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NEBOSH Fire Certificate Element 4 Part 1

Issue Oct 2011Fire Protection in Buildings

2We cant see it coming,, we cant hear it, we cant smell it but we know when it gets us.Building Regulations 2000In general covers new builds and modificationsSchedules A-K contain information on structures, fire, moisture, toxic substances, noise, ventilation, hygiene and drainage.

Part B (Fire Safety) of the Building Regulations and Approved Document B

Volume 1 - DwellinghousesVolume 2 Buildings Other Than DwellinghousesFlats (including multi-storey flats & mixed-use buildings) can be found in Volume 24Schedule B FireB1 Means of warning and escapeB2 Internal fire spread (linings)B3 Internal fire spread (structure)B4 External fire spreadB5 Access facilities for the fire service

Appendices regarding fire performance materials with regards test methodsPart B (Fire Safety) of the Building Regulations and Approved Document BFire Resistant PropertiesofCommon Building MaterialsResistance to collapse Load BearingFire & Smoke Penetration IntegrityTransfer of Excessive Heat InsulationResistance of Fire Doors Stop the spread of smoke, fumes or heat.Elements of a Structure a. A member forming part of a structural frame of a building or any other beam or column b. A load bearing wall or load bearing part of a wall c. A floor d. A gallery e. An external wall f. A compartment wallTimberTimber burns at the surfaceDoes not expand when heatedDoes not collapse suddenlyFire resistance depends on: -Thickness & cross sectional areaTightness of jointsType of woodTreatment

Reinforced Concrete Frames

Types: - Reinforced, Pre-stressed (pre & post tensioned)Resistant to fireFire resistance depends on type & thickness of concrete used & protection afforded by the concrete to the steel

Brickwork & BlockworkResistant to fireResistance depends on: -ThicknessPlastering or coatingWhether load bearing or notCavities within the bricks or blocks

Structural SteelNon-combustibleSteel expansion causes buckling can affect stability of buildingSteel looses strength in a fire

Sheet MaterialsFibre board can be fire resistant if impregnatedPlaster boards retard fire spreadPlywood/chipboard depends on properties of woodPlastic has little fire resistance Glass breaks unless wired or tempered

Lining MaterialsMostly non-combustibleSome older types may contain wood dustPlaster (calcium hydroxide) has good fire resistance

B2 Internal Fire Spread (linings)To inhibit the spread of fire within the building the internal linings shall resist the spread of flame over their surfaces and if ignited a rate of heat release or a rate of fire growth which is reasonable in the circumstances.B3 Internal Fire Spread (structure)The building shall be designed and constructed so that in the event of fire, its stability will be maintained for a reasonably period.Consider:DesignMaterialsCompartmentationShaftsConcealed spaces (cavities)Protection of openings and fire stopping

CompartmentationTo prevent fire, heat, and smoke from spreading beyond locations of origination

Building elements such as fire walls, fire dampers, and fire doors, are designed to seal off one location from the next.

Increases the safety by allowing evacuating building occupants because smoke and fire are not able to escape into exit passageways.

Containment of fire and smoke reduces property damage and prevents small fires from growing.

In order for compartmentation efforts to be effective fire barriers must be maintained

Compartmentation30 min fire resistanceMaintains building structureAllows sufficient time to escapeMinimises destructionAssists firefighting

To prevent fire, heat, and smoke from spreading beyond locations of origination.

Cavity Barriers18

Compartment Walls/ Floors Junction19Openings & VoidsThese can eliminate the protection afforded by the compartmentAny opening will allow fire to spread quicklyVoids eg cable ducts, suspended ceilings & floors provide ready routes for fire spreadFire Stopping ensures barriers to fire spread are replaced

B4 External Fire SpreadThe external walls of the building shall adequately resist the spread of fire over the walls and from one building to another, having regard to the height, use and position of the building.The roof of the building shall adequately resist the spread of fire over the roof, from one building to another, having regard to the use and position of the building.B1 Means of warning and escapeThe building shall be designed and constructed so that there are appropriate provisions for the early warning of fire, and appropriate means of escape (MOE) in case of fire from the building to a place of safety and effectively used at all times.

B1 Means of warning and escapeB1 will be met if:There are routes of sufficient numbers and capacity which are suitably locatedThe routes are sufficiently protected from the effects of fire by enclosure where necessaryRoutes are adequately lit and sign postedAppropriate facilities to either limit the ingress of smoke to the escape routes or to restrict the fire and remove the smokeArrangements for early warningProtection of escape routes

Means Of EscapeStructural means forming an integral part of the building whereby persons can escape from fire by their own unaided efforts to a place of safetyConsider structure, travel, fire, place of safety. Main principles BS5588 and Acops and The Building Regulations 2000Strategic Factors Affecting Means Of EscapeOccupancyConstructionTime of evacuationExitsTravel DistanceManagementMaximum Travel DistancesWhere more than one route is available25 m high risk area45 m normal risk area60 m low risk area

Where only single escape route is available12 m high risk area25 m normal risk area45 m low risk area

Escape RoutesStairways, corridors and areas near the fire exits should be kept clear of obstructions and material which can catch fire.The escape route should lead to a final exit and a safe place.If the stairway is not protected, the travel distance should be in line with those for single escape routes and the final exit should be easy to see and get to from the stairway at ground-floor level.High-risk rooms should not generally open directly into a fire-protected stairway.Alternate means of escape usually requiredStairs & CorridorsMinimum width 800mm stairs (increases with number of persons) but not to exceed 1.4m unless central handrail fitted 1.2m corridorsOne stairway up 4 storeys onlyStairways to have handrailsTreads and risers of stairs of correct dimensionsStructure 30 mins fire resistance

Stairs, Corridors and PassagesFire Protection 30 minutes minimumBe ventilatedSub-divide corridors (If longer than 12m)Not cause bottle necksHeight 2mBe continuous to the exit pointCorrect lightingManagement actions to maintain MOE

Emergency LightingAimTo indicate clearly the escape routeIlluminate routes to allow safe movementTo ensure call points and equipment can be locatedConsider natural light - day/nightSitingEscape route lightingOpen area lighting anti-panic lightingHigh risk lightingDifferent types MaintainedSustainedSelf containedLow level lightingTesting Daily, Monthly, 6 monthly

SignageThe H&S (Safety Signs & Signal) Regs 96Two types- EC Pictorial & BS5449 Pictorial and wordsTypes Include -Directional arrows, equipment, alarms, assembly pointsRead from both sidesNot obscured

Fire DoorsBS 476Does not obstruct route when openSelf closing with smoke stopsThree hinge, Colour coded rawl plugs. i.e FD 30/30Width 850 if more than 50 personsSmoke sealed intumescent strips30 minutes fire resistanceEasily opened and in direction of travelMagnetic hold-backs are okayFinal exit to unobstructed place of safetyNever lockedHave visibility panels45 degree ruleRoller shutters should be capable of manual operationAmount 60=1 600=2 More than 600=3

APPROVED DOCUMENT M - THE BUILDING REGULATIONS

1.general guidance on Vision Panel dimensions, however if Vision Panels form part of a fire resisting door set then the area of the glass may be determined by the fire resistance properties and the manufactures s specifications etc.2.All door glazing on traffic routes and public areas should be Safety Glazing Standard, in addition to any fire resistance required.

Final Exit DoorsOpen in direction of exit (outwardly)Have "push bar" openers (panic bolts)Be marked "FIRE EXIT"Do not open directly to stairsExternal area free from vegetation and other obstacles

Place of Safety

MOE For Vulnerable PeopleEvacuation lifts, refuges and chairsUse of graphic, aural, tactile signagePersonal Emergency Evacuation Plan (PEEP)

Fire DetectionSmoke DetectionOptical or ionisationOptical detects obscuration of light by smokeIonisation detects by change in electrical chargeHeat DetectionFixed rate or temperature riseUsed where there is heat under normal conditions (kitchens)Flame DetectionInfra-red or ultra-violetUsually used with other types

Ionisation Smoke DetectorAmericium 241 enables current to flow between the inner and outer chambers. As smoke enters the detector an increase in voltage occurs between the two chambers. The voltage increase triggers the detector at a preset threshold. Ionisation detectors respond well to fast-burning fires

Optical Smoke Detectorsmoke from a fire scatters the light from the LED if smoke seen on the two following pulses, the alarm lights up. optical smoke detectors respond well to slow-burning fires.

Heat DetectorTwin thermistors detect change in heatDifference in temperatures triggers the alarmStatic response detectors have one sensor at preset temperatureThey have wide openings to allow good air movement over the sensing thermistor

Flame DetectorA flame detector is designed to detect ultraviolet (UV) or infra-red (IR) radiation emitted by fire. Dual IR flame detectors are sensitive to low-frequency, flickering infra-red radiation. Detector can operate even if the lens is contaminated by a layer of oil, dust, water vapour or ice. Flame detectors are effective in protecting areas where flaming fires may be expected.

Alarm SystemsComponentsAutomatic detector Spot (static)Line (linear heat laid around an area)Beam (of light IR large areas)Sampling (pipe work pulling air through a detector)Scanning (moving/sweeping a large area)

Manual call point

Alarm sounder

Control panel

Categories of Fire Alarms & Detection SystemsSystems generally designed & installed to BS 5839Property risk/protection (to summon the Fire & Rescue Service in the early stages of a fire)

Category P1 installed throughout all areas of the building.Category P2 Systems installed only in defined parts of a building.

Life Risk/ ProtectionCategory M Manual system (call points & sounders only)Category L Automatic fire detection systems intended for the protection of lifeL1 Installed throughout all areas of a buildingL2 Installed only in defined parts of the buildingL3 Designed to give a warning at an early enough stage to enable occupants to escape safely before routes are impassable due to fire, smoke or toxic gases. (other than possibly those in the room of the fires origin)L4 Installed in escape routes comprising of circulation areas (stairways and corridors) Objective is to provide warning of smoke within escape routes.L5 Systems in protected areas and or location of detectors designed to satisfy a specific fire safety objective other than the above categories.

Fire Alarm ZoningZones are a convenient way of dividing up a building to assist in location of a fire.Zones are not physical features (normally the zone boundary coincide with walls, floors and fire compartments)Zone basic rules:Single zone should not exceed 2,000m2Two faults should not remove protection from an area > 10,000m2 (for addressable systems) Addressable= Gives unique ID to the actuating device detector/call point which has been activated.Floor area < 300m2 regarded as one zone.Total floor area > 300m2 zones restricted to single floor levelsException to above: stairwells, lift shafts or other vertical shafts should be considered as one or separate zonesThe max distance travelled within a zone to locate the fire should not exceed 60m.

Alarm Signalling Objective to warm occupants of a fire situationOne sounder located near the control panel on a separate circuit Sounders should sound similar to avoid confusionMinimum of 65db in general areas or 5 db above background noise.High noise areas visual indication may be required.Sleeping 75db at bedhead (30 db should be allowed per door so sounder per bedroom is recommended)Impaired hearing other means of signalling may be required

Alarm Receiving CentresPermanently manned (normally a commercial organisation)Upon receipt of a fire signal notify the fire service

Factors in the Selection of Fire Alarm & Detection SystemsLife RiskProcess RiskBehavioural issuesSocial Behaviour Minimising false Alarms (unwanted alarms, Equipment false alarms malicious alarms)Requirements for Vulnerable People (disabilities and/or mobility problems)

Requirements for Maintenance & TestingRRFSO 2005 States equipment & devices are subject to suitable system of maintenance and maintained in an efficient state.... Good repairOne regime to comply with is would be:Daily Check System is not indicating a fault if required corrective actions are taken.Weekly Check Test the system by operation of a call point (different one each week)Periodic Subject to RA (but should not exceed 6 months)Check system log, visually inspect all items of equipment(obstructed or inappropriate due to change of use), amount of false alarms, standby power, remote signalling ,any other checks required (beam detectors for alignment etc) all call points over the 12 months plus cabling, programming and audible checks.