Gas Boiler Installation Safety

Toolbox Talk Record

Ref: TBT-MBS-008  |  Issue: 1  |  Date: March 2026
PresenterProject
LocationDate

What?

Why?

Prevent gas explosionsIncorrect gas connections and leaking joints cause gas accumulation and explosions that destroy buildings and kill occupants.
Carbon monoxide deathsIncorrectly installed flues and boilers produce lethal carbon monoxide that kills silently in occupied buildings.
Legal requirementThe Gas Safety Regulations 1998 make it a criminal offence for unregistered persons to work on gas appliances.
Do Don't
  • Confirm the installer is Gas Safe registered before any gas work begins.
  • Carry out a gas tightness test on all new connections before commissioning.
  • Position the flue terminal in accordance with Building Regulations clearance distances.
  • Test for carbon monoxide in the room after commissioning to confirm safe operation.
  • Use safe manual handling techniques or mechanical aids for wall-mounting boilers.
  • Isolate the electrical supply before making any wiring connections to the boiler.
  • Complete the commissioning certificate and benchmark log after every installation.
  • Check the gas meter and supply pipe capacity before connecting a new boiler.
  • Purge the gas supply pipe of air before attempting to light the boiler.
  • Leave the customer with operating instructions and the Gas Safe notification record.
  • DON'T allow anyone not Gas Safe registered to work on the gas installation.
  • DON'T commission the boiler without completing a gas tightness test first.
  • DON'T position the flue terminal where exhaust gases could re-enter the building.
  • DON'T skip the carbon monoxide spillage test after commissioning the boiler.
  • DON'T lift and wall-mount a heavy boiler without assistance or lifting aids.
  • DON'T make electrical connections without isolating the supply and testing for dead.
  • DON'T leave the installation without completing the benchmark commissioning record.
  • DON'T connect a boiler to a gas supply that has insufficient capacity for the load.
  • DON'T use jointing compound or tape not approved for gas connections.
  • DON'T test for gas leaks with a naked flame; use approved leak detection fluid.

See also: Mechanical Building Services Safety | Gas Escape and Emergency Procedures