Be clear about regulator/relief device clearances

Safety officers perform assessments daily throughout the province to ensure the requirements of applicable codes and regulations are met.

In addition to the on-site assessment, all non-compliances are logged in an effort to capture common themes and to gain a better understanding of  safety risks.

The photo, taken by a safety officer during a physical assessment,  shows a commonly found non-compliance. The direct vent appliance termination has been installed without the required clearance to the utilities regulator which contains an internal relief device.


Relief devices are installed within a piping system in order to protect the downstream equipment in the event of an over-pressure condition in the gas system. Should these devices need to relieve, it is important that they can do so safely by having the necessary clearances to building openings, mechanical air intakes, sources of ignition, appliance air intakes, and appliance vent outlets.

If this relief device vents gas to the atmosphere without the necessary clearance to a mechanical air intake, there is potential for the appliance to draw in extra gas through the appliance air intake, causing a possible unsafe condition. See the information bulletin on Clearance to Regulator / Over Pressure Relief Device.

The requirements for relief device clearances can be found in Table 5.2 of the B149.1.

In addition to this, Directive No. D-GA 2014-04 on Appliance Air Intake Clearance From Regulator/Over Pressure Relief Device Vent Outlet further clarifies the designation of direct vented category III or IV appliances combustion air intake as a mechanical air inlet.

If you have any questions, contact your local Technical Safety BC gas safety officer or call 1 866 566 7233 and we will have a gas safety officer get in touch with you.

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