Natural Gas detector

We are building 2 test cells. Each will have natural gas in them, we need gas detectors. Anyone have suggestions on make/model?

Thanks

g.mccormick said:

We are building 2 test cells. Each will have natural gas in them, we need gas detectors. Anyone have suggestions on make/model?

Thanks

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I use the DET-TRONICS branded with good success.

I have had good luck with sensors from ATI http://www.analyticaltechnology.com/public/productlist.aspx?CategoryID=1001

And is another for you. General Monitors. Standard for the utility I used to work for.

http://www.generalmonitors.com/Gas-Detectors/c/201?N=10010&Ne=10011

We us a mix of Drager, Crowcon and ATi for all out fixed gas detection. I prefer working with crowcon out of the 3.

Do you mean fixed gas detectors, as opposed to portable gas detectors?

We use Det-tronics brand in my natural gas compressor station.

You need to answer the following so you can begin to select an appropriate sensor or a combination of sensor/transmitter/controller. Some sensors have analog outputs representing the 0-100% LEL reading and some have relays built in (some have both).

1. What will the hazardous area classification of your test cell be (where the sensor will be located)?
2. Do you want a live display of the level? If yes, do you want it locally in the cell or remotely in another room, or both?
3. What do you want to happen when you reach a high gas level? For example, do you want only a sensor, and the sensor will control the effect using built-in relays (not recommended)? Do you want the sensor to be just an analog input to a transmitter or controller located closeby which will control the actions when a high level is detected?

There are options depending on your answers, and of course your budget.

Kent

Yes I need a fixed gas detector. Mount on wall type.

1. I don't know what the classification will be (I honestly do not know what specifies what as far as classification). I doubt that we will go expolsion proof on everything.
2. For level, I'd like a 4-20ma for level. This will come into our data acq. and control system. We will monitor and set limits/take action there. I think I'd also like to have relays with programmable levels. From them we could have other functions happen if the daq system misses it.
3. I'm thinking that at 20% lel I will abort test (this will be 2 minute shutdown of engine). Run ventilation to full speed with no recirculation. After engine shutdown, I will turn off gas line solenoid valve.
At 40%, I will emergency shutdown (kill battery power, ignition, gas line solenoid) immediately. Again full ventilation fan with 0% recirculation.

I don't have any experience with test cells, but you MUST have the test cell properly classified before the protection system can be designed.

A quick internet search for "engine test cell classification" provided examples and discussions on how and why they are classified, ranging from cells to test large turbine engines to small automotive ones. Also discussed are the fuels used such as natural gas, diesel, and gasoline.

The search would not lead you to make the classification - unless you have the required authority and knowledge to do so.

You are, however, going in the right direction with ventilation as being an integral part of the design.

The cells will have diesel and natural gas available. Typically only 1 fuel type in use at a time. The cells will have a scavange system along with the ventilation system. Scavenge system will be on when NG is in use. It appears the cell would be classified ast class 1 div 2. It appears also that aslong as we keep everything 18" above floor and 18" below ceiling we should be ok.
Cost is definitely a concern, I believe some of the MSA system are in the $8k range.