot cylinder. When the fire detection unit actuates the release device eon the pilot cylinder, the discharge shall provide sufficient pressure operated cylinder in the No. 1 position, farthest from the connection of the supply pipe to the manifold. For multiple-hazard systems, sufficient additional tests shall be made to ensure proper operation of the selector valve and interlocks for each hazard. In addition to the automatic detection devices, all manual releases should be tested.

4.1.2 Discharging the entire gas supply shall be made on systems protecting rotating electrical equipment of 3 000 kVA and over or on smaller units that are important to operation and production. The equipment shall be operated at full speed when carbon dioxide is discharged. A concentration of 30 percent should be reached within one minute and maintained while the rotating equipment decelerates but for a minimum of 20 minutes.

4.1.3 Where several similar units of totally enclosed rotating electrical equipment have identical gas requirements, a satisfactory concentration of gas for one unit having greatest gas leakage shall be considered as acceptable. The leakage rate for each unit shall be determined, while it is operating at normal speed, by discharging sufficient gas through the initial discharge nozzles to obtain concentration readings.

4.1.4 Concentration tests shall be made also for total flooding systems where additional compensating gas of 10 percent or more -of normal flooding requirements is provided, as for unprotected openings, ventilating faces that cannot be shut down, or subzero enclosures. Test shall also be made if the adequacy of the quantity of gas becomes questionable. The required concentration shall be determined by the maximum permissible oxygen content for that material creating the

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hazard.

4.1.4.1. Gas samples shall be taken at points at least 0.61 m above highest point of flammable occupancy, except where the hazard occupies the entire enclosure, as rotating electrical equipment may do. Here the sample point shall be at the highest possible point of hazard but in no case below the centre line of the rotating shaft.

4.2 Representative samples drawn from all components of the installation shall be tested individually.

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4.3 The fire alarm system of the installation shall be tested in~accordance with the provisions of IS : 2 189-1976*.

5. INSTRUCTION MANUAL

5.1 An illustrated instruction manual shall be supplied by the manufacturer for the normal operation, testing and maintenance of the installation. It shall contain an ilhtstrated and itemized list of all parts requiring replacement.

6. WORKMANSHIP AND FINISH

6.1 All components of the installation shall be of sound workmanship and finish.

6.2 All parts normally requiring replacement shall be readily available and shall fit correctly.

7. LABELLING AND MARKING

7.1 All operating components of the installation shall be suitably labelled indicating the function mode of operation of each and also suitably marked where required ( set 3 ). /

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*Code of practice for installation of automatic fire alarm system using heat sensitive type fire detectors (jkt revision )

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( Continued fram page 2 )

Code of Practice for Fire Fighting Equipment and Fire Alarm Systems, BDC 22 : 4

Cvnvaner SHRI V. B. NIKAM

Representing

Municipal Corporation of Greater Bombay ( Bombay Fire Brigade ), Bombay .,

Members

CHIEF FIRE OFFICER Delhi Municipal Corporation (Delhi Fire Service ), Delhi

SHRI R. K. BRARD~AJ ( Alternate ) SHRI S. M. DESAI State Bank of India, Bombay SHRI EDWIN D’ SOUZA Electronic Control Device, Bombay

SHRI EUSTAOE D’ SOUZA ( Altsrnate ) SRRI K. R. EASWARAN Mather & Platt ( India ) Ltd, Bombay

SERI S. C. PRBBHU ( Alternate ) FIRE ADVISER Ministry of Home Affairs SHRI A. K. GIJPTA Cent;;or~~~lding Research Institute ( CSIR ),

SHRI MAHENDRA PARSHAD Ministry of Defence ( R & D ) SHHI FAQIR CHAND ( Alternate )

SH~I B. R. MEHTA The Institution of Fire Engineers ( India), New Delhi

SHRI GULSHAN JA~QI ( Altcmutc) SHRI D. K. PODDA~ Tariff Advisory Committee, Bombay

SERI B. SAMANTO ( Alternate ) SHRI J. PRAKASH Prakash Security Devices (I), Allahabad

SRRI P~onro~ PRARASH ( Alternate ) S.HRI HARISH SALOT Vijay Fire Protection Systems Pvt Ltd, Bombay &RI G. K. SEAH~ Steeiage Industries Ltd, Bombay

SHRI M. K. II~ANI ( dlternnte ) SHRI B. V. WANLY Urban Development, Public Health & Housing

Department, Bombay

32

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amagundam

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ate: 18-08-2006 Tim

e 11:16:59