Replacement air quantity must prevent negative pressures in the commercial cooking area from exceeding how many Pa (inches of water column)?

Replacement air quantity must prevent negative pressures in the commercial cooking area from exceeding how many Pa (inches of water column)?

• A. 2.5 Pa
• B. 3.5 Pa
• C. 4.98 Pa
• D. 6.0 Pa

Answer: (C)

When a commercial kitchen exhaust hood is pulling air out, makeup air needs to enter the space to keep the pressure from swinging too negative. The replacement air quantity is set so that the negative pressure in the cooking area does not exceed a specific limit. That limit is about 4.98 Pa, which is roughly 0.02 inches of water column. Keeping the negative pressure at or below this value helps prevent backdrafts, door difficulty, and leakage around the hood. So the threshold is 4.98 Pa (≈0.02 in. w.c.). The other numbers don’t match the standard limit: they represent lower or higher values than the published maximum, which is 4.98 Pa.

When a commercial kitchen exhaust hood is pulling air out, makeup air needs to enter the space to keep the pressure from swinging too negative. The replacement air quantity is set so that the negative pressure in the cooking area does not exceed a specific limit. That limit is about 4.98 Pa, which is roughly 0.02 inches of water column. Keeping the negative pressure at or below this value helps prevent backdrafts, door difficulty, and leakage around the hood.

So the threshold is 4.98 Pa (≈0.02 in. w.c.). The other numbers don’t match the standard limit: they represent lower or higher values than the published maximum, which is 4.98 Pa.