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Tuesday in Construction World
Feb. 13th, 2024 02:19 pmAnother Tuesday, another MEPFP coordination meeting. I went into this one distressingly well prepared and it’s a good thing, too. I had the architect review my document (2 drafts, we went with the second, but with some additions) and he was okay with it so that went out a day or so before the meeting giving everyone time to read it.
Unfortunately, the engineer explicitly ignored the I Don’t Want to Talk About Utility Billing Practices. Actually, the engineer did a lot worse than that. He brought up the You Would Need 3 Container Sized Batteries to back up this house. He seemed to think that if we produced more electricity than was credited under net metering, we would have to do that entirely separate from the grid, which of course no one thinks. This engineer isn’t an electrical engineer _and the electrical engineer who reports to him was in the same meeting_ along with the solar guy, who also couldn’t get very many sentences in over the mechanical engineer manager who just can’t seem to shut up. Among his gems today: 220.70 is part of new code that was just active as of four days ago, so if we’d permitted in December, we couldn’t have used its provisions. Uh, yeah, try March 2023.
Whatever. We all know he’s a problem.
We’re going with the 800 service that the utility is prepared to give us, and we’ll probably need to shed at least some load for calculation purposes, mostly because the HVAC load calculation is still probably excessive conservative in the code. So I went looking for load to shed that I wouldn’t mind not having for a few days if the controller decided Something Was Wrong and shut itself and everything connected to it off until someone came in with a troubleshooting guide and/or parts. R. and I tracked down the three heat pumps on the pool, which are 70 amps each. And I’m like, hmmm. Does anything bad happen if those are turned off for a few days? Like, what temperature is the pool after a few days of that?
So I called the HVAC guy. He doesn’t put his phone number in his email, so I called his business and very politely asked if I could talk to him. I was put on hold while I was approved and HVAC guy actually took my call and I thanked him for doing so and asked if anything bad would happen to the house if the pool heaters were turned off. He agreed those were really obvious things to turn off first, and that nothing would happen but don’t mess with the air control in the pool room. Fine by me!
Best of all, I now understand the order of control: 220.70 compliant device is the first thing upstream from the pool heat pumps, then whatever more flexible controller / scheduler we want in place (for if we go to batteries or backup generation or whatever). Excellent! I sent an email.
Next question: we know that a 100 kW generator and a “3 day” tank (I asked — that’s spec’ed at full load, so we’re talking over a thousand gallons of diesel sitting in a tank. Hard pass.) is cartoonishly oversized. Let’s see if we can figure out how 100 kW was calculated. What is that in amps, for example?
100000 / 120 = 833.
So, that’s probably how that was calculated. Basically, the diesel generator maps to the service size. Hilarious.
R. and I noodled around a bunch trying to understand 220. It is kinda gross. Like, an outlet has a different calculated load value, depending on building type (plausible?), room type (also, plausible?) and square feet of the room (I mean, I guess?). I got distracted when I saw the electric dryer table, and I went to make sure that the laundry (3 GE all in ones is what is spec’d) were NOT listed as dryers, since they are ventless, and the dryers in the code are clearly assumed to be vented, judging by their table. They seem to be calculated either as washing machines or something very similar, so that’s good … but there are 4 on the panels but only 3 on the plans. That was distracting. I send the electrician and email and he was very nice. He knows there is cruft in there and intends to fix it after he gets the updates from the engineers. Reasonable.
So then I went off and look at RFIs in procore, because I finally logged in on my laptop. Procore does not work super good on an ipad, alas. There’s an open one for the pool (cover? Basically), so I went and looked at what kinds of options are out there for pool covers and you know, there’s a range, but the range is a lot weirder than I expected because I stumbled over Liquid Pool Covers and then wondered if that was for real, so I went looking for science on the topic and wound up looking at graphs on ResearchGate of the results of someone putting a bunch of containers of water in a wind tunnel and measuring it with and without the stuff in Liquid Pool Covers at various wind speeds (unsurprisingly, it doesn’t work as well when it is quite windy).
I’m kinda wondering about this? I’d never heard of it before, but it’s weirdly plausible and also disturbingly awesome.
Unfortunately, the engineer explicitly ignored the I Don’t Want to Talk About Utility Billing Practices. Actually, the engineer did a lot worse than that. He brought up the You Would Need 3 Container Sized Batteries to back up this house. He seemed to think that if we produced more electricity than was credited under net metering, we would have to do that entirely separate from the grid, which of course no one thinks. This engineer isn’t an electrical engineer _and the electrical engineer who reports to him was in the same meeting_ along with the solar guy, who also couldn’t get very many sentences in over the mechanical engineer manager who just can’t seem to shut up. Among his gems today: 220.70 is part of new code that was just active as of four days ago, so if we’d permitted in December, we couldn’t have used its provisions. Uh, yeah, try March 2023.
Whatever. We all know he’s a problem.
We’re going with the 800 service that the utility is prepared to give us, and we’ll probably need to shed at least some load for calculation purposes, mostly because the HVAC load calculation is still probably excessive conservative in the code. So I went looking for load to shed that I wouldn’t mind not having for a few days if the controller decided Something Was Wrong and shut itself and everything connected to it off until someone came in with a troubleshooting guide and/or parts. R. and I tracked down the three heat pumps on the pool, which are 70 amps each. And I’m like, hmmm. Does anything bad happen if those are turned off for a few days? Like, what temperature is the pool after a few days of that?
So I called the HVAC guy. He doesn’t put his phone number in his email, so I called his business and very politely asked if I could talk to him. I was put on hold while I was approved and HVAC guy actually took my call and I thanked him for doing so and asked if anything bad would happen to the house if the pool heaters were turned off. He agreed those were really obvious things to turn off first, and that nothing would happen but don’t mess with the air control in the pool room. Fine by me!
Best of all, I now understand the order of control: 220.70 compliant device is the first thing upstream from the pool heat pumps, then whatever more flexible controller / scheduler we want in place (for if we go to batteries or backup generation or whatever). Excellent! I sent an email.
Next question: we know that a 100 kW generator and a “3 day” tank (I asked — that’s spec’ed at full load, so we’re talking over a thousand gallons of diesel sitting in a tank. Hard pass.) is cartoonishly oversized. Let’s see if we can figure out how 100 kW was calculated. What is that in amps, for example?
100000 / 120 = 833.
So, that’s probably how that was calculated. Basically, the diesel generator maps to the service size. Hilarious.
R. and I noodled around a bunch trying to understand 220. It is kinda gross. Like, an outlet has a different calculated load value, depending on building type (plausible?), room type (also, plausible?) and square feet of the room (I mean, I guess?). I got distracted when I saw the electric dryer table, and I went to make sure that the laundry (3 GE all in ones is what is spec’d) were NOT listed as dryers, since they are ventless, and the dryers in the code are clearly assumed to be vented, judging by their table. They seem to be calculated either as washing machines or something very similar, so that’s good … but there are 4 on the panels but only 3 on the plans. That was distracting. I send the electrician and email and he was very nice. He knows there is cruft in there and intends to fix it after he gets the updates from the engineers. Reasonable.
So then I went off and look at RFIs in procore, because I finally logged in on my laptop. Procore does not work super good on an ipad, alas. There’s an open one for the pool (cover? Basically), so I went and looked at what kinds of options are out there for pool covers and you know, there’s a range, but the range is a lot weirder than I expected because I stumbled over Liquid Pool Covers and then wondered if that was for real, so I went looking for science on the topic and wound up looking at graphs on ResearchGate of the results of someone putting a bunch of containers of water in a wind tunnel and measuring it with and without the stuff in Liquid Pool Covers at various wind speeds (unsurprisingly, it doesn’t work as well when it is quite windy).
I’m kinda wondering about this? I’d never heard of it before, but it’s weirdly plausible and also disturbingly awesome.