Server Room Humidity
Posted by unreadable_captcha@reddit | sysadmin | View on Reddit | 34 comments
Hi guys, we recently had a cooling malfunction in our server room, luckily it happened during the day so we cought it right away. Anyways that prompted my boss to finally have a temp/humidity sensor installed in the room.
I installed it today in the rack and this is what the Humidity sensor shows https://i.imgur.com/a0eZP5d.png you can see how it fluctuates between 55-75%, how much of an issue is that? I read that "optimal levels" would be between 40-60% so that would be a bit high but my question was more about fluctuation. The AC unit will be replaced since there is apparently a leak so is that something we should be mindful about when choosing the new units?
I don't know much about server room cooling systems so any advice is welcome.
thanks!
TheOnlyKirb@reddit
At a particular remote site we have, the humidity where two servers and networking equipment resides has sat around 80-83% for several days, and upon returning to normal levels things were fine.
As an additional piece of info, every time we open the server room door in our main office, the humidity spikes to around 70% for a little bit till the AC catches up.
I used to be rather concerned about this, but after seeing the equipment continue on without issue, and reassurance from my manager (with a lot more knowledge on this from experience) I no longer worry too much.
If it's sitting at around 90-95% then I would be more worried, but below that, I wouldn't worry. Fluctuations are somewhat normal
blue_skive@reddit
I'm in the tropics and my server room humidity is 75-85% all day everyday. Facilities refused to do anything about it. I got the Facilities manager to agree in writing that if anything were to happen because of humidity, his department would bear responsibility. That was about 10 years ago...so far so good.
unreadable_captcha@reddit (OP)
thanks for replying.
I was expecting some fluctuation but 20% seems a lot (again I know nothing about it). also just to add some details the server room was closed the whole time, and before 8:20 the sensor was on my desk thats why the graph is flat.
Temps on the other hand are stable at 19-20°C
I guess I can (and have to) live with it for now
Ssakaa@reddit
I'd overlay temp on that too. If that inverts vs temp, it was possibly just holding a relatively steady level of water in the air (which is a higher relative humidity at lower temps). If the AC was leaking into the room instead of draining properly, you'll have that, since it'll just cycle the moisture back into the air instead of removing it. 70% is a bit high, but not bad enough to damage things for a brief period, but as things cool again, as others note, watch the dew point.
unreadable_captcha@reddit (OP)
temperatures are stable between 19-20°C there is no pattern that match the humidity.
But we know our AC has some leaking issues, that's what caused the overheating problem in the room and prompted all this. but according to the HVAC guy who came for the repairs the leak is only on the cooling elements on the roof, not in the room....but there might still be some correlation.
watchthebison@reddit
If you overlap the temperature readings over the graph are they also fluctuating in the same manner?
The sensor will be relative humidity and not absolute. Relative humidity decreases as temperature increases, because warmer air can hold more moisture.
unreadable_captcha@reddit (OP)
temp does not do that, it stays between 19-20°C, without any obvious fluctuation pattern
ZAFJB@reddit
You want to check dewpoint, which is the temperature at which water will start condensing out of the air. Usually that is much lower than ambient temperature.
You only need to worry if they are close together.
If humidity is very high >80%, then when you bring the aircon back online, you need too cool down slowly so you don't hit dewpoint by cooling to fast before the air has had a chance to dry out.
Yo may have to prop the server room door open to help the air dry out.
braytag@reddit
Well, unless I'm missing something in my physic understanding, since everything will be much hotter than your "cooled air", dew can't form no?
Ssakaa@reddit
Inside the equipment will be, but the sheet of metal getting blasted with cold air at the front of the rack very well could drop below dew point, condense, and provide droplets that can "rain" through your servers with their internal fans pulling it in.
1Original1@reddit
Not even to mention if that faulty AC has a condensation tray/line issue and you suddenly get an overload of frost, that's a drip hazard right there
DDOSBreakfast@reddit
Why move to the cloud when you can move the cloud into your server room?
Smart_North_3374@reddit
Gave me a good chuckle here
AugieKS@reddit
Looks like you can rent an industrial dehumidifier from Home Depot for about $50 a day. Overkill? Maybe, but might buy peice of mind for exec and OP, and that's a blip compared to other costs.
Adorable-Lake-8818@reddit
$62 a day for one that removes 144 pints a day / 18 gallons a day. Plus tax. Ask me how I know. Toilet leak and we had to run it this week to get the water out of the walls. HIGHLY RECOMMEND you do that.
ShadowCVL@reddit
This is an excellent answer. The operating range for equipment is usually in the 20-80% NON CONDENSING humidity.
As long as your ambient doesn’t go below your dew point you are pretty much okay.
KingSlareXIV@reddit
I don't think the range of values is a problem for the equipment, but I don't understand how you are getting 20% fluctuations over 10 minutes periods.
I don't know how your facility is set up, but as you describe it as a "room", I am going to assume it's located inside an office. I can't see the office hitting 80% humidity without people complaining, and this is where I'd expect less-conditioned air to be coming from normally.
It makes me think you live in a humid climate and have outside air infiltrating the room somehow. Which isn't good.
Sinister_Nibs@reddit
Oscillating fan…
gruesse98604@reddit
Excellent first step, to ensure the temp/humidity readings are accurate! Surprised this is the first post I've seen to recommend it.
Also might just get a standalone dehumidifier (assuming you have a place to drain water).
sryan2k1@reddit
Extremely oversized AC for the load causing short cycling.
KingSlareXIV@reddit
I considered that, but wouldn't that just lead to a consistently high humidity level?
unreadable_captcha@reddit (OP)
here is the full graph starting from yesterday, up until the fluctuations the sensor was sitting on my desk https://i.imgur.com/urhlIYk.png.
The server room is inside our office, on the second floor and we are in Switzerland so not a particularly humid climate
theborgman1977@reddit
Optimal is 20% to 30% any higher than 45% and any lower than 20% you are in the danger area.
Lower than 20% you can have a static charge.
buzzy_buddy@reddit
get a dehumidifier and have it drain somewhere so you don't constantly have to empty the container.
kingdead42@reddit
Just be aware that dehumidifiers are another source of heat in the room, so that may not be a great idea generally. Though in this case, I suspect that the AC may be oversized for the needs and running in short bursts.
buzzy_buddy@reddit
fair point.
also it definitely is running in short bursts judging by the graph. i think they could also raise the temp on the termostat at which the AC turns on and this would likely help humidity levels.
kingdead42@reddit
Yeah, I don't think it would matter in this case, but wanted to mention it in case someone is thinking about a dehumidifier for their server room without being aware of the potential for it increasing their AC load.
EViLTeW@reddit
My best guess is that the sensor is sitting right in the line of fire of an AC vent. The room is humid, but when the AC is on it's blowing dry air directly onto the sensor and dropping the reading. As soon as the blower shuts off, the RH% jumps back up. Try moving the sensor somewhere else as far away from a vent as possible on an outside wall.
Sinister_Nibs@reddit
And way from the door.
unreadable_captcha@reddit (OP)
good point. I tried to put in a place where it's not directly blasted by the AC but I will move it somewhere else and see if it makes a difference
wideace99@reddit
For humans not servers :)
A/C will cool but also dry the air, remember the dripping water hose outside near the compressor ? This is the inside humidity leaving the room, which is good since servers don't need humidity.
No_Balance9869@reddit
Controlling the temperature and humidity in a server room is critical to the proper functioning of the equipment. High temperatures can fry equipment, and humidity can shorten its lifespan. Servers and the data they process, transmit, and store cost a lot of money. Consider cooling equipment for server rooms and data centers that can control humidity. Avoid comfort air conditioning units like those used to cool your bedroom or living room.
00001000U@reddit
Something to be mindful of. Humidity and temperature can all be wildly inaccurate depending on where you are in your room. Some spots could be 50%, others 60%, while your supply is feeding the room 67%. There is no uniform "we're filling a volume" here.
qwertymartes@reddit
Maybe ask in r/hvacadvice