[Tagging] Fire hydrants vs suction_point

[Moritz]

Hi all.

I'm back from vacation and see that there was a huge progress in the 
proposal.

And there seems to be a consensus for grouping all things where 
firefighters can attach their pump under emergency=fire_hydrant.

But I think there are some issues left:

# Fire Water wells

A pipe connected not to a pond but to the groundwater.

Should be

water_source=groundwater

How to tag the water level (distance between water level and ground 
level)?

water_level=6 (in meters) ?

Also there are water wells which have a water level below approx 8 m and 
due to physics there is an additional pump needed. This pump is 
integrated in the
water well at water level and is either driven by electricity or 
external applied water pressure.

The pressure tag is not suitable for it as the water does not need to be 
sucked out and the pressure is not known.
But the information is important for fire fighters to know which 
additional equipment they need.

pump_type=bilge_pump|electric_pump|none ?


# Water tanks

water_source=water_tank

The capacity of the water_tank should also be attached to the hydrant.

water_volume=small|medium|large|# (small 75–150 m^3, medium) 150–300 m^3 
and large>300 m^3 or numeric value).

# Fire water pond

water_volume=# (numeric value in m^3).

# fire_hydrant:class=*

Should be clarified what AA, A, B, C means.

Cheers
Moritz

Am 2017-09-06 00:24, schrieb Viking:
> Hi all.
> 
> @Marc
> 
>> and is this tag well used? I am not able to judge whether values are 
>> realistic
> 
> Well, as in every tag, there are wrong values. But now, with a more
> clear description on the wiki, there will be less errors and future
> corrections will be possible.
> Anyway all values of fire_hydrant:diameter=# should go in the new tag
> diameter=#, or whatever else we choose.
> 
> 
>> what do others think? if somebody find it is not appropriate, I think 
>> that it would be desirable to split out the "meaning change"
>> to validate the rest of the proposal.
> 
> At this point, after the discussion of pros and cons, I think that the
> "meaning change" has no more sense.
> 
> 
> @Francois:
> 
> fire_hydrant:count=#  -->  devices=#
> 
> +1 I'm against grouping more than one hydrant one a node, but if we
> want to keep this possibility, devices=# for me is better.
> 
> 
>> A pressurized hydrant : emergency=fire_hydrant + optional 
>> water_source=network + even more optional pressure=*
>> A pillar connected to a water tank where water can be pumped from :
>> emergency=fire_hydrant + water_source=water_tank + pressure=0
>> A pipe going permanently in a river or a pond where water can be 
>> pumped from :
>> emergency=fire_hydrant + water_source=pond + pressure=0
> 
> +1
> 
> 
> @Martin:
> 
>> unfortunately this is not yet defined unambiguously
> 
> In hydraulics in general, the diameter is the nominal one [0] that is
> related but not equal to the inner diameter. On hydrants in
> particular, the number that is die-casted on them, is the nominal
> diameter of the undergound junction towards the water network.
> Also couplings diameters are always nominal diameters of the threads 
> [1].
> Maybe it is enough to document on the wiki that when diameter=* is
> used for hydrants, it is referred to nominal diameter?
> 
> 
>> Not sure about pressure=0 though, shouldn't that be 1? The wiki 
>> mentions also "suction" for dry hydrants
> 
> In hydraulics, pressure normally is measured relatively to atmospheric
> pressure. So 0 is correct. However, to avoid misunderstandings, we can
> keep pressure=suction for these cases.
> 
> Best regards,
> Alberto
> 
> [0] https://en.wikipedia.org/wiki/Nominal_Pipe_Size
> [1] https://en.wikipedia.org/wiki/ISO_metric_screw_thread
> 
> 
> 
> 
> 
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