Our solution revolves around our BS6173:2009 certified interlock controls, the EMX50, EMX20 and EMX10. The EMX50 has been fully certified to comply with the BS6173 standard by Advantica, an independent NAMAS laboratory and who are now part of BSI. The EMX50 requires an input signal from each fan. This may be from a standard differential pressure switch, in the most basic and most economic form. Alternatively an electronic version can be employed, as in our EPS10, depending upon the amount of differential air pressure available from the fan. Additionally, if preferred, an indirect method of air flow detection may be used, for example our motor current sensors, the ECS10 and ECS10E. Whilst not our preferred method, our tests have shown that both the ECS10 and the ECS10E can be used reliably and in complete safety. By popular demand from our customers, we are now also offering an EMX controller with integrated ECS10/e current sensor known as the EMSxx Combi. Note that all of our controllers and microprocessor based sensors employ an internationally accepted ‘safe start’ procedure.
The choice of sensor can make a considerable difference to the cost of a system and depends on the specific application. If there is enough air pressure difference, at least 0.3 mbar (33 Pa), then a low cost mechanical air pressure switch can be used. Where appropriate, we can measure for pressure drop and advise on the installation of a suitable set of sensors. In all cases it is important that the volumetric flow is tested and NOT the static pressure.
In installations where gas burning equipment without flame failure operate, our gas leakage GLT10 control must be fitted to comply with BS6173. This would operate after the fan interlock had passed start up, to check if for example an unprotected gas tap has been left open. In this instance, the gas valve would be held shut until the gas tap is closed and the installation re-tested and verified as gas-tight.