Installation Within a Building

Where containment at the property line cannot be achieved or is waived based on extenuating circumstances, installation within a building is often desirable as the unit can be installed in a mechanical room or other area that has heat and light. Access and drainage considerations must also be satisfied and the devices should be located to avoid electrical panels, areas of excessive heat, etc.

1. Above grade installations shall be provided with adequate clearances and discharge can be directed to floor or drains or through a sidewall above grade via screened louvers, scuppers, pipe sleeves with flap valves, etc., in accordance with the drainage requirements.

2. Below grade or basement installations are acceptable for DCVA's. RPZA's are only allowed below grade where one or more of the following conditions can be met:

a. Where an adequate gravity drainage system is provided to accommodate a relief valve failure.

b. Where water level alarms are installed to detect flow from the device and alert maintenance or security personnel.

c. Where sump pumps are sized to accommodate a relief valve failure and are connected to emergency power.

d. Where the floor area and volume below the device could accommodate discharge from a relief valve failure. For 2 inch and smaller units, 2,000 cubic feet is generally acceptable. For larger units, the time to submerge the device based on the maximum discharge rate and floor area/volume should be no less than 8 hours.

In any of the above cases, the property owner must be made aware of the potential for water damage in the event of a discharge.