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Question from someone out of the industry for a while and don't have a copy of 62-2010 to refer to....what allowances does 62-2010 give for buildings with partial occupancy?

I remember with 62-89...

Debate between me designer/contractor and younger designer about small server room - load less than 10 tons.

I want to have a plain jane chilled water fan coil for daytime cooling and a plane jane...

My company leases over 200 apartment units around town and they are all cooled with ductless splits (we're in Asia). Some of the occupants are turning their tstats down 66F at all times. We pay the...

Any message board similar to this one, but with commercial fire protection as its focus....or....any of you guys fire alarm system gurus who can answer a question for me?

I think I'll go with prog stat. For something as simple as retail, I don't want to complicate things. After we leave I can see the manager fiddling with stuff and messing it up. Thanks all!

Office building with an old 200 ton Carrier water cooled chiller. CV AHU's throughout with RAT sensor turning off and on the AHU. No controls on anything other than that.

Currently, if there's a...

Large retail - 20 ton unit - 2 stage Trane DX split. Currently using RAT sensors to control space temp. Another "HVAC guy" says we should change it to a programmable tstat in the space because it's...

Apologies right up front in that I'm "out" of the HVAC industry and in the facilities business, but I can't find an answer to this question.

ASHRAE 189 is code-enforceable for green...

And can someone suggest a tstat that will turn the AHU fan off when the CHW valve is closed when space temp is met?????

And for what it's worth...each AHU has 3 way valves. All are cooling only.

Building built in 1950
2 - 60 ton water cooled Carrier chillers in 1975
12 - 15 to 25 ton vertical CHW AHU's

Each air handler is CV in a mechanical room.
Each AHU has one manual thermostat in...

But VVT still seems odd since the interior needs cooling when exterior needs heat. They could use CCN controls and someone else's FB. But I guess you're back to needing hot h20 which is going to...

Wanted to run something by you guys. I'm in NC and talking to a HVAC sub in NY - Albany specifically. We were talking about the way mid-size office buildings are designed up there vs NC. Using a...

Is the return air blowing across a DX coil cooled because....

1) As the refrigerant leaves the expansion valve, the refrigerant is evaporating due to the warm return air and subsequent change in...

Anyone know of an HVAC sub in South Texas with experience doing commercial geo thermal jobs?

My background is commercial and I know a condenser water loop going to a closed loop tower has anti-scaling chemicals installed and the water/tower is checked regularly.

Do you have to add...

Running chilled water and gas. 3" up to 6". What are the pro/copns of victaulic versus just welding it?

What about just the need to have an disconnect of any type(fused or not)? I know I've seen that someplace - I just don't know where.

Is the need for a fused disconnet only in the electrical code or is there a note in the mech code about it? If you could site where the reference is in either code I'd appreciate it.

So pressurize stairwell, but my understanding is elevator shafts should be negative? Right or wrong?

Can someone give me some guidelines - or point me to a website - that generally describes how stairwells and elevator shafts are to be designed relative to positive or negative pressure, necessity of...

Having never designed outside of NC, I've always used what I was taught for when you need an economizer which was any unit 3,000 cfm and above.

Then I went looking and found all sorts of different...

I found a couple of recent projects here in NC still using '89 numbers and couldn't figure out why. But I guess if the local code people haven't caught on....

Wow - ask a question about outside...

I haven't designed in some years now and wondered if ASHRAE 62.1-2004 is now the standard everyone uses for determining outside air calculation?

Saw an ad in an HVAC mag about R-421 being a direct replacement for R22 and it meets the non-ozone requirements coming up. Why don't I hear more about this? All I hear about is R-410a. Any...