Fire safety - existing non-residential premises: practical guidance

Chapter 5: Reducing the Likelihood of Fire

127. An effective strategy should be in place to reduce the likelihood of a fire starting. At its simplest, this means separating flammable and combustible materials from ignition sources and ensuring that equipment and installations are maintained.

Housekeeping and Storage

128. Control of combustible materials should be achieved by attention to good housekeeping principles. By carefully considering the type of material, the quantities kept and the storage arrangements, risks can be significantly reduced. Appropriate practices are:

• Not storing combustible materials in plant rooms, boiler rooms, attics, service voids and shafts, electrical main or sub-switch rooms.
• Control and frequent disposal of packaging, waste and other combustible rubbish.
• Loose storage, bins and waste external to the building, sited well away from the building so that any fire cannot affect external walls or overhanging eaves.
• External bins and storage containers secured to prevent movement.
• Regular building checks to ensure that storage arrangements are appropriate.
• Combustible material in external storage areas should be divided into separate stacks or piles with sufficient space separation between them to restrict the spread of fire.

129. In temporary classrooms buildings, boarding or ‘skirts’ should be fitted around the base to prevent combustible material being placed under the structure.

130. A feature in older sports stands may be the existence of voids under seating decks which can be a resting place for litter. Voids below seating decks should be separated from the deck to prevent litter falling through and accumulating below the seating deck.

Storage and Use of Dangerous Substances

131. Certain substances and materials are by their nature flammable, oxidising or potentially explosive. These substances are controlled by legislation, in particular the Dangerous Substances and Explosive Atmospheres Regulations 2002. The principles of safe handling and storage are:

• Avoid the use of flammable materials and liquids wherever possible or substitute flammable substances and materials with those that are preferably non- flammable or with those that are less flammable.
• Reduce the quantity of dangerous substances to the smallest reasonable amount necessary for use.
• Correctly store dangerous substances, for example in a fire-resisting metal enclosure: all flammable liquids and gases should ideally be locked away, and segregated if necessary, to reduce the chance of them being involved in a fire or used in deliberate ignition.
• Ensure good ventilation is provided by way of high and low level vents to allow any flammable vapours to be dispersed.
• Ensure that all staff are aware of the fire risk of dangerous substances present and the precautions necessary.

132. The presence of flammable liquids increases the chance of a fire starting and its rate of development. For example, a leak from a container of flammable liquid may produce flammable vapours which can travel some distance away from the source of the leak, increasing the likelihood of reaching a source of ignition. The risk can be reduced by ensuring the storage and use of flammable liquids is carefully managed and materials contaminated with flammable liquids are properly disposed of. Further guidance is available on the Fire and Explosion section of the HSE website at www.hse.gov.uk/fireandexplosion/.

133. Where gases are stored in cylinders these should ideally be stored and used in the open air outside the building and be located where they cannot be interfered with, and where they will not affect the means of escape. They should not be beside heat, a source of ignition or readily ignitable material and care should be taken to minimise the possibility of involvement in a fire.

134. Acetylene cylinders are found in many workshops and pose particular problems if subjected to fire. If heated in a fire, an acetylene cylinder can fail violently due to progressive decomposition of the acetylene, even after the fire has been extinguished. Due to this potential for explosion, SFRS may establish a 200 m hazard zone. A small fire can therefore result in major disruption to the affected area, adjoining premises and transport networks.

135. Under normal circumstances, Liquefied Petroleum Gas (LPG) is flammable and is heavier than air. Where LPG cylinders or cartridges are used, these should be stored and used in the open air outside the building. Care should be taken to minimise the possibility of involvement in a fire.

136. The total stock of LPG for display or demonstration in retail areas should be kept to the minimum necessary to meet business needs. The maximum stock should be in accordance with HSE guidance.

137. Some premises use bulk LPG fixed installations for cooking or heating, comprising an external tank and supply piping. In these installations there is a need to ensure that there are no fires in the vicinity of the LPG tank, and to consider the maintenance of the installation and piping.

138. Guidance on the safe storage and use of LPG is available from the supplier, and the trade association for the LPG industry, Liquid Gas UK (www.liquidgasuk.org), and on the gas safety pages of the HSE website at www.hse.gov.uk.

139. Flammable propellants are often used in aerosol cans. Aerosols are liable to explode if involved in a fire, causing spread and intensification of fire and possibly damaging doors so that they fail to function in restricting the spread of fire and smoke. These potential consequences should be taken into account and appropriate use, storage and disposal arrangements put into place for aerosols, taking into account the quantities involved. Manufacturers’ instructions should be followed. Storage should be away from escape routes and no storage should be allowed in boiler houses or other areas containing fixed sources of ignition. They should not be stored or placed in damp areas where the container might corrode. Aerosol cans can overheat and rupture in direct sunlight therefore avoid placing aerosol cans containing LPG/flammable liquid propellant on window ledges.

140. The ignition of combustible dusts can result in fires which range from a slow smoulder to very rapid combustion or, where the dust is dispersed in the atmosphere, a dust explosion. Dust flammability is affected by factors such as particle size and moisture content. Dust should not be allowed to accumulate, since dust deposits can be disturbed and give rise to a dust explosion.

141. Sources of oxygen can sometimes be found in some chemicals (oxidising materials), which can provide a fire with additional oxygen and so assist it to burn, or oxygen supplies from cylinder storage. High concentrations of oxygen can cause materials to burn extremely rapidly and some materials, which are not normally considered combustible, can burn in an enriched oxygen atmosphere. Oxygen is dangerous when in contact with grease or oil.

Furniture and Textiles

142. The choice of furniture, fittings and textiles, can influence the ease of ignition and growth of a fire. There is a need to consider the combustibility and flammability, particularly in premises where large numbers of people assemble. In entertainment premises this consideration includes theatrical curtains, drapes and scenery. Items used in theatrical productions or other events such as concerts, should be durably flame-retardant.

143. It is difficult to assess dried or artificial foliage in terms of flame retardance. These and similar items could be subject to ignition tests using a suitable ignition source such as the match equivalent flame, prior to introduction. Consideration may also be given to the location, ease of access by the public and the overall amounts of artificial foliage/decorative materials present.

144. In places of assembly and entertainment, upholstered furniture (and composites of cover material and infill) should meet the standards in the Furniture and Furnishings (Fire) (Safety) Regulations 1988^[3] and in addition, pass the flammability standard in BS 5852 with ignition sources 0 and 5. BS EN 1021: Part 1 offers an acceptable direct equivalent standard to ignition source 0 of BS 5852. Upholstered furniture should be maintained so that there are no tears which have caused the filling material to be exposed.

145. Where the fire performance of curtains needs to be controlled, textile fabrics for curtains (including nets, linings and blackout curtains) should meet the standards of BS 5867: Part 2 Type B.

146. Textile floor coverings bonded to the floor present a lower fire risk than those loosely laid. BS 5287 contains an assessment system for textile floor coverings.

147. Polypropylene chairs should have flame retardant polypropylene shells.

Cellular Foam Fillings

148. Gymnasium mats and crash pads with cellular foam fillings are often used in sports halls or gyms and may burn fiercely and generate dense toxic smoke if involved in fire. Gymnastic mats and similar equipment should contain combustion modified high resilience foam and comply with the provisions of BS 1892: Part 3. When not in use they should be kept in a locked store which has a minimum of 60 minutes fire-resistance.

149. Soft play environments can contain a large volume of foam in various shapes. The covered foam should meet BS 5852 with ignition sources 0 and 5.

Safe Use of Equipment

150. Lack of preventive maintenance increases the likelihood of fire starting in equipment. A competent person should regularly maintain (and where necessary clean) machinery, equipment and plant, including cooking, heating and office equipment. Appropriate signs and instructions on the safe use of equipment may be necessary.

151. Generally, equipment ventilation points should be kept clear to avoid becoming clogged or blocked. A build-up of grease or fat deposits should be removed from equipment in kitchens, including extraction equipment.

152. There should be a procedure for reporting faults. Faulty equipment should be taken out of use when it is identified or suspected of being defective, and thereafter repaired or replaced.

Electrical

153. Electrical installations^[4] and electrical equipment can be a significant cause of fire. Possible causes include:

• Equipment faults.
• Overheating cables and equipment due to overloading or loose connections.
• Incorrect installation, use or maintenance.
• Damaged or inadequate insulation.
• Combustible materials placed close to heat-producing electrical equipment.
• Arcing or sparking.
• Modifications to an installation by unskilled/incompetent persons.

154. Some precautions are:

• Maintenance of installations and equipment should be done only by persons competent to do so.
• Electrical equipment should only be used for its designed purpose.
• Correctly wired and fused extension leads and plugs should be used.
• Sockets and extension leads should not be overloaded.

155. To reduce the potential for a fire occurring, there should be an effective programme of planned preventive maintenance for electrical installations and equipment.

156. On the legislation.gov.uk website, details of the Dangerous Substances and Explosive Atmospheres Regulations can be found here: Dangerous Substances and Explosive Atmospheres Regulations 2002. This sets out the hazardous area classifications for protecting against potentially explosive atmospheres. This methodology is used to select appropriate, certified equipment (installed and portable) and vehicles etc, including electrical equipment. Where only certified equipment should be installed, this also applies to electrical fire safety systems such as a fire warning system.

157. Guidance on electrical safety, including FAQs on maintaining portable appliances, is available on the HSE website at www.hse.gov.uk/electricity/index.

Smoking

158. Careless use of cigarettes and other smoking materials is a common cause of fire. A cigarette can smoulder for some time, especially when surrounded by combustible material, however, smoking is banned in all wholly or substantially enclosed public places. Staff should be aware of the potential for fires associated with illicit smoking. Where smoking takes place in external areas, consideration should be given to minimising the risk of combustible materials being ignited.

Managing Building Works and Alterations

159. Fires often occur when buildings are undergoing refurbishment or alteration. Before any major building work or decoration, the fire safety risk assessment should be reviewed and additional risks considered and evaluated. There are three aspects of building work that should be considered:

• The introduction of new ignition sources and combustibles and the associated risk of fire occurring during the work.
• The potential interference with the existing fire safety measures while the building work is underway.
• Whether the building work will result in adverse changes to existing fire safety measures.

160. To ensure that fire safety measures are not compromised and that adequate controls are in place, it is important to ensure co-operation between the building contractor and management. It may be appropriate to specify site-specific fire precautions in contract conditions.

161. Examples of issues that may arise with building work and that need to be considered and controlled are:

• The potential for fires to be caused by hot work such as soldering, welding, flame- cutting, roof repair, paint stripping.
• Increased quantities of combustible materials and accumulated waste.
• Obstruction of internal and external escape routes.
• Loss of normal storage facilities.
• Fire safety equipment, such as automatic fire detectors being out of use.
• Fire-resisting construction being breached or fire-resisting doors being wedged open.

162. Hot work should only be undertaken when suitable precautions and equipment are in place. This may be the use of an industrial quality fire blanket to mask areas adjacent to the work being carried on, an appropriate fire extinguisher provided immediately to hand, or where the activity presents a high fire risk, an observer standing-by to identify any fire propagation from sparks or other source. Areas where hot work is undertaken should be frequently inspected during the first 30 minutes after the work is completed, and then 30 minutes later to ensure that no materials are smouldering. A ‘permit to work’ system is a useful procedure and management tool which allows a degree of control over contractors or staff who may be carrying out hot work.

163. Modern buildings of timber frame construction contain combustible material in the structure. Care needs to be taken with tools or heat sources where any construction work or alteration involves drilling or cutting openings in the outer cladding or the inner plasterboard skin.

164. The content of skips, waste containers or combustible material may be subject to deliberate ignition. Storage, preferably in lockfast non-combustible containers, should be away from the building so that any fire cannot affect external walls or overhanging eaves.

165. Only the minimum materials necessary for the work in hand should be allowed within the building or close to the exterior of the building.

Keeping Escape Routes Clear

166. There needs to be control over the provision of combustible materials in escape routes. If a fire were to occur in an escape route or spread to material in the escape route, this could be a particularly difficult and threatening situation, preventing occupants from escaping.

167. Stairways that form part of escape routes should be kept clear of combustible items and items that could be a source of ignition. Items kept in corridors should be controlled, consistent with the need for the normal functioning of the premises.

168. The maintenance of adequate escape route width and prevention of obstruction is also relevant. Escape route width is covered in Chapter 7.

169. Examples of some items which are normally unacceptable in stair and protected escape routes are:

• Gas cylinders, gas pipes, meters and similar fittings.
• Cooking appliances.
• Upholstered furniture.
• Coat racks.
• Electrical equipment such as photocopiers and battery chargers.
• Storage of combustibles.

Fire-Raising

170. The possibility of deliberate fire-raising should be considered. This may be particularly relevant in areas with a history of vandalism or fire-setting.

171. Appropriate precautions should be taken. This may involve ensuring the outside of the premises is well lit and secure against unauthorised access, and that waste stored external to the building is kept in lockfast bins or stores. Security measures should not compromise the means of escape and the ability to evacuate including those working late or alone.

172. In schools some fires are started deliberately and there has been a trend for deliberately started fires to occur during school time.

Tented Structures

173. The ignitability and flame-spread characteristic of tents, marquees and air supported or pneumatic structures should be considered. In addition, certain plastics used in the construction of such structures can produce highly toxic fumes when subjected to heat.

174. Tent membranes and fabrics, including wall hangings and other decorative display materials, should be of inherently flame retardant fabric or durably flame retardant fabric when tested to BS 5438 or BS 7157. Materials should be free of flaming molten droplet characteristics and should not support combustion.

175. A test certificate to show compliance with the appropriate standard should be obtained from the manufacturer or supplier.

Pyrotechnics and Special Effects

176. Pyrotechnics and special effects may produce light, colour, heat, sound or smoke, or a combination of these. They are used in outdoor and indoor places of entertainment or assembly for a variety of purposes such as outdoor firework displays and in theatres and other venues to enhance performance.

177. Operators of pyrotechnics and special effects should be suitably qualified to manage such equipment. Pyrotechnics/special effects should be obtained from a reputable supplier who can demonstrate suitability of products. The manufacturer’s and supplier’s instructions regarding use and storage should be followed as should the Event Safety guidance issued by the HSE.

178. The use of pyrotechnics needs to be carefully controlled. Fireworks and pyrotechnics intended for outdoor use should not be used within buildings or structures. The indoor use of outdoor pyrotechnics has been a cause of fire in entertainment venues worldwide which have included multiple fatalities (see case studies annex).

179. Factors to consider prior to the use of pyrotechnics and special effects include:

• Positioning pyrotechnics in an area upstage of the safety curtain where installed.
• The height that will be reached by any flaming effect.
• Safe positioning away from audience, performers and flammable materials.
• Escape routes for firers of fireworks.
• The potential for heat, flame or sparks starting fires in adjacent materials.
• Burning residue from pyrotechnics setting off non-fired pyrotechnics.
• Potential for smoke effects to obscure signage and escape routes or actuate smoke detectors.
• Gaps in flooring might allow sparks or material to fall through to ignite combustible materials below.
• Hot surfaces on special effects machinery.
• Noise levels affecting fire warning or verbal evacuation signals.
• The co-ordination and co-operation between occupiers and participants at events to ensure their awareness of the use of pyrotechnics.