Introduction to Emergency Lighting
The Regulatory Reform (Fire Safety) Order (RRFSO) 2005, which came into force in October 2006, charges the responsible person in control of non-domestic premises and the common areas of a House in Multiple Occupancy (HMO) with the safety of everyone in the building, whether working, visiting or living there. This duty of care includes the provision of emergency lighting. Article 14 (2) (h) of the RRFSO states:
"Emergency routes and exits requiring illumination must be provided with emergency lighting of adequate intensity in the case of failure of their normal lighting".
Emergency lighting is part of the fire safety provision of a building and cannot be ignored: as noted by the Industry Committee for Emergency Lighting (ICEL), which is the foremost UK authority on emergency lighting and provides third party accreditation for components and products for emergency light fittings under the auspices of the Lighting Industry Association (LIA):
"The legal requirement is that non-domestic buildings must be safe at all times, even if mains power failure occurs. Therefore, nearly all such buildings must have emergency lighting fitted".
The responsible person
The umbrella standard for emergency lighting is BS 5266-1 (Code of practice for emergency lighting). The British Standards Institution (BSi) guide to this code describes the duties of the "responsible person" as follows:
"The responsible person has to be able to demonstrate that the hardware of fire safety systems and their maintenance are adequate to protect the occupants. Fire protection products and related services should be fit for their purpose and properly installed and maintained in accordance with the manufacturer's instructions or the relevant British Standard." (A Guide to Emergency Lighting Second Edition, 2012, p 211)
Even though this duty of care can in practice often be shared or delegated, it remains a daunting prospect for lay people who have no knowledge of fire safety and find themselves in the position of being legally accountable for the protection and well being of others in this regard
The responsible person can be anyone who has some control over a building or areas within it, including inter alia facilities management companies, landlords and lettings agents.
Emergency lighting systems: what is involved?
Following the fire risk assessment (FRA), which will surface the various issues that have to be addressed, the procedure in respect of emergency lighting will be:
- Planning and design of the system
- Positioning of emergency lighting luminaires (wall / ceiling mounted lights and signs)
- Permanent installation of all fittings
- Periodic testing / maintenance of the system
Every building will have its own specific requirements in respect of emergency escape illumination, the role of which, as noted above, is to take over from the normal lighting provision in the event of a power or circuit failure. Of course, these levels of 'normal' lighting will vary, even within an individual building. Different areas inside will have different levels of natural illumination: for example, rooms with external windows have the benefit of daylight, while unglazed, internal areas such as corridors and stairwells must always have lighting provided.
If a building is occupied at night, there must usually be provision for emergency lighting in all areas, including those that are naturally lit during the day. One exception may be in the case of 'borrowed' light from external street lamps (switched on during the hours of occupancy of the premises): if this is a reliable source of lighting and reaches sufficiently inside the building to illuminate the escape routes, it can sometimes be considered sufficient, depending on who will be using them. As noted by the HM Government Fire safety risk assessment: large places of assembly (May 2006, p 28): "Exceptionally, in the parts of the premises used by staff and where the escape routes are simple and straightforward, borrowed lighting, e.g. from street lamps where they illuminate escape routes, may be acceptable". In other words, people who are familiar with the building may be able to evacuate safely in the hours of darkness by borrowed light; it is never acceptable practice, however, for members of the public to use escape routes that are only illuminated by such means. Emergency lighting must always be provided in this case.
What is emergency lighting?
The BSi guide to emergency lighting, referenced above, explains that:
"For the purposes of the British and European standard BS EN 1838, 'emergency lighting' is the generic term for equipment that provides illumination in the event of failure of supply to the normal lighting" (p. 1). There are two main types of emergency lighting: (i) emergency escape lighting; (ii) standby lighting (p. 2).
Emergency escape lighting is defined as "that part of emergency lighting that is provided to enable safe exit in the event of failure of the normal supply".
Standby lighting is defined as "that part of the emergency lighting provided to enable normal activities to continue in the event of failure of the normal mains supply".
The guide further offers this important distinction between emergency escape lighting and standby lighting: while the former constitutes part of the fire protection of a building, the latter does not (unless it meets the same equipment design and installation requirements as emergency escape lighting systems). As such, from the point of view of fire safety provision, emergency escape lighting is the significant type of emergency lighting, and will be the focus of the remainder of this article.
Emergency escape lighting
There are three main aspects of emergency escape lighting: 1) escape route lighting; 2) open area / anti-panic area lighting; 3) high risk task area lighting.
- Escape route lighting is the part of an emergency lighting system provided to enable the swift and safe evacuation of a building by illuminating its escape routes, such as corridors and stairways, and also the location of fire-fighting equipment, e.g. fire extinguishers and safety / security equipment such as keyboxes holding emergency keys to exit doors. As such, escape route lighting can be seen to be a fundamental requirement of fire safety provision in all non-domestic premises and public areas of HMOs, whatever their use or occupancy levels.
- Large public buildings such as shopping malls, museums and exhibition halls, etc., attract significant numbers of visitors who will not be familiar with the layout of the premises. Panic may therefore ensue should emergency evacuation be triggered by the sounding of the fire alarm. Open area / anti-panic lighting is relevant in such situations to aid in the identification of escape routes and exits and the guidance of people towards them.
- High risk task lighting is a specific type of emergency lighting provided to ensure the safety of people involved in a potentially dangerous process or situation. It must be sufficient to enable the requisite shut-down procedures to be implemented. This type of lighting will only apply across a limited range of scenarios.
The above distinctions serve to emphasise the role of emergency escape lighting in fire safety and how it is adapted and applied, on a case by case basis, according to the specific use and occupancy levels of a particular building and / or areas within it.
Where is emergency escape lighting necessary?
In detail, as noted in the HM Government publication Fire safety risk assessment: offices and shops (p 100), an emergency escape lighting system should normally cover the following:
- Each exit door
- Escape routes
- Intersection 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
- Fire-fighting equipment
- Fire alarm call points
- Equipment that would need to be shut down in an emergency
- 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.
What are emergency lighting luminaires?
There are two main types of luminaire, the relevant standard for which is BS EN 60598-2-22: self-contained and centrally supplied.
The self-contained luminaire, as it name suggests, contains all the essential components (i.e. battery, charger, control unit, lamp, diffuser and any test or monitoring facility) for it to function as an independent emergency light. As noted in the Fire Protection Association (FPA) Emergency Lighting Handbook (2012), this is the most common form of emergency lighting and is usually designed to be fitted to a wall or ceiling to illuminate a certain area or building feature. A typical example is the surface-mounted, rectangular bulkhead luminaire, although a wide range of self-contained luminaires is available including square, round and recessed / inset models.
Centrally supplied luminaires, also known as 'slaves' because they cannot function independently, are defined by BS EN 60598-2-22 as follows: "luminaire for maintained or non-maintained operation which is energized from a central emergency power system that is not contained within the luminaire". Slave fittings contain the lamp and some of the control gear but the charger, battery and often the changeover device are located remotely and provide the supply to a number of luminaires. Again, the luminaires themselves come in a range of shapes and styles. The FPA handbook, referenced above, contains a useful table highlighting the pros and cons of slave versus self-contained luminaires (p 21):
|Central power sources
||Ease / speed of installation
||Limited lamp power
|Long battery life if maintained
||Regular battery maintenance
||Operation limit to battery operation temperature
|Few temperature effects
||Loss when central system in fire
||No battery room required
||Shorter life batteries
|Easier / automatic testing
||Battery cabinet often required
||No regular battery maintenance
||Not suited to harsh or hazardous environments
|Real time monitoring
||No loss of total system
||Cost of periodic testing greater
Maintained, non-maintained and switchable emergency lighting
As noted in the HM Government guide to fire safety in offices and shops, referenced above:
"Emergency escape lighting can be both 'maintained', i.e. on all the time, or 'non-maintained', which only operates when the normal lighting fails. Systems or individual lighting units (luminaires) are designed to operate for durations of between one and three hours after the mains power supply fails. In practice, the three-hour design is the most popular and can help with maintaining limited continued use of the premises during a power failure (other than in an emergency situation)" (p 100).
Maintained emergency lights usually have two values for lumens (the measure of luminous flux, i.e. light flow, from a light source) in their technical description: a value for the output when the light is powered by the mains supply and another for the output when the emergency light is powered by the back-up battery. The latter is usually around 10 per cent of the full output.
Maintained emergency lights are often available as switchable units. This means that they can be switched between maintained and non-maintained modes of operation using an ordinary, wall-mounted light switch. This is useful in areas where there is no requirement for constant lighting, e.g. stairwells in a high-rise block of flats, where the light is only required when somebody takes the stairs instead of the lift. The emergency lights will, of course, still come on in case of a power failure, even when the switch is in the 'off' position. However, as indicated above, the emergency light output will be about 90 per cent lower than usual.
A disadvantage of non-maintained emergency lighting is that the condition of the lamp can only be ascertained through regular testing; it is no good waiting for a power cut to discover that it isn't working. This problem can be overcome, however, by installing self-testing emergency lights.
Non-maintained operation is usually favoured wherever possible, being cheaper
in terms of energy consumption and the life of the fitting's components. In some
premises, however, such as theatres and cinemas, the luminaires must always be
lit, i.e. in maintained mode, so there is sometimes no choice in the matter.
In respect of maintained emergency lighting in areas where high levels of light
are normally required, for example in the corridors of office blocks, a combined
or sustained emergency luminaire can be installed. This type of unit contains
two or more lamps, at least one of which is energised by the emergency supply
and the rest by mains electricity. The mains powered part of these lights can
usually be controlled by ordinary light switches. Typically, all the lamps will
be lit under normal circumstances, but if the electricity supply should fail just
the emergency lamp(s) will come on, powered by the battery.
Emergency luminaires are also available as signs; a typical example is the pictogram
of the man running either through or towards an open doorway, with a directional
arrow. Others may also bear some text, e.g. 'Fire Exit'. These lighting units
are available in both maintained and non-maintained versions in a range of styles,
from the simple box type through to the elegant 'blade' design with a slimline
body. They can be wall or ceiling mounted or suspended from high ceilings with
decorative chains. Pictograms and pictograms with text should not be mixed in
the same premises.
Another type of illuminated sign is the photoluminescent or 'glow-in-the-dark'
style, which again shows the man running with directional arrow and doorway, plus
the words 'Exit' or 'Fire Exit'. These are available in three different sizes
for wall mounting. These are not luminaires as such, but do serve to mark the
fire escape route.
Photoluminescent marker tape, paint and floor discs are also useful for low level marking of escape routes, particularly at changes of level in the building, e.g. stairwells and uneven floors. As noted in the HM Government guidance reference above (p 101):
"To complement emergency escape lighting, people, especially those unfamiliar with the premises, can be helped to identify exit routes by the use of way-guidance equipment. Way-guidance systems usually comprise photoluminescent material, lines of LEDs, or strips of miniature incandescent lamps, forming a continuous marked escape route at lower level. These systems have proved particularly effective when people have to escape through smoke, and for partially-sighted people. They can be particularly useful in premises where they can provide marked routes on floors and in multi-storey premises they can direct people to escape routes which are seldom used."
LED emergency lighting: the way ahead?
With the focus increasingly on protecting the environment as well as energy and cost saving, the Light Emitting Diode (LED) is becoming an increasingly popular choice of light source for emergency lighting luminaires. In addition, the government is currently offering a financial incentive to switch to low energy products: the Enhanced Capital Allowance (ECA) scheme enables businesses to claim a 100% first year capital allowance on investments in certain energy saving equipment, against the taxable profits of the period of investment.
LEDs contain no mercury and their low energy consumption, high efficiency and long life (typically 10 years) mean they are more environmentally sound than almost any other type of light source. They come on instantly, unlike some energy saving bulbs, and the fact that they are much smaller than, for example, the traditional fluorescent tube means that there is scope for much more stylish designs in emergency luminaires. State of the art models even incorporate three self-tests: a continuous battery test, a lamp test and a duration test. Over the lifetime of the product, this represents a significant reduction in maintenance costs.
Maintenance and testing of emergency escape lighting
Government guidelines (Fire safety risk assessment: offices and shops, p 101) state that all emergency escape lighting systems should be regularly tested and properly maintained to an appropriate standard (i.e. BS 5266 - Code of practice for the emergency lighting of premises). This testing has traditionally been undertaken manually although, as noted above, emergency luminaires are available with a self-test facility.
Depending on the type of installation, trained members of staff should be able to carry out most of the routine tests by themselves. As the test methods will vary, there may be some doubt, in which case it is recommended that advice is sought from the supplier or another competent person.
A typical test is via a key operated switch that is located either near the main fuse board or adjacent to relevant light switches. This is also known as a 'secret key' switch, as it designed to allow testing of emergency lights while preventing non-authorised operation of the test switch.
Testing would usually include the following:
- A daily visual check of any central controls if a centrally powered system with slave luminaires is installed;
- A monthly function test by operating the test facility for a period sufficient to ensure that each emergency lamp illuminates; and
- An annual full discharge test to ensure that the lamps are lit for the full discharge period (usually 3 hours) and that the batteries are re-charging
Particular care needs to be taken following a full discharge test. Batteries typically take 24 hours to re-charge and the premises should not be re-occupied until the emergency lighting system is fully functioning, unless alternative arrangements have been made.
It is best practice to keep a record of all tests in the fire safety logbook.
Digital Addressable Lighting Interface (DALI)
At the cutting edge of emergency lighting technology is DALI - an international standard created specifically for digital lighting control. It guarantees the compatibility of products from different manufacturers and thus enables the combination of lighting solutions and various types of luminaire in a single installation. A DALI addressable emergency lighting system also performs all the requisite scheduled tests to BS 5266: each luminaire in the system reports its test results back to the central panel or computer and, if a fault is detected, the unique address of the luminaire means that the source as well as the nature of the problem is immediately identified. Up to 120 luminaires can be controlled and monitored by a DALI touchscreen panel and, with the possibility of networking up to 10 such panels, a maximum of 1200 emergency luminaires can be monitored, with minimal maintenance costs.