EMERGENCY LIGHTING REGULATIONS BS5266-1 2005
Guidance on new Regulations for Emergency Lighting of Premises
An emergency luminaire will either be of the self-contained type, i.e. with all components integral to the luminaire body (battery, charging circuit, mains ballast etc), or “slave” to a central battery system where only the lamp (and an inverter if fluorescent) are located within the luminaire body and the supply on power failure is fed from some centralised point.
The majority of systems installed in the United Kingdom are of the self-contained type, but both options have their own advantages and disadvantages. These are summarised below for guidance:
CENTRAL BATTERY SOURCE
- Maintenance and routine testing is easier with only one location to consider;
- Superior battery life, between 5 and 25 years dependant upon type;
- Environmentally stable in a protected environment, luminaires able to operate at relatively high or low ambient temperatures;
- Large batteries are cheaper per unit of power and luminaires are usually less expensive.
- High capital equipment costs;
- High installation and wiring costs with essential MICC or Pirelli FP200 type cable to each slave luminaire;
- Poor system integrity – failure of battery or wiring circuit can disable a large part of the system;
- Requirement for ‘battery room’ to house cells and charger circuits etc, may also require ventilation of acid gases;
- Localised mains failure may not trigger operation of emergency lighting in that area.
- Voltage drop on luminaires wired furthest from the central battery could become a problem.
SELF-CONTAINED – SINGLE POINT
- Speedy and low cost installation procedure;
- Standard wiring material may be used (failure of mains supply due to cable burning through will automatically satisfy the requirement for a luminaire to be lit);
- Low maintenance costs – periodic test and general cleaning only required;
- Low hardware equipment costs – no requirement for extended wiring,special ventilation etc.
- Greater system integrity with each luminaire independent of the other;
- System can easily be extended with additional luminaires;
- No special sub-circuit monitoring requirements.
- Limited environmental operating range (batteries may be adversely affected by a relatively high ambient temperature);
- Battery life is limited to between 2 and 4 years dependant upon application;
Testing requires isolation and observation of luminaires on an individual basis.
In general then, the decision to use either a central battery or a self-contained system is likely to be cost dominated. If an installation has longevity and low maintenance as priorities, then the higher cost of central battery may be acceptable on a very large project. Usually, luminaire and installation costs will be a major consideration, particularly on smaller jobs, and it is this criterion which makes the self-contained luminaire the most popular choice.
Basic Installation Design:
The design of an emergency lighting scheme in the context of BS 5266:part 1:1999, the code of practice for emergency lighting of premises, with particular reference to the contractor designing the installation.
What is emergency lighting?
Emergency lighting is a self-descriptive term. It is of course lighting for an emergency, whether it be caused by fire – when it is essential to quickly locate fire fighting equipment and identify exit routes from the premises.
Or break in the normal lighting supplies leading to sudden darkness and the resultant hazard to human life, either through physical danger or panic.
Emergency lighting is normally required to operate fully automatically and give illumination of a sufficiently high level to enable persons of all ages to evacuate the premises safely.
Most new buildings now have emergency lighting installed during the course of building, the design and type of equipment normally being specified by the relevant local authority, Architect or Consultant.
The British Standard provides the would be emergency lighting scheme designer with laid down guide lines which form the general basis for him to work on. British Standard BS 5266-1:2005 includes in its scope:
- Residential Hotels,
- Nursing Homes,
- Schools and Colleges,
- Licensed Premises,
- Multi-Storey Dwellings etc.
Although this standard recommends the types and durations of emergency lighting systems relating to each category of premise it should be remembered that the standards are minimum safe standards for the types of premises and that a higher standard may be needed for a particular installation.
Type of system
Most emergency lighting schemes fall into one of the following categories:-
- Non-maintained – The emergency light units only illuminate in the event of a mains failure.
- Maintained – The emergency light units are illuminated at all times using the same lamps for both normal and emergency operation.
- Sustained – The emergency light units are fitted with 2 No. Lamps or 2 No. Sets of lamps, one of which operates on mains 240V a.c.supply, the other which operates from the battery supply in the event of mains failure. It is basically a non-maintained system with the addition of mains lamps which should be illuminated whenever the premises are occupied.
The type of system and emergency duration is often expressed in abbreviated form as per the following examples:-
M3 – Maintained System,emergency duration 3 hours.
NM2 – Non-maintained System,emergency duration 2 hours.
S1 – Sustained System,emergency duration 1 hour.
Local authorities and Fire Prevention Departments quite often publish their own recommendations regarding the types of system and emergency durations, and these of course must be taken into account when designing a system as they may compliment BS 5266 or even over-ride it.
It should always be borne in mind that the system, once installed will have to comply with the most stringent of the requirements, whether the British Standard or the Local Authority regulations prevail.
How much light?
Having decided on your basic system consideration should now be given to the siting of the lighting units and signs within the particular premises involved, which will then form the basis on which your selection of equipment can be made.
The actual degree of illumination should be closely related to the nature of both the premises and its occupants with special consideration being given to old persons homes, hospitals, crowded areas such as pubs, discos and supermarkets, and to whether or not the premises are residential.
BS5266 recommends a minimum level of only 0.2 in corridors (permanently unobstructed) and 0.5 lux minimum for anti panic areas to exclude 0.5 metre border around the room. (Detailed computer point calculations or luminaire manufacturers spacing tables should be used)
Siting of luminaires/signs
Lighting units and signs should be sited so as to clearly show the exit routes leading to the final exits from the premises. Where the exit route or final exit is not readily identifiable a sign should be utilised rather than a lighting unit.
Particular attention should be paid to individual stairways, changes in level, corridor intersections, changes in direction, the outside of each final exit, control/plant rooms, lifts, toilet areas over 8m (although in some peoples opinion all toilets of public access and especially those for the disabled should have emergency lighting).
Access to fire alarm call points, fire fighting equipment etc. should be clearly illuminated.
In general, if common sense is used when siting the luminaires and signs to cover these areas, then the completed scheme will meet most requirements.
Ballrooms, dancehalls, licensed Cinemas, licensed Bingo halls and Ten Pin bowling alleys are subject to other requirements and standards.
Guidance on new regulations for emergency lighting of premises, Ballrooms and Dancehalls, licensed Cinemas, licensed Bingo halls and Ten Pin bowling alleys.
Defined Escape Routes (Existing Buildings)
For routes that are permanently unobstructed and up to 2m wide the horizontal illuminance at floor level on the centre line (b) of the escape route shall be at least 0.2lux. A minimum of 1lux is preferable and essential where there are points of emphasis.
High Risk Task Area lighting
In areas of high risk the maintained illuminance shall not be less than 10% of the required maintained illuminance for the task (a desk for instance not open area). This will be subject to a minimum illuminance of 15lux . The uniformity ratio for task area lighting should be a minimum of 10:1 (0.1). The minimum duration shall be the period for which the risk exists to people.
Standby lighting should comply with all emergency lighting requirements if used for emergency lighting. Where standby lighting is lower than maintained illuminance it should not only be used to shut down processes.
Lighting Practices (all areas)
In order to identify safety colours, the minimum colour rendering index for lamps used in emergency luminaries shall be 40. The luminaire should not substantially detract from this. Observe caution if the sole luminaire has a legend.Fluorescent and Tungsten ra is >40.
The minimum duration for any emergency lighting luminaire shall be 1 hour. This is increased to 2 hours in public areas where members of the public may be unaware of emergency exit routes or positions. In areas where dimmed lighting is used, a maintained emergency system must be installed, in other areas a maintained system is advantageous.
The ratio to maximum and minimum luminance of a sign (on a single colour) shall not exceed 10:1 (0.1). The ratio of the luminaire of white parts to be coloured parts of the legend shall not exceed 15:1 (0.06) and not be less than 5:1 (0.2).
For an internally illuminated sign the maximum viewing distance shall be 200 times the sign height.100 times for an externally illuminated sign.
Attention is drawn to the requirement for the format of the sign, which should comply with the minimum requirements set in council directive 92/58/EEC of 24 June 1992 – provision for safety and/or Health signs at work. These signs are the Euro legend type.
Emergency luminaires shall be sited in accordance with BS5266. Attention shall be made to the manner in which luminaires are positioned as well as luminaire type, to minimise glare. Glare can obstruct viewing of obstructions and signs and it is therefore important that glare is considered.
On a horizontal escape routes, open areas (anti-panic) and High Risk areas, the luminous intensity in candelas (cd) of the luminaire shall not exceed the values in Table 1 within the zones 60 degrees to 90 degrees from the downward vertical in all angles of azimuth.
For all other types of escape route the limiting values shall not be exceeded at all angles.