NEBOSH Fire Certificate

Element 4 Part 1

Issue Oct 2011

Fire Protection in Buildings

Building Regulations 2000

• In general covers new builds and modifications• Schedules 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 - Dwellinghouses

Volume 2 – Buildings Other Than Dwellinghouses

Flats (including multi-storey flats & mixed-use buildings) can be found in Volume 2

Schedule 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 methods

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

Fire Resistant Propertiesof

Common Building Materials

• Resistance to collapse Load Bearing• Fire & Smoke Penetration Integrity• Transfer of Excessive Heat Insulation• Resistance 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 wall

Timber

• Timber burns at the surface• Does not expand when heated• Does not collapse suddenly• Fire resistance depends on: -

Thickness & cross sectional areaTightness of jointsType of woodTreatment

Reinforced Concrete Frames

· Types: - Reinforced, Pre-stressed (pre & post tensioned)

· Resistant to fire· Fire resistance depends on type &

thickness of concrete used & protection afforded by the concrete to the steel

Brickwork & Blockwork

• Resistant to fire• Resistance depends on: -

ThicknessPlastering or coatingWhether load bearing or notCavities within the bricks or blocks

Structural Steel

· Non-combustible· Steel expansion causes buckling can affect

stability of building· Steel looses strength in a fire

Sheet Materials• Fibre board can be fire resistant if

impregnated• Plaster boards retard fire spread• Plywood/chipboard depends on

properties of wood• Plastic has little fire resistance • Glass breaks unless wired or tempered

Lining Materials

• Mostly non-combustible• Some older types may contain wood

dust• Plaster (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:• Design• Materials• Compartmentation• Shafts• Concealed spaces (cavities)• Protection of openings and fire stopping

Compartmentation

•To 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

Compartmentation

• 30 min fire resistance• Maintains building

structure• Allows sufficient time to

escape• Minimises destruction• Assists firefighting

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

Cavity Barriers

Compartment Walls/ Floors Junction

Openings & Voids

• These can eliminate the protection afforded by the compartment

• Any opening will allow fire to spread quickly• Voids eg cable ducts, suspended ceilings &

floors provide ready routes for fire spread• “Fire Stopping” ensures barriers to fire spread

are replaced

B4 External Fire Spread

• The 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 escape

• The 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 escape

• B1 will be met if:• There are routes of sufficient numbers and

capacity which are suitably located• The routes are sufficiently protected from the

effects of fire by enclosure where necessary• Routes are adequately lit and sign posted• Appropriate facilities to either limit the ingress of

smoke to the escape routes or to restrict the fire and remove the smoke

• Arrangements for early warning• Protection of escape routes

Means Of Escape

“Structural means forming an integral part of the building whereby persons can escape from fire by their own unaided efforts to a place of safety”– Consider – structure, travel, fire, place of

safety. – Main principles BS5588 and Acop’s and The

Building Regulations 2000

Strategic Factors Affecting Means Of Escape

• Occupancy• Construction• Time of evacuation• Exits• Travel Distance• Management

Maximum Travel Distances

Where more than one route is available• 25 m – high risk area• 45 m – normal risk area• 60 m – low risk area

Where only single escape route is available• 12 m – high risk area• 25 m – normal risk area• 45 m – low risk area

Escape Routes

• Stairways, 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 required

Stairs & Corridors

• Minimum width 800mm stairs (increases with number of

persons) but not to exceed 1.4m unless central handrail fitted

• 1.2m corridors• One stairway up 4 storeys only• Stairways to have handrails• Treads and risers of stairs of correct dimensions• Structure 30 mins fire resistance

Stairs, Corridors and Passages

• Fire Protection 30 minutes minimum• Be ventilated• Sub-divide corridors (If longer than 12m)• Not cause bottle necks• Height 2m• Be continuous to the exit point• Correct lighting• Management actions to maintain MOE

Emergency Lighting• Aim

– To indicate clearly the escape route– Illuminate routes to allow safe movement– To ensure call points and equipment can be located

• Consider natural light - day/night• Siting

– Escape route lighting– Open area lighting – anti-panic lighting– High risk lighting

• Different types – Maintained– Sustained– Self contained– Low level lighting

• Testing – Daily, Monthly, 6 monthly

Signage

• The H&S (Safety Signs & Signal) Regs 96• Two types- EC Pictorial & BS5449 Pictorial and

words• Types Include -

– Directional arrows, equipment, alarms, assembly points

• Read from both sides• Not obscured

Fire Doors BS 476 Does not obstruct route when open Self closing with smoke stops Three hinge, Colour coded rawl plugs. i.e FD 30/30 Width 850 if more than 50 persons Smoke sealed – intumescent strips 30 minutes fire resistance Easily opened and in direction of travel Magnetic hold-backs are okay Final exit to unobstructed place of safety Never locked Have visibility panels 45 degree rule Roller shutters should be capable of manual operation Amount – 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 Doors

• Open in direction of exit (outwardly)• Have "push bar" openers (panic bolts)• Be marked "FIRE EXIT"• Do not open directly to stairs• External area free from vegetation and

other obstacles

Place of Safety

MOE For Vulnerable People

• Evacuation lifts, refuges and chairs• Use of graphic, aural, tactile

signage• Personal Emergency Evacuation

Plan (PEEP)

Fire Detection

• Smoke Detection• Optical or ionisation• Optical detects obscuration of light by smoke• Ionisation detects by change in electrical charge

• Heat Detection• Fixed rate or temperature rise• Used where there is heat under normal conditions

(kitchens)

• Flame Detection• Infra-red or ultra-violet• Usually used with other types

Ionisation Smoke Detector

• Americium 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 Detector

• smoke 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 Detector

• Twin thermistors detect change in heat• Difference in temperatures triggers the alarm• Static response detectors have one sensor at

preset temperature• They have wide openings to allow good air

movement over the sensing thermistor

Flame Detector

• A 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 Systems

• Components• Automatic 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 Systems

• Systems generally designed & installed to BS 5839• Property 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/ Protection

• Category M Manual system (call points & sounders only)

• Category L Automatic fire detection systems intended for the protection of life

• L1 Installed throughout all areas of a building

• L2 Installed only in defined parts of the building

• L3 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 Zoning

• Zones 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 2,000m2

• Two 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 levels• Exception to above: stairwells, lift shafts or other vertical shafts should

be considered as one or separate zones• The max distance travelled within a zone to locate the fire should not

exceed 60m.

Alarm Signalling

• Objective to warm occupants of a fire situation• One sounder located near the control panel on a

separate circuit • Sounders should sound similar to avoid confusion• Minimum 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 Centres

• Permanently manned (normally a commercial organisation)

• Upon receipt of a fire signal notify the fire service

Factors in the Selection of Fire Alarm & Detection Systems

• Life Risk• Process Risk• Behavioural issues• Social Behaviour Minimising false Alarms (unwanted

alarms, Equipment false alarms malicious alarms)

• Requirements for Vulnerable People (disabilities and/or mobility problems)

Requirements for Maintenance & Testing

• RRFSO 2005 States “ equipment & devices are subject to suitable system of maintenance and maintained in an efficient state.... Good repair”

• One 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.