Systems & CodeQuestion 42 of 110
An air gap is used to protect a potable outlet discharging over a flood-level rim. What is the minimum air gap for an effective opening of 1 in diameter, using the rule of two times the effective opening?
a.1 in
b.2 in
c.1-1/2 in
d.4 in
Explanation
The minimum air gap is twice the effective opening diameter, so 2 x 1 in = 2 in, and never less than 1 in in any case. The air gap is the most reliable backflow protection because it is a physical break that cannot fail mechanically. Near a wall the multiplier increases to three times the opening.
Law Reference: UPC §603.4.6Practice all 110 questions free — no signup required.
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