Fire safety - existing non-residential premises: practical guidance

Chapter 7: Provision and Use of Means of Escape

228. Once a fire has been detected and a warning given, everyone in the premises should, if necessary, be able to move or be assisted away from the fire to a place of reasonable safety such as an enclosed protected stair or another fire compartment from where they should be able to continue to escape to an unenclosed safe area beyond the premises. Means of escape is the provision of safe escape routes for people to travel from any point in a building to an unenclosed safe area, and includes the measures to maintain those routes. The number and capability of people present will influence the assessment of the escape routes. The escape routes must be sufficient to enable the maximum number of people likely to use the premises at any time to safely escape.

229. Escape must also be considered from external areas like enclosed yards and from within perimeter fences provided for security purposes at outdoor events.

230. Means of escape should be provided both in terms of the number and capacity of escape routes and in terms of their protection from fire and smoke. When determining whether premises have adequate escape routes, a number of interdependent factors should be considered, including:

• The characteristic, number and location of people in the premises.
• The construction of the premises and the potential for fire and smoke spread.
• The fire compartmentation of the premises.
• The time it will take people to escape.

231. The provision of means of escape and the fire protection given to an escape route will vary depending on the level of risk within the premises and the occupants. In some premises a single escape route will be acceptable, in other cases there should be at least two exits and independent escape routes from each storey of the premises.

232. In public access premises, persons will generally use routes with which they are familiar therefore there is advantage if escape routes are aligned with the general access and circulation routes.

Escape Routes

233. A room containing more than 60 persons should have at least two exits, a room with more than 600 should have at least three exits. But a greater number of exits may be necessary, this will depend on the actual numbers resorting and travel distance to the nearest room exit.

234. Even where the number of persons is low, at least two escape routes may be necessary from:

• A storey over 7.5 m in height.
• A basement used by the public (other than only toilets).
• A basement more than 4.5 m deep.

235. In an auditorium that has more than one exit, at least one exit should be provided not less than two thirds of the distance from the stage or screen to the back of the room.

236. The direction of travel of alternative escape routes from any point within a room should:

• Diverge at an angle of at least 45 ^o, or
• After a single direction of escape (limit as shown in table 7) then diverge at an angle of at least 45 ^oo plus 2½ for every metre travelled in the single direction.

237. Escape routes should be via a direct and unobstructed route. Once occupants have left a room they should ideally not have to pass through another room to reach a protected escape route or a place of safety. In existing low risk situations, escape may be from an inner room through an outer room (see paragraph 258).

238. Where travel distance is to a compartment that does not itself contain either a final exit or direct access to a protected stair, then the next adjoining compartments should contain either a final exit or direct access to a protected stair.

239. An escape route should not be by way of:

• A lift (unless specifically designed for evacuation).
• An escalator.
• Turnstiles, other than those with breakout facility opening in the direction of escape.
• A fire shutter which closes automatically in the event of fire.
• A manual sliding door, other than one to which the general public does not have access.
• Revolving or automatic doors unless arranged to fail safely in the outward opening position in accordance with BS 7036.
• A window.

240. Where children are at a different location in a building from adults, then the adults may desire to go to the child facility if the fire alarm sounds. This could involve adults travelling against the normal direction of escape and this needs to be considered. Where practicable, relocating the child facility may avoid this.

241. A clear headroom for escape routes and circulation areas is at least 2 m, and not less than 1.9 m in a doorway.

242. The width and geometry of escape routes should be sufficient to facilitate the evacuation method used and for the number of occupants. The aggregate unobstructed width in mm of all escape routes from a room, or storey, should be at least 5.3 x the occupancy capacity of the room or storey.

243. If a room or storey requires 2 or more escape routes, consideration should be given to one of the exits being affected by fire. Under these circumstances, when calculating the width of exits, the largest exit should be discounted. The aggregate width of the remaining exits needs to be capable of accommodating the total number of occupants of the room or storey.

244. Escape routes from rooms or storeys which accommodate up to 100 people should be at least 1000 mm wide. For up to 225 people, the minimum width is 1100 mm. At least 1200 mm is more appropriate for occupants with sensory, cognitive and/or mobility impairments.

245. An escape route should not normally narrow in the direction of escape but at doorways the width can generally be reduced by 150 mm. Where up to 100 people use the escape route, the clear opening width at the doorway should be at least 800mm. For up to 225 people, it should be at least 850 mm.

246. To assist with evacuation, a door across an escape route should open in the direction of escape where there are 60 persons or more (or in factories 10 persons), or where occupants may need to exit quickly, or the door is a final exit. In other situations it is good practice for a door to be outward opening if practicable.

247. The area outside final exit doors should have suitable underfoot conditions for persons evacuating and pathways so that persons can move away from the building. Where escape is across grass or open ground, including from tented structures and open air locations, the surface should be capable of withstanding the traffic volumes, taking account of weather conditions and avoiding the potential for trips and falls.

248. In multi-occupied buildings, escape routes from individual occupancies should normally be independent of parts in separate occupancy; people should not have to go through another occupier's premises to escape as the route may be secured or otherwise unavailable.

249. In storage areas, the width of gangways between fixed obstructions such as racking or shelving may not be less than 530 mm. In bulk storage of spirituous liquor, gangways may not be less than 400 mm.

250. In part of a building with fixed seating consideration should be given to seating arrangements. Gangway widths and seatway lengths should allow ease of escape for the numbers present. A gangway (or exit door) should be provided at each end of a row of more than 12 fixed seats.

Shopping Centres

251. There will normally be at least 2 directions of travel from every part of a mall and from every mall-level shop without passing through a space in single occupation. Each shop with a frontage to the mall, other than small units, will normally have an alternative escape route that is not through the mall.

252. The aggregate unobstructed width, in mm, of all escape routes from a mall should be at least 2.65 multiplied by the occupancy capacity of the entire centre.

253. Each exit from a mall should be at least 1.8 m wide. Where occupancy levels will be higher than in other parts of the shopping centre, a wider exit would be appropriate in those parts. The entrances used by the public should have the greatest escape route width as evacuees will tend to use the egress routes with which they are familiar.

254. Where a service corridor is used for means of escape from a shop, the width would be based on the total number of persons that evacuate into the corridor from the largest shop plus an additional width of 1 m to allow for goods in transit.

Travel Distance

255. There should be a limit on the distance that persons have to travel to reach a place of reasonable safety. Travel distance is the distance measured along the actual route of escape (having regard to the layout) from any point within a storey to the nearest door giving direct access to either another compartment; a protected stair; or to a final exit. From a mall-level storey of a shop in an enclosed shopping centre, travel distance may be measured to the mall. Travel distance benchmarks are given in Table 7.

Table 7 - Travel distance benchmarks

Use	Single direction distance (m)	Maximum distance* (m)
Primarily for persons who need more time to evacuate, such as disabled people, or people with learning difficulties Boiler room	9	18
Public-access buildings Education and day care High hazard storage	15	32
Non public-access buildings Enclosed car park	18	45
Within a protected escape route	100	unlimited

* this includes the single direction distance

256. Travel distance benchmarks for occupants of buildings will not be appropriate for some large or underground travel facilities. Greater distances may be acceptable in railway stations with a large dispersal volume for smoke and heat from a fire, and in underground facilities where combustible materials have been reduced to a point where there is little to burn.

257. A single direction of escape is travel before there is the choice of escape routes. See Figures 3, 4 and 5. A single direction of escape may involve persons moving towards or past a fire, if the fire occurs between the occupant and the choice of escape routes.

Inner Rooms

258. An inner room is a room where access to a circulation area can only be achieved by passing through an access room (see Figure 6). A fire could develop unnoticed in the access room preventing the occupants of the inner room escaping. The risk to persons in the inner room will be less if the access room contains limited combustibles and ignition sources; and travel distance from any point in the inner room to the exit from the outer room are short. A smoke alarm or automatic smoke detector in the access room may give an early warning and may be appropriate where the risk of fire occurring in the access room is high and cannot be reduced.

Stairs

Escape stairs

259. To protect escape routes from fire, the normal standard for escape stairs is for stairs to be enclosed within a fire-resisting enclosure (creating a protected zone) such that the enclosing structure between the stair and the rest of the building has fire-resistance and any door in the enclosing structure is a self-closing fire door. Each escape stair should have its own independent final exit.

260. However, an enclosure is not normally necessary for:

• An escape stair within a single storey where the difference in level is not more than 1.8 m.
• An external escape stair with a total rise of not more than 1.6 m.
• An escape stair from a gallery where the gallery has;
  • an occupancy capacity of not more than 60 or;
  • an occupancy capacity of 61 to 100 and at least one route of escape is by way of a protected zone, an external escape stair, or another compartment.

261. If the enclosure has an external wall that projects beyond the face of a building or is set. back in a recess, the route may be vulnerable should fire break through an adjacent window, door, or other opening. Radiated heat or flames from the fire may impede escaping occupants. Therefore an external wall of a building which makes an angle less than 135^o with the external wall of the enclosure might need to have fire-resistance.

262. The width of an escape stair should be at least the width of any escape route giving access to it. A check should be made that the width of an existing escape stair is suitable for the persons who would use it and the method of evacuation. Where there is simultaneous evacuation, the number and capacity of stairs serving a building needs to be sufficient for the number of persons to allow the occupants of all storeys to evacuate at the same time.

263. Where part of a building has only one escape route by way of an escape stair, if access to the escape stair is by way of a protected lobby, this will provide an additional barrier to fire and may afford people additional time to escape. A protected lobby is where there are two self-closing fire doors between the adjoining accommodation and the stair.

264. Access by way of a protected lobby is also relevant to a storey at a height of more than 18 m.

265. Where an escape stair also serves a basement storey, a self-closing fire door at ground floor level separating the basement stair enclosure from the stair enclosure serving the rest of the building will provide improved protection to the means of escape from any fire that may start in the basement.

266. Ideally, an escape stair (including landings) and the floor of a protected lobby will be non-combustible. Where an existing escape stair is combustible, consider the potential for the stair to be directly affected by fire, such as a fire occurring in an under-stair cupboard, and the possibility of lining the underside of the stair with non- combustible material.

267. A small room, reception, cupboard or toilet may be sited within the enclosure of an escape stair if the fire risk is considered low and all other parts of the building served by the escape stair have at least one other escape route.

268. The evacuation speed of people with a mobility disability can be slow and there may be a space within the protected stair so that they can wait temporarily until it is safe to use the stair - a space capable of accommodating a wheelchair and measuring not less than 700 mm x 1200 mm. These spaces should not be used for storage. Modern buildings may have an emergency voice communication system in the temporary waiting space to assist the escape process and reduce the anxiety of occupants making use of the space.

External stairs

269. An external escape stair may present problems for persons evacuating a building because people can feel less confident using an unenclosed stair at a height. For this reason, an external escape stair may only be suitable where the topmost storey height is not more than 7.5 m; and the stair is used only by those who can safely use it. Appropriate weather protection may be necessary to enable the stair to be used in all weather conditions.

270. An external escape stair should lead directly to a safe area beyond the premises and should be non-combustible.

271. An external escape stair may be unusable if fire occurs in the building. External stairs with a rise of more than 1.6 m may need to be protected against fire from within the building with at least 30 minutes fire-resistance.

Escape across Flat Roofs

272. Where the occupants of premises can safely use it, an escape route may be across a flat roof, and be an alternative additional provision to another escape route in the premises.

273. An escape route across a flat roof should:

• Be clearly defined, illuminated and guarded with barriers not less than 1.1 m in height.
• Have a slip free surface;
• Have fire-resistance for a distance of 3 m on either side of the route.
• Have no unprotected openings from adjacent structures, within 2 m.

Door Fastening

274. It is important that doors necessary for escape be easily openable while the premises are occupied. Where a door across an escape route has to be secured against entry, it should be fitted with a fastening which is readily operated without a key, from the side approached by people making their escape. Where a door is operated by a code, combination, card, biometric data or similar means, it should be capable of being manually overridden from the side approached by people making their escape. The potential for persons having to retrace their route during an evacuation to use an alternative escape route, should also be considered.

275. Push pad devices (to BS EN 179) are suitable securing devices for outward opening final exit doors where occupants can be expected to be familiar with the devices. In other cases, panic exit devices operated by a horizontal bar (to BS EN 1125) are suitable.

276. When premises are being used out of normal hours, including use by community or outside groups, or by security or cleaning staff, in addition to arranging and controlling access, sufficient escape routes and exits require to be kept available for the duration of the occupation.

Electrically powered locks

277. Electrically powered locks can be operated by electromagnetic or electromechanical means.

278. Electrically powered locks should not be installed on a door which provides the only route of escape for persons, or which serves a room or storey with more than 60 persons, or a door on a fire-fighting shaft.

279. Electrically powered locks should return to the unlocked position:

• On operation of the fire warning system.
• On loss of power.
• On actuation of a manual door release unit positioned at the door on the side approached by people making their escape (where the door provides escape in either direction, a unit should be installed on both sides).

280. Access control systems may be in the form of revolving doors, sliding doors, ticket barriers, or entrance gates. Where there is no alternative adjacent means of escape, access control systems across the escape route should in the event of a fire, power failure, or malfunction, continue to provide a means of escape without reducing the width by automatically opening and remaining open; or being readily pushed to the outward open position by occupants in an emergency.

281. In railway stations, fences and automatic barriers are often used for revenue protection purposes. The potential impact of these on escape needs to be assessed and the consequences considered in respect of congestion, reduction in escape width and emergency opening arrangements.

282. BS 7273: Part 4 provides detailed guidance on the electrical control arrangements for the fail-safe release of powered locks.

Automatic opening doors

283. An internal door may be linked to a motion sensor or other device so that the door opens automatically to facilitate movement of occupants. Some devices can be triggered by smoke movement which may cause a door to open precisely at the time when it should be closed as a barrier to fire and smoke. These doors should be linked to the fire warning system so that the automatic opening function is disabled if the fire warning system is triggered (but still permitting the door to be manually opened). If the door is a fire door, the opening mechanism should not reduce the fire-resistance of the door. When the automatic opening function is disabled following activation of the fire warning system, the fire door’s normal self-closing function should continue to operate.

284. Automatic opening doors should not be placed across escape routes unless they are designed in accordance with BS 7036 and are either:

• Arranged to fail safely to outward opening from any position of opening, or
• Provided with a monitored fail-safe system for opening the door from any position in the event of mains supply failure and also in the event of failure of the opening sensing device; and open automatically from any position in the event of operation of the fire alarm in the fire alarm zone within which the door is situated.

Powered sliding doors

285. Powered sliding doors often open in response to a motion sensor. Such a door across an escape route, should be fail-safe and should open:

• On operation of the fire warning system; where installed.
• On loss of power.
• On activation of a manual door release unit positioned at the door on the side approached by people making their escape (where the door provides escape in either direction, a unit should be installed on both sides).

286. BS 7273: Part 4 contains detailed guidance on the electrical control arrangements for fail-safe operation of powered sliding doors.

Lighting

287. Escape routes should be provided with lighting to allow persons to safely use these routes in the event of a fire occurring or in the event of failure of the normal lighting power supply.

Escape route lighting

288. Premises should be provided with lighting in the escape routes to the extent necessary to ensure that in the event of an outbreak of fire, illumination is provided to assist in escape and to aid staff in implementing the emergency fire action plan.

289. If there are escape routes that are not permanently illuminated, such as external stairs, then a marked switch or some other means of switching on the lighting, such as a motion sensor, should be provided.

Emergency escape lighting

290. Emergency lighting is lighting designed to operate or remain in operation automatically in the event of a local or general power failure. The size and type of the premises and the risk to the occupants will determine whether there is a need for emergency escape lighting.

291. Emergency lighting can be stand-alone dedicated units or incorporated into normal light fittings. Power supplies can be rechargeable batteries integral to each unit or a central battery bank. Single ‘stand-alone’ emergency lighting units may be sufficient in some premises and these can sometimes be combined with exit or directional exit signs, though the level of general illumination should not be significantly reduced by the sign.

292. Emergency lighting is described as ‘maintained’ if it is permanently illuminated, and ‘non-maintained’ when it only operates if the normal lighting fails.

293. In small premises, in which the escape routes are simple and straightforward, borrowed light may be relied upon to illuminate escape routes.

294. A system of automatic emergency lighting is likely to be needed in large complex premises, particularly in those with extensive occupied basements, sub- surface railway stations or where there are significant numbers of people. If some escape routes are internal and without windows, then some form of emergency lighting may be required. Emergency lighting may be necessary in a room with more than 60 occupants and escape routes serving such a room and escape routes in public access buildings which have two storey exits.

295. A maintained system should be installed in premises such as cinemas, theatres or nightclubs where the normal lighting can be dimmed or reduced below the levels required for escape route identification and illumination while the premises are occupied.

296. An emergency lighting system provided for escape purposes may be used to illuminate the following:

• Internal and external escape routes, exit doors and escape route signs.
• Intersections of corridors.
• Staircases so that each flight receives adequate light.
• Changes in floor level.
• Fire-fighting equipment.
• Fire alarm call points.
• Signs.
• Equipment that needs to be shut down in an emergency.

297. In the case of a building with smoke control, the units should be below the smoke reservoir so that it is not rendered ineffective by smoke filled reservoirs.

298. British standards relevant to emergency lighting systems are BS 5266: Part 1 and BS EN 1838.

Signs and Notices

299. In small simple premises where the locations of escape routes and fire- fighting equipment are readily apparent then fire signs may not be necessary.

300. Escape route signs are used to indicate escape routes not in normal use and are only necessary where there might otherwise be confusion regarding the route to follow in the event of fire. The following criteria apply to escape route signs:

• They should provide enough information to enable people to identify escape routes.
• There the location of an exit is not obvious, signs with directional arrows may be provided along the route.
• Escape route and exit signs should not be fixed to doors as they may not be visible if the door is open.
• Signs mounted above doors should be at a height of between 2 m and 2.5 m above the floor.
• Signs on walls should be mounted between 1.7 m and 2 m above the floor.

301. The legibility of an escape sign is determined by the size of the sign, the level of illumination and the distance over which it is viewed. Signs should be in pictogram form. The pictogram can be supplemented by text if necessary to make the sign easily understood. Guidance on the use of escape route signs is available in BS 5499: Part 10.

302. In public access buildings, persons may be unfamiliar with the location of alternative exits and signs identifying exit location are important. In shops, the presence of advertising and customer information or shop dressing needs to be arranged so that it does not distract from, or obscure escape signs. In storage premises, escape signs should not be obscured by stored goods. In places of entertainment and assembly, advertising, information or other display material should be arranged so that it does not distract attention from, or obscure escape signs.

303. Signs to indicate the location of non-automatic fire safety equipment may be necessary if there is any doubt about its location, such as fire extinguishers that are kept in cabinets or in recesses. Other signs may also be necessary such as:

• ‘Fire door keep shut’ or ‘Fire door keep locked shut’ on fire doors.
• ‘Automatic fire door – keep clear’.
• How to operate the securing devices on doors.
• Location of sprinkler stop valve.

304. New safety signs should comply with BS EN ISO 7010.

305. Notices are used to provide instructions on how to use any fire safety equipment and the actions to be taken in the event of fire. Notices containing details of the emergency fire action plan specific to the premises should be permanently displayed in appropriate positions throughout the building. A distinction may be required between notices that are designed for visitors as opposed to those for staff.

306. In small premises where there is a limited number of people and there is no fire warning system, notices may not be necessary.

307. As well as positioning fire instruction notices on escape routes adjacent to fire alarm call points, they should be located where staff frequently assemble in the premises.