Intumescent Drop Seals



Intumescent threshold seals play a crucial role in acoustic (and other) performance.  As well as offering acoustic ratings of between 31 and 35 dB Rw, dependent on the doors construction, it has also been smoke tested to achieve a maximum of just 3 cubic metres leakage per hour.

If you don’t seal the bottom of the door, you won’t achieve an acoustic rating.  The automatic intumescent drop seal is fitted into the bottom rail of the door and it operates by using a spring mechanism to activate the seal. It is non-friction, can be cleaned and conforms to ease of access requirements.

Halspan Automatic Intumescent Threshold Seals are an ideal solution for sealing the gap between the bottom of the door and the threshold. The benefits provided by the SLS‐DRP series seals are acoustic performance, fire and smoke sealing, gas/air prevention and light nuisance prevention as well as providing a dirt and insect barrier. Fully mortised into the bottom of the door and the mechanism activates when the door is closed, lowering and self‐levelling the seal to the floor. When the door is opened, the seal lifts clear of the floor and retreats into its housing. There is no need for a threshold plate with this seal.


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