Acoustic, smoke & fire containment systems

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Acoustic Sealing for Door Assemblies

I need to achieve the highest acoustic rating possible on a standard door, can you help?

Our recommended acoustic seals will certainly help you get the best acoustic performance possible from the door assembly you have - but it's important to remember that no sealing system will improve the acoustic performance of the door leaf itself. Every door leaf will have a maximum acoustic performance, which will have been determined by testing the door construction with all the gaps around the edges filled (caulked). Many combinations of our seals have been proven to maintain a door leaf's acoustic performance to the same level as if the gaps were filled, and that's the best acoustic performance you will be able to achieve.

Some of our recommended solutions are as follows - please click on the product page links for more information:

  • For fire rated doors, our DS or Finesse™ or combined acoustic, smoke and fire seals - the complete solution in one seal. Both the DS and Finesse™ have been proven to achieve an acoustic performance of 31dB Rw on a standard architectural solid door core, when tested in conjunction with a Lorient LAS8001 si automatic threshold seal
  • For non-fire rated doors, we would always recommend our Batwing® acoustic and smoke seal. It has also achieved 31dB Rw on a standard architectural solid door core, when tested in conjunction with a LAS8001 si drop seal.

Please remember it is essential to fit a threshold seal to complete the system. You may find it helpful to read our FAQ on threshold sealing.

To find out more about our recommended acoustic solutions, please refer to our Acoustic Sealing Systems manual, available to download from this website. This also contains more information about how doors are tested, and the acoustic performance of various types of standard door construction.

I've heard that some seals on the market can achieve acoustic ratings of around 40-50dB Rw.  IS that right, and how is it possible?

You need to be very careful when you look at the acoustic rating of door seals. The door and the sealing system always work in combination, so the only way to really know how a seal will perform in practice is to test it on a full-size, working door assembly. Lorient always do that, and we'd suggest you ask for a copy of the full test evidence for any seal that claims to offer exceptionally high acoustic performance ratings. Be careful if you find that any part of the door perimeter has been artificially caulked (filled) for testing purposes; or that the door assembly was smaller than it would be in reality; or that a non-standard door construction was used; or that the gap size is less than the usual 3-4mm - any of these things may result in the seal being given an 'artificial' acoustic performance that it couldn't actually achieve in practice.

We're more than happy to provide specifiers and Lorient customers with a copy of our test evidence so you can make an informed choice!

Do I need to fit a threshold seal – and if so, why? 

BS999 (an Approved Document to the Building Regulations for England & Wales) states that if a fire rated door has a gap of over 3mm at the threshold, then you do need to fit a threshold seal. It's very difficult to know before the door is installed whether the gap will be over or under 3mm, so we do always recommend fitting a threshold seal.

There are other reasons for this too. It is often assumed that the threshold is a low-risk area, but research has proven that this is not the case - an unsealed threshold presents a major cold smoke hazard. That is why undercutting the threshold of a door leaf to provide extra ventilation is extremely risky too. Threshold sealing is also essential for acoustic containment, as an acoustic sealing system will only be effective if it incorporates every gap around the door, and that includes the threshold. For more information on our threshold seals, please refer to our Lorient Architectural Seals door bottom seals or drop seals products.

If I fit a drop seal, do I need to fit a threshold plate too?

A threshold plate is a good idea, for several reasons:

  • It will help to ensure a good seal is maintained at the threshold, by giving a firm surface for the drop seal to rest against.
  • If you are sealing dissimilar surfaces (eg, carpet and vinyl), the threshold plate can cover the join to prevent both wear and tripping hazards. Our threshold ramps can also easily accommodate differences in floor heights, to make access easier for all.
  • If your floor surface is particularly liable to wear and tear in places below the door (eg, a high level of traffic, or over a carpet that may become compressed over time), then a threshold plate will help to prevent these uneven areas affecting the threshold sealing.

Please refer to our Lorient Architectural Seals threshold plates and ramps for details of what we can offer.