§ 13.05.030. General definitions.

As used in this section, unless the context indicates otherwise, the following words shall have the following meanings:

"Air gap separation" means the method of preventing backflow through the use of an unobstructed vertical distance through the free atmosphere between the lowest opening from any pipe or faucet supplying water to a tank, plumbing fixture or other device and the flood level of the receptacle.

"Approved backflow prevention device" or "device" means a method to prevent backflow approved by the Massachusetts Department of Environmental Protection for use in Massachusetts.

"Atmospheric vacuum breaker" means an approved backflow device used to prevent back siphonage which is not designed for use under static pressure.

"Backflow" means the flow of water or other liquids, mixtures or substances into the distribution pipes of a potable water supply from any source other than the intended source.

"Backflow preventer with intermediate atmospheric vent" means a device having two independently operating check valves separated by an intermediate chamber with a means for automatically venting it to the atmosphere in which the check valves are force-loaded to a normally closed position and the venting means is force-loaded to a normally open position.

"Barometric loop" means a loop of pipe rising at least thirty-five feet, at its topmost point, above the highest fixture it supplies.

"Contaminant" means any physical, chemical, biological or radiological substance or matter in water.

"Cross connection" means any connection between a distribution pipe of potable water from a public water system and any waste pipe, soil pipe, sewer, drain or other unapproved source. Without limiting the generality of the foregoing, the term "cross connection" shall also include any bypass arrangements, jumper connections, removal section swivel or changeover connection and other temporary or permanent connection through which backflow can or may occur.

"Double check valve assembly" means a backflow prevention device which incorporates an assembly of check valves, with shutoff values at each end and appurtenances for testing.

"Potable water" means water from any source which has been approved by the department of environmental protection for human consumption.

"Pressure vacuum breaker" means an approved backflow prevention device designed to prevent only back siphonage and which is designed for use under static line pressure.

"Public water supply system" means a system for the provision to the public of piped water for human consumption as defined in 310 CMR 22.02(8).

"Reduced pressurer backflow preventer" means an approved backflow prevention device incorporating (1) two or more check valves; (2) automatically operating differential relief value located between the two checks; (3) two shutoff valves; and (4) necessary appurtenances for testing; and which is designed to operate so that (5) the pressure in the zone between the two check valves is maintained at a value less than the pressure on the public water system side of the device; and (6) at cessation of normal flow, the pressure in the zone between the two check valves is maintained at a value less than the pressure on the public water system side of the device; and (7) in the case of leakage of either check valve, the differential relief valve shall operate to maintain reduced pressure in the zone by discharging to the atmosphere.

(C.O.07-23 § 1 (part))