The Regulatory Reform (Fire Safety) Order (RRFSO) 2005, which came into force in October 2006, charges the responsible person(s) in control of non-domestic premises with the safety of everyone, whether employed in or visiting the building.
Under Article 14 of the RRFSO, this duty of care includes ensuring that "routes to emergency exits from premises and the exits themselves are kept clear at all times" (14: 1) and that these "emergency routes and exits must lead as directly as possible to a place of safety" (14: 2: a).
In other words, the entire escape route up to and including the final exit from a building must remain unobstructed at all times, while the distance people have to go to escape (the travel distance) must be as short as possible.
In terms of fire safety, the final exits on an escape route in a public building are known as fire exits. They may or may not be located on the usual route of traffic when the premises are operating under normal circumstances. The final exit doors should open easily, immediately and, wherever practicable, "in the direction of escape", i.e. outwards into a place of safety outside the building. Sliding or revolving doors must not be used for exits specifically intended as fire exits. The emergency routes and fire exits must be well lit and indicated by appropriate signs, e.g. "Fire Exit – Keep Clear". In locations that require illumination, emergency lighting of adequate intensity must be provided in case the normal lighting fails, and illuminated signs used. This is because, as noted in the HM Government publication "Fire Safety Risk Assessment: Offices and Shops" (May 2006): "The primary purpose of emergency escape lighting is to illuminate escape routes but it also illuminates other safety equipment".
The HM Government publication "A short guide to making your premises safe from fire" (June 2006) is invaluable in interpreting the RRFSO. It distinguishes between "fire exit doors", i.e. the final exit doors that open into a place of safety outside the premises, and "doors on the escape routes", which are internal doors forming the escape route through the premises. The important point is that all of these doors should be usable "without a key and without any specialist knowledge" in a fire situation.
The Door & Hardware Federation (DHF) "Code of Practice: Hardware for Fire and Escape Doors" (November 2012) also highlights the fact that escape route doors can form part of the fire compartmentation of the building. In such cases, there will be additional requirements to ensure that the door itself and the escape hardware fitted does not compromise the fire-resisting performance of these fire doors.
Whereas a fire door is an internal door designed to compartmentalise a section of a building in the event of a fire and/or protect an escape route through it for a minimum length of time, typically 30 minutes (FD30), it is not necessary for a fire exit door at the end of the escape route to be of fire resisting standard or to be kept closed. Its role is to enable the swift and safe egress of people from a building into a place of safety outside rather than to contain the smoke and flames of a conflagration.
This gives rise to another issue, however. Fire exit doors must, by their very nature, be incorporated into the external walls of a building and, although the RRFSO states that they "must not be so locked or fastened that they cannot be easily and immediately opened by any person who may require to use them", i.e. when exiting a building in a fire situation, they do have to be secured in such a way as to prevent unauthorised entry under normal conditions.
This tension between the two functions of a fire exit door is recognised in the various HM Government guides to fire safety risk assessment in public and commercial premises published by the Department for Communities and Local Government (DCLG). For example, the guide to "Large Places of Assembly" (May 2006) states that "guidance on fire exits starts from the position that doors on escape routes should not be fitted with any locking devices", but goes on to note that the security aspect can be addressed by the installation of dedicated hardware that prevents unlimited access but still enables the occupants of a building or area to open the door easily if there is a fire.
The guidelines identify two main categories of such fire exit door fastening hardware: panic bars (i.e. push bars or touch bars) and emergency pads (i.e. push pads).
Panic bar are designed for use by members of the public or other visitors to public premises who are not familiar with the building. In these circumstances, a panic situation could easily arise if people have suddenly to evacuate the premises, i.e. when the fire alarm sounds. A panic bar will release the fire exit even when people are pressed tightly against the bar and door and unable to move their hands. All final escape doors that could be used by members of the public during an escape are therefore categorised as panic exit doors and must be fitted with escape hardware that has been certified to BS EN1125.
To secure a fire exit fitted with a push bar against unauthorised access, the push bars contain locking mechanisms to keep the exit door closed: either latches or bolts. Panic bars with bolts are sometimes called panic bolts, and panic bars with latches can also be called panic latches. Both mechanisms are, of course, released from the inside by depressing the push bar or touch bar that runs the width of the door leaf.
Latch fastening is suitable for use on single doors or the active leaf (i.e. the first opening leaf) of rebated double doors. Bolt fastening features a vertical bolt that secures the door at the top and bottom. When the panic bar is depressed, the bolt retracts simultaneously from top and bottom to release the door; if, however, an attempt is made to force the door from outside, for example by levering the bottom bolt out of position, the top bolt will remain in situ, and vice versa. This security feature is known as "two point independent locking".
Single vertical bolts are suitable for use on single doors and the inactive (i.e. second opening leaf) of rebated double doors. (NB A rebate, or rabbet, is a channelled groove cut into the edge of one door leaf so that the other fits snugly into it). In the latter case, the action of depressing the panic bar on the inactive leaf and pushing against the door will also cause the active leaf to open. Non-rebated double doors should be secured with double bolts.
In order to open fire exit doors, fitted with panic hardware, from the outside, an appropriate outside access device will have to be fitted: for example, a knob or lever operated unit with either a cylinder lock and key or a heavy duty keypad lock.
An emergency exit is the final exit on an escape route in commercial premises, e.g. offices. DCLG fire safety guidelines state that "premises with limited numbers of staff or others who are familiar with the building and where panic is not likely may use alternative devices (to panic bars), for example push pads or lever handles". All final exit doors that are used only by trained personnel are categorised as emergency exit doors and must be fitted with emergency exit hardware certified to BS EN179.
As with the door-fastening devices for panic exit hardware, there are two main types: latches and bolts. The release mechanism of each type is activated by a push pad and the deployment of these fastening devices is the same as for panic devices, according to whether single or double exit doors (rebated/non-rebated) are installed.
Outside access devices for use with push pads include knob or lever operated units with cylinder or keypad locks. For internal doors that are part of the escape route but protect restricted areas under normal working conditions, e.g. doors to the back rooms and counters in a banking hall, keypads facilitating access by authorised personnel can be installed that work in conjunction with lever handles for egress.
Regular maintenance of panic and emergency exit hardware is essential in preserving the escape route in a building. Points to check and address as necessary include, inter alia:
This is in addition to ensuring that the exit itself is kept clear of any obstruction that would hinder the working of the exit hardware or the escape of people from the building.
It may also be helpful to know that it is possible to fit a hold-back device on all panic and emergency exit operating mechanisms, to enable fire/emergency exit doors to be held open (also known as "dogging"). Should the door also be a fire door, however, fire door retainers would be required to hold the door open legally.
There are two main sources of guidance that should be consulted when considering the above question for your premises: the Building Regulations and British Standards.
Current building regulations contain guidance on the widths of escape routes and exits for new-build, non-domestic properties and the communal areas in purpose built blocks of flats in "The Building Regulations 2010, Fire Safety, Approved Document B, Volume 2 – Buildings Other Than Dwellinghouses".
The following information is extracted from Approved Document B Volume 2 relating to the design for horizontal escape.
The width of each escape route and exit depends on the number of persons needing to use them; not that all routes and exits must be a certain width based on the total number of people the whole premises is designed for. Each route and exit should not be less than the dimensions given in the following table:
| Maximum Number of Persons | Minimum Width (mm) |
|---|---|
| 60 | 750 |
| 110 | 850 |
| 220 | 1050 |
| More than 220 | 5 per person |
In calculating exit capacity, the document notes the further points:
If a storey or room has two or more storey exits it has to be assumed that a fire might prevent the occupants from using one of them. The remaining exit(s) need to be wide enough to allow all the occupants to leave quickly. Therefore, when deciding on the total width of exits needed according to the above table, the largest exit should be discounted.
The total number of persons which two or more available exits (after discounting) can accommodate is found by adding the maximum number of persons that can be accommodated by each exit width. For example, 3 exits each 850mm wide will accommodate 3 x 110 = 330 persons (not the 510 persons accommodated by a single exit 2550mm wide).
The current BSI "Code of practice for fire safety in the design, management and use of buildings" (BS 9999: 2017) takes a complementary approach to this calculation, based on two main factors: occupancy characteristic and fire growth rate.
Combining these two factors creates the risk profile of a specific building. This means that, rather than the prescriptive formula evident in earlier BSI publications on the matter, there is scope for a much more interpretative approach, on a case by case basis, which takes into account the specific features of an individual building. This is especially significant when considering the issue of escape routes and fire exits in existing premises, particularly if they are of an historical or heritage nature.
The occupancy characteristic is principally determined according to whether the occupants are familiar or unfamiliar with the building (i.e. the difference between emergency and panic exits) and whether they are likely to be awake or asleep.
Page 26 of the Standard contains the following table (numbered 2 in the document):
| Occupancy Characteristic | Description | Examples |
|---|---|---|
| A | Occupants who are awake and familiar with the building | Office and industrial premises |
| B | Occupants who are awake and unfamiliar with the building | Shops, exhibitions, museums, leisure centres, other assembly buildings, etc. |
| C | Occupants who are likely to be asleep: | This category is sub-divided as follows: |
| Ci Long-term individual occupancy | Flats without 24-hour maintenance/management control on site | |
| Cii Long-term managed occupancy | Serviced flats, halls of residence, boarding schools, etc | |
| Ciii Short-term occupancy | Hotels |
NB Two further categories of occupancy characteristic, "Occupants receiving medical care" (D) and "Occupants in transit" (E) are not covered by BS 9999: 2017.
The fire growth rate is estimated according to the nature and quantity of combustible materials in a specific building, as follows:
| Category | Fire Growth Rate | Examples |
|---|---|---|
| 1 | Slow | Limited combustible materials |
| 2 | Medium | Stacked cardboard boxes |
| 3 | Fast | Baled clothing, stacked plastic products |
| 4 | Ultra-fast | Flammable liquids |
NB Category 4 is not covered by BS 9999:2017
Examples of the risk profiles created by combining occupancy characteristic and fire growth rate include the following (BS 9999:2017, p 28):
A2: administration office, classroom
A2/A3/A4: storage and warehousing
B1: banking hall, reception area, foyer
B2: theatre/cinema, museum, restaurant
B3: department store, supermarket, furniture store
Cii2: dormitory, study bedroom (e.g. in halls of residence)
At pp 82/83, the document notes that the minimum door widths according to risk profile and when minimum fire protection measures are provided are as given in the table below. This is with the provisos that the total door width should be:
a) not less than the aggregate of the exit widths given in the table;
b) not less than 800mm, regardless of risk profile
| Risk Profile | Minimum width per person (millimetres) |
|---|---|
| A1 | 3.3 |
| A2 | 3.6 |
| A3 | 4.6 |
| B1 | 3.6 |
| B2 | 4.1 |
| B3 | 6.0 |
| C1 | 3.6 |
| C2 | 4.1 |
| C3 | 6.0 |
As with the Building Regulations, the British Standards guidance assumes that, if a storey has two or more storey exits, a fire might prevent the occupants from using one of them. Therefore, the remaining exit(s) need to be wide enough to allow all the occupants to leave quickly.
Example:
The total number of persons that two or more available exits can accommodate is found by adding the maximum number of persons for each exit width. For example, 3 exits, each 850mm wide, in a building with a B1 risk profile, would accommodate the following number of persons:
It will be noted that this example indicates that a larger maximum number of persons (236) can be accommodated by an exit width of 850mm in a building with a low risk profile than as stated in the Building Regulations table above (110). This would suggest that the Building Regulations estimate is based on the worst case scenario from the point of view of fire growth rate.
In accordance with Article 14 (g) of the RRFSO, "emergency routes and exits must be indicated by signs".
This is because an escape route will not necessarily be the route people would use under normal circumstances. In a fire situation, the travel distance to a place of safety must be as short as possible, and the purpose of fire exit signs is to facilitate this by identifying the escape route(s) and enabling people to find the exit nearest to them. The travel distance should be measured from the farthest point in a room to the door leading to a protected stairway or, if there is no protected stairway, to the final exit of the building.
Government guidelines state that, if there is only one escape route, the travel distance should not be more than 18 metres. This reduces to 12 metres where there is a high risk of fire starting or spreading but can be increased to around 25 metres in low risk areas.
If there is more than one escape route, the travel distance should not exceed 45 metres; this reduces to 25 metres in high fire risk areas and can be increased to 60 metres where the risk is low.
BS 5499 and BS ISO EN 7010 compliant fire escape route signs affix easily to walls and are available in three sizes, with a viewing distance of 30 metres, 22 metres and 17 metres. The signs may read "Fire exit" or "Exit", but all show a man running through a rectangular doorway with a directional arrow pointing the way. Photoluminescent (glow-in-the-dark) versions of these signs are useful in areas of low visibility.
Illuminated fire exit signs should be fitted along escape routes, particularly in those sections of a building that have no natural light; they are battery powered (trickle charged from the mains electricity supply) and will light the escape route in the event of a power failure. They can be mounted on walls or ceilings, or suspended from chains where ceilings are high. Again, they show the man running, a directional arrow and a rectangular doorway, and may bear the words "Fire Exit".
Fire exit doors themselves should bear an appropriate sign, e.g. "Fire Exit – Keep Clear", with an illuminated fire exit sign above. The panic exit hardware must carry a "Push Bar to Open" sign. For emergency exits in commercial premises, each push pad must carry a "Push" sign where the pad is to be depressed.
HM Government fire safety risk assessment guides
Door and Hardware Federation: Code of Practice Hardware for Fire and Escape Doors
https://www.dhfonline.org.uk/fire_safety/requirements-for-escape-doors/6.htm
(doc:676 V1.0). Our articles are reviewed regularly. However, any changes made to standards or legislation following the review date will not have been considered. Please note that we provide abridged, easy-to-understand guidance. To make detailed decisions about your fire safety provisions, you might require further advice or need to consult the full standards and legislation.
