[talk-au] What to tag a fire-fighting water tank?

[John Henderson]

I'd be inclined to go for used-defined tags. The existing tags do not 
accurately describe the feature, and are at best misleading.  A suggestion:

emergency=water
water=tank

As far as capacity is concerned, I'd opt for the standard unit for 
measuring large water volumes - megalitres (ML).

1 ML = 1000 cubic metres exactly.

In my experience, large water tanks are never stored under pressure. 
Rather, the water surface is at atmospheric pressure, and the position 
of the tank on a hill provides any pressure to taps below it.  So the 
lack of pressure is a given.

A large tank under pressure could be a dangerous thing.

John H

On 30/10/11 14:46, cam_daw at fastmail.fm wrote:
> I've come across some large water tanks for fire fighting purposes, and
> was wondering what exactly to tag them as.
>
> I've found a few in the Kinglake area, there's a few more to put on the
> map too.
>
> Pictures of them:
> http://imageshack.us/photo/my-images/843/20111022040.jpg/
> http://imageshack.us/photo/my-images/510/p1020609n.jpg/
>
> Where some of them are:
> http://www.openstreetmap.org/browse/node/1476005382
> http://www.openstreetmap.org/browse/node/1472743040
>
> Best-suited tag that's not quite spot-on:
> https://wiki.openstreetmap.org/wiki/Tag:emergency%3Dfire_hydrant
>
> What I'm wanting to know, is what should I call the fire_hydrant:type
> tag?
> I've temporarily put down "tank", but maybe it should be "reservoir" as
> proposed in
> http://wiki.openstreetmap.org/wiki/Proposed_features/Fire_Hydrant
>
> Next thing would be to tag the capacity (or estimated capacity), which
> would be in meters cubed, estimated by doing a
> (pi*radius*squared)*height
> And perhaps a tag to say that the water is not stored under pressure,
> and would probably require a pump.
>
> Any suggestions would be welcome.  Otherwise I guess I could contact the
> CFA up there for ideas.