16 May Ignition Sources : Electricity

The recent spate of tall building fires have highlighted the need for ongoing fire safety management, to prevent fires from starting and spreading. In the first of a series of fire safety management briefings, Russ Timpson will highlight the key knowledge Fire Safety Managers need to know about the most common types of ignition sources in tall buildings.

Most people will be familiar with the triangle of fire, the mainstay of many fire safety training sessions. We know that we need air (O2) and a fuel source (fire load), but most importantly we need a source of ignition to start the process. If we eliminate sources of ignition we eliminate unwanted fires.

There have been a limited number of statistical surveys of ignition sources from real fires in tall buildings. However, from those that are available we can focus our attention on the most common cause of unwanted ignition – electricity. Electrical ignition sources can cover a multitude of issues. The most common are:

Incorrect fitting/specification
electric appliance or equipment is not fitted correctly i.e. proximity to combustible objects

Electrical malfunction
when a component or connection fails, and as a consequence overheats causing ignition, i.e. thermostat on a heating device fails

Short circuit
something causes a fire higher current (amps) to be drawn by a device i.e. water ingress

Incorrect use/operation
exceeding design use and inappropriate loading i.e. overloading

Design faults
flaw in a design only becomes apparent after prolonged use i.e. recall of domestic appliances

Wear and tear
equipment and electrical leads degrade due to working environment i.e. kitchen appliances

The electrical fittings in a tall building can be split into five main categories:

1. Mains power and fixed electrical wiring i.e. switchboards, bus bars and fixed wiring
2. Fitted items of equipment i.e. lift motors, HVAC
3. Portable equipment i.e. catering, office equipment
4. Lighting – fixed and portable
5. Temporary i.e. contractors/construction

So, what are the main things that can be done to make sure electricity does not start fires?

Competency
make sure that the person charged with maintaining the power systems and electrical integrity is competent and has the appropriate technical qualifications. Allow only competent people to maintain the electrical equipment, including contractors. Make competency part of any preferred contractor selection criteria.

Know the system
ensure a firm understanding of the electrical distribution system within the building and business. When was it fitted? Are there original schematic diagrams? Has the system been altered and amended? What are the system protection components – how do they work?

Audit portable equipment
carry out regular audits of portable electrical equipment and remove anything that is unsuitable or damaged. Have a clear policy of what can and cannot be brought into the building and plugged into the system; especially heating and catering equipment (i.e. blower heaters and toasters)

Thermography audits
it is now commonplace for thermographic surveys to be undertaken in building to spot electrical equipment and connections that are overheating and failing. Using specialist cameras that detect infra-red heat, thermography is a valuable tool to prevent electrical fires.

Provide adequate power points
eliminate the need for multi-plug adaptors and extension leads by providing adequate sockets. Extension leads are a temporary measure (1 week max as a sample policy) and one electrical plug per socket is also a simple and effective policy. This should be combined with good cable management to eliminate electrical leads being damaged by wear and tear (i.e trolleys).

Temporary lighting
make sure that any work/event that requires temporary or ‘effect’ lighting has a risk assessment and method statement for use.

Monitor power consumption
understand the power consumption in the building and therefore be aware when there is any unusual ‘heavy’ loading and why.

This list is not exhaustive, however, if the simple steps are followed by those responsible for fire safety management the risk of an electrical ignition leading to fire will be significant reduced.

FME is delighted to have multi award winning Russ Timpson, founder and CEO of Horizonscan, providing a series of fire safety management “briefings”. His experience includes International Fire Strategy for BAA, Head of Safety for Virgin Atlantic and the development of business continuity plans for several multi-national companies. Russ is the secretary of the Tall Buildings Fire Safety Network and his specialisation is the facilitation of crisis simulation exercises.

In December 2015 Russ was named International Fire Professional of the Year at Fire Magazine’s annual Excellence in Fire & Emergency Awards