Exit strategy

A correctly specified, installed and maintained emergency lighting system facilitates the prompt evacuation of a building affected by fire and smoke says Richard Merchant, Commercial Director at TheisCraft

Anyone who has been in an unfamiliar building when a fire alarm is activated will know how vital an emergency lighting system is in such a situation. It gives occupants a way of evacuating a building safely in the event of a fire and its role, as part of an overall life safety system, should never be ignored or underestimated.

PLAY BY THE RULES
UK fire safety legislation states that people in a building must be able to find their way to a place of total safety if there is a fire, by using escape routes that have enough lighting.

Evacuation can be hindered by a lack of detailed knowledge of the internal connectivity of the building space, along with confusing and poorly thought out instructions. Studies have also shown that in these situations occupants usually make use of familiar routes – typically using an exit through which they entered the building. Even more worryingly, research from the University of Greenwich, as part of its Human Behaviour in Fire Network (HUBFIN) study, found that only 38 per cent of people see passive signage in an emergency.

To address these issues, the Regulatory Reform (Fire Safety) Order 2005 places the onus on a designated ‘responsible person’ within an organisation to carry out assessments to identify, manage and reduce risk, and put appropriate measures in place. However, there is still a lack of awareness of the risks around not dealing with emergency lighting correctly.

STANDARD ISSUE
Legislation should be adhered to in order to identify a building’s specific emergency lighting requirements. The Workplace Directive 89/654 states that signs, in accordance with national regulation, must indicate specific routes and exits. Additionally, The Construction Products Directive 89/106/EEC says that the purpose of an emergency lighting installation is to ensure that lighting is provided promptly, automatically and for a suitable time in a specific area when normal power supply to the lighting fails.

This is all encapsulated in BS 5266-1, Code of practice for the emergency lighting of premises. BS 5266-1 provides information on the correct lighting provision for the safety of people and provides facilities managers with information regarding minimum levels of illumination, duration of operation and the maximum brightness levels needed to prevent glare. When persons have designed, installed, commissioned and maintained systems in line with the standard, they can be confident they have a properly designed scheme.

APPLIANCE OF SCIENCE
There have been significant advancements in the technology deployed in emergency lighting systems in recent years, with the result that they now offer a level of intelligence that combines high levels of reliability and ease of use. Furthermore, light emitting diode (LED) luminaires offer significant additional benefits in terms of size, lifetime and energy efficiency. LED luminaires offer some impressive features and 3W fittings are available that run at 700mA and come in standard format three hour duration.

There are a number of factors facilities managers need to consider when specifying a system. Good quality LED products from a reputable vendor will have a higher output and better spacing performance, meaning fewer units are needed to achieve the required level of illumination. This may not only reduce the outlay on products but also the installation cost, as well as energy expenditure over the long-term.

It is also advisable to verify what supported evidence is available from a manufacturer to substantiate that its solution is compliant with building, legal, safety and quality standards, and any other relevant rules and regulations. In addition, a manufacturer should be able to supply evidence to support its product’s functionality claims.

TESTING TIMES
In order to comply with BS 5266-1, all emergency lighting systems must undergo a short duration test on a monthly basis and an additional annual test for the full rated duration of the emergency lights. A full record sheet needs to be maintained for each emergency luminaire and entered into a logbook, which must be available for inspection by the authorities at any time. Failure to provide full test records can result in legal action and closure of a building, and if the system is defective, the insurance policy for a building may be invalid.

Modern systems utilise the digital addressable lighting interface (DALI) protocol, as set out set out in IEC 62386, so that full remote operation and self-test is possible. DALI assigns an address to each luminaire, allowing management of each individual device, and this can be as simple as a single luminaire containing a driver and a sensor. Scheduling of monthly self-tests and annual duration tests can be set up via the internet, with all test results automatically logged.

STATE-OF-THE-ART
The most sophisticated emergency lighting test systems consist of one or more touchscreens, with each one supporting up to 10 DALI emergency hubs. The hubs have two separate DALI field networks supporting up to 64 devices each, with each touchscreen and associated emergency hub having the capacity to manage up to 1,280 devices. These devices can be allocated to one of 16 testing groups, so up to eight touchscreens can be networked together to form a system that can potentially accommodate up to 10,240 DALI devices.

Given the high safety importance of system testing, it makes sense to automate this function. Software can be used to monitor all the luminaires linked to the system and can schedule and run a test, with the additional ability to schedule tests in designated areas. There is also the ability to carry out either functional or durational tests, which are time definable.

FEATURES AND BENEFITS
A high quality emergency lighting system will give occupants a way of evacuating a building safely in the event of a fire. The regulations, standards and guidance when it comes to specification, installation testing and maintenance are comprehensive, and designed to ensure that each building’s particular needs are thoroughly examined and understood. It is therefore imperative that FMs understand their legal obligations in this area and act accordingly.