is 15493 (2004): gaseous fire extinguishing …restrictions on the production of certain halon fire...
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IS 15493 (2004): Gaseous Fire Extinguishing Systems -General Requirements [CED 22: Fire Fighting]
IS15493:2004
Indian Standard
GASEOUS FIRE EXTINGUISHING SYSTEMS —GENERAL REQUIREMENTS
ICS 13.220.10
0 BIS 2004
BUREAU OF INDIAN STANDARDSMANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG
NEW DELHI 110002
August 2004 Price Group 10
Fire Fighting Sectional Committee, CED 22
FOREWORD
i’his Indian Standard was adopted by the Bureau of Indian Standards, after the draft finalized by theFire Fighting Sectional Committee had been approved by the Civil Engineering Division Council.
Attention is drawn to Montreal Protocol on substances that deplete the ozone layer. As India is a signatoryto the Protocol. country programme was drafted wherein suitable alternative clean agents have been identifiedin the place of HaIons 1301 and 12I 1. As per the approved programme, this standard has been formulated forthe identified alternatives. The agents covered in this standard are thus introduced in response to internationalrestrictions on the production of certain Halon fire extinguishing agents under the Protocol signed in 1992, asemended.
[t is important that the fire protection of a building or plant be considered as a whole. Gaseous clean agentsystems form only a part, though an important part, of the available facilities, but it should not be assumed that(heir adoption necessarily removes the need to consider supplementary measures, such as the provision of portabletire extinguishers or other mobile appliances for first aid or emergency use, or to deal with special hazards.
Gaseous fire suppression systems covered in these Indian Standards are designed to provide a supply ofgaseo~ls exting~lishillg mediuln for the extinction of fire invo]ving high value assets.
Gaseous clean agents have for many years been a recognized effective medium for the extinction of flammableliquid fires and fires in the presence of electrical and ordinary Class A hazards, but it should not be forgotten, inthe planning of comprehensive schemes, thatthere may be hazards for which these mediums are not suitable, orthat in certain circumstances or situations there may be dangers in their use requiring special precautions. Thesedifficulties have been addressed in this standard.
Various methods of supplying clean agent to, and applying it at, the required point of discharge for fire extinctionhave been developed in recent years, and there is a need for dissemination of information on establishedsystems and methods. This standard has been prepared to meet this need. New requirements to eliminate theneed to release clean agents during testing and commissioning procedures are included. These are linked tothe inclusion of enclosure integrity testing.
The requirements of this Indian Standard are made in the light of the best technical data available at thetime of drafting this standard but, since a wide field is, covered, it has been impracticable to consider everypossible factor or circumstance that might affect implementation of the recommendations.
It has been assumed in the preparation of this Indian Standard that the execution of its provisions isentrusted to people appropriately qualified and experienced in the specification, design, installation, testing,approval, inspection, operation and maintenance of systems and equipment, for whose guidance it has beenprepared, and who can be expected to exercise a duty of care to avoid unnecessary release of clean agent.
Specific requirements and advice on these matters can be obtained from the appropriate manufacturer of theclean agent or the extinguishing system. Information may also be sought from the appropriate fire authority,the health and safety authorities and insurers. In addition, reference should be made as necessary to otherstatutory regulations.
It is essential that fire equipment be carefully maintained to ensure instant readiness when required. Routinemaintenance is liable to be overlooked or given insufficient attention by the owner of the system. The importanceof maintenance cannot be too highly emphasized.
For the purpose of deciding whether a particular requirement of this standard is complied with, the finalvalue, observed or calculated. expressing the result of a test or analysis, shall be rounded off in accordancewith IS 2 : 1960 ‘Rules for rounding off numerical values (revised)’. The number of significant places retainedin the rounded off value should be the same as that of the specified value in this standard.
1S 15493:2004
Indian Standard
GASEOUS FIRE EXTINGUISHING SYSTEMS —GENERAL REQUIREMENTS
1 SCOPE
This standard specifies provisions andrecommendations for general requirements, type ofclean agent and their containers, container arrangement,distribution systems, such as piping, nozzles, pipesupports, alarm system, type of enclosure etc.
NOTES
1 This standard covers the general requirements
applicable to totai tlooding clean agent systems likeHalo-Carbon agents and inert gas agents. In addition,individual requirements for each type of clean agentsystem are covered un-der separate standards. Detaileddesign guidelines are specitied, in other standards. Hencebefore designing a protection with a particular cleanagent, both the standards should be read together. Whereverthere is a difference, the individual standard takesprecedence,
2 This standard prescribes minimum requirements fortotal flooding clean agent tire/extinguishing systems.Protection with carbon dioxide is not covered in thisstandard.
3 Nothing in this standard is intended to restrict newtechnologies or alternate arrangements provided the levelof safety prescribed by this standard is not diluted.
2 REFERENCES
The standards listed in Annex A contain provisionswhich through reference in this text, constituteprovisions of this standard. At the time of publication,the editions indicated were valid. All standards aresubject to revision and the parties to agreementsbased on this standard are encouraged to apply themost recent editions of the standards indicatedin Aflnex A.
3 TERMINOLOGY
For the purpose of this standard, the followingdefinitions shall apply.
3.1 Adjusted Minimum Design Quantity( AMDQ ) — The minimum design quantity of agentthat has been adjusted in consideration of designfactors.
3.2 Approved — Acceptable to a relevant authority.In determining the capability of the installations,the authorities may base their acceptance withappropriate standards. The design and systemapproval shall be from national or internationalapproving authority or lab of repute.
3.3 Authority — The organization, office or individual
responsible for approving installation or equipmentor a procedure.
3.4 Automatic — Performing a function without thenecessity of human intervention.
3.5 Automatic/Manual Switch — A means ofconverting the system from automatic to manual( manual override) and vice-versa.
3.6 Class A Fires — Fire in ordinary combustiblematerials, such as wood, cloth, paper, rubber, manyplastics, electrical and electronic hazards withoutany flammable fiid or gas.
3.7 Class B Fires — Fire in flammable liquids,oils, greases, tars, oil-based paints, lacquers andthe like.
3.8 Clean Agent — Electrically non-conducting,vaporizing, or gaseous clean agent that does notleave a residue upon evaporation. The word agentwherever appearing in this document shall mean asclean agent.
3.9 Clearance — The air distance between cleanagent equipment, including piping and nozzlesand unenclosed or uninsulated live electricalcomponents at other than ground potential.
3.1O Containers — A cylinder or other vessels usedto store the clean agent.
3.11 Container-Discharge Valve — A valve directlyconnected to a container which when actuatedreleases the clean agent into the distributionpiping.
3.12 Control Device— A device to control the sequenceof events leading to the release of clean agent.
3.13 Concentration
3.13.1 Design Concentration — The concentration( including safety factor ) of the clean agentnecessary to extinguish a fire of a particular fuel.
3.13.2 .Extinguishing Concentration — Theconcentration ( without safety factor ) of theagent necessary to extinguish a flame ofa particularfuel at atmospheric pressure.
3.13.3 Hazardous Concentration — Theconcentration that exceeds the LOAEL( see 3.28) for the agent used.
1
.
IS 15493:2004
3.13.4 Injected Concentration — The concentrationof the agent necessary to develop under free effluxconditions the required design concentration.
3.13.5 Maximum Concentration — The concentrationachieved from the actual clean agent quantity at themaximum ambient temperature.
3.13.6 Residual Oxygen Concentration — Theresulting concentration of oxygen achieved withina protected area after the discharge of agent intothe area.
3.14 Design Factor ( DF ) — A fraction of the agentminimum design quantity ( MDQ ) added theretodeemed appropriate due to a specific feature of theprotection application or design of the suppressionsystem.
3.15 Directional Valve — A device for controllingthe passage of the clean agent from a supplymanifold and directed to pre-selected area(s) ofprotection.
3.16 Discharge Inhibit Switch — A manuallyoperated switch that prevents the automatic dischargeof the clean agent.
3.17 Distribution System — All the pipe workand fittings downstream of any container dischargevalve.
3.18 Engineered Systems — A system in whichthe supply of the clean agent stored centrally isdischarged through a system of pipe and nozzles inwhich the size of each section of pipe and nozzleorifice has been calculated in accordance withrelevant clauses of ttiis standard. The design flowrates from nozzles may vary according to the designrequirements of the hazard.
3.19 ‘Fill Density— The mass of gaseous agent perunit volume of container ( kg/m3 ).
3.20 Final Design Quantity ( FDQ ) —A quantityof agent determined from the agent minimumdesign quantity as adjusted to account for designfactors and pressure adjustment.
3.21 Flooding Quantity — Mass or volume of cleanagent required to achieve the design concentrationwithin the protected volume within the specifieddischarge time.
3.22 Gross Volume — The volume enclosed bythe building elements around the protectedenclosure, less the volume of any permanentimpermeable building elements within theenclosure.
3.23 Holding Time — Period of time during which aconcentration of clean agent greater than the fire
2
extinguishing concentration surrounds the hazard.
3.24 Inert Gas Agent — A clean agent that containsas primary components one or more of the gasesIGOI,IG55, IG100or !G541.
3.25 Inerting — The prevention of reignition ofa flammable or explosive atmosphere by establishinga suitable concentration of the clean agent.
3.26 Liquefied Gas — A gas or gas mixture ( normallya halocarbon ) which is liquid at the containerpressurization level at room temperature ( 20°C ).
3.27 Lock-Off Valve — A mechanically operateddevice which prevents a clean agent from beingdischarged through distribution pipe work to theprotected area.
3.28 Lowest Observed Adverse Effect Level( LOAEL ) — The lowest concentration of clean agentat which an adverse toxicological or physiologicaleffect has been observed.
3.29 Manual — Requires a human intervention toaccomplish a function or task.
3.30 Maximum Working Pre-ssure —Equilibriumpressure within a cylinder at the maximum workingtemperature. For liquefied gases, this is at maximumfill density and may include super-pressurization, ifapplicable.
3.31 Minimum Design Quantity ( MDQ ) — Thequantity of agent required to achieve the calculatedminimum design concentration.
3.32 Monitoring — The supervision of the operatingintegrity of an electrical, mechanical, pneumatic orhydraulic control feature of a system.
3.33 No Observed Adverse Effect Level( NOAEL ) — The highest concentration of a cleanagent at which no adverse toxicological orphysiological effect has been observed.
3.34 Non-liquefied Gas — Gas or gas mixturewhich, under reserve pressure and allowablereserve temperature conditions, is always presentin a gaseous form.
3.35 Normally Occupied Area — An area where,under normal circumstances, humans are present.
3.36 Normally Unoccupied Area — Area notoccupied by people but may be occasionallyentered for brief periods.
3.37 Nominal Size — A numerical designation .ofsize which is common to all components in a pipingsystem other than components designated byoutside diameters or by thread size. It is a convenientround number for reference purposes and is only
IS 15493:2004
loosely related to manufacturing dimensions. 4 GENERAL INFORMATION AND
3.38 Operating Device — Any component involvedREQUIREMENTS
between actuation and release mechanisms, 4.1 General
3.39 Pre-engineered Systems — Those having 4.1.1 Extinguishing gases are thr.ee-dirnensionalpre-determined flow rates. nozzle pressures and agents that are used effectively to suppress firequantities of clean agent. These systems have the through physical or chemical action. Separatespecific pipe size, maximum and minimum pipe properties of specific gases are provided in otherlengths, flexible hose specifications, number of parts of this standard.titt~ngs and number and types of nozzles prescribedby a testing laboratory.
3.40 Primary Release — Release of clean agentinitiated by detection system or manual operationunder normal operating conditions.
3.41 Release — The opening of the cylinder anddirectional valves leading to the physical dischargeor emission of clean agent into the enclosure.
3.42 Safety Factor ( SF ) — A multiplier of theagent flame extinguishing or inertingconcentration to determine the agent minimumdesign concentration.
3.43 Safety Interlock — A switch that monitors theoccupation of the protected area and automaticallyinhibits the discharge of the clean agent when thearea is occupied.
3.44 Sea Level Equivalent of Agent — The agentconcentration ( volume, percent ) at sea level forwhich the partial pressure of agent matchesthe ambient partial pressure of agent at a givenaltitude.
3.45 Sea Level Equivalent of”Oxygen — The oxygenconcentration ( volume, percent ) at sea level forwhich the partial pressure of oxygen matches theambient partial pressure of oxygen at a givenaltitude.
3.46 Secondary Release ( Slave) —A release thatis a consequence and dependent on the operationof the primary release, for example, pneumaticconnection.
3.47 Super-pressurization — The addition of a gasto the clean agent container, where necessary, toachieve the required pressure for proper systemoperation.
3.48 Total Flooding — The act and manner ofdischarging an agent for the purpose of achieving aspecified minimum agent concentration throughouta hazard volume.
3.49 Total Flooding Systems — A fire fighting systemthat is arranged to discharge cl,ean agent into anenclosed space to achieve the appropriate designconcentration.
4.1.2 Gaseous total flooding systems may be usedto suppress fires of Classes A and B type as definedin 3.6 and 3.7. However, for suppressing fires whereflammable gases may be present, the possibility ofexplosion, during and after system discharge shouldbe considered.
4.1.3 Clean agent gas extinguishing systems areuseful within the Iimits. of this standard inextinguishing fires in specific hazards or equipmentand in occupancies where “an electrically non-conductive medium is essential or desirable, or whereclean-up of other media poses a problem.
4.1.4 Where clean agent gas extinguish& systemsare used, a fixed enclosure shall be provided aboutthe hazard that is adequate to enable the specificconcentration to be achieved and maintained for the=specified period of time.
4.1.5 The effects of agent decomposition on fireprotection effectiveness shall be considered whenusing clean agents in hazards with high temperatures( for example, furnaces and ovens, etc ).
4.1.6 The design, installation, service andmaintenance of the gas extinguishing systemsshall be performed by those competent in therespective field in accordance with IS 15496:2004.
4.1.7 The installer of the clean agent system shallbe certified by a reputed national/internationalagency/laboratory and sLIch certification shall bevalid at the time of installation.
4.2 Suitability and Application
4.2.1 Total Flooding Svstems
Gaseous fire extinguishing systems are usedprimarily to protect hazards that are in enclosures orequipment that, in itself, includes an enclosure tocontain the agent for establishment of requiredconcentration and maintenance thereof for therequired pwiod. Some typical hazards that maybe suitable include, but or not limited to, thefollowing:
a) Within enclosures, such as rooms, vaults,enclosed machines, containers, storage tanksand bins;
3
1S 15493:2004
b) For enclosed electrical hazards, such astransformers, control cubicles, switch boards,circuit breakers, and rotating equipment;
c) Forenclosed flammable liquid/gas storageand processing areas;
d) For engines using tlammable fuels;
e) For electronic hazards, such as computers,data processing equipment, control room,telecommunication facilities;
t) Sub-floors and other concealed spaces; and
g) Other high value assets.
4.2.2 Some of the gaseous fire extinguishingsystems may also be used for explosion preventionand suppression where flammable materials maycollect in confined area.
4.3 Limitations
4.3.1 Gaseous fire extinguishing systems shallnot be used on tires involving the following materialsunless they are pre-evaluated for the purpose:
a)
b)
c)
d)
e)
f)
Certain chemicals or mixture of chemicals,such as cellulose nitrate, gun powder, whichare capable of rapid oxidation in the absenceof air;
Reactive metals, such as lithium, sodium,potassium, magnesium, titanium, zirconium,and plutonium;
Metal hydrides or metal amides, some of whichmay react violently with some gaseousagents;
Chemicals capable of undergoing auto-thermal decomposition, such as certainorganic peroxides and hydrazine or;
Mixtures containing oxidizing materials, suchas sodium chlorate or sodium nitrate; and
Environments where significant surfaceareas exist at temperatures greater thanthe breakdown temperature of theextinguishing agent and are heated by
means other than the tire.
4.3.2 Electrostatic charging of non-groundedconductors may occur during the discharge ofgaseous fire extinguishing systems. Theseconductors may discharge to other objects causingan electric arc of sufficient charge to initiate explosionin potentially explosive atmospheres.
4.4 Other Information
4.4.1 All devices in respect of the gaseous fireextinguishing systems shall be designed for theservice they will encounter and shall not be readilyrendered inoperative or susceptible to accidentaloperation. Normally, the system components shall bedesigned to function properly from – 210 to 55°Cor marked to indicate temperature limitations inaccordance with the specifications.
4.4.2 Gaseous fire extinguishing systems may beemployed to protect more than one enclosure, ifnecessary, by means of directional valves. Wherethere are two or more enclosures simultaneouslyinvolved in a fire by reason of their proximity, suchenclosures shall be protected by individualsystems designed to allow simultaneous operation,or a single system sized and arranged to dischargeon all potentially involved hazards simultaneously.
4.4.3 Systems employing simultaneous dischargeof different agents to protect the same enclosureshall not be permitted.
4.5 Applicability of Clean Agents
4.5.1 The fire extinguishing clean agents addressedin the standard are electrically non-conducting andleave no residue upon evaporation.
4.5.2 Tables I and IA show the details of cleanagents that are covered in this standard. Whilerequirements that are common to all these agentsare prescribed in this standard, individualrequirements for each agent are covered underseparate standards.
Table 1 Halocarbon Agents
( Clause 4.5.2 )
SI No. Clean AgentFormulae
(1) (2)
i) CHC12CF~CHC1F2CHCIFCF3( Detoxified )
ii) CF3CHFCFJ
Chemical Name CommercialName
(3) (4)
Dichiorotritluoroethane ( HCFC- 123,4.75 percent )Chlorodifloromethane ( HCFC-22. HCFC Blend A82 percent}Chlorotetrafluoroethane ( HCFC- 124,9.5 percent )Isoproponyl - 1-Illetllylcyclollcxtille( 3.75 percent )
Heptatluoropropane HFC-227ea
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IS 15493:2004
Table IA Inert Gas Agents
( C/uuse 4.5.2 )
SI No. Clean AgentFormulae
(1) (2)
i) Ar
ii) Nz
iii) NzAr
iv) NzArC02
Chemical Name CommercialName
(3) (4)
Argon ( 100 percent ) lGO1
Nitrogen ( 100 percent ) IG 100
Nitrogen ( 50 percent )Argon ( 50 percent ) ICi 55
Nitrogen ( 52 percent )Argon ( 40 percent ) [G 541Carbon dioxide ( 8 percent )
4.5.3 As such, both these standards, that is, forgeneral and individual requirements should be readtogether before designing a system. Whererequirements in both the standards differ, standardcovering individual requirements shall takeprecedence.
5 REQUIREMENTS REGARDING SUBM1SS1ONOF PLANS
Plans shall contain sufficient details to enable anevaluation of the protected enclosure(s) or localprotection(s) vis-a-vis the effectiveness of thesystem. Details shall include the property involvedin the hazard(s), location(s), the enclosure limitsand isolation of the hazards and the exposure of thehazards.
5.1 Plans for submission to the authorities shallbe drawn up in accordance with the followingrequirements:
a)
b)
c)
d)
e)
f)
~)
h)
Plans for integrity of fittings shall be clear,contain all required details includingscale and point of compass and shall be clearlydated;
Name of the enterprise, location and
detailed postal address;
Location and construction of the protectedenclosures, walls and partitions;
Cross and longitudinal sectional elevationsof the protection enclosures showing thefull height, schematic diagram, ceilings, falsefloors, etc;
Type of clean agent proposed to be used;
Concentration summary, that is, design,extinguishing, injected and inerting, etc:
Type of the hazards proposed to beprotected including descriptions of theoccupancies, surroundings, wall/ceilingopenings, etc;
Location of the gas containers and
5
j)
k)
m)
n)
P)
0
r)
s)
t)
u)
v)
details of the contents, such as volume,pressure, nominal capacity in agent mass atstandard conditions of temperatures andpressures;
Descriptions of pipes and fittingsindicating also their specifications, pressureratings, etc;
Descriptions of nozzles employedindicating their size, orifice area, type,angle, etc, and their locations;
Electrical cabling and terminations;
Descriptions of detectors employedindicating their locations, mounting, etc;
Bill of material and equipment schedule foreach component proposed for the syste]n.Suppliers/manufacturer-s names, details ofapprovals, quantity, etc;
Isometric drawings showing the agentdistribution system indicating the lengthsand diameters of each pipe segment, nodalreference, fittings including unions, reducers,orifices, strainers, nozzles, flow rates in allsegments, equivalent orifice areas, etc;
Plan view of the enclosures showing theentire agent piping system along withceiling, floors, false floors, walls, partitions,pipe supports, agent containers, cabling,panels, detectors, etc;
Details showing the pipe supports, agentcontainer securement, etc;
Location of ducts and similar devices,dampers, air handling systems, ventingarrangements and their details withsupporting calculations, etc;
Schematic display of the operation of thesystem giving chmnologica] sequence ofoperations prior to the discharge of the agentinto the protected enclosures;
Schematic diagrams showing the location
IS 15493:2004
w)
Y)
and layout of all the power and indicatingequipment connections, control panels,annunciate panels, etc;
Tables showing the calculations for enclosurevolumes, agent quantity, methods used todetermine number and location of audibleand visual indicating equipment, number andlocation of detectors, etc; and
Other features like interconnection withother type of fire protection systems, etc, withthe proposed system.
5.2 The details of the system shall includeinformation and calculations on the amount of agent;container storage pressure; internal volume of thecontainers; the location, type and flow rate of eachnozzle including equivalent orifice area; the location,size and equivalent lengths of pipe, fittings, siphontube, valve, discharge head and flexible connectorhose; and the location and size of the storage facility.Pipe size reductions and orientation of tees shall beclearly indicated. Details shall be available on locationand function of the detection devices, operatingdevices, auxiliary equipment and electrical circuitry.All the apparatus, equipment used in the system shallbe easily identifiable.
5.3 An as-built drawing shall be submitted uponcompletion of the installation for approval. Instructionand maintenance manuals that include a fullsequence of operations and a full set of drawings andcalculations shall be available on site.
5.4 Flow Calculations
System flow calculations along with the workingdrawings shall be submitted to the authorities inadvance for approval. The hydraulic calculationsshall be performed using calculation method approvedby the authorities.
6 SAFETY REQUIREM-ENTS
6.1 Safety Precautions ( for Personnel)
The discharge of some of the gas agents in fireextinguishing concentrations creates serious hazardsfor personnel in both the protected area and the areasto which the gas may migrate and also to propertiesin the vicinity of agent discharge. These hazards mayinclude reduced visibility, suffocation and toxicity,during and afterthe discharge period. The relevantinformation on the above is available in Annex B.
The tox[city information on the gaseous fire agentsis given in Table 2. More details are specified inother relevant standard. Where hazardousconcentrations of agent may exist, Iock-offvalves shallbe fitted to the system.
In areas, where there is a likelihood of significantdifference between gross and net volumes of theenclosure, utmost care shall be exercised in pnopersystem design to ensure that maximum concentrationsare not exceeded.
6.1.1 Safety Precautions (for Protected Areas )
a)
b)
6.1.2
Normally occupied area — The minimumsafety precautions taken shall be inaccordance with Table 2A and provisionstherein, and
Normally unoccupied areas — The maximumconcentration shall not exceed the LOAELfor the agent used unless a lock-off valve isfitted.
Warning — Any change to the enclosurevolume, or addition or removal of contentsthat was not covered in the original designwill affect the concentration of agent. In suchinstances the system shall be re-calculatedto ensure that the required designconcentration is achieved and that the NOAELor the LOAEL are not exceeded.
For unoccupiable areas, the maximumconcentration may “exceed the LOAEL for theextinguishant used, without the need for a lock-off valve to be fitted.
6.1.3 Protection of Occupants
In any use of the gaseous system, where there is apossibility that people may enter or have difficultyseeking egress from the protected enclosure, suitablesafeguards shall be provided. Such safety aspectsas personal training, warning signs, pre-dischargealarms and safety interlocks shall be provided. Meansof proper ventilation after fire should be readilyavailable.
6.2 Safety Precautions ( Total Flooding Systems)
6.2.1 In areas protected by total flooding systems,that are capable of being occupied, the provision ofthe following safety aspects shall apply:
a) Mandatory requirements:
1)
2)
A time delay shall be provided forevacuation prior to agent discharge.The agent discharge delay time shall bebased on an engineering assessment ofegress time for occupants in the areaprotected,
Safety interlocks and lock-off valvesshall be provided wherever requiredas per Table 2.
6
1S 15493:2004
Table2 Toxicity Information on Clean Agent Suppression Systems
( Clauses 6.1 and6.2.l )
S1 No.
(1)
i)
ii)
iii)
iv)
v)
vi)
Clean Agent
(2)
HCFCBlend A
HFC-227ea
IG-541
IG-55
IG-1OO
IG-01
Chemical Formula
(3)
CHC12CF3 ( 4.75 percent )CHCIF2 ( 82 percent )CHC1FCF3 ( 9.5 percent )Detoxified (3.75 percent)
CF2CHFCF3
Nitrogen ( 52 percent )Argon ( 40 percent )Carbon dioxide ( 8 percent )
Nitrogen ( 50 percent )Argon ( 50 percent )
Nitrogen ( 100 percent )
Argon ( 100 percent )
NOAEL LOAEL LC50 or ALC( Percentage by Volume )
r(4) (5) (6)
10 >10 64
9 10.5 >80
43 52 Notapplicable
43 52 Notapplicable
43 52 Notapplicable
43 52 Notapplicable
Table 2A Minimum Safety Precautions
( Clauses 6.1.1 and%.2.l )
S1 No. Injected Agent RequirementsLevels r
Inhibit Egress Safety Lock-off’Switch and in 30 s Interlock Valve
Time Delay
(1) (2) (3) (4) (5) (6)
i) Up to NOAEL Required Not required Not required Not required
ii) Above NOAEL and Required Required Required Not requiredup to LOAEL
iii) Above LOAEL Required Not Applicable’) Required Required
NOTE — The-purpose of the table is to avoid unnecessary exposure ot’occupants to the agent discharged, Factors suchas the time for egress and the risk to the occupants by the fire must be considered when determining the system dischargetime delay.
1)con~ntration levels above LOAEL are-not permitted in occupied areas and question of egress does not ark.
3)
4)
5)
6)
m
Exit routes which shall be kept clear atall times and the provision ofemergency lighting and adequatedirection signs to minimize traveldistances,
Outward swinging self-closing doorswhich can be opened from insideincluding when locked from the outside,
Continuous visual and audible aIarmsat entrances and designated exits untilthe protected area has been made safe,
Warning and instruction signs shall bearranged as per clause,
Pre-discharge alarms within such areasthat are distinctive from all other alarmsignals and that will operate immediatelyupon detection of fire,
7
8)
9)
Means of prompt ventilation of such areasafter any discharge of agent. Forced draftventilation will often be necessary. Careshall be taken to completely dissipatehazardous atmospheres and not justmove them to other locations, as agentsare generally heavier than air, and
instructions and drills of all personnelwithin or in the vicinity of protectedareas, including maintenance andconstruction personnel who may bebrought into the area, to ensure theircorrect actions when the system operates.
b) Recommendatory requirements:
1) Adding an odour to the agent so thatthe hazardous atmospheres arerecognizable,
IS 15493:2004
2) Self-contained breathing apparatusand personnel trained for its use, and
3) Means to detect a hazardousatmosphere in or around the protectedarea.
6.2.2 Electrostatic Discharge
To avoid a situation as stated in 4.3.2, the componentsof the inerting system, such as pipe work, etc, shallbe bonded and earthed as per National ElectricalCode( SP30 : 1985).
6.3 Miscellaneous Hazards
Certain other types of hazards associated with theusage of gaseous systems are as under:
a) Noise — Discharge ofa gaseous system cancause a noise loud enough to be startling,but not enough to cause traumatic injury;
b) Turbulence — The turbulence caused by thehigh velocity discharge from nozzles may besufficient to dislodge substantial objectsdirectly in its path, such as ceiling tiles andlight fittings. Therefore, tiles and light fittingsshould be properly anchored. Systemdischarge may also cause enough generalturbulence in the enclosure to move unsecured-paper and light objects;
c) Elec~rical clearance — Where exposedelectrical conductors are present, all systemcomponents shall be located no less thanthe minimum clearances from the energizedparts. The clearances stipulated in NationalElectrical Code shall be maintained for safeoperating conditions. Where the design basicinsulation level is not available and wherenominal voltage is used for the design criteriathe highest minimum clearance listed for thepurpose shall be used; and
d) Other hazards, if any, appropriate to theselected gaseous agent as specified in theother clauses of this standard shall be givendue attention.
7 REQUIREM-ENTS FOR THE PROTECTEDENCLOSURES
7.1 Unclosable Openings
a)
b)
The protected enclosure shall have sufficientstructural strength and integrity to containthe agent discharge;
The area of the unclosable openings suchas ventilator openings within the enclosureshall be kept to as least as possible to avoidingress of the agent through the leakagesto the adjoining areas. Where confinementof the agent within the enclosure is not
c)
d)
e)
f)
g)
practicable, protection shall be extendedto include the adjacent connected hazardsor work areas;
Particular attention should be given toopenings around cable, duct and pipelines( similar utility services ) penetratingthrough the wall(s) and floor(s);
In case of unavoidable openings, suchopenings should be restricted to as minimumas possible;
In such cases, quantity of agent need to besuitably increased in consultation with theauthorities concerned for maintaining thedesired concentration within theenclosure;
In case of item (c) above, the openingsshould be effectively sealed or preferablyfire studded; and
Injecting more quantity of agent in most ofthe cases, will only increase the rate of lossof agent through such openings. Hence,openings in the wall(s) and floor(s) shall bekept only to optimum requirements withincrease in quantity of agent as discussedin item (d) above.
7.2 Air Handling System and Similar Services
a) Humidification and air handling systemscatering to the protected areas shall becapable of automatic shutdown prior to theagent discharge, Also dampers shall beavailable inside the systems to stop flowof agent through ducts and similar meansand these shall close automatically prior toagent discharge;
b) Where it is necessary for air handlingsystems to be kept operating to providecooling arrangement for essential equipment,quantity of the agent shall need to besuitably increased to include the volumes ofboth air and the ventilation system inaddition to the volume of protectedenclosure in consultation with the authoritiesconcerned for maintaining the desiredconcentration within the enclosure;
c) The operations within the enclosure thatare likely to di-sperse the discharge of theagent, such as pumps, spray guns, heaters,etc, shall not be left running during thedischarge of the agent and suitable provisionsshall be available to shut them down priorto agent discharge; and
d) In case of extinguishment of deep-seatedfires such as those involving solids.Unclosable openings shall be provided
8
only in the ceiling level and such openingsnear the walls and partitions shall beavoided.
8 COMPONENTS OF GASEOUS FLOODINGSYSTEMS
8.1 Agent Supply and Container Arrangement
8.1.1 Agent Supply
a)
b)
c)
d)
Quality Requirement — The clean agentshall comply with quality and puritystandards appr~priate to the agent selectedfor extinguishment. Each batch of agentmanufactured shall be tested and certifiedto applicable specification. Agent blendsshall remain homogeneous in storage anduse within the approved temperaturerange and envirornnental conditions at theplace of installation;
Quantity Requirements ( Main ) – Theamount of agent in the system shall be atleast sufficient for the largest singlehazard or group of hazards to be protectedsimultaneously;
Quantity Requirements (Reserve) – Samequantity equivalent to the largest singlehazard or group of hazards to be protectedsimultaneously shall be available asreserve. However, if the replenishing ofagent supply takes more than 7 days at thesite of installation, authority concernedmay insist on more quantity to be keptavailable as reserve; and
Uninterrupted Protection — Whereuninterrupted protection is required, boththe main and reserve supply shall bepermanently connected to the distributionpiping and arranged for easy change-over.
t?.1.2 Agent Storage
a)
b)
c)
d)
Agent shall be stored in containers designedto hold that specific agent at ambienttemperatures,
Agent containers shall be charged to a filldensity or super-pressurization level withrange specified by the manufacturers,
Agent storage temperatures shall notexceed 55°C or be less than–21 “C. Externalheating or cooling shall be employed tokeep the temperature of the agent storagecontainer within the above limits if situationwarrants so,
The agent containers used in the floodingsystems shall be designed to meet therequirements of the Department of
IS 15493:2004
Explosives, Nagpur,
Each agent container shall have apermanent nameplate or other permanentmarking that indicate the details asper Table 4.
A reliable means shall be provided todetermine the pressure in refillable super-pressurized containers, and
Th~ agent containers connected to acommon manifold shall conform as per theprovisions in Table 5.
Table 4 Marking on Storage Container
[ Clause 8. 1.2(e) ]
S1 No. Clean Agent Marking on Container
(1) (2) (3)
i) Halocarbon clean Name of the agentTare and agents gross weightsSuper-pressurization level ofthe container
ii) inert gas clean Name of the agentagent Pressurization level of the
containerNominal agent volume
Table 5 Arrangement of Containers withCommon Manifold
[ C/ause 8. 1.2(g) ]
S1 No. Clean Agent Containers withCommon Manifold
(1) (2) (3)
i) Halocarbon clean Agents in a multipleagents container system — all
ii)
containers supplying thesame manifold outlet fordistribution of the sameagent shall beinterchangeable, of samenominal size and ca~acitv.filled with same n;min;lmass of agent andpressurized to the samenominal working pressure
Inert gas clean Agents shall be permitted toagents utilize multiple storage
container sizes connectedto the common manifoldprovided the containers areall pressurized to the samenominal working pressure
8.1.3 Storage Container Arrangement
The arrangement of storage containers andaccessories shall be as follows:
a) Containers and accessories shall be locatedand arranged so that inspection testing,
9
IS 15493:2004
b)
c)
d)
e)
9
g)
h)
recharging and other maintenance isfacilitated, and interruption to protection iskept to a minimum;
Containers should be located outside andas near as practical to the enclosureprotected. Containers protecting a singlerisk can be located within the enclosurethey serve, only if sited so as to minimizethe risk of exposure to fire and explosion;
Containers shall be located so as not to besubject to severe weather conditions or tomechanical, chemical or other damage.Where excessive climatic or mechanicalexposures are expected, suitable guards orenclosures shall be provided;
Containers shall be adequately mountedto allow free passage of air around the baseand suitably supported to provide forconvenient individual servicing or contentweighing. There shall be enough spacefor a full on-site inspection of the base ofthe container;
In manifold systems, non-return valvesor other automatic means shall be providedto prevent a loss of agent and to ensurepersonnel safety if the system is operatedwhen any containers are removed formaintenance;
Containers brackets or devices integralwith the container for attachment tostructures shall be designed to cater for themaximum expected mass, vibration effectsand shock loading, appropriate to theinstallation;
Reserve containers, where provided, shallbe permanently sited or arranged for easychangeover; and
Storage containers are located in areaswhere their leakage could lead to ahazardous concentration, considerationshall be given to the installation of gasdetectors or other means to providewarning on the onset of hazardousconditions.
8.2 Agent Distribution Arrangements
8.2.1 General
a) Pipe network, fitting shall be of non-combustible construction having physicaland chemical properties such that theirintegrity under stress can be predicted withreliability;
b) In severely corrosive atmospheres, special
c)
d)
e)
0
@
corrosion resistant materials shall berequired for pipes, fittings or supportbrackets and steelwork;
Before final assembly, pipes and fittingsshall be inspected visually to ensure theyare free of burrs, swelter and rust and thatno foreign matter is inside and the full boreis clear. After assembly, the system shall”bethoroughly blown through with dry air orcompressed gas. The pipe work shall be.freeof particulate matter and oil residue beforethe installation of nozzles and dischargedevices;
A dirt trap consisting of a ‘tee’ with a cappednipple at least 50 mm long should beinstalled at the end of each pipe run. Draintraps should also be necessary if there is apossibility ofa build-up of water;
In systems where valve arrangementsintroduce sections of closed piping, suchsections shall be equipped with thefollowing:
1) Indication of agent trapped in piping;
2) Means for safe manual venting; and
3) Automatic relief of excess prtssure,where required.
Pressure relief devices, which can includethe selector valve, shall be fitted so thatthe discharge, in the event of operation, willnot endanger the personnel; and
In systems using pressure-operatedcontainer valves, automatic means shall beprovided to vent any container leakage thatcould build up pressure in the pilot systemand cause unwanted opening of the containervalve. The means provided for pressureventing shall not prevent operation of thecontainer valve.
8.2.2 Piping Network
8.2.2.1 The piping used in the installation shallconform to the following requirements:
a)
b)
c)
10
Cast iron or non-metallic pipes shall not beused anywhere;
Where used, flexible pipes, tubing, or hosesincluding connections shall be of approvedmaterials with adequate temperature andpressure ratings; and
The thickness of the pipes shall be inaccordance with the provisions laid downin IS 6631. The internal pressure used forthis calculation shall not be less than thegreater of either of the following values:
IS 15493:2004
1) The normal charging pressure in theagent container at21°C.
2) 80 percent of the maximum pressure inthe agent container at the maximumstorage temperature of not less than55°C using the maximum allowable filldensity specified by the manufacturer,inapplicable.
d) Pipe joints shall be either threaded, weldedor flanged type only and other types ofjointing shall not be allowed.
In no case shall the value used, for the minimumpiping design pressure, be less than that specified inTables 6 and 7 for the conditions shown.
For halocarbon agents Table 6 shall be used and forinert gas agents Table 7 shall be used.
Where different fill densities, pressurization levelsor higher storage temperatures other than the
values shown in the tables are used with prioracceptance of the -authorities, the minimum designpressure for the piping -shall be adjusted to themaximum pressure in the agent container atmaximum temperature, using the basic designcriteria specified in items C(1) and c(2) above.
8.2,3 Pipe Fittings
a) The sizes and dimensions of pipe fittingsshall be in accordance with 1S 1239 ( Part 2 ).Fittings shall be capable to withstandminimum rated working pressure equal to orgreater than the minimum workingpressure specified in 8.2.2.1 (c) for the cleanagent being used. For systems that use apressure reducing device in the distributionpiping, the fittings downstream the deviceshall have a minimum rated workingpressure equal to or greater than themaximum anticipated pressure in thedownstream piping;
Table6 Minimum Design Working Pressure for Halocarbon Clean Agent System Piping
( Clause 8.2.2.1)
S1 No. Clean Agent Agent ContainerMaximum Fill
Densitykg/m2
(1) (2) (3)
i) HFC-227ea 9921 1521 120
ii) HCFCBlendA 900900
I)SuPer.Pressurized with nitrogen.
Agent ContainerChargingPressureat 21OC
kPa
(4)
1 0341)2 482])4 1371)
4 1371)2 4821)
Agent ContainerChargingPressure
at 55°CkPa
(5)
1 70335854950
58603723
MinimumPiping Design
Pressureat 21°C
kPa
(6)
1 36528683958
46892979
Table 7 Minimum Design Working Pressure for Inert Gas Clean Agent System Piping
( Clause 8.2.2.1)
S1 No. Clean Agent Agent ContainerCharging Pressure
at 21°CkPa
(1) (2) (3)
i) IG-O I 1634120424
ii) IG-541 1499719996
iii) IG-55 155212042430636
iv) IG-100 1658022311
Agent ContainerCharging Pressure
at 55°CkPa
(4)
1827122778
1775523671
170652275334 130
1930026014
Minimum Design Pressure at 21°CrPiping Upstream
>Piping
of Pressure DownstreamReducer of Pressure
kPa ReducerkPa
(5) (6)
16341 672314997 6728
14997 689519996 6895
15318 655020424 655030633 6550
16580 689522311 6895
11
IS 15493:2004
b) Cast iron fittings shall not be used Allthreads used in joints and fittings shallcomply with relevant Indian Standards;
c) Welding ofjoints shall comply with relevantIndian Standards; and.
d) Where copper, stainless steel, or othersuitable tubing is jointed with compressiontype fittings, manufacturers pressure andtemperature ratings of the fittings shallnot be exceeded.
8.2.4 Pipe Installation and Supports
a) In the installation of pipe work, care shall betaken to avoid possible restrictions due toforeign matter, faulty fabrication or improperinstallation. Pipe ends shall be reamed aftercutting, where required;
b) Where there is a possibility of explosions,the piping shall be attached to supports thatare least likely to be displaced; and
c) The maximum distance between supports shalltake into account the total mass of pipe andthe agent used. Distance between supportsis indicated in Table 8.
Table 8 Maximum Pipe Work Distances
[ Clause 8.2.4(c)]
S1 No.
(1)
i)
ii)
iii)
iv)
v)
vi)
vii)
viii)
ix)
x)
xi)
xii)
xiii)
xiv)
Nominal Diameterof Pipe
mm
(2)
6
10
15
20
25
32
40
50
65
80
100
125
150
200
Maximum PipeWork Distance
mm
(3)
0.5
1
1.5
1.s
2.1
2.4
2.7
3.4
3.5
3.7
4.3
4.8
5.2
5.8
8.2.5 Discharge Nozzles
a)
b)
Nozzles, including nozzles directlyattached to containers, shall be of approvedtype and located with the geometry of theenclosure under consideration.
The type, number and placement of
12
nozzles shall be such that:
1)
2)
3)
4)
5)
6)
The design concentration shall beachieved in all parts of the enclosure;
The discharge shall not unduly splashflammable liquids or create dust cloudsthat might extend the fire, create anexplosion or otherwise adversely affectthe occupants;
The velocity of discharge shall notadversely affect the enclosure or itscontents;
The discharge nozzles shall be providedwith frangible discs or blow-out capswhere clogging by foreign materials ispossible. These devices shall providean unobstructed opening upon systemoperation and shall be arranged so theywill not injure personnel;
.Nozzle shall be suitable for theintended use and shall be approved fordischarge characteristics. The dischargenozzle consists of the orifice and anyassociated horn, shield or baffle;
Nozzles shall be of adequate strengthfor use”with the expected workingpressures, be able to resist nominalmechanical abuse, and be constructedto withstand expected temperatureswithout deformation; and
Nozzle discharge orifice inserts shallbe ofcorrosion-resistant material.
order to minimize the possibility ofc) Inlifting or displacement of lightweightceiling tiles, precautions shall be taken tosecurely anchor the tiles for a minimumdistance of 1.5 m from each discharge nozzle.
9 DETECTION, ACTUATION, ALARM ANDCONTROL SYSTEMS
9.1 General
9.1.1 Detection, actuation, alarm and controlsystems shall be installed, tested and maintainedin accordance with 1S2189.
9.1.2 Automatic detection and automatic actuationshall be used.
9.2 Automatic Detection
9.2.1 Automatic detection shall be by anyapproved method or device capable of detectingand indicating heat, flame, smoke, combustiblevapours or any abnormal condition in the hazard,such as process trouble, that is likely to producefiie.
1S 15493:2004
9.2.2 Adequate and reliable primary and 24 hminimum standby sources of energy shall be used toprovide for operation of the detection, signaling,control and actuation requirements of the system,
9.2.3 When a new agent system is being installedin a space that has an existing detection system, ananalysis shall be made of the detection devices toassure that the detection system is in goodoperating condition and will respond promptly to afire situation. This analysis shall be done to assistin limiting the decomposition products from asuppression event.
9.3 Operating Devices
9.3.1 Operating devices shail include agentreleasing devices or valves, discharge controls andshutdown equipment necessary for successfulperformance of the system.
9.3.2 Operation shall be by approved mechanical,electrical or pneumatic means, adequate and reliablesource of energy shall be used.
9.3.3 All devices shall be designed for theservice they will encounter and shall not readily berendered inoperative or .iusceptible to accidentaloperation. Devices normally shall be designed tofunction properly from –2OOto 55°C or marked toindicate temperature limitations.
NOTE — Also care shall be taken to thoroughlyevaluate and correct any factors that could result inunwanted discharge.
9.3.4 All devices shall be located, installed or suitablyprotected so that they are not subject to mechanical,chemical or other damage that would render theminoperative.
9.3.5 A mean of manual release of the systemshall be provided. Manual release shall beaccomplished by a mechanical manual release orby an electrical manual release when the controlequipment monitors the battery voltage level of thestandby battery supply and will provide a lowbattery signal. The release shall causesimultaneous operation of automatically operatedvalves controlling agent release and distribution.
9.3.6 The normal manual control(s) for actuationshall be located for easy accessibility at all times,including at the time of a fire. The manual control(s)shall be of distinct appearance and clearly recognizablefor the purpose intended. Operation of any controlshall cause the complete system to operate in its normalfashion.
control for activation shal I be located not more than1.2 m above the floor.
9.3.8 Where gas pressure from the system or pilotcontainers is used as a means for releasing theremaining containers, the supply and dischargerate shall be designed for releasing all of theremaining containers.
9.3.9 All devices for shutting down supplementaryequipment shall be considered integral part of thesystem and shall function with the systemoperation.
9.3.10 All manual operating devices shall beidentified as to the hazard they protect.
9.4 Control Equipment
9.4.1 Electric Control Equipment
The control equipment shall supervise theactuating devices and associated wiring and, asrequired, cause actuation. The control equipmentshall be specifically listed for the number and typeof actuating devices utilized and their compatibilityshall have been approved.
9.4.2 Pneumatic Control Equipment
Where pneumatic control equipment is used, thelines shall be protected against crimping andmechanical damage. Where installations could beexposed to conditions that could lead to loss ofintegrity of the pneumatic lines, special precautionsshall be taken to ensure that no loss of integrity willoccur. The control equipment shall be specificallylisted for the number and type of actuating devicesutilized and their compatibility shall have beenapproved.
9.5 Operating Alarms and Indicators
9.5.1 Alarms or indicators or both shall be used toindicate the operation of the system, hazards topersonnel, or failure of any supervised device. Thetype ( audible, visual or olfactory ), number, andlocation of the devices shall be such that theirpurpose is satisfactorily accomplished. The extentand type of alarms or indicator equipment or bothshall be approved.
9.5.2 Audible and visual pre-discharge alarms shallbe provided within the protected area to give positivewarning of impending discharge. The operation ofthe warning devices shall be continued after agentdischarge until positive action has been taken toacknowledge the alarm and proceed with appropriateaction.
9.3.7 Manual controls shall not require a pull ofmore than 18.1 kg ( 178 N ) nor a movement of more 9.5.3 Abort switches generally are notthan 355 mm to secure operation. At least one manual recommended, however, where provided, the abort
13
IS 15493:2004
switches shall be located within the protected areaand shall be located near the means of egress fromthe area. An abort switch shall not be operatedunless the cause for the condition is known andcorrective action can be taken. The abort switchshall be of a type that requires constant manualpressure to cause abort. The abort switch shall notbe of a type that would allow the system to be left inan aborted mode without someone present. In allcases the normal and manual emergency controlshall override the abort function. Operation of theabort function shall result in both audible and distinctvisual indication of system impairment. The abortswitch shall be clearly recognizable for the purposeintended.
9.5.4 Alarms indicating failure of superviseddevices or equipment shall give prompt and positiveindication of any failure and shall be distinctivefrom alarms indicating operation or hazardousconditions.
9.5.5 Warning and instruction signs at entrances toand inside protected areas shall be provided.
9.5.6 Indication lamps shall be provided to indicatethe status of the abort switch, that is, Green colourfor ‘Auto’, Yellow colour for the ‘Manual’ and Redcolour for ‘Discharge’ modes.
9.6 Time Delays
9.6.1 For clean agent extinguishing systems, apre-discharge alarm and time delay, sufficient toallow personn-el evacuation prior to discharge, shallbe provided. For hazard areas subject to fastgrowth fires, where the provision of a time delaywould seriously increase the threat to life andproperty, a time delay shall be permitted to beeliminated.
9.6.2 Time delays shall be used only for personnelevacuation or to prepare the hazard area fordischarge.
9.6.3 Time delays shall not be used as a means ofconfirming operation of a detection device beforeautomatic actuation occurs.
10 COMMISSIONING AND ACCEPTANCE
The minimum requirements for the commissioning andacceptance of the gaseous extinguishing system shallbe as follows.
10.1 General
The completed system shall be reviewed and testedby a competent person to meet the approval of theauthority. Only equipment and devices designedto national standards shall be used in the systems.
To determine that the system has been properlyinstalled and will function as specified, the testsspecified in 10.2.2 to 10.2.9 shall be performed.
10.2 Review of Mechanical Components
10.2.1 The piping distribution system shali beinspected to determine that it is in compliance withthe design and installation documents.
10.2.2 Nozzles and pipe size and, if appropriate,pressure-reducing devices, shall be in accordance withsystem drawings. The means for pipe size reductionand attitudes of tees shall be checked for conformanceto the design.
10.2,3 Piping joints, discharge nozzles and pipingsupports shall be securely fastened to preventunacceptable vertical or lateral movement duringdischarge. Discharge nozzles shall be installed in sucha manner that piping cannot become detachedduring discharge.
10.2.4 During assembly, the piping distributionsystem shall be inspected internally to detect thepossibility of any oil or particulate matter whichcould soil the hazard area or affect the agentdistribution due to a reduction in the effectivenozzle orifice area.
10.2.5 The discharge nozzles shall be oriented insuch a manner that optimum agent dispersal can beeffected.
10.2.6 [f nozzle deflectors are installed, they shallbe positioned to obtain the maximum benefit.
10.2.7 The discharge nozzles, piping and mountingbrackets shall be installed in such a manner that theywill not potentially cause injury to personnel, Agentshall not directly impinge on areas where personnelmay be found in the normal work area, or on any looseobjects or shelves, cabinet tops, or similar surfaceswhere loose objects could be present and become-:”.:1-.Illlssllcs.
10.2,8 All agent storage containers shall be properlylocated in accordance with ‘approved for construction’set of system drawings.
10.2.9 All containers and mounting brackets shallbe securely fastened in accordance with themanufacturer’s requirements.
10.2.10 An adequate quantity of agent to producethe desired specified concentration shall beprovided. The actual enclosure volumes shall bechecked against those indicated on the systemdrawings to ensure the proper quantity of agent. Fanrundown and damper closure time shall be taken intoconsideration.
1
14
IS 15493:2004
10.2.11 Unless the total piping contains notmore than one change in direction fitting between thestorage container and the discharge nozzle, andunless all piping has been physically checked fortightness, the following tests shall be carried out:
a)
b)
All open ended piping shall be pneumaticallytested in a closed circuit for a period of 10min at 3 bar. At the end of 10 rein, the pressuredrop shall not exceed 20 percent of the testpressure, and
All closed-section pipe work shall behydrostatically tested ‘to a minimum of1.5 times the maximum working pressure for2 min during which there shall be noleakage. On completion of the test, the pipework shall b~purged to remove moisture.
It is recommended that hydrostatic testing be carriedout at the manufacturer’s works where practicable.
WARNING — Pneumatic pressure testing createsa potential risk of injury to personnel in the area,as a result of airborne projectiles if rupture of thepiping system occurs. Prior to conducting thepneumatic pressure test, the protected area shallbe evacuated and appropriate safeguards shallbe provided for test personnel.
10.2.12 A test using nitrogen, or a suitablealternative, shall be performed on the pipingnetwork to verify that flow is continuous and that thepiping and nozzles are unobstructed.
10.2.13 Where required, suitable venting facilitiesshall be provided for the release of excessive pressurebuild-up during discharge of the agent. Individualstandards for gaseous agents provide details for thedesign of venting facilities.
10.3 Review of Electrical Components
10.3.1 All wiring systems shall be properly installedin compliance with the appropriate NationalStandard and the system drawings..a,c. and d.c. wiringshall not be combined in a common conduit unlessproperly shielded and grounded.
10.3.2 All field circuitry shall be tested for groundfault and short circuit condition. When testing fieldcircuitry, all electronic components ( such as smokeand flame detectors or special electronic equipmentfor other detectors, or their mounting bases ) shallbe removed and jumpers properly installed to preventthe possibility of damage within these devices. Replacecomponents after testing the circuits.
10.3.3 Adequate and reliable primary standbysources of energy which comply with 9.2.2 shall beused to provide for operation of the detection,
signaling, control and actuation requirements of thesystem.
10.3.4 All auxiliary functions ( such as alarmsounding or displaying devices, remote annunciators,air handling shutdown, power shutdown, etc ) shallbe checked for proper operation in accordance withsystem requirements and design specifications.
Alarm devices shall be installed so that they areaudible and visible under normal operating andenvironmental conditions.
Where possible, all air handling and power cut-offcontrols should be of the type that once interruptedrequire manual restart to restore power.
10.3.5 Check that for systems using alarm silencing,this function does not affect other auxiliary functions,such as air handling or power cut-off where they arerequired in the design specification.
10.3.6 Check the detection devices to ensure thatthe types and locations are as specified in thesystem drawings and are in accordance with themanufacturer’s requirements.
10.3.7 Check that manual release devices areproperly installed, and are readily accessible,accurately identified and properly protected toprevent damage.
10.3.8 Check that manual release devices used torelease agents require two separate and distinctactions for operation. They shall be properlyidentified. Particular care shall be taken wheremanual release devices for more than one system arein close proximity and could be confused or thewrong system actuated. Manual release devices inthis instance shall be clearly identified as to -whichhazard enclosure they protect.
10.3.9 Check that for systems with a main/reservecapability, the main/reserve switch is properlyinstalled, readily accessible and clearly identified.
10.3.10 Check that for systems using inhibitswitches requiring constant manual force, these areproperly installed, readily accessible within thehazard area and clearly identified.
10.3.11 Check that the control panel is properly installedand readily accessible.
10.4 Preliminary Functional Tests
10.4.1 Where a system is connected to a remotecentral alarm station, notify the station that the firesystem test is to be conducted and that anemergency response by the fire departmen(or alarmstation personnel is not required. Notify all concernedpersonnel at the end-user’s facility that a test is to
15
IS 15493:2004
be conducted and instruct them as to the sequenceof operation.
10.4.2 Disable or remove each agent storagecontainer release mechanism and selector valve,where fitted, so that activation of the release circuitwill not release agent. Reconnect-the release circuitwith a functional device in lieu of each agent storagecontainer release mechanism.
For electrically actuated release mechanisms, thesedevices may include suitable lamps, flash bulbs orcircuit breakers. Pneumatically actuated releasemechanisms may include pressure gauges, Refer tothe manufacturer’s recommendations in all cases.
10.4.3 Check each resetable detector for properresponse.
10.4.4 Check that polarity has been observed on allpolarized alarm devices and auxiliary relays.
10.4.5 Check that all required end-or-line deviceshave been installed.
10.4.6 Check all supervised circuits for correct faultresponse.
10.5 System Functional Operational Test
10.5.1 Operate the detection initiating circuit(s).All alarm functions shall occur according to thedesign specification.
10.5.2 Operate the necessary circuit to initiate asecond alarm circuit if present. Verify that allsecond alarm functions occur according to designspecifications.
10.5.3 Operate the manual release device. Verifythat manual release functions occur according todesign specifications.
10.5.4 Where appropriate, operate the inhibitswitch. Verify that functions occur according to thedesign specifications. Confirm that visual andaudible supervisory signals are received at the controlpanel.
10.5.5 Check the function of all resettable valvesand activators, unless testing the valve will rele~seagent. ‘one-shot’ valves, such as those incorporatingfrangible discs, should not be tested,
10.6 Remote Monitoring Operations ( IfApplicable )
10.6.1 Disconnect the primary power supply, thenoperate one of each type of input device while onstandby power. Verify that an alarm signal is receivedat the remote panel after the device is operated.Reconnect the primary power supply.
10.6.2 Operate each type of alarm condition andverify receipt of fault condition at the remotestation.
10.7 Control Panel Primary Power Source
10.7.1 Verify that the control panel is connected to adedicated unstitched circuit and is labelled properly.This panel shall be readily accessible but access shallbe restricted to authorized personnel only.
10.7.2 Test a primary power failure in accordancewith the manufacturer’s specification, with the systemfully operated on standby power.
10.8 Review ofEnclosure-integrity
It is preferable to subject all total flooding systemsto an Enclosure Integrity ~est in order to detectand seal the significant leakage paths that couldresult in-failure of an enclosure to withhold designconcentration for a specified period ( see 7,1and 10.10 ).
10.9 Completion of Functional Tests
When all functional tests are complete ( see ‘10.6to 10.9 ), reconnect each storage container so thatactivation of the release circuit will release the agent.Return the system to its fully operational designcondition. Notify the central alarm station and allconcerned personnel at the end-user’s facility thatthe fire system test is complete and that the systemhas been returned to full service condition by followingthe procedures specified in the manufacturers’specifications.
10.10 The complete installation shall be tested inone of the two methods narrated below:
a) Full-scale discharge test, and
b) Enclosure integrity test.
Where the authorities concerned insist onfull-scale discharge test, the test shall beconducted in accordance with various provisionsunder Annex C and results of the test ( that isconcentration achieve-d, discharge time, holdingtime ) shall conform to various provisions availablein other clean agent standards with particularreference to the agent used. Otherwise, the enclosurewhere total flooding system is installed, shall besubject to’ enclosure integrity test’ in accordance withvarious provisions under Annex D to demonstratethe retention time ( of the required concentrationwith the-enclosure ] as specified in other standardswith particular reference to the agent used.
10.11 Completion Certificate and Documentation
The installer shall provide to the user a completion
16
certificate, a complete set of instructions, calculationsand drawings showing the system as-installed, anda statement that the system complies with all theappropriate requirements of this standard, and givingdetails of any departure from appropriaterecommendations. The certificate shall give the designconcentrations and, if carried out, reports of anyadditional test including the door fan test.
11 SYSTEM HYDRAULIC FLOWCALCULATIONS
11.1 General
System flow calculations shall be carried out at anolninal agent storage temperature of 21 “C, shallhave been validated by an accredited approvalauthority by appropriate tests as described in thisstandard, and shall be properly identified. Thesystem design shall be within the manufacturer’sspecified limitations.
NOTES
1 Variations from the nominal 21 “C storagetemperature will affect flow conditions used incalculations.
2 Prc-engineered systems do not require a flowcalculation when used within approvedlimitations.
11.2 Balanced and Unbalanced System
11.2.1 A balanced system shall be one in which:
a) each actual or equivalent pipe length fromthe container to each nozzle are all within 10percent of each other, and
b) the discharge rate of each nozzle is equal.
11.2.2 Any system that does not meet the criteriamentioned in 11.2 shall be considered to be anunbalanced system.
11.3 Friction Losses
Allowance shall be made for the frictionlosses in pipes and in container valves, dip tubes,flexible connectors, selector valves, time delaydevices and other equipment ( for example, pressure-reducing devices ) within the flow line.
NOTE — The flow of a liquefied gas will be a twophase phenomenon, the fluid consisting of a mixtureof liquid and vapour, the proportions of which aredependent on pressure and temperature. The pressuredrop is non-linear, with an increasing rate of pressureloss as the line pressure reduces by pipe friction.
11.4 Pressure Drop
The pressure drop shall be calculated using two phaseflow equations for liquefied gases and single phaseNow-equations for non-liquefied gases.
IS 15493:2004
NOTE — These equations use friction factors andconstants dependent on pressure and densityobtained empirically. As the equations cannot be solveddirectly, a cornputcr programme is usually used toassist with the large number of iterative calculationsin which pipe and nozzle sizes and if appropriate,size of pressure reducing devices, are selected withinprescribedpressurelosses.
11.5 Valves and Fitting
Valves and fittings shall be rated for resistancecoefficient or equivalent length in terms of pipe,or tubing sizes with which they will be used.The equivalent length of the cylinder valvesshall be listed and shall include siphon tube ( wherefitted ), valve, discharge head and flexibleconnector.
11.6 Piping Length
The piping length and nozzle and fitting orientationshall be in accordance with the manufacturer’sapproved manual to ensure proper systemperformance.
11.7 Drawings
If the final installation varies from the prepareddrawings and calculations new ‘as- built’ drawingsand calculations shall be prepared.
11.8 Liquefied Gases ( Specific Requirements)
11.8.1 Allowance shall be made for changes inelevation as specified in the relevant standardrelating to the specific agent.
11.8.2 Minimum discharge rate for liquefied agentsshall be sufficient to maintain the velocity requiredfor turbulent flow to prevent separation.
NOTE— 11’turbuleat flow is not maintained, separationof the liquid and-gaseous phases will occur, which canlead to unpredictable tlow characteristics.
11.8.3 For information on two-phase flow for liquefiedhalocarbon gases ( see Annex E ).
12 ENGINEERED AND PRE-ENGINEEREDSYSTEM
12.1 General
All agents are suitable for use in both engineeredcentral storage, system and pre-engineered( modular or packaged ) systems, as describedin 12.2 and 12.3.
12.2 Engineered
An engineered system uses large storagecontainers installed in central location. Thecontainers are manifold together and a singlepipe feeds the nozzle located inside the
17
IS 1-5493:2004
hazard area. Predicting pipe pressure losses anddesigning nozzle orifice sizes required complexflow calculations for both agent and nitrogenphases .( in case of halocarbon gases ) and foragent ( in case of line gases ), which takes intoaccount the minimum and maximum volumes or theenclosure.
12.3 Pre-engineered
A pre-engineered system involves a singlecontainer the maximum of two nozzles and a smallpiping network. This system can be multiplied tocover larger volume areas. The larger area is viewedas a number of smaller areas each protected by asingle modular unit.
13 PHYSICAL PROPERTIES
Physical properties of inert gas and halocarbonagents are shown in the Tables 9 and 10.
14 TRAINING
14.1 All persons who may be expected to operate,maintain, test or inspect fire extinguishing systemsshall be kept continuously and adequately trained inthe functions they are expected to perform.
14.2 Personal working in an enclosure protectedby or gaseous extinguishant shall be trained andkept fully conversant with the operation and useof the system, particularly regarding safetyrequirements.
Table 9 Physical Properties of Inert Gas Agents
( Clause 13 )
S1 No.
(1)
i)
ii)
iii)
iv)
v)
vi)
vii)
viii)
ix)
Properties
(2)
Molecularweight
Boiling point at 760 mm Hg
Freezing point
Critical temperature
Criticalpressure
Specific heat, vapour atconstant pressure ( 1 atm )and 25°C
Heat of vaporization atboiling point
Relative dielectric strengthat 1 atm at 734 mm Hg,25°C (N2 = 1.0)
Volubility of water in agentat 25°C
Units
(3)
N/A
T
T
T
kPa
Kj/kg”C
Kj/kg
TWA
NIA
IG-01
(4)
39.9
-189.85
-189.85
-122.3
4903
0.519
163
1.01
0:006percent
IG-1OO
(5)
28.0
-195.8
-210.0
-146.9
3399
I .04
199
I .0
0.oo1 3percent
IG-541
(6)
34.0
-196
–78.5
NIA
NIA
0.574
220
1.03
0.015percent
IG-55
(7)
33.95
-190.1
–199.7
-134.7
4150
0.782
181
1.01
0.006percent
18
IS 15493:2004
Table 10 -Physical Properties of Clean Halocarbon Agents
( C/ause I 3 )
S1 No<
(1)
O
ii)
iii)
iv)
v)
vi)
vii)
viii)
ix)
x)
xi)
xii)
xiii)
xiv)
Properties
(2)
Molecular weight
Boiling point at 760 mm Hg
Freezing point
Critical temperature
Critical pressure
Critical volume
Critical density
Specific heat, liquid at 25°C
Specific heat vapour at constant pressure( 1 atm ) and 25°C
Heat of vaporization at boiling pointat 25°C
Thermal conductivity of liquid at 25°C
Viscosity, liquid at 25°C
Relative dielectric strength at I atm at734 mm Hg, 25°C ( Nz = 1.0 )
Volubility of water in agent at 210C
Units
(3)
N/A
“c
“c
“c
kPa
Cchnole
kglms
Kj/kg°C
Kj/kg “C
Kjlkg
Whll”c
Centipoises
N/A
Pp m
HCFC Blend A
(4)
92.90
-38.3
<107.2
124.4
6647
162
577
1,~56
0.67
225.6
0,0900
0.21
1.32
0. I2 percentby weight
HFC 227ea
(5)
170.03
-16.4
-[31
-101.7
2912
274
621
1.184
0.808
132.6
0.069
0.184
2.00
0.006 percentby weight
ANNEX A
( Clause 2 )
LIST OF REFERRED INDIAN STANDARDS
IS No. Title IS No. Title
1239 Mild steel tubes, tubtrlars and(Part2 ): 1992 other wrought steel fittings:
6631:1972 Specification for steel pipes for
Part 2 Mild steel tubulars andhydraulic purposes
other wrought steel pipe fittings(fourth revision )
SP 30:1985 National Electrical Code
2189:1999 Selection, installation and 15496:2004 Inspection and’maintenance of
maintenance of automatic fire gaseous fire extinguishing
detection and alarm system — systems — Code of practice
Code of practice
19
ANNEX B(Clause 6.1 )
INFORMATION ON SAFETY TO PERSONNEL ANDOF COMBUSTION
DECOMPOSITION PRODUCTS
II-l Any hazard to personnel created by thedischarge of gaseous extinguishants shall beconsidered in the design of the system, in particularwith reference to the hazards associated withparticular extinguishants in the other standards ofclean agents. Unnecessary exposure to all gaseousextinguishants shall be avoided.
B-2 The decomposition products generated by tbeclean agent breaking down in the presence of veryhigh amounts of heat can be hazardous. All of thepresent halocarbon agents contain fluorine. In thepresence of available hydrogen ( from water vapour,or the combustion process itself ), the maindecomposition product is hydrogen fluoride ( HF ).
B-3 These decomposition products have a sharp,acrid odour, even in minute concentrations of only afew parts per million. This characteristic provides abuilt-in warning system for the agent, but at the sametime creates a noxious, irritating atmosphere for thosewho must enter the hazard following a fire.
B-4 The amount of agent that can be expected todecompose in extinguishing a fire depends .to alarge extent on the size of the fire, the particularclean agent, the concentration of the agent, and thelength of time the agent is in contact with theflame or heated surface. If there is a very rapidbuild-up of concentration to the critical value, thenthe fire will be extinguished quickly and thedecomposition will be limited to the minimumpossible with that agent. Should that agent’sspecific composition be such that it couldgenerate large quantities of decompositionproducts, and the time to achieve the critical value islengthy, then the quantity of decompositionproducts can be quite great. The actual concentrationof the decomposition products then depends onthe volume of the room in which the fire was burningand on the degree of mixing and ventilation.
B-5 Although the vapour from halocarbon gas haslow toxicity, the decomposition products can bevery hazardous. The most widely accepted theory is
that the vapour must decompose before the agentcan inhibit the combustion reaction. Decompositiontakes place on exposure to a flame or to a hot surfaceat a temperature above 480°.C. In the presence ofavailable hydrogen ( from water vapour or thecombustion process itself), the main decompositionproduct is hydrogen fluoride ( HF ).
B-6 The decomposition products .of halocarb.onagents have a characteristic sharp acrid adour, evenin minute concentrations of only a few parts permillion. This characteristic provides abuilt-in warningsystem for the extinguishant, but at the same timecreates a noxious, irritating atmosphere for those whohave to enter the enclosure following a fire. The actualconcentration of the decomposition productsdepends on the volume of the enclosure in whichfire is burning and the degree of mixing andventilation.
B-7 Longer exposure of the vapour to tempera-tures in excess of 482°C would produce greaterconcentrations of these gases. The type and sensi-tivity of detection, cwpled with the rate of discharge,should be selected to minimize the exposure time ofthe vapours to the elevated temperature if theconcentration of breakdown products is to beminimized. In most cases, the area would be untenablefor human occupancy due to the heat and breakdownproducts of the fire itself.
B-8 Clearly, longer exposure of the agent to hightemperatures would produce greater concentrationsof these gases. The type and sensitivity of detection,coupled with the rate of discharge, should be selectedto minimize the exposure time of the agent to theelevated temperature if the concentration of thebreakdown products is to be minimized.
B-9 Non-liquefied agents do not decomposemeasurably in extinguishing a fire. As such, toxic orcorrosive decomposition products are not found.However, breakdown products of the fire like carbonmonoxide itself can still be substantial and couldmake the area untenable for human occupancy.
20
IS 15493:2004
ANNEX C
(-Clause 10.10 )
REQUIREMENTS FOR FULL-SCALE
C-1 SCOPE
This clause sets out a procedure to determinecompliance of the gaseous total flooding systemwith the requirements for discharge time, concentrationand holding time.
C-2 PRINCIPLE
The system is operated, discharge time is measuredand concentration readings are taken at a specifiedheight at nominated periods.
C-3 TEST MEDIUM
The test medium shall be the concerned halocarbonor inert gas.
C-4 APPARATUS
The following apparatus is required:
a)
b)
c)
A chart recorder type concentration metercalibrated in strict accordance with themanufacturer’s instructions,
A suitable time-measuring device, and
Temperature-measuring equipment.
C-5 PROCEDURE
The procedure shall be as follows:
a) Ensure that the preliminary checks, inaccordance with respective standardpertaining to gaseous fire extinguishingsystem have been completed,
b) Electrically isolate all flooding systemsserving adjacent enclosures,
c) 1) Concentration measurements shouldbe made at a minimum of three points,one-at the highest hazard level,
2) Locate sampling points in the enclosureat the specified heights ( see 10 ). Donot locate sampling points nearer than200 mm to ceiling unless the combustiblesbeing protected extend within that area,in which case special design
considerations may be necessary,
3) If more than one space or compartmentis being simultaneously protected,locate a sampling point in each space inaccordance with the above criteria.Additional sampling points may be
d)
e)
f)
g)
h)
DISCHARGE TEST
4)
required by the appropriate authority,and
Where the geometry of the enclosuredoes not lend itself to sampling in theabove manner, take a minimum of threesamples at locations agreed upon by theappropriate authority.
Set the continuous chart recorder typeconcentration meter for the agent concernedand check that the meter is calibrated inaccordance with the manufacturer’sinstructions so that it will recordconcentration levels at each samplingpoint for 10 min from commencement ofdischarge,
Record temperature in enclosure,
Ensure that plant which is capable ofaffecting system performan-ce, for example,air-hand(ing plant is in its normal operatingmode,
Activate the system and record the dischargetime ( see 11 ), and
Record concentration readings and holdingtimes ( see 11 ).
C-6 RECOMMISS1ONING
Restore all systems to a fully operational status.
C-7 REPORTING
The following shall be reported:
a) 1) installation, designer and contractor;
2) enclosure identification;
3) enclosure temperature prior to discharge;
4) design concentration; and
5) position of sampling points.
b) Date and time of test,
c) Discharge time,
d) Concentraticms at each sampling pointat I and 10 min from the commencement ofdischarge, and
e) System deficiencies.
Cross-check various observed parameters with therespective operating clauses are in conformitytherewith.
21
1S 15493:2004
ANNEX D
( Clause 10.10)
REQUIREMENTS FOR TESTING ENCLOSURE INTEGRITY
D-1 TEST FOR DETERMINATION OFPREDICTED MINIMUM HOLD TIME
D-1.1 Principle
A fan is temporarily located within an accessopening to pressurize and repressurize the enclosure,A series of pressure and air flow measurements ismade from which the leakage characteristics of theenclosure; are established.
The predicted hold time is calculated usingthese leakage characteristics on the followingassumptions:
a)
b)
c)
d)
e)
That leakage occurs under the worstconditions, that is, when one-half of theeffective leakage area is at the maximumenclosure height and represents theinward leakage of air, and the other half ( thelower leakage area ) of the total effectiveleakage area is at the lowest point in theenclosure and represents the outwardleakage afextinguishant/air,
That all leak flow is one-dimensional, i.e.ignoring stream functions,
That flow through any particular leak areais either into or out of the enclosure andeither from or into an infinitely large space,
That the system is at sea-level, at atemperature of 20”C, and atmosphericpressure of 1.013 bar absolute, and
An enclosure integrity test is deemedsuccessful when at least 80 percent ofthe design concentration is availablewithin the enclosure at the expiry of10 min (see D-2.10).
D-1.2 Apparatus
a)
b)
c)
d)
Fan unit, consisting of a frame which will fitinto and seal an access opening in theenclosure, and one or more variable speedfans, with low flow facilities, capable ofgiving a differential pressure of not lessthan 25 Pa across the enclosure boundary,
Two pressure-measuring devices, one tomeasure enclosure differential pressureand one to measure fan flow pressure,
Flexible tubing, for connecting thepressure-measuring devices,
Chemical smoke pencils and/or smokegenerator,
e)
o
Two thermometers, to measure ambienttemperatures, and
Signs, reading “DO NOT OPEN —PRESSURE TEST IN PROGRESS” and“DO NOT CLOSE — PRESSURE TEST INPROGRESS”.
NOTE — Additional apparatus, such as measuringtapes, torches, ladders. tools to remove floor and ceilingtiles, computer or other calculating device, may benecessary.
D-1.3 Calibration of Apparatus
a)
b)
Fan Unit — Calibrate the fan unit at theintervals and by the method recommendedby the manufacturer. Keep records and, whereappropriate, calibration certificates. Use aflow meter accurate to + 5 percent and apressure-measuring device accurate to+ 1 Pa.
Press ure-Measttring Devices — Thepressure-measuring- devices shall becalibrated not more than 12 months beforea test. Records shall be maintained and,where appropriate, calibration certificates.
If inclined manometers are used, changethe fluid not more than 3 mcrnths before thetest. Level and zero inclined manometersbefore each test,
D-1.4 Preliminary Preparation
a)
b)
c)
Obtain a description from the user of theair-handling equipment and extinguishant-extraction systems in the enclosure,
Check for the following:
1)
2)
3)
4)
raised platform floors and false ceilingspaces;
visually obvious leaks in the enclosure;
adequate return paths outside theenclosure between all leaks and the”fanunit; and
conflicting activities in and around theenclosure.
Provide the following information to the user:
1) a description of the test;
2) the timerequired to complete the test;
.3) what assistance will be needed from theuser’s staffl and
4) Information on any necessarydisturbance to the building or itsservices during the test ( for example,
LL
IS 15493:2004
removal of floor or ceiling tiles,shutdown of air-handling systems,holding doors open and/or shut ).
D-1.5 Evaluation of Enclosure
Obtain or prepare a sketch plan showing the walls,the location of the door and other openings throughw-hich air will flow during the test, and the locationof any ducts penetrating the enclosure, and anydampers in the ducts. Show the status ( that is,whether open or closed when the extinguishantsystem is discharged ) of each door, hatch anddamper, and which access opening(s) is (are) to beused for the fan unit.
Show the location of floor and sink drains.
D-1.6 Measurement of Enclosure
Measure the protected enclosure volume as necessaryand record the following:
a) Overall height of the protected enclosure,
b) Height of the highest hazard in theenclosure, and
c) Gross volume of the protected enclosure.
D-1.7 Test Procedure
a) Preparation for Test
1) Advise supervisoryarea of the test.
personnel in the
2) Remove papers and objects likely tobe disturbed by the turbulence from thefan.
3) Block open sufficient doors outsidethe enclosure envelope to provide anadequate return path for air betweenthe fan unit and the enclosure leaks,while correcting any breach of anyrequirements of the facility, includingrequirements for security, fire protectionand environmental boundaries.
4) Using the sketch plan ( see D-1.5), setall air-handling equipment andextinguishant-extract ion systems tothe state they would be in at the timeof extinguishant system discharge,except for the following:
i) Recirculating air-handlingequipment without fresh air make-up which does not give a biaspressure across the enclosureboundary or otherwise precludeaccurate testing, and which wouldbe shut down on extinguishantdischarge, may be left operating
5)
6-)
n
8)
during the test if this is neededto avoid temperature build-upin equipment such .as computers;and
ii) Recirculating air-handlingequipment which would continueto operate on extinguisharitdischarge should be shut down, ifit creates excessive bias pressure.
Post the appropriate signs on doors[see D-1.2 (f) ].
Open doors and remove floor or ceilingtiles within the extinguishant- protectedportions of the enclosure envelope sothat the extinguishant- protected volumeis treated as one space. Do not removefalse ceiling tiles if the volume above thefalse ceiling is not protected withextinguishant.
Close all doors and windows in theenclosure envelope.
Check that liquid traps in the floor andsink drains are sealed with liquid.
b) Setting up Door Fan Unit
1)
2)
3)
4)
Set up the fan unit in an access openingleading from the enclosure into thelargest volume of building spacewhich will complete the air-flow pathfrom the fan, via the enclosure, leaks andbuilding space back to the fan.
Gently blow into or suck from theflexible tubing so that the readings ofthe pressure-measuring devicestraverse the full scale. Hold themaximum reading for not less than 10s.
Release the pressure and zero thedevices.
Connect the enclosure differentialpressure-measuring device. Ensurethat the open ends of the flexibletubing near the fan unit are awayfrom its air stream path and any otherair flows which might affect thereadings.
Use the fan(s) to raise or lower thepressure of the enclosure byapproximately 15 Pa. Check alldampers with smoke and ensure thatthey are closing properly. Check doorsand hatches and ensure correctclosure, Inspect the wall perimeter( above and below any false floor) andthe floor slab for any major leaks andnote their size and location.
23
1S 15493:2004
C) A4easurement of Bius Pressure
1) Seal the fan unit inlet or outlet and, withoutthe fan(s) operating, observe theenclosure differential pressure-measuringdevice for at least 30s.
2) Ifa bias p~essure is indicated, use smoketo detect the consequent air flow and itsdirection. If the existence of a biaspressure is confirmed, record thepressure-measuring device reading as thebias pressure (Pb).
3) If the enclosure is large, or if the biaspressure is largely caused by wind orstack effects, repeat the measurement atone or more different access openings.Record all the values measured and usethe largest positive value ( or if onlynegative values are recorded, the valueclosest to zero ) as the bias pressure.
A bias pressure as low as 0.5 Pa can affect the accuracyof the test result. If the bias pressure has a numericalvalue greater than 25 percent of fire extinguishant/air column pressure, then.the hold time is likely to below and the enclosure may not hold the specifiedextinguishant concentration. The source of theexcessive bias pressure should be identified and, ifpossible, permanently reduced.
10 the event of fluctuating bias pressures ( such asthose created by wind effects), it may not be possibleto achieve the necessary correlation accuracy in thefan test results. These fluctuating pressures may needto be eliminated before an accurate fan test can becarried out.
d) Measurement of Leakage Rate
1) Measure the air temperature insidethe enclosure, Te, and measure the airtemperature outside the enclosure TO,atseveral points. If the location of leaksis not known, use the average value;otherwise, use the average valueweighed according to the knownlocation of the leaks.
2) Unseal the fan inlet or outlet andconnect the fan flow pressure- measuringdevice.
3) Use the fan unit to repressurize theenclosure to the maximum extent, butby not more than 60 Pa. Allow theenclosure differential pressuremeasuring reading to stabilize ( whichmay take up to 30s ) and record the value( Pf+ Pb ) which will be negative. Repeatat not less than four more fan unitflow rates to give five readings more
or less evenly spaced over the rangedown to 10 Pa.
4) Use the fan unit to pressurize theenclosure and repeat the procedureof (d) (iii). Again record the value of
( Pf + Pb ), which will be positive.NOTE — For calculation purpose, either Pf or Pb orthe average of the two can be taken.
D-2 CALCULATIONS
D-2.1 Notations
Q = air leakage rate, in m3/s;
c = flow coefficient;
P = pressure within enclosure, in Pa;
N = slope of the graph;
R~ = density of agent /air Mixture, in kg/m3;
Agent Densi@, kg/m3
Air 1.202
HCFC Blend A 3.84
HFC-227ea 7.26
IG-541
IG-55
RA =
R~ =
PM =
G=
HO =
H=
A=
v“~=
Q. =
TL =
T~ =
ELA =
K=
ILA =
LLF =
ALL =
c .
1.41
1.41
density of air, in kg/m3;
density of agent, in kg/m3;
agent/Air column pressure, in Pascal(Pa);
gravitational acceleration, 9.81 m/s2;
total height of the enclosure, in m;
minimum acceptable height in theenclosure, in m;
area of the enclosure, in m2;
volume of the enclosure, in m3;
uncorrected agent/air mixture leakagerate, in m3/s;
corrected agent/air mixture leakage rate,in ins/s;
temperature within the enclosure, in ‘C;
temperature outside the enclosure, in “C;
equivalent leakage area, in m2;
discharge coefficient ( 0.61 toI depending upon nature of leakageopenings );
total leakage area, in m2;
lower leak fraction;
area of lower leaks, in m2;
agent concentration, in percent;
24
,-
1S 15493:2004
Cp =
C3 =C4 =T=
pass concentration in percent( 80 perc~nt of the design agentconcentration );
equation simplification constant;
equation simplification constant; and
retention time of pass concentration(CP) within the enclosure, in seconds.
D-2.2 After pressurizing ( depressurizing ) theenclosure to various pressures, correspondingflow rates in 1/s for each room pressure shall berecorded wherefrom the flow at 1 Pa pressure i$determined. This value (C) is deemed as flowcoefficient ( constant ) for the purpose ofcalculation.
The formula establishing a relation between flowand the pressure is Q = CPN where Q = Air leakagerate, in m3/s, C = Flow coefllcient, P = Pressure withinenclosure in Pa and N = Slope of the graph.
NOTE — The value of N can be determined bysubstituting observed values for Q, P and C in the aboveequation.
D-2.3 The next step will be to determine the densityof agent/air mixture ( R~ ):
RM= (RG)( c)+ (RA)(1OO-C)
100kg/m3
100
D-2.4 The next step will be to determine the,agent/air column pressure (PM):
P~=(G)(HO) (R~– RA)Pa
D-2.5 The next step will be to determine theuncorrected agent/air mixture leakage rate:
-Qm=(c)(pM)Nm3/sD-2.6 The next step will be to determine the corrected
agent/air mixtuFe leakage rate:
QM=(Qm)(TL+z7s)M3,S
(TP+273)
D-2.7 The next step will be todetermine the equivalentleakage area ( ELA ):
(1.271 )(Q~) mzELA = _
vPM
D-2.8 The next step will be to determine the totalleakage area ( TLA ):
TLA=(K)(ELA)m2
D-2.9 The next step will be to determine the lowerleak fraction ( LLF):
ALLLLF = —
TLA
D-2.1 O The next step will be to determine the retentiontime ( T):
T= (A)[(c3~o+c4)(1-h’) _(qf+c4)( I-iv)] s
(1-N) (C3)(LLF)(TLA)
where
(2G)(RM-RA)C3=
l/N(R~)+(RA)[]flF 1
2 ( Static pressure inside enclosure)C4=R~
NOTES
1 If static pressure is negative, then treat it as zero.
2 If static pressure is positive, then consider actualvalue.
25
IS 15493:2004
ANNEX E
( Clause 11.8.3 )
1NFORMATION ON TWO-PHASE FLOW FOR LIQUEFIED HALOCARBON GASES
E-1 As the extinguishant in the liquid phase flows
from the storage container, the pressure drops or
recedes. The pressure recession varies withcontainer fill density. It is assumed that there wasthermodynamic equilibrium between the liquid andvapour phases in the storage container. In actual tests,it has been noted that there is a sharp drop in pressureduring the initial rush of liquid into the distributionsystem. This is due to a lag between the pressuredrop and the onset of boiling in the container. As boilingcommences, the pressure returns to the pressuresshown on the curves for respective gaseousextinguishants representing the calculated pressurein the storage container versus the percentagedischarge of extinguishant from the container for both2.5 MPa and 4.2 MPa systems.
E-2 AGENT IN PIPE WORK
Agent flows through the distribution system inboth liquid and vapour phase. As the liquid phaseflows through the distribution system thepressure continues to drop, causing the liquid to boil.The volume of the vapour phase increases with thedecreasing pressure and hence the density of themixture drops. To maintain a constant flow rate, thespeed through the distribution system mustcontinuously increase down the pipe work. Thepressure drop for a given flow rate is no-tlinear, as itis with water, but is variable along the pipe.
E-3 DENSITY -OF AGENT IN DISTRIBUTIONSYSTEM
Using the thermodynamic properties of theAgent, including the nitrogen used for super-
pressurization, the density of the two-phase mixturein the distribution system can be calculated. Thedensity of the Agent leaving the storage containervaries over the course of the discharge, The densityis lowest at the start of discharge and increasesuntil the last of the liquid leaves the container.
E-4 TEMPERATURE
The drop in container pressure as the Agent flowsfrom the container causes remaining Agent in thecontainer to cool. As a result, liquid that is belowambient temperature is introduced to the distributionsystem. During a system discharge the temperatureof the Agent leaving the storage container recedesas a function of instantaneous container pressure.
E-5 INITIAL VAPOUR TIME
At the start of discharge virtually all the liquid phase
26
Agent entering the distribution system is vaporizedbefore it reaches the nozzles, due to heating bythe pipe work and the initial low pressure in thesystem. The initial vaporization limits the flow ofAgent through the distribution system because themass flow of vapour is much lower than that ofliquid.
E-6 LIQUID FLOW
There is a significant delay between the opening ofthe discharge valve and the first appearance of liquidat the nozzles. Some of the delay is due to the flowrestriction presented by the container and distributionsystem, however much of delay is due to the initialvapour phase flow of the Agent.
E-7 PHASE SEPARATION
The flow of Agent in the distribution system is a“two-phase flow ( containing both liquid and vapour ). Ina properly sized distribution system the flow willbe highly turbulent throughout the system and thetwo phases will mix homogeneously. [fthe pipes aretoo big the phases may tend to separate, which cancause a variety of flow problems and can in some casesresult in a reduced flow rate.
E-8 AVERAGE PRESSURE CONDITIONS
Pressure at the nozzle is not constant throughoutdischarge because the pressure in the storagecontainer is constantly decreasing. If one were .toattempt manual calculation it would be desirable touse an average pressure condition. It is difficult toarrive at an average as the volume of piping has amarked effect on the average nozzle ( pressure,density and velocity conditions ), all of which, havea marked effect on discharge quantities and times.
E-9 AVERAGE NOZZLE PRESSURE
The nozzle pressure used for calculations is thepressure when half the liquid phase has beendischarged from the nozzle. The timing of this is usedto-calculate an average pressure drop in the distributionsystem. To calculate the correct storage containerpressure, allowance must be made for the amount ofliquid in the piping system.
E-10 PERCENT IN DISTR1BUTION SYSTEM
The points outlined above are taken intoconsideration to calculate the average containerpressure during discharge. The ratio of the pipevolume to the volume of Agent supply expandedunder flowing conditions varies with averagecontainer pressure, The former quantity shall bereferred to as percent-in-the-pipe.
-Bureau of Indian Standards
BIS is a statutory institution established under the Bureau of Indian Standards Act, 1986 to promoteharmonious development of the activities of standardization, marking and quality certification of goods andattending to connected matters in the country.
Copyright
131Shas the copyright of all its publications. No part of these publications may be reproduced in any formwithout the prior permission in writing of BIS. This does not preclude the free use, in the course of implementingthe standard, of necessary details, such as symbols and sizes, type or grade designations. Enquiries relatingto copyright be addressed to the Director (Publications), BIS.
Review of Indian Standards
Amendments are issued to standards as the need arises on the basis of comments. Standards are also reviewedperiodically; a standard along with amendments is reaffirmed when such review indicates that no changes areneeded; if the review indicates that changes are needed, it is taken up for revision. Users of Indian Standardsshould ascertain that they are in possession of the latest amendments or edition by referring to the latest issueof ‘BIS Catalogue’ and ‘Standards : Monthly Additions’.
This Indian Standard has been developed from Doc : No. CED22(7011 ).
Amendments Issued Since Publication
Amend No. Date of Issue Text Affected
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