In Part 1 of his mini-series on emergency lighting requirements, Frank Bertie, Chief Technical Officer at NAPIT, explains why evacuation routes must be clearly illuminated in accordance with BS 5266 emergency lighting requirements.
In this series of articles, I’ll be looking at the requirements for emergency lighting within premises that have a variety of solutions depending on the assessment of the type, use and operation of each building.
BS 5266-1 provides a Code of Practice (CoP) on the methods to achieve the functions that an emergency lighting system has to provide to ensure a safe means of escape, or an area of safety, or continued operation of the premises. This article will provide an understanding of BS 5266 and how to apply each Clause.
Emergency lighting systems
The CoP gives an explanation of the types of emergency lighting systems and a description of what each system will cover. While the following systems are listed individually, they can be combined within a single system. Emergency lighting can perform the following functions:
a) Emergency escape lighting, which provides illumination of escape routes, signs and points of emphasis to assist occupants to evacuate the premises,
b) Emergency safety lighting, which provides lighting for safe movement in the premises when the occupants need not evacuate the premises immediately,
c) Standby lighting, powered by an alternative power supply, which provides sufficient lighting to operate the premises normally in the event of a total failure of the main power supply.
British Standards
Within BS 5266-1 there is a further list of normative references, which include a range of BS, BS EN, BS EN ISO, IEC, BS ISO standards that are essential to how emergency lighting systems are designed, installed and commissioned. These are set out in three levels, as indicated in Fig 1, comprising of the base document, the system standards and the product standards.
As you would expect for an emergency lighting system, the requirements of BS 7671 are an integral part of the range of standards referenced in the CoP. As with fire detection and fire alarm systems, emergency lighting is sometimes seen as not having to comply with the requirements for BS 7671 because of the reference within Regulation 110.1.3.
The details include wording that BS 7671 is intended to be applied to all electrical installations, although it also specifies that it may need to be supplemented by other British or Harmonized Standards.
BS 5266 and BS EN 1838 for emergency lighting are included in Regulation 110.1.3 (ii). These are repeated again within Regulation 560.9, which states emergency lighting systems shall comply with the relevant parts of BS 5266 series and BS EN 1838.
Emergency lighting and electrical installations
As emergency lighting is a more integral part of the electrical installation than the fire systems, the relationship between BS 7671 and BS 5266 is more interlinked, therefore understanding the requirements of all of the relevant standards is essential to those working in this area.
The design must first consider the emergency lighting system in conjunction with the type of premises, taking into account any particular legislation that may be applicable and state the type of system that is required.
Prior to the installation of an emergency lighting system, the owner and/or occupier would need to have discussions with the architect, lighting engineer, installer, local building control and, if necessary, the electrical supplier.
The emergency strategy for the premises will need to be agreed, taking into account either the immediate evacuation or continued occupation of the premises.
Essential information is required at the design stage, which will cover escape routes, open areas, high risk task areas, fire and other safety equipment, and details of normal lighting and controls.
The information will form part of the records to be retained by the responsible person for the premises and must be available throughout the lifetime of the installation to allow revisions, alterations and upgrading to be carried out on the premises to ensure that the emergency lighting system remains operational and compliant with relevant legislation and standards.
Escape or safety protection
When a building has been designated for escape or safety protection, the requirements for emergency escape lighting should be in accordance with BS EN 1838 and the relevant recommendations of BS 5266-1.
Therefore, in the event of a failure of supply to the normal lighting, there should be a provision of emergency escape lighting that allows those present within the premises to evacuate safely. This will involve the ability to clearly locate and identify the escape routes by being able to follow the escape route directional signs, including any exit signs at doors.
Determining emergency lighting levels
The illuminance levels for any emergency lighting system have to take into account the layout of the areas with escape routes and any open areas, as well as any extenuating circumstances that can have an effect on the operation of the luminaires, such as voltage reductions or voltage drops, battery lifespan, lamp aging, and dirt and dust accumulation.
Lighting should be uniform and avoid any variations in lighting levels that could create dark spots in the building areas covered by the emergency lighting. Also, the luminaires should be situated at least 30˚ out of the line of sight to prevent glare.
Where there are defined escape routes, the CoP provides the minimum requirements for the illuminance at floor level for an escape route up to two metres wide that should not be less than that of 1 lx, see Fig 2.
Open areas with floor areas greater that 60 m2 or other such areas included in the risk assessment should be provided with horizontal illuminance of 0.5 lx, but the perimeter of the area can be excluded for the border of 0.5 m.
Another location to consider is any area that would be classed as a high-risk task area, which could cause potentially dangerous situations if the lighting was subject to failure.
In order to permit safe and proper shut-down procedures for the safety of the operator, staff or any other occupants, the illuminance should be no less than 10% of the normal lighting levels at those areas where the tasks are being performed.
Conclusion
It is essential that those individuals who are technically responsible and those who install and commission work on electrical installations with emergency lighting systems in such premises have adequate training and knowledge.
Without access to this range of standards, it wouldn’t be possible to confirm whether emergency lighting systems have been installed in accordance with the standards.
Compliant emergency lighting systems require competence and knowledge. A BAFE Third-Party certification under NAPIT is a highly recognised and excellent way to demonstrate competency, one that is likely to become even more common as standards raise and accountability increases.
If you’re an electrician and are looking to develop your skills and increase the range of work you’re competent to undertake, a specialised course with NAPIT Training can be of immense benefit.
To get more NAPIT training course dates/details, click here
To get more details about NAPIT membership, click here
