[Beowulf] Swimming in oil..

Stu Midgley sdm900 at gmail.com
Mon Feb 11 15:25:49 PST 2019

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 at 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.
> --
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Dr Stuart Midgley
sdm900 at gmail.com
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