Figure #5 - Simplified Building Pressurization Diagram

If local exhaust is constant, pressurization flow (and hence pressurization) is controlled by maintaining “AHU Intake - AHUExhaust”

Equation #1 - Pressurization Flow

Regardless of the type of air handling system used, a positive pressurization flow is required to maintain positive building pressure.

SUPPLY FAN-ONLY SYSTEMS
On systems having only supply fans (no exhaust at the air handler), maintaining a positive pressurization flow requires that the outside air intake flow rates be measured and directly controlled. ^{1, 2, 3, 27, 29} Control is most effectively accomplished by modulating an outside air control damper in conjunction with a modulating return air control damper.^{1, 2, 3, 27, 29} (Figure #6).

Figure #6 - Systems without Return or Relief Fans

<Prev 1 2 3 4 5 6 7 8 9 10 11 Next>