§ 12.5-559 — ATMOSPHERIC VACUUM BREAKER (AVB)

§ 12.5-559 ATMOSPHERIC VACUUM BREAKER (AVB).

(a) AVBs provide minimal protection and are approved for very low hazard application only. AVBs protect against backsiphonage only and are prohibited where there is potential for backpressure. (b) The assembly shall be installed a minimum of six inches above the highest use outlet or overflow level downstream from the assembly. (c) Shutoff valves downstream from the assembly are prohibited. (d) AVBs shall be allowed only for those applications where there is less than 12 hours per day continuous use. (e) AVBs shall not be installed in an area subject to flooding or where damage may occur from water discharge. (f) AVBs shall be allowed for point-of-use protection only in accordance with the plumbing code. AVBs are not recognized as adequate protection by the director, so additional protection may be required. [image omitted; see the official code] Standard Detail No. 12.5-559.1 Atmospheric Vacuum Breaker Notes: (1) No control valves or shutoffs allowed downstream. (2) Install assembly at no more than 60 inches above ground level. (3) Install assembly at least six inches above highest downstream use piping. (4) No pumps or backpressure source allowed. (5) No chemical addition into system allowed. (Ord. 12274, § 1, passed 11-28-1995)