Keith Golding, MD of Quantitech Limited, is urging stack testers and the managers of prescribed industrial processes to check the MCERTS certificates of their Flame Ionisation Detectors (FIDs). He says, "The FID fuel gas for which the certificate is valid is now specified so process operators should ensure, for example, that if the certificate specifies a Hydrogen/Helium mix, any compliance monitoring must also use this mixture or results will be invalid.
"Users of the Sick Bernath 3006 need not be concerned because the MCERTS field test was conducted with both fuel gas options – Hydrogen and Hydrogen/Helium mix. However, Hydrogen is by far the more preferable option."
The fuel gas for FIDs is an important issue because H2/He gas is at least three times the cost of Hydrogen gas, so one might assume that all FIDs would run on Hydrogen. However, some FID manufacturers are unable to achieve the MCERTS performance requirements whilst running on Hydrogen and have to resort to the more expensive H2/He mixture.
This situation is exacerbated by the high fuel gas flow rates (up to 180cc/min) that are required by some FIDs. In contrast, the market leading Sick Bernath 3006 portable FID has an MCERTS certificate to confirm high performance levels using Hydrogen gas at very low flow rates (20cc/min).
Explaining the significance of the fuel gas, Keith Golding says, "The use of this expensive gas mixture at high flow rates means that fuel costs can be an astonishing 27 times greater. However, the cost of the fuel gas is not the only significant issue; high flow rates necessitate a large supply of gas which can create logistical problems and health and safety issues when transporting large bottles in the field.
"Typically the 3006 is able to operate for a full working week from one small 1 litre bottle of Hydrogen, so the MCERTS approved ability of this instrument to run on Hydrogen at very low flow rates is a major advantage to process operators and stack testers."