Standards for Non-Residential Properties

An RP type backflow preventer or an air gap must be provided at the outlet to the water meter. If the meter is in an underground vault outside the building the RP must be installed in an above ground heated enclosure immediately after the meter. The size of the device must match the size of the meter. Installation must follow Division of Water Standard Detail Drawings unless otherwise approved.

Either an RPDA type backflow preventer or an air gap with a water meter must be provided at the end of the service line. The size of an RPDA must match the size of the service line. The backflow preventer may be installed inside where the water line enters the building, as long as the length of the service line from the property line to the backflow preventer does not exceed 150'. Otherwise the RPDA must be installed near the property line in an above ground heated enclosure. Installation must follow Division of Water Standard Detail Drawings unless otherwise approved. If the fire suppression system uses water only, in some cases a DCDA type backflow preventer may be used in lieu of the RPDA. If installed outside the building DCDAs may be located in a vault or an above ground heated enclosure.

Piping for processes using toxic chemicals and water cannot be interconnected in any way that could provide a path for the toxic chemical to get into the public water system. If water is needed for use with the chemical it must be provided through an air gap at the point of use. An RP is also needed at the meter.

Wells, ponds for fire suppression systems, etc. cannot be interconnected in any way that could provide a path for the water from the auxiliary system to get into the public water system. If water from an auxiliary system is used to supplement a process or equipment using City of Columbus water, or vice versa, the water from the City of Columbus must be fed through an air gap.

A low pressure cutoff switch must be provided.

Installed on or after August 8, 2008:
Either a discharge throttling valve or a variable speed controller must be provided.

Installed before August 8, 2008 without a low pressure cutoff switch:
Either a discharge throttling valve or a variable speed controller must be provided.

Installed before August 8, 2008 with a low pressure cutoff switch:
No modification is required

An Air Gap provides the best protection. This is quite simply a vertical opening/gap between the outlet of the pipe or faucet supplying water and the potential source of contamination. The gap, measured from the bottom of the fill outlet to the overflow elevation of the tank/basin, must be at least twice the height of the fill pipe diameter, and no less than 1”. For instance, a 2” diameter fill pipe requires a 4” air gap.

A Reduced Pressure Assembly, also known as a Reduced Pressure Zone (RPZ) assembly is the next best thing to an air gap. RPs must meet ASSE Standard 1013 and may not be installed in a pit/vault.

A Reduced Pressure Detector Assembly is an RP type device that also contains a special type of meter for fire-only water service lines. RPDAs must meet ASSE Standard 1047 and may not be installed in a pit/vault.

A Double Check assembly is effective in certain uses, but less effective than an RP. DCs must meet ASSE Standard 1015.

A Double Check Detector Assembly is a DC type device that also contains a special type of meter for fire-only water service lines. DCDAs must meet ASSE Standard 1048.

Shuts off the pump if the pressure on the suction side of the pump drops to 10 psi or less.

Automatically throttles (reduces) the flow of the pump by closing a valve on the discharge side of the pump to maintain the pressure on the suction side to 10 psi or greater.

Automatically reduces the flow of the pump by slowing the pump speed to maintain the pressure on the suction side to 10 psi or greater.

5/8" - 1" Meter/Service Size
L-9002B(PDF, 52KB) and L-9002E(PDF, 29KB)

1 1/2" Meter/Service Size
L-9002B(PDF, 52KB) and L-9002C(PDF, 46KB)

2" Meter/Service Size and Larger
L-9002B(PDF, 52KB) and L-9002F(PDF, 55KB)

L-9002B(PDF, 52KB) and L-9002G(PDF, 38KB)

L-9002B(PDF, 52KB) and L-6317C(PDF, 39KB)

L-9002B(PDF, 52KB) and L-9002G(PDF, 38KB)

L-9002B(PDF, 52KB) and L-6317C(PDF, 39KB)

L-9002B(PDF, 52KB) and L-6317A(PDF, 53KB) and L-6317B(PDF, 44KB)