Emergency Lighting

Emergency lighting 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 Building Regulations, the relevant local authority, the  architect or consultant.

The British Standard provides the emergency lighting designer with laid down guide lines which form the general basis for the designer to work to. British Standard BS 5266: Part 1: 2011 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.

What is Emergency lighting? - Lighting provided for use when the supply to the normal lighting fails

Emergency Lighting is a general term and is divided into emergency escape lighting and standby lighting.

Emergency escape lighting – that part of emergency lighting that provides illumination for the safety of people leaving a location or attempting to terminate a potentially dangerous process before doing so.

Standby lighting – That part of emergency lighting is provided to enable normal activities to continue substantially unchanged. This article does not include standby lighting as it is not a legal requirement and is a facility that the employer may or may not require.

Furthermore emergency escape lighting is divided into escape route lighting, open area lighting and high risk task area lighting.

Escape route lighting – That part of emergency escape lighting provided to ensure that the means of escape can be effectively identified and safely used when the location is occupied.

Open area lighting (in some countries known as anti-panic lighting) – That part of emergency escape lighting provided to avoid panic and provide illumination allowing people to reach a place where an escape route can be identified.

High risk task area lighting – That part of emergency escape lighting that provides illumination for the safety of people involved in a potentially dangerous process or situation and to enable proper shut down procedures for the safety of the operator and other occupants of the premises.

 

Consultation and Design

The first stage of installing emergency escape lighting is consultation and design. The designer, responsible person and the fire risk assessor should meet and decide where the escape lighting is required and mark up a plan showing the areas to be covered, the type (power supply), mode of operation, facilities and duration.

Type (Power Supply)

Self-Contained – Single Point

Advantages:

The installation is faster and a lower cost.
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.
The integrity of the system is greater because each luminaire is independent of the other.
System can easily be extended with additional luminaires.
No special sub-circuit monitoring requirements.

Disadvantages:

The environmental conditions will vary throughout the system and batteries may be adversely affected by a relatively high or low ambient temperatures
Battery life is limited to between 2 and 4 years dependent upon application.
Testing requires isolation and observation of luminaires on an individual basis.

In general, 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.

Central Battery Source

Advantages

Maintenance and routine testing is easier with only one location to consider.
The life of a battery is between 5 and 25 years dependent upon type.
Environmentally stable in a protected environment, luminaire able to operate at relatively high or low ambient temperatures.
Large batteries are cheaper per unit of power and luminaire are usually less expensive.

Disadvantages:

High capital equipment costs.
The cost of the installation and wiring the system is expensive because fire resisting cable like MICC or Pirelli FP200 type is required to each satellite luminaire.
Poor system integrity – failure of battery or wiring circuit can disable a large part of the system.
A 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 luminaire wired furthest from the central battery could become a problem.

Mode of Operation

Maintained or Non-Maintained is the principle consideration and this is decided by the use of the premises.

Maintained emergency luminaire is a luminaire in which the emergency lighting lamps are energized at all times when normal or emergency lighting is required.

Maintained is generally used in places of assembly like theatres, cinemas, clubs and halls, the full list is contained within the BS 5266. These premises usually dim the lights during the time the premises are occupied and the emergency escape lighting prevents total darkness.

Non-maintained emergency luminaire is a luminaire in which the emergency lighting lamps are in operation only when the supply to the normal lighting fails. Non-maintained is used mainly in the workplace or similar premises where the normal artificial lighting is illuminate during the time the premises is occupied.

Combined emergency luminaire is a luminaire containing two or more lamps, at least one of which is energized from the emergency lighting supply and the others from the normal lighting supply – a combined emergency luminaire is either maintained or non-maintained.

Compound self-contained emergency luminaire is a luminaire providing maintained or non-maintained emergency lighting and also providing emergency supply for operating a satellite luminaire.

Satellite emergency luminaire is a luminaire for maintained or non-maintained operation which derives emergency operation supply from an associated compound self-contained emergency luminaire.

 

Facilities

A) Luminaire including test device is where the luminaire contains Self-Test Module for testing purposes.

B) Luminaire including remote test device is where a Centralised Testing System is used to test the system.

C) Luminaire with inhibiting mode is a control mode used to inhibit the emergency lighting luminaire from operating, thus preventing the discharge of the emergency lighting batteries, at times when the building is unoccupied. If a mains failure occurs at such a time the batteries will remain fully charged so the building may be occupied when required. It is performed by an inhibit switch that must be interlocked with the essential building services so that the premises cannot be inadvertently occupied without the emergency lighting being recommissioned.

D) High risk task luminaire is for risk task area lighting in areas of high risk the maintained luminance shall not be less than 10% of the required maintained luminance for the task (a desk for instance not open area). This will be subject to a minimum luminance of 15 lux. 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.

Duration in minutes

The time required to evacuate the premises depends on the size and complexity. The duration is dependant not only on the time to evacuate the premises, but also if they are evacuated immediately on a supply failure or if they reoccupied immediately the supply is restored. The minimum duration of an emergency escape system is 1 hour.

A minimum duration of 3 hours should be used for emergency escape lighting if the premises are not evacuated immediately, such as sleeping accommodation, or if the premises will be reoccupied immediately the supply is restored without waiting for the batteries to be recharged.

Duration of 1hour should only be used if the premises are evacuated immediately on supply failure and not reoccupied until full capacity has been restored to the batteries.

In BS 5266 there is detailed information on the duration of system in various premises.

Emergency lighting classifications

The old NM or M with the duration in hours has be replaced with a these emergency lighting classifications, and there is a code, consisting of a letter/number/letter/number.

 1) Type

X – Self-contained
Y – central battery

2) Mode of operation                                               

0 Non-maintained
1 maintained
2 combined non maintained
3 combined maintained
4 compound non maintained
5 compound maintained
6 satellite

3) Facilities

A including test device
B including remote test device
C including inhibiting mode
D high risk task luminaire

4) Duration in minutes.

10, 60,120 or 180

The classification is expressed in as per the following example:

[x][0][***][180] – Self-contained, Non-maintained, ***, 3 hours duration.

***    This is added as applicable at the time of installation.

 

Emergency Luminaires

Self-contained emergency luminaire is a luminaire providing maintained or non-maintained emergency lighting in which all the components, such as the battery, charging circuit, mains ballast, lamp, control unit, test and monitoring facilities (where provided) are contained within the luminaire or adjacent to it i.e. within 1m cable length.

Centrally supplied emergency luminaire is a luminaire for maintained or non-maintained operation, which is, energized from a central emergency power system that is not contained within the luminaire. 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.

Siting of luminaires and emergency 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. Safelincs has provided a graphical guide for the location of emergency lights.

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 luminaire and signs to cover these areas, then the completed scheme will meet most requirements.

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

Note. Detailed computer point calculations or luminaire manufacturers spacing tables should be used. The above is a short resume’ consequently the appropriate standard should be studied for a full understanding.

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 1 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 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.

The level of illumination in certain rooms will vary depending on the purpose of the room and all these levels are contained in the appendices to BS 5266 Part 1 2011.

Note. The above is a short resume’ consequently the appropriate standard should be studied for a full understanding.

Commissioning Certificate and Logbook

BS5266 and the European Standard both require written declarations of compliance to be available on site for inspection.  It should detail,

The quality of the installation and that it conforms to the IEE regulations, including the main circuit of the normal lighting system feeding non-maintained fittings.

Photometric performance is required and evidence of compliance with light levels has to be supplied by the system designer.

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.

A declaration of a satisfactory test of operation is necessary and 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. A free fire safety logbook with sections for emergency lighting tests can be downloaded for free from Safelincs.

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.

Servicing and testing

To test an emergency lighting system you need to simulate a mains power failure on the normal lighting circuit or circuits or individual luminaires. This will force the emergency lighting system to operated and use the battery supply. This can be done manually or automatically.

Manual Testing

You can achieve a simulated mains failure by providing a switch to isolate all lighting circuits or individual circuits or individual luminaires. If manual testing is utilised, the following points should be considered:

In a non-maintained system with a single switch for the whole building or a separate switch used for each circuit you then simulate the mains failure and you have to walk the whole or part of system to check all emergency luminaire are operating correctly. When you restore the mains supply you have to walk the whole or part of system again to check that the emergency lights are recharging.

If all luminaires are individually switched, 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 system 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.

General

BS EN 50172:2004/ BS 5266-8:2004 Emergency escape lighting systems, specifies the minimum provision and testing of emergency lighting for different premises and also additional information on servicing can be found in BS 5266 – Part 1 – 2005 Emergency lighting.

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 calibre and reliability of staff available to do the testing and 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 luminaire are tested.

When automatic testing devices are used the information shall be recorded monthly and annually. For all other systems, the tests shall be carried out as described below and the results recorded.

Regular servicing is essential. The occupier/owner of the premises shall appoint a competent person to supervise servicing of the system. This person shall be given sufficient authority to ensure the carrying out of any work necessary to maintain the system in correct operation.

Routine inspections and tests

Where national regulations do not apply, the following shall be met.

Because of the possibility of a failure of the normal lighting supply occurring shortly after a period of testing of the emergency lighting system or during the subsequent recharge period, all full duration tests shall wherever possible be undertaken just before a time of low risk to allow for battery recharge. Alternatively, suitable temporary arrangements shall be made until the batteries have been recharged.

The following minimum inspections and tests shall be carried out at the intervals recommended below. The regulating authority may require specific tests.

Daily

This is a visual inspection of indicators to identify that the system is in a ready condition and does not require a test of operation.

Monthly

If automatic testing devices are used, the results of the short duration tests shall be recorded.

For all other systems the tests a short functional test should be carried out in accordance with BS EN 50172:2004/ BS 5266-8:2004.

The period of simulated failure should be sufficient for the purpose of this clause whilst minimising damage to the system components e.g. lamps. During this period, all luminaires and signs shall be checked to ensure that they are present, clean and functioning correctly.

Annually

If automatic testing devices are used, the results of the full rated duration test shall be recorded.

For all other systems a functional test should be carried out as per monthly test but for its full rated duration in accordance with the manufacturer’s information in accordance with BS EN 50172:2004/ BS 5266-8:2004.

British and European Standards – 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- 2011 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 60598-1: 2008 Luminaire’s.  General requirements and tests. Check out the 60598 series for particular requirements.

BS EN 62034:2006 Automatic test systems 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 luminaire for emergency lighting

Check out your local reference library or purchase copies from BSI Online insert the BS number to see what standards are available and their titles. These links may not be inclusive but do indicate the some of the standards that are available.

Regulatory Reform (Fire Safety) Order

The Regulatory Reform (Fire Safety) Order guides have a “Section 5 Further guidance on emergency escape lighting” which will provide you with additional relevant information. Check out The Regulatory Reform (Fire Safety) Order guides.