By: Greg Thaler (Marks Supply – Burlington)

To size a Natural Gas Regulator you will need three things. Inlet pressure, Outlet pressure and the Flow requirements.

Inlet pressure is the pressure of the gas on the supply side usually 10, 5 or 2 psi. This can be determined with a pressure gauge (if there is one installed), referring to the mechanical drawings or by contacting the Gas Company. Outlet pressure is the pressure you are running the gas lines to the equipment at. This is measured in inches of water column (27.7”WC = 1psi). The majority of cases this is 7”WC. If your system requires a different pressure Norgas Actaris gas regulators can be adjusted by changing out the color coded springs.

Flow Requirement relates directly to the BtuH requirements for the equipment you are installing. Please note, in the charts attached SCFH means Standard Cubic Feet per Hour which equals 1000 BtuH for natural gas.

Inlet, outlet and Flow requirements will allow you to determine the valve type and orifice size needed. Always size over the required flow to allow for future additions and or over demand situations. Please note the line size is not a significant factor in determining the correct regulator. A ¾ gas regulator sized to the inlet, outlet and flow requirements will give you all the gas you need even when installed on a 1” line. If you require assistance sizing gas regulators please call your local Marks Supply branch.