Venting exhaust of agilent gcs

[dlntx9]

I do environmental consulting work and have a small home office/ lab. I'm working on improving temp control of the room I have my gc's in. I have the following agilent instruments; 2 5890's 1 6890 1 7890 and 2 6850's. Having more than two running at a time warms the room up pretty quickly even with the extra ac unit. I have the exhaust adapters from agilent and just finished ducting them all together and plan to run it to a roof mounted exhaust fan. I could not find any info from agilent of what the max cfm pull could be on the gc exhaust.

Do I need to worry about a max cfm on the fan I buy? The ones I've been looking at range from 500 -3000 cfm. I'd rather go larger in case I ever need to tie in anything else but wasn't sure I'd need to limit the pull from the gc exhausts.

[Steve Reimer]

We have 200cfm or so for each snorkel we attach to a GC. I don't know of any limitation on draw since the box is open to the lab air.
Do you have enough supply air to counterbalance the exhaust?

[wss]

I do environmental consulting work and have a small home office/ lab. I'm working on improving temp control of the room I have my gc's in. I have the following agilent instruments; 2 5890's 1 6890 1 7890 and 2 6850's. Having more than two running at a time warms the room up pretty quickly even with the extra ac unit. I have the exhaust adapters from agilent and just finished ducting them all together and plan to run it to a roof mounted exhaust fan. I could not find any info from agilent of what the max cfm pull could be on the gc exhaust.

Do I need to worry about a max cfm on the fan I buy? The ones I've been looking at range from 500 -3000 cfm. I'd rather go larger in case I ever need to tie in anything else but wasn't sure I'd need to limit the pull from the gc exhausts.

That's a lot of GC's for a small home office/lab...

I've considered using a passive/wind powered ventilator (we call them Whirlybirds in Australia, not sure if that term is in common use elsewhere) hooked up to some insulated ducting, but no idea if that's feasible. I don't think that the cfm would matter terribly but then again I'm not an HVAC engineer.

[James_Ball]

We have all of ours vented into a central rooftop blower on the lab, it definitely pulls a lot of air but not a problem for the instruments. In fact it actually pulls air into the oven when they are cooling helping them cool faster. We also vent the split vent and septum purge into the exhaust tubing to any fumes from those get pulled out of the room.

[LALman]

I do environmental consulting work and have a small home office/ lab. I'm working on improving temp control of the room I have my gc's in. I have the following agilent instruments; 2 5890's 1 6890 1 7890 and 2 6850's. Having more than two running at a time warms the room up pretty quickly even with the extra ac unit. I have the exhaust adapters from agilent and just finished ducting them all together and plan to run it to a roof mounted exhaust fan. I could not find any info from agilent of what the max cfm pull could be on the gc exhaust.

Do I need to worry about a max cfm on the fan I buy? The ones I've been looking at range from 500 -3000 cfm. I'd rather go larger in case I ever need to tie in anything else but wasn't sure I'd need to limit the pull from the gc exhausts.

When I first started working at my lab 50'x25'x12' ceilings; the GC's all vented into the lab; both the ovens and the split vents. I used the Restek oven vent adapters and ran 4" duct to vent them above the ceiling tiles into the additional 12' of second story space which is very leaky. I vent the GC outlets into cylinders packed with activated carbon. For my vacuum backing pumps I got the SISweb exhaust vent kits.

So, 4' of 4" vent hose into the ceiling seems to work fine without any exhaust pull. But if you are pulling it with an exhaust fan you need separation between GC vent and the exhaust hood so the entrained extra flow keeps the peak temperatures low in the vent so it does not kill the fan.