10-21-2009 10:27 PM
Natural gas will ignite only when the mix of air and gas reaches the flamebility limits.. If the gas is too dilute it will not explode.. It needs a buid up over time.. Firstly gas is lighter than air and will reach the highest part of the room.. If ventilators are provided at this point, then the gas will not collect and increase the concentration to flameable limits.. We also have in the market Mentane sensors, commonly used in coal mining applications, with alarm which will alarm if the concentration goes up.. Lastly when you provide room ventilation always provide positive pressure inside the room.. Never suck or exhaust air from the room or enclosure and create negative pressure..
Hope this will be useful..
12-01-2008 06:48 AM
When you install smaller power ratings of Gas powered Gensets inside the facility apart from the usual safety measures of installing Gas Detectors,Fire Alarm systems,and all fail safe controls ensure that
1. The system is serviced regularly if this is being used only for stand by application.Ensure that No electrical connections are exposed near the area.
2.Ensure having a trained operator trained by the manufacturer
3.If it being in a crowded community area/near gas station/Schools etc ensure installing of warning sysyem and Auto Fire tender Alarm etc.
4.Ensure that the Exhaust Chimney is fitted with a spark arrestor and sufficiently cleaned periodically to avoid any sparks.
11-24-2008 06:58 AM
You need to ventilate the room anyway to get air for combustion, so arrange the ventilation to be sufficient to dilute any gas leaks.
Usually, the gas is fed to the engine at atmospheric pressure or just above this.
I know of only one gas engine (Waukasha) that has a high pressure gas train.
You need to fit flammable gas detectors around the gas train to detect any gas leaks. On gas detection, stop the engine but keep the room ventilation running.
There is a specification IGE/UP/3, Gas Fuelled Spark Ignition and Dual Fuel Engines, published by The Institution of Gas Engineers & Managers, which we use in the UK. If you can get a copy, it will help (wherever you are).
Hope this helps,