Fireplaces, chimneys and flues

6.8

6.8.29Flue testing

Installations shall be tested before use.

Flues should be checked during construction to ensure:

  • there are no obstructions in the flue
  • mortar or other blockages are removed
  • when the flue is complete, a visual check should be made and obstructions cleared.

Coring ball test for solid fuel appliances

When a visual test cannot be conducted, or is inconclusive, the coring ball test should be conducted as follows:

  • a suitable concrete or metal ball should be attached to a strong cord or rope
  • the ball should be slowly lowered from the flue outlet to the bottom of the flue (the fireplace recess or the appliance connection)
  • where a blockage or obstruction is found, it must be removed and the test repeated until the flue is completely clear of obstruction.

Smoke test for solid fuel appliances

This test is designed to show that a flue draws adequately and that there are no leaks between the appliance and the terminal.

It must be conducted when neither the flue to be tested or adjacent flues are in use. The test should be conducted as follows:

  • The flue should be warmed for 10 minutes with a heat source such as a blow lamp. Where an appliance is fitted, all doors, including flue access doors, should be closed.
  • Two purpose-made smoke pellets should be placed in the appliance firebox or in the bottom of the flue and ignited, then closed or sealed off and the smoke allowed to rise.
  • When smoke appears at the top of the flue, the outlet should be sealed with a blow-up rubber ball or other airtight closing system.
  • The whole structure forming the flue should be inspected externally for smoke leakage. This should include the top of cavity walls and any other possible smoke paths, even those terminating some distance from the flue.
  • The test should be continued for a minimum of five minutes.

Flues for gas appliances

For gas appliances, more sophisticated flue tests may be required and should be conducted by the appliance installer.

Flues for oil appliances

Flues for oil fired appliances should be tested as required by the appliance manufacturer.