Spillage Test (for lay visitors)
The first important test before fitting a gas fire, after checking the construction requirements, is the flue-flow test. That involves the use of a smoke pellet in the flue, to ensure the smoke generated is efficiently removed. A larger volume of smoke is used than is used for the spillage test. Full details of the flue-flow test (an extensive protocol) will not be discussed here as it is not immediately relevant to the subject of these pages. Below is a repeat of the previous sketch with an exaggerated caricature to help lay understanding.
In a nutshell for the benefit of lay visitors, the gas fire is set working on full flame, with doors and windows tight shut. A smoke match is then introduced under the draught diverter at e on the sketch. That is to say under the open base of the draught diverter. For the record this test is also carried out under additional challenging conditions known to RGI. That includes testing with any fans working in the same or an adjacent room.

If the products of combustion (POC) are being evacuated efficiently up the flue, the smoke introduced at e will be pulled into the draught diverter, as if by a vacuum cleaner. If the flue fails to clear POC, the smoke from the smoke match will 'spill' into the room and choke the RGI, hence the expression spillage test.

Carrying out the spillage test at the base of draught diverters is well known to RGI and commonplace on open-flue boilers. Principle old as gas itself. However this represents a profound shift from the spillage test shown in the original MI. Nothing wrong with that in theory but we have to ask why the change. The spillage test position on gas fires traditionally, has always been (and still is) carried out at the front of the gas fire, as shown in the original MI.
Which begs the question, why the change ? This change also suggests the gas fire has been altered but we will discover the truth in due course. The new spillage test position actually represents a significant shift in the context of gas fires. There has to be a mighty powerful reason. It is not therefore unreasonable to assume, in the light of the changes to 32.689.33, that using the more traditional spillage testing position will not suffice. This is discussed on the Ramifications page.
To see an example of a smoke match see this pop-up page which includes a brief video. This page will pop-up in a new window. Close the pop-up page to return to this page.
Return to Home Page
Previous page Next Page