A typical architectural door leaf with FD30 fire performance has a mass of only 18-22kg/m2 below the requirement stated in Approved Document E. Therefore, to meet the requirements of Approved Document E it is essential to establish the acoustic performance of the doorset to at least 29dB Rw.
Door construction can help to some extent. Because sound is created by pressure fluctuations, it is the vibration of the door leaf that causes some of the sound to be transmitted. A very dense or moderately flexible door leaf is harder to set into vibration providing a better acoustic barrier. However, even a heavier door, without seals, will not meet the minimum 29dB Rw requirement. This is because although some sound will be transmitted through the door leaf itself, the majority of the sound passes through the gaps around the perimeter of the door leaf. The reference to Approved Document B should also be noted. In many residential situations, the door that must provide acoustic protection will also need to provide fire and smoke protection. For most purposes, a standard FD30 door leaf will provide a good basis for an acoustic door assembly to meet the 29dB Rw minimum requirement of Approved Document E. However, without a sealing system the acoustic performance will only be in the region of 22dB Rw. Fitting a traditional brush-type smoke seal will offer only a minor improvement in acoustic performance, still falling well below the 29dB Rw minimum required by Approved Document E.
Therefore, for any door assembly, a professionally designed and engineered sealing system for acoustic, smoke and fire containment must be incorporated in order to ensure that the door assembly will comply with the requirements.
A 'good' sealing system can only be determined by testing against the referenced standards, using a full size door assembly, and observing at all times the benchmark of 29dB Rw minimum for the whole assembly.
These may be incorporated in doors without a major loss of acoustic performance and in many situations can increase the acoustic performance provided that thick enough glass is used. Lorient System-36 PLUS range of glazing gaskets provides optimum acoustic performance for most types of door constructions including FD30/FD30S/FD60 and FD60S. Please refer to Lorient technical department for further information.