Gas monitors

[mnfire46]

Can anybody tell me if an air monitor without a air pump is as effective as one with a pump, and what some of the operational differences may be?
thanks in advance...

[Capt7215]

Biggest issue will be you will need to enter the potential hazard area to get a reading. With a pump you can throw the probe & line in and sample remotely. It really depends on how you're going to use it. For confined space entry it is a definite plus as opposed to lowering the meter in & then pulling it back out & checking the peak readings. For overhaul air monitoring or the occasional CO alarm call you could get by without a pump.

[CanadianFyrTrks]

I've used both and find them equally as effective for gas sniffing.

The Pump is Certainly a bonus when checking horizontal confined spaces...

[GTRider245]

Biggest issue will be you will need to enter the potential hazard area to get a reading. With a pump you can throw the probe & line in and sample remotely. It really depends on how you're going to use it. For confined space entry it is a definite plus as opposed to lowering the meter in & then pulling it back out & checking the peak readings. For overhaul air monitoring or the occasional CO alarm call you could get by without a pump.

This basically sums up everything I was going to say.

[fyrmnk]

Pump is also good for checking gas line fittings in ceilings for gas leaks, particularly with a telescoping wand attachment. You do have to account for the delay when you have tubing, etc. attached, usually 1-2 seconds per foot.

[JamesIdealCal]

What everyone else above said for the most part. One thing I'd throw out there is that with pumped instruments you have to make sure you keep those filters clean on the probe/monitor. I've seen countless monitors with burned out pumps because the filters were never cleaned and the pump had to work super hard to pull air over time. Also on pumped units, the in bound pumps are fickle occasionally. If one fails you're basically holding a paperweight. If you have the option, try and get a unit that has a field detachable pump. That way if the pump dies on you, you can rip it off and still use the unit in diffusion mode. Honeywell Impact comes to mind as a good example here, but there are a bunch. If I didn't see so many problems with the GfG 450 in terms of battery, I'd hold them up as a stellar example as well. Also, if you get a pumped unit you need to grab a different regulator than you would on diffusion units. Pumped units need either a flow match (which is a huge pain in the butt to use) or a demand flow regulator (expensive but well worth it).

Everything I can think of off the top of my head.

Any other questions, feel free to email me, james@idealcalibrations.com.

James Moore
www.idealcalibrations.com

[Rico3101]

I pretty much agree with what everyone here is saying. Just a little bit more.. monitors without pumps are also known as 'passive' monitors and ones with pumps are also called 'active' monitors. At my previous department, we used 'active' monitors, mainly because we were measuring for stuff that was really bad and such (hypergols, rocket fuels). We used the monitors with pumps because 1) we were measuring samples in the parts per billion (ppb) range, and 2) the active monitors will pick up stuff quicker than passive monitors. With the active monitors, the pump draws the air sample into the monitor sooner. When dealing with stuff that can be IDLH in the parts per billion range, we opted for immediate alarmm notification as soon as possible. When using a monitor without a pump, you have to wait for the air, sample, gas, or whatever to get into to monitor and saturate the sensor before the monitor will alert you.

When dealing with really bad stuff that you need to measure on a p.p.b. range, I think an active monitor would be best. If your just looking at using the monitor as a 4-gas, or something similar, you should be fine with a passive monitor, no pump.

Also, like someone above mentioned, you have to be careful withh monitors that have pumps. If you don't maintain the filters, you can and willl burn the pumps... not a cheap fix. I'm not a sales rep or anything, just a regular but nerdy fireman sharing my personal experience, but R.A.E. systems makes active monitors that have a feature that will shut the pump off if the pump starts working too hard due to a clogged filter, pinched tubing, etc. This feature protects the pump and all you need to do is just reset the monitor and you can keep using it once you fix whatever causes the pump to shut down.

Hope this helps, and if it doesn't make sense, sorry. I haven't had enough coffee today... but hopefully it gives some insight.