Door Industry Journal - Spring 2020

109 THE door industry journal spring 2020 Also online at: www.dijonline.co.uk Fire & Security Q. What’s the difference between a brush seal and one with flexible fins? A. Brush seals were the first on the market back in the 1970s, hence they have popular appeal as the traditional smoke seal solution. While they’re still effective as smoke seals, the Building Regulations now have requirements for doors to also provide acoustic containment and be easy to operate to allow access for all. With these requirements, the brush- style smoke seal is sometimes not up to the job. Brushes are particularly poor at providing acoustic containment, as the filaments allow air to pass straight through, and where air goes – sound goes too. They also provide plenty of friction, which makes doors more difficult to operate. Fin-style seals provide a much more comprehensive and hygienic solution. They have better acoustic containment properties (particularly ones with multiple fins) and much lower frictional resistance. It’s important that the fin seal remains continuous around ironmongery for both acoustic and smoke containment. Offset fins make this much easier. Q. Can you paint over fire and smoke seals? A. Over-painting of intumescent seals would not compromise performance in a fire situation. However, do not paint over the flexible elements of smoke seals as this will certainly compromise smoke containment performance. If the smoke seal part of the seal has already been painted over, replace it. Q. I’m working on a hospital project that needs a sealing system that will stand up to rigorous cleaning. What do you recommend? A. There are perimeter and threshold sealing products available with carriers and gaskets which are impervious to most strong cleaning chemicals, making them ideal for hospitals. Where smoke protection is needed, fins will harbour much less dust and dirt than brushes and are easier to wipe clean. Some products are available with anti-microbial additives, which might be an advantage. Check with us for details. Q. Approved Document M says that doors need to be easy for everyone to use. Which products do I choose? A. Leading brands have been designed with ease of access in mind, and the recommended seals would provide exceptionally low frictional resistance to ensure the seal interferes as little as possible with the smooth operation of the doorset. Considerations include: • For a combined acoustic, smoke and fire sealing solution, choose a one-seal solution, which carries test evidence and third-party accreditation. Remember that brush-style fire and smoke seals provide very high levels of frictional resistance, so won’t be suitable. • For acoustic and smoke containment only, either for new door assemblies either fit a surface mounted, self-adhesive, retrofit seal or alternatively, an architectural perimeter seal mounted onto the doorstop, will provide a compression seal that will provide minimal interference. • It’s vital to have a seal at the threshold for effective acoustic and smoke containment, and good automatic threshold drop seals have been designed with high efficiency mechanisms, so doors can be opened with the minimum of effort. • There are also a number of threshold ramps available for situations where different floor levels need to be accommodated. For more information visit www.norseal.co.uk