you raise a great issue... the fluid we use has a specific gravity around 0.8g/cc so is lighter than water. As you point out, some of the other fluids are VERY heavy.
We have oil immersed data rooms on the 1st (above a basement carpark) and 20th floors of normal commercial buildings... those wouldn't be possible with other fluids :) The weight can dramatically impact how you build your DC, floor etc. Which can significantly impact price. And lets be clear... by "swimming" I was just reaching into the tank (head first) upto about my waste, in fluid, to grab a blanking plate on the bottom of the tank :) On Tue, Feb 12, 2019 at 2:17 AM Lux, Jim (337K) via Beowulf < beowulf@beowulf.org> wrote: > Stu reports swimming, but perhaps he was really more wading. > > > > A significant problem with large vats of liquid, whether used for cooling > electronic equipment, or just storage, is that if the density is > significantly less than that of water, you don’t float. Humans are just > slightly positively buoyant in water (with full lungs). Change that to oil > or corn syrup or scotch whisky with a density of 0.9, and it’s like having > 5-10 kg of weight on you, and that takes a lot of work to stay on the > surface. > > This is a well known hazard in the petroleum processing industry (aside > from the fact that the air above the tank’s liquid surface is probably full > of all manner of unhealthy things and not oxygen) – you fall in the big > tank, you die. > > > > Diala AX (a HV insulating oil I’ve used) has a specific gravity of 0.885, > and is somewhat more viscous than water (not a lot) – if you fell into it, > and couldn’t support yourself by standing on the bottom or equipment within > the tank, you’d need to be rescued pretty quickly. The increased viscosity > would also mean that it’s more work to keep “treading oil” to stay above > the surface. > > > > USP white mineral oil is about 0.85 g/cc. We had a thousand gallon tank > of this where I used to work, and there was a whole discussion about safety > – it was a wide flat tank, so in theory, if you fell in, you could stand up > (except that the tank was polyethylene and it **is** oil.. there were > questions about whether you could stand up on the slippery surface) > > > > Of course, you can get oil in all densities – the stuff they use for road > surfacing is quite dense. > > > > > > Fluorinert FC-40 (which I’ve also used) is quite dense – 1.85 g/cc – you’d > float well above the surface like a cork. A quick glance at the line card > for Novec® shows they’re all pretty dense - 1.4g/cc is the least dense. > > > > -- > > > _______________________________________________ > Beowulf mailing list, Beowulf@beowulf.org sponsored by Penguin Computing > To change your subscription (digest mode or unsubscribe) visit > http://www.beowulf.org/mailman/listinfo/beowulf > -- Dr Stuart Midgley sdm...@gmail.com
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