Guide to Conversion of Traditional Buildings

2.10 Escape lighting

Standard 2.10

Every building must be designed and constructed in such a way that in the event of an outbreak of fire within the building, illumination is provided to assist in escape.

2.10.1 Type of standard

Mandatory Standard

In the case of conversions, as specified in regulation 4, the building as converted shall meet the requirement of this standard (regulation 12, schedule 6).

2.10.2 Commentary

While the full implementation of this standard is essential, the introduction of escape route lighting and emergency lighting into a historic building can be dealt with in a way that causes minimum disturbance to both the aesthetics and fabric of the building. However, unsympathetic installations, which are introduced without regard to historic character, should be avoided. For example, the use of intrusive bulkhead fittings and surface mounted, fire-protected cables are unlikely to be acceptable in buildings of greater cultural significance. The use of self-contained emergency luminaires may be more easily accommodated than the installation of a protected circuit to the existing lighting system.

2.10.3 Issues to be considered

Issue - Risks to historic / traditional buildings

1. Siting of devices Location of fixtures and fittings and routing of cables. Aesthetic damage to historic character, destruction of finishes.

2. Introduction of ignition sources Hiding batteries, LED drivers, Lutron Nodes and other equipment within voids introduces an additional fire hazard.

2.10.4 Recommendations to meet the standard

It is recommended that specialist advice for design and construction should be sought from those with appropriate heritage and fire expertise.

The technical requirements for escape route lighting or emergency lighting in different building types are well covered in publications referred to within the Technical Handbooks. BS EN 1838 2024 gives details on the requirements for most building types and recommends that lighting levels for emergency lighting should be expanded upon those previously recommended in BS 5266. With the advent of low energy LEDs, a 3-hour emergency light is common, whilst one hour emergency lighting is gradually being superseded.

A protected circuit for escape route lighting can be created by running a fire-protected power supply from a distribution board near the origin of the electrical supply for the building. Suitable materials for this are Mineral Insulated Copper Sheathed (MICS) or Mineral Insulated Copper Covered (MICC) cables or fire-protected soft bodied fire resisting cables.

If emergency lighting is required, the two main generic options are central battery systems or self-contained emergency luminaires.

Central battery systems are those in which emergency luminaries, located in various parts of the building, are powered by a central battery via fire-protected cables. Local relays, usually positioned at the distribution board supplying the lighting circuits, switch the emergency luminaires on in the event of a power failure in any given lighting circuit.

Self-contained emergency luminaires contain a battery pack and charging feed within the luminaire. If the control equipment within the battery pack senses a loss of power to the permanent charging circuit, then the luminaire will switch on.

These two systems have relative advantages and disadvantages. The central battery system is more suited to larger buildings whereas the self-contained solution is suited to smaller buildings. These relative advantages apply also to installation and maintenance costs. The luminaires associated with central battery systems tend to be more discreet and compact than those for self-contained systems. Both systems can be arranged to operate certain luminaires in the general lighting scheme as emergency luminaires.

However, arranging this is more straightforward and usually more cost effective with the self-contained option than with the central battery system. The central batteries have a life of between 5 and 10 years and must be kept optimally between 15°C and 20°C to avoid overheating and reducing the battery life, so locating them in a warm boiler room is not advisable. Some battery manufacturers state that every increase of 10°C above 20°C halves the battery life.

Emergency lighting must be functional, but great care is also required when designing an installation for a historic building because the aesthetic impact of the luminaires can be significant. Low level emergency lighting could be considered with careful consideration of the siting of battery and control mechanism.

A further option for emergency lighting that can produce more sympathetic solutions is a hybrid system, which utilises inverter and battery packs located near to the emergency luminaires and connected to these via fire protected cable. The luminaries are switched on when the charging feed to the battery pack is interrupted (as in the self-contained system). This arrangement can be used to power a single lamp in a chandelier, for instance, and is particularly useful when aesthetic considerations make it difficult to utilise more standard emergency lighting solutions. Care must be taken to ensure that the battery and inverter is not concealed in hidden voids as they are potentially an ignition source.