Section Env-Dw 505.08 - Approved Backflow Prevention Devices(a) Only approved backflow prevention devices shall be used.(b) Only the types of backflow prevention devices listed in Table 505-1 below shall be used for the containment of on-premise hazards for low and high degree of hazard situations respectively: Table 505-1
Acceptable Backflow Prevention Devices for Degrees of Hazards
| Low Degree of Hazard | High Degree of Hazard |
| Air gap | Air gap |
| Pressure vacuum breaker | Reduced pressure backflow device |
| Double check valve assembly | A combination of the above |
| Reduced pressure backflow device | |
| A combination of the above | |
(c) A backflow prevention device shall not be installed in a location where it will: (1) Be subject to corrosive fumes, grit, or sticky or abrasive liquids;(2) Be subject to flooding or mechanical abuse;(3) Not be easily accessible for testing and repair;(4) Be in a pit or built into or close to walls or other obstructions; or(5) Be in a vertical position unless the backflow prevention device was certified for that orientation.N.H. Code Admin. R. Env-Dw 505.08
(See Revision Note at part heading for Env-Dw 505) #10615, eff 6-1-14