Purging Assembly & Purging Procedure

[Admin]

There are always questions surrounding TSSA compliance audits and purging tools.  Clause H.7, of the CAN/CSA-B149.1S1-07 Natural gas and propane installation code, outlines the purging procedure and Figure H.1 describes an approved purging assembly.

(Clause H.7)  The purging procedure shall be as follows:
(a)  Use only the approved purging assembly.  See Figure H.1.
(b)  Inspect the purging assembly prior to use.  Replace worn or damaged hose, and ensure that all joints are tight.
(c)  Ensure that the manual shut-off valve for the appliance is closed.
(d)  Connect the purging assembly to the appliance dirt pocket, where so equipped, or to the appliance piping, as close to the appliance as is practicable.
(e)  Ensure that no sources of ignition are present within the purge area and that the purge area is well ventilated.
(f)  Determine the approximate purging time from Table H.1.  Ensure that the purge does not exceed 100 s.
(g)  Open the manual shut-off valve for the appliance.
(h)  Begin purging by fully opening the automatic shut-off release purging valve on the purging assembly.  Purge in a continuous and uninterrupted manner.  Caution:  Under no circumstances shall the automatic shut-off release purging valve be fixed in the open position.
(i)  Terminate purging when the smell of gas is detected at the purging valve outlet or when the approximate purging time has been reached.  Do not exceed the purging time by more than 10 s.
(j)  When purging is terminated, close the manual shut-off valve and disconnect the purging assembly from the piping system.
(k)  Reassemble the appliance piping, open the manual shut-off valve, and soap test the affected joints to ensure that there are no leaks.