Air Pressure Control Valves and Air Pressure Stabilisers

Protecting individual doors

The protection mechanism for individual doors is examined below based upon the assumption that only one door is open at any time. Within the overall supply volumes available it is not possible to provide protection for more than one open door at a time.

Theatre - Disposal door open

Single door - Required flow 0.47 m3/s. (Sterile) - (Dirty)

Opening this door causes the pressure in the Utility to rise to + 25 Pa but does not affect the pressure in the Theatre. Provided there is sufficient extract i.e. 0.41 m3/s and that the rise in pressure will now cause outflow to the Corridor of 0.06 m3/s a flow of 0.47 m3/s can be obtained across the Theatre to Utility door.

Where the Disposal adjoins the Dirty Corridor its extract is 0.1 m3/s which is insufficient to produce the required flow across the Theatre to Disposal door. It is therefore necessary to size the door transfer grille in the Disposal to Dirty Corridor door to pass 0.37 m3/s.