Electrical causes of fire, hot work and site precautions — Fire Safety Practice

Sample questions

1. 01You are walking a refurbishment floor looking for fire risks. Which of these does HSG168 list as an ignition source rather than a fuel?

   • AOffcuts of PVC trunking on the floor
   • BPackaging from a delivery of cable drums
   • CHeat from a disc cutter used on steel
   • DScaffold sheeting tied to the outside

   Why: HSG168 lists heat from friction, such as disc cutters, among the ignition sources on site. Packaging, scaffold sheeting and plastic offcuts are all on its list of things that burn, so they are fuel. Prevention means keeping the heat away from them.

2. 02A bundle of oil-soaked rags has been left in a warm corner of a plant room. How does HSG168 treat material like this?

   • AAs fuel that can only burn if a flame reaches it
   • BAs a self-heating material that can ignite
   • CAs a risk only if someone smokes nearby
   • DAs an oxidising agent that adds oxygen to a fire

   Why: HSG168 lists self-heating materials, such as oil-soaked rags, among the ignition sources on site: they can heat up and catch fire with nothing else lighting them. Thinking they need an outside flame or a smoker misses that, and they are not an oxidising agent.

3. 03In a toolbox talk, a supervisor says the Fire Safety Order lists heat, fuel and oxygen as a legal requirement. What is the correct position?

   • AIt is a CDM rule for construction sites only
   • BIt is a rule in BS 7671 for wiring systems
   • CIt is a teaching model from HSE guidance
   • DIt is set out word for word in article 8

   Why: HSE guidance says a fire needs three things to start: heat, fuel and oxygen. The "fire triangle" is only a teaching name for that model. The law does not list the three; it places duties on people to take precautions against fire, and the model is a practical way to decide what those precautions are.