Getting smoke control systems right is essential in a building, since the system should, in the event of a serious fire, save lives.
But it is not simple.
First you have to understand the regulations; then you have to apply them correctly to your specific building and select and install the correct equipment; you have to commission it properly and, finally, you have to maintain it. Get all this right and it will be worth the effort since you can feel secure that you have done your best to protect the building occupiers.
There is a hierarchy of documents with which you need to comply, starting with the EU Directives, Building Regulations and Approved Documents, and moving down to BS9999 and BS7346, as well as trade-association guides. Some regulations are mandatory while others are recommendations and guidance. Some are specific to particular building types, so you need to fully understand them. To make things even more difficult, there are some inconsistencies in the regulations, as changes filter through.
You may, with expert advice, want to take a fire-engineering approach, in which you prove the performance will be adequate while following fewer prescriptive rules. This can help make the building design more flexible but, since it involves working from first principles and proving that the building will perform properly, it is not always a simple solution. It also relies on the competence and integrity of the fire engineer, who may not be an expert in all areas.
Once it comes to designing for a specific building, you need a detailed understanding of the building design and how it will be used in order to specify the correct system. In particular, in high-rise buildings, it is important to make the right choice between pressurisation and smoke-shaft systems. There is no universal “right” choice, but there’s certainly a best choice for each individual building as well as plenty of wrong choices. Too often, when people do not understand what is required, they specify incorrectly, wasting money and, in some cases, compromising safety.
The wisest design in the world will not be effective if it is not installed properly. That is why the commissioning process is so important. You should do it in two steps.
The first step is to make sure that the build quality is good and the installation complete, with no air leaks. If you have a smoke-shaft system, you should pressure-test the smoke shaft before installation of the ventilation system, to make sure that the air leakage rates are within acceptable limits.
If you have a pressurisation system, you cannot do these tests until the whole building is complete. But you can, in both cases, check the quality of the build – make sure that penetrations are properly sealed, that there are no gaps in mortar joints, that plasterboard is adequately bonded at the edges. Demanding that problems like this are put right at an appropriate stage will remove the need for far more making good at a later stage, when the pressure is also on to finish the job.
The second step is the final commissioning, checking that everything is working properly. Seemingly trivial changes, such as moving from a hard floor to carpet, will have an impact on pressures and flow rates, so there may need to be some final adjustments. But if you carried out the earlier checks on build quality and remedied any errors before final finish, you will not find yourself tearing up the building to fix leaks.
If you follow these procedures – regulation, design and commissioning – then you should have an effective smoke extraction system that will do everything possible to safeguard the safety of the building occupants in case of fire – provided that you maintain it properly. But that is another story.
For more information on your responsibilities when maintaining smoke control systems, read our blog post on the topic.
Colt is the UK’s most experienced supplier and servicer of smoke control systems and fire curtains. If you want an intelligent, considered approach to fire safety, contact Colt.