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.

S.P.S Prep - Corridor door open

Single door - Required flow 0.39 m3/s. (Sterile) - (Transitional)

When this door is open the pressure in the S.P.S. Prep drops to 3 Pa but there is insufficient supply volume to enable the door protection volume to be achieved unless the door transfer grille between Theatre and S.P.S. Prep is sized to pass 0.23 m3/s in the reverse direction to that of normal flow, which in itself is not entirely desirable. This figure is arrived at by taking the supply to the Prep of 0.1 m3/s plus the inward door leakage from the Theatre which will be 0.06 m3/s in this situation from the required door protection volume.