Fire Protection
Design
Detectors and alarms
First responsibility of an active fire-protection system is to detect fire. Detectors and alarms are selected according to their speed of response, the expected nature of fire and the sensitivity of detector to distinguish between such fire and normal environment. However an over-sensitive detector may generate frequent false alarms. Fire alarms may be very basic to alert the occupants to evacuate but it may be highly sophisticated to conduct activation of sprinkler, homing of elevators or notify the fire brigade.
Fire hydrant & hose
Fire hydrants are usually pillar like structure emerging from below ground level. They supply water to hoses for fire fighting. It is supported with breeching inlet, wet or dry riser, and landing valve. Its compatibility in terms of size or nominal diameter with fire brigade equipment is maintained by all standard manufacturers. Fire hoses allow fire-fighters to work closer to the fire without endangering their engines and to increase the accuracy of water placement.
Sprinklers
Sprinklers are considered the most effective fire suppression equipment. Buildings fitted with sprinkler seldom suffer from severe fire damage. Because of its importance, NFPA 101 Life Safety Code makes use of sprinkler mandatory for all occupancies. If direct supply from public main is not sufficient for a sprinkler requirement, a booster fire pump is used.
Portable fire extinguisher
They act as ‘first-aid’ for any fire hazard and expected to be operated by the common occupants under panic. Hence training for use is always recommended. However a fire as small as trash-can and confined in the origin should only be fought with extinguisher and fire brigade should be informed immediately. Extinguishers come in a wide range of size and extinguishing agent. Selection is based on characteristics of anticipated fire, type of building, hazard to be protected, ambient temperature etc. These factors are expressed as types of fire and hazard classes (low, medium, high). Special considerations are made for special hazards namely pressurized flammable liquid or gas, cooking grease etc.
Fire door
Fire doors are intended to fulfil two requirements – compartmentalization to contain the fire to the area of origin and provide fire resistant and smoke free access to escape routes. Unlike ordinary doors, fire doors need to retain its integrity at a very high temperature. The core, face, glazing (if any), hinges, bolts, latches etc should be able to withstand deformation or charring up to the specified time. A pre-hung, prefinished door is always preferred as it ensures high quality control.
Services for fire escape
For a safe and panic-free quick evacuation, escape lighting should illuminate the escape route and mark it clearly without any ambiguity. The fire alarm call points and fire fighting equipment located in exit route should also be illuminated. An engineered smoke control system includes many features, such as supply mode, number of air change, clear layer, smoke reservoir, fire rating etc. Natural and powered smoke exhaust ventilations are not used together. For buildings with >24m height or > 4 levels of basements, pressurization is adopted.
Grading for detector selection
| Factor | Grading criteria | Grade | ||
| Detector | ||||
| Performance | Selected as per performance as mentioned:
Heat: acts slower, but higher resistance to environment. Smoke: Speed is medium. Flame: Fastest among all, but due to high sensitivity needs some precaution to avoid false alarm. For e.g. Time delay, dual sensor, shielding etc. Usually it acts as supplementary of the other two systems. |
Yes: 5
No: 1 |
||
| Applicability | Type | Sub-type | Suitable location | Yes: 5
No: 1
|
| Heat | Type A: fixed + rate of rise | Moderate temperature < 45°C. and where rise in temperature is unusual | ||
| Type B: fixed | Rapid rise is common and max. temp. < 45°C. | |||
| Type C: high temp. fixed + rate of rise | Temperature < 75 °C. | |||
| Type D: high temp fixed | Rapid rise is common and max. temp. < 75°C | |||
| Type E: special purpose fixed | When A or D can’t be used due to severe corrosion, high ambient temp etc. | |||
| Smoke | In general | Away from exhaust gas, cooking fume, dusty atmosphere like aerosol, tobacco smoke, air turbulence or excess vibration. | ||
| Ionization type | Clean burning fire smoke with small particles. | |||
| Photoelectric | Dense smoke of large particles, smouldering. | |||
| Flame | IR detector | In absence of very hot object, oven, furnace, sunlight, incandescent lamp. | ||
| UV detector | In absence of electric arcing, lightning, welding, UV lamp, quartz halogen lamp. | |||
| Mounting | The number, location and spacing are design decisions as per SS CP 29. But the mounting should obey the following guidelines: | Yes: 5
No: 1 |
||
| Type | Mounting guidelines | |||
| Gen. | Provision of accessibility should be designed along with detector. | |||
| Heat | At highest point of ceiling or on joist/ beam soffit (<300mm).
Away from damp, regular high ambient temperature, vibration, air current etc |
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| Smoke | Away from heat flow from roof, 3m above floor, min 400mm away from supply air outlet.
Min 300 mm above any partitions for unobstructed smoke path. Preferably on a point in the direction of natural air circulation. |
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| Flame | Usually in indoors away from sunlight.
Rigidly fixed on stable support with a field of view not blocked by structural member, equipment or furniture. |
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Grading for design of alarm system
| Factor | Grading criteria | Grade |
| Alarm | ||
| Selection | Sound should be distinguishable from general clutter or other signals in building.
Visual alarm where background noise is excessive, e.g. night clubs. If possible background noise should be cut off when a fire alarm is activated. For hotel, or warehouse, auto fire alarm and for smaller building, manual call points are suitable. |
Yes:5
No: 1 |
| Location | Planning: type, no. & location as per SS CP 10. All zones should be covered.
Accessibility: Clear space of 300mm in radius and 600mm in depth. Manual call points: at located at 1.4m from floor, on the access route and jut out from wall for a better visibility. Exposure: No exposure to dampness, corrosion, extreme environment such as flammable gas that affects the reliability. Should never be installed in the same conduit of other services to prevent mechanical damage. |
Yes:5
No: 1 |
| Connectivity | Independent of building automation system (BAS) if it is provided.
Compatible with other component of fire alarm system, even if they are made by different manufacturers. Else problem in synchronization happens. Red in colour for easy identification. Cables of low and extra low voltage should be segregated to remove electromagnetic interference. |
Yes:5
No: 1 |
| Alarm panel | ||
| Location | At any one of this accessible and visible location (as approved by the authority):
At fire command centre. Main entrance lobby or a remote place accessed by authorised person. In the guardhouse or in the fire fighting lobby. Care to be taken for exposure to very damp or corrosive environment. |
Yes:5
No: 1 |
| Legibility | Various colour coding and indicators fixed on mimic panel point out the alarm position precisely. Else it becomes difficult to find in which part of the building, the alarm has been actuated.
For a very big building, arrangement and location of the detailed indicators may be marked on a separate panel adjacent to main panel. |
Yes:5
No: 1 |
| Indicator design | One LED for each indicator. It has much longer life than normal lamps. | 5 |
| Two filament lamps in parallel or one lamp + failure indicator. | 3 | |
| Anything else. | 1 | |
| Safety | Signalling transformer enclosed and accessible to authorized persons only.
Activation of audible / visible alarm on removal of any detector, forceful opening of a locked cabinet or disconnection of a call point (short circuit or ground fault is often responsible). Control program is monitored and can be altered by authorized person only. Electrically supervised system. |
Yes:5
No: 1 |
| Connectivity | Connected to fire station through an approved alarm monitoring station.
Connected to monitoring station via approved leased line, with backup phone. Independent of circuit from other building components and BAS. |
Yes:5
No: 1 |
| Power supply | Extra LV supply segregated from other supplies of the building.
Stand-by batteries for a full power back up for min 24 hours. It should be able to activate full emergency evacuation alarm for min 10 min. Wiring with PVC or MIMS cable (SS CP 5). |
Yes:5
No: 1 |
Grading for design of fire hydrant and accessories
| Factor | Grading criteria | Grade |
| Location | Planning: number and location as per SCDF guideline. Breeching inlets are placed as close as possible to rising main and fire hydrant.
Access: should not be obstructed by parking, loading, unloading bay landscaping, building elements etc. Riser should not be located in same shaft with gas, fuel or electricity. Identification: easy visibility and identification are must (SS 508-3). Safety: protected from mechanical damage. E.g. knocking by moving cars or falling debris during fire. Should be safe from theft or vandalism. Valve pit accessible for inspection and cleaning. |
Yes:5
No:1 |
| Security | Precaution should be taken so that parts are not stolen or broken.
No unauthorised handling that can make the system inactive. For e.g. valves that should remain in open position are closed by laymen. In a glass box (for dry riser) or recessed alcove (for wet riser) to prevent vandalism but such facility must allow free turning of hand-wheel or secured with a strap shut with a brass padlock. |
Yes:5
No:1 |
| Material | Hydrant pillar should be strong, rust proof and parts of gunmetal (BS EN 1982).
Rising main and other pipe work made of wrought iron or steel. The pit cover on the roadway should be able to withstand vehicular load. |
Yes:5
No:1 |
| Water supply | Design: supply from public source, natural source or storage tank as needed.
Backup: stand by pump, compartmentalisation of tanks etc. Water quality: clean and fresh. |
Yes:5
No:1 |
Grading for design of fire hose
| Factor | Grading criteria | Grade |
| Cabinet location | Number and distribution as per SS CP 29. Usually it is located in every floor, except ground floor.
Access or visibility not unobstructed from for e.g. parking, furniture, equipment, partition wall etc. Protected from mechanical damages e.g. at parking, loading – unloading bay etc. In such areas, the reel should be mounted above head but nozzle retainer, hose guide and inlet valve are kept at 900 mm. The location should allow 180 ° opening of cabinet door. Wall mounted type is only allowed in riser main shaft. |
Yes:5
No: 1 |
| Cabinet spec. | Size and mounting as per guideline (Fig. #).
Made of fire proof and maintenance-free (mainly corrosion) material. Locked cabinet with tempered glass panel or solid metal cabinet without lock. |
Yes:5
No: 1 |
| Hose | Made of non-kinking reinforced rubber or reinforced PVC suitable for particular use- for e.g. working pressure, exposure, (BS 3169).
20mm or 25mm nominal diameter. Length < 30 m and terminating in “shut-off” branches with 40 mm or 60 mm nozzles. Dutch role type fastened with Velcro strap. |
Yes:5
No: 1 |
Grading for design of sprinkler system
|
Factor |
Grading criteria |
Grade |
|
| Selection | Design adhering to hydraulic principles and based on parameters such as, hazard class, discharge density, AMAO or assumed maximum area of operation (NIFSP, 2006). Usual requirement is 75L/min for 2.5m wide area.
Type is based on the function: |
Yes:5
No:1 |
|
| Type | Suitability | ||
| Dry | Artificial ambient temp is almost freezing or above 70°C. | ||
| Wet | No chance of freezing. | ||
| Wet pipe with tail-end dry pipe | Comparatively small area with temp range close to freezing or above 70°C. | ||
| Pre-action | Faster action than dry type is required and damage from broken head or leaky pipe of wet system to be avoided. | ||
| Note: ESFR – early suppression fast response is special type and used only for nominated high pile storage risk. | |||
| Location | Spacing & location: Horizontal & vertical distance range should be based on hazard class as recommended by code.
Above false ceiling (>0.8m deep) or voids made of combustible material. Below services, walkways, galleries, stairway chutes etc of >1m width at <150mm from adjacent walls or partitions. No building element should hinder the flow from sprinkler. For e.g.: structural obstructions (girder, beams, trusses, column, partitions etc) or services (ducting, cable tray, walkways etc). |
Yes:5
No:1 |
|
| Material | Pipes made of corrosion resistant materials such as copper, steel or plastic.
Fire tank is of sound construction less prone to leakage or corrosion. |
Yes:5
No:1 |
|
| Support | Able to support pipes filled with water, the stress from building movement, internal pressure due to flow without showing sign of sway.
Support components of approved geometry and corrosion resistant material. From building or ducts but independent of support of ceiling seething or associated suspension system. |
Yes:5
No:1 |
|
| Water quality | Fresh water, free from fibre or suspended material those accumulate in piping. If water is taken from natural sources like river, strainer is used. | 5 | |
| Salt or brackish water but sprinklers are charged with fresh water. | 3 | ||
| Water of any other standard. | 1 | ||
| Pump location | Housed in a room made of non-combustible and fire resistant material and preferably protected by sprinkler.
Adequate ventilation, lighting and access around the machines. Mounted at a height of 150 mm on an insulated padding. |
Yes:5
No:1 |
|
Grading for selection of portable fire extinguisher
| Factor | Grading criteria | Grade | ||
| Selection | Cl. | Burning material | Suggested extinguisher | Yes:5
No: 1 |
| A | Carbonaceous combustible materials: paper, wood, cloth, plastic, furnishing, rubber etc. | Water, multipurpose powder, BCF/ Halon 1211, BTM/ Halon 1301 or foam type. | ||
| B | Liquids or liquefiable solids, solvents, paints, oils, thinner, flammable gas. | Powder, Halon 1211, Halon 1301, Carbon dioxide, mechanical foam such as aqueous film forming foam (AFFF). | ||
| C | Live electrical equipment. | Halon 1301, Halon 1201, Carbon dioxide and powder type. | ||
| D | Combustible metals- sodium, potassium, magnesium etc. | Approved for use on specific combustible metal hazard. | ||
| Note: Usage of Halon 1211 and Halon 1301 is highly restricted in many countries as per the Montreal Protocol of 1997. | ||||
| Location | Planning: number and location based on max travel route.
Accessibility: near the expected hazard zone but not too close that cannot be accessed during emergency. Visibility: seen along an escape route – preferably near room exit, corridor, staircase, lobby, and landing. Should not be in concealed positions behind doors, in cupboards or deep recesses or in a concealed place. Exposure: not to corrosive environment, physical impact, excess heat or cold. |
Yes: 5
No: 1 |
||
| Quality | The body and the parts should be of approved quality to prevent rusting, early damage or deterioration (SS 232 -1-6). | Yes: 5
No: 1 |
||
Grading for design of fire door
|
Factor |
Grading criteria |
Grade |
| Selection | Fire rating: selected in terms of stability, integrity and insulation as per requirement of local fire authority and code (SS 332).
Quality: exact prototype design confirmed by fire test and cyclic movement endurance test conducted by an accredited body. Customization: allowed only for height and width of leaf and latch-set, metallic finish etc. But not allowed for thickness, internal construction, facing, edging and construction technique. Note: single swing door should not be used as double swing and vice versa. |
Yes:5
No:1 |
| Operation | Easy: manual, without the use of a key, tool, special knowledge or effort for operation from inside.
Automatic: self closing and self latching from any angle. No bolted door is allowed for commercial buildings. Direction: swing outside towards the safe area in the direction of exit travel. Locks allow free exit but re-entry at few selected floors only. |
Yes:5
No:1 |
| Detailing | The gap around door leaf must be 3-10 mm at bottom with floor finishing and <3 mm for other sides. A smaller or larger gap lead to rubbing or loss of smoke tightness respectively.
Hinges: made of steel as it allows low friction and free swing. Latching elements: bolt, striking plate and bolt-retaining plate should have temperature of fusion based on fire rating of door. E.g. 890°C and 1030°C for 2 hour and higher rating. Glazing: Glass panel, vision panel or viewing lens of limited dimension and application is only permitted if found suitable in full fire test. Travel limiting device: buffer or stopper protect side hung or double acting door from damage due to forceful operation. |
Yes:5
No:1 |
| Marking | Etched, embossed or stamped metal tag should carry the information about: manufacturer, fire rating of frame and doorset, brand name.
Identification number of individual doorset. For one sided resistance, an arrow should mark which side faced furnace. |
Yes:5
No:1 |
Grading for design of services for fire escape
|
Factor |
Grading criteria |
Grade |
| Emergency lighting | ||
| Power supply | Self contained, or by centralized battery that can supply power for min 1 hr. | 5 |
| Standby generator: theoretically OK, but may not work (NIFSP, 2006). | 3 | |
| Charging system | Current limiting and constant –potential charging system. It ensures long battery life and auto boost charging | 5 |
| Other approved method | 3 | |
| Lighting system selection | Maintained lights: power supplied for all the times by mains, but if mains fail, power is supplied by standby system. | 5 |
| Non-maintained (NM): power is supplied only when supply to normal lighting fails. It has the following disadvantages (BS 5266-1):
For local distribution board (DB), there is no protection against failure of any normal lighting circuit on DB. Self-contained type lighting does not work if connected to normal lighting of another area. Central battery operated lights doesn’t switch on in emergency if the local circuit is without any facility to monitor the critical normal lighting circuit. Needs monitoring of all critical lighting units under central battery pack. |
3 | |
| Lamp selection | Lighting design takes into consideration the effect of voltage drop, ageing of lamp, dirt, deteriorating battery performance.
With protective enclosure to mitigate the effect of dust, corrosion & humidity. Note: A min. output of 0.5Lux with uniformity ratio 1:40 is to be achieved. |
Yes:5
No:1 |
| Battery discharge | These preventative design features are essential for successful functioning of the system. In general the basic recommendations are:
Preventive measure for over-discharge of battery if it operates for more than rated period or when voltage < 85% of system voltage. Automatic recharging within 24 hours. CB on outgoing battery circuit to prevent discharge during fault. Provision of manual or automatic discharge test facility. |
Yes:5
No:1 |
| Battery location | Cool, dry, ventilated and secured location. The storage room should have fire proof construction.
Visual or audible alarm to indicate any fault or tampering is installed in a readily noticeable place. |
Yes:5
No:1 |
| Smoke control | ||
| Safety & back-up | Secondary source of power supply.
Standby fan(s) as back-up to provide the designed smoke extraction rate in case of duty fan fails and get automatically activated. Both auto and manual activation of smoke control becomes fully operational within 60 sec. of activation. All wirings are protected circuits that can perform during fire hazard. |
Yes:5
No:1 |