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Intumescent Plugs

Fire doors may be vulnerable to the intense heat transferred through the mass of metal that door hinges and latch plates represent. This can cause charring and ignition. Intumescent plugs, comprising a short length of metal tubing filled with intumescent material, are used to protect these ares by preventing the passage of flaming or hot gases by smothering the surrounding areas on activation.

The plugs are located in holes drilled through hinges, striker plates and pivot mechanisms

Two 7mm diameter plain holes are drilled through each plate in addition to the existing screw holes. These holes are offset in order that the plates are not weakened. After fitting the hinges, 6mm diameter x 40mm deep holes are drilled, through the plain holes, into the wood and plugs are inserted flush with the hinge plates

The layout of the countersunk holes for fixing screws in 100mm butt hinges varies according to the manufacturer. Three of the most common are shown here, together with suggested positions for Sealmaster Intumescent Plugs.
Sealmaster Intumescent Plugs

Where plugs have to be fitted to longer butt hinges this must be at the rate of two extra plugs per 50mm of additional length of hinge.

Screw fixing holes +
Sealmaster Intumescent Plugs


Two 7mm diameter plain holes are drilled in the plate, so as not to weaken it, or affect its normal operation.

The plugs are fitted into the wood in the same manner as for hinges.Gaps around mortised areas should be filled with Intumescent Compound or Plaster to reduce fire spread.

Intumescent sealing around pivot doors can be completed by incorporating Sealmaster Intumescent Pivot MechanismPlugs in the top strap assembly. The positioning of the plugs is determined by the shape of the strap and the layout of the screw fixing holes, as these can vary according to make.

Pivot Mechanism


intumescent plugs

  • Lock Striker Plate
    Lock / Latch Striker Plate