Pressurization is one of several possible methods of smoke control in buildings in the event of fire

A pressurization system protects spaces from smoke ingress such as the staircase, lift shaft, lobby, corridor, or other compartments by use of pressure differentials and air velocities through open doors.

Pressurization is seen as the higher standard of smoke control (it is however not suggested that it is the only effective method in all circumstances). The system provides positive pressurization by injection of clean outside air to the space to be protected.

The stairwell is a priority in terms of protection, with airflow away from the stair being provided.

Pressurization is not a new idea. The Fire Research Station published Fire Research Note No.958 ‘Pressurization of escape routes in buildings’ in 1972. This was the predecessor to the first UK code of practice (BS 5588 Part 4) which was published in 1978, updated in 1998 and effectively became the European Standard, EN 12101 Part 6 in 2005.

Recently (2022) EN 12101-13 relating to the design of pressure differential systems, and EN 12101-6 now cover specifications – kits and components.

The pressurization system supply air fans introduce air into the required spaces via supply air ductwork/shafts and grilles. The fans should be located at ground level, away from rising smoke.

Pressure control is usually carried out by use of constant speed fans with pressure relief dampers or variable speed fans with pressure sensor control.

A key item which must be considered with any system is a means of ‘air release’ from the fire floor. This allows the air which enters the fire zone to escape allowing both pressure differentials and open-door air velocities to be achieved. Various options are available by natural and/or mechanical means.

Two large fans at ground level

D+H UK have the necessary experience with not only the design of stair pressurization systems but also on-site practical experience which is extremely important in order to ensure the whole process runs smoothly.

We have extensive experience with the service and maintenance of the systems, for example, where systems over 20 years old continue to provide reliable and effective protection.


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