Note for Guidance

The Fire Safety Advice Centre

Emergency Lighting

Introduction.

Emergency lighting is a self-descriptive term and is lighting for an emergency situation when the main power supply fails. The loss of mains electricity could be the result of a fire or a power cut and the normal lighting supplies fail. This may lead to sudden darkness and a possible danger to the occupants, 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 construction, the design and type of equipment is normally specified by the relevant local authority, architect or consultant.

The British Standard provides the emergency lighting designer with laid down guide lines which form the general basis for him to work on. British Standard BS 5266: Part 1: 2005 includes in its scope residential hotels, clubs, hospitals, nursing homes, schools and colleges, licensed premises, offices, museums, shops, 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 two lamps or two sets of lamps. One of which operates on mains 240V AC 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.
  

Emergency Luminaires

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) is 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.

Emergency Power Supplies

Central Battery Source

Advantages

• 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.

Disadvantages:

• 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

Advantages:

• Speedy and low cost installation;
• 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 luminaire's;
• No special sub-circuit monitoring requirements.

Disadvantages:

• 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 luminaire's 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.

How much light?

BS5266 recommends the provision of a horizontal illumination at floor level on the centre line of a defined escape route (permanently unobstructed) not less than 0.2 lux and 0.5 lux minimum for anti panic areas to exclude 0.5 metre border around the room. In addition, for escape routes of up to 2m wide, 50% of the route width should be lit to a minimum of 0.1 lux. Wider escape routes can be treated as a number of 2m wide bands. 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 person’s homes, hospitals, crowded areas such as pubs, discos and supermarkets, and to whether or not the premises are residential.

Typical emergency lighting units

Siting of luminaire's/signs

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. This will then form the basis on which your selection of equipment can be made.

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 utilized 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 8m2 (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, 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.

Note. Detailed computer point calculations or luminaire manufacturers spacing tables should be used.

Areas to be covered

There is legislation, guides, British and European standards that require emergency lighting to be installed and the ares it should cover. An emergency escape lighting system should normally cover the following ares,

• each exit door;
• escape routes;
• intersections of corridors;
• outside each final exit and on external escape routes;
• emergency escape signs;
• stairways so that each flight receives adequate light;
• changes in floor level;
• windowless rooms and toilet accommodation exceeding 8m2;
• firefighting equipment;
• fire alarm call points;
• equipment that would need to be shut down in an emergency;
• lifts and areas in premises greater than 60m2.

It is not necessary to provide individual lights (luminaires) for each item above, but there should be a sufficient overall level of light to allow them to be visible and usable.

Testing

BS EN 50172:2004/ BS 5266-8:2004 Emergency escape lighting systems. Specifies the minimum provision and testing of emergency lighting for different premises

The system should include adequate facilities for testing the system condition. These need to be appropriate for the specific site and should be considered as part of the system design. Discussions with the user or system designer should identify:

• The caliber and reliability of staff available to do the testing
• The level of difficulty in performing the test
• Discharge tests need to be done outside normal working hours. In buildings that are permanently occupied the test should be phased so only alternate luminaires are tested.

The testing requirements are:

Function test

• All emergency luminaires should be tested be breaking the supply to them and checking that they operate satisfactorily.
• The supply must then be restored and the charging indicators must be seen to be operating correctly.
• This test must be performed at least once per month.

Discharge test

• The luminaires must be tested for their full rated duration period and checked for satisfactory operation. The supply must then be restored and the charging indicators rechecked. This test must be performed at least annually.

Manual Testing

If manual testing is utilised, the following points should be considered:

• Is a single switch to be used? Unless the whole building is to be switched off, a separate switch should be used for each circuit. As the feed to non-maintained circuits must be taken from the switch this will probably mean that the building will have to be walked around twice, once to check the luminaires and once to check that they are recharging
• Are luminaires to be individually switched? In practice, only a single walk around the building will be needed. However, the test switches could spoil the decor of the building and they must be of a type that is tamper proof.

After the tests it is recommended that the performance of the luminaires should be logged.

Automatic Testing

If the costs of an engineer time and the disruption caused by manual testing are excessive, automatic systems should be considered. Different formats are available to match particular site requirements.

Commissioning Certificate

BS5266 and the European Standard both require written declarations of compliance to be available on site for inspection. These consist of

1. Installation quality.
   IEE regulations must have been conformed with and non-maintained fittings fed from the main circuit of the normal lighting system, as required in BS 5266
2. Photometric performance.
   Evidence of compliance with light levels has to be supplied by the system designer.
3. Declaration of a satisfactory test of operation.
   A log of all system tests and results must be maintained. System log books, with commissioning forms, testing forms and instructions should be provided by the installer.
   

On completion of the installation of the emergency lighting system, or part thereof, a completion
certificate should be supplied by the installer to the occupier/owner of the premises. The Building Control Department should insist upon a copy of this certificate which will be retained with the Building Regulations Authority.

Maintenance

Finally, to ensure that the system remains at full operational status, essential servicing should be defined. This normally would be performed as part of the testing routine, but in the case of consumable items such as replacement lamps, spares should be provided for immediate use.

Summary of guidance covering emergency lighting.

British Standard 5266 - Emergency Lighting

Emergency lighting is now covered by a series of interdependent standards which can be seen as forming a hierarchy as shown below.

Base guidance document

BS 5266-1 Emergency lighting-Part 1: Code of practice for emergency lighting of premises
Gives general rules and guidance on the provision and operation of emergency lighting in most premises other than dwellings

System standards

BS EN 1838:1999/ BS 5266-7:1999 Lighting applications - Emergency lighting
Specifies the illumination to be provided by emergency lighting (including luminance, duration and colour)

BS EN 50172:2004/ BS 5266-8:2004 Emergency escape lighting systems
Specifies the minimum provision and testing of emergency lighting for different premises

Product standards

BS EN 60598-2-22:1999 Luminaires for emergency lighting. Specifies self contained and centrally powered luminaires for use in emergency lighting systems.

IEC 62034-1 Automatic test system for battery powered emergency escape lighting. Specifies a test system for battery powered emergency lighting

BS EN 50171:2001 Central power supply systems. Specifies central power supply systems for luminaires for emergency lighting

Check out your local reference library or purchase copies. Check out BSI Online and insert the BS number to see what standards are available and their titles.

Regulatory Reform (Fire Safety) Order

The guides for the above order has a "Section 5 Further guidance on emergency escape lighting" which will provide you with relevant information. Check out Fire safety law and guidance documents for business

Approved Document "B"

Check out Approved Document "B"

This handout provides a general overview and basic information on this topic. It may not apply to everyone, consequently to find out if this guide applies to you and to get more information on this subject, study all the relevant legislation, guides and British/European Standards. Also you should seek advice from an expert on the subject or your local Fire Safety Officer or Fire Safety Professional.

The Fire Safety Advice Centre. Permission is granted to print and photocopy this material for nonprofit educational uses.

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This page was last checked and modified on Saturday, 8 November, 2008 18:13