UK underground fire hydrant - GIF

[nova_robotics]

What's wrong with having above ground hydrants?

[desbromilow]

What's wrong with having above ground hydrants?

can't speak for anyone else, but when I look as US above ground hydrants I see a few things different from the below ground hydrant used in parts of Australia... namely:
#1- above ground used to counteract the effects of freezing - not an issue in a lot of Australia
#2 - takes up real estate above ground (limits where people park, etc)
#3 - seems that other people can access the hydrants (movies often show kids playing in the water from hydrants) - my local council would be quite cranky if people were accessing mains pressure water free of charge
#4 - the above ground hydrant would require regular servicing at a higher level and cost than the simple valve and hook assembly of a below ground unit - the high wear component (where the hose line attaches) is carried in the truck and inspected regularly - cheap to replace, and only need 1-2 per truck, not one every x distance along every street
#5 - no above ground hazards for traffic interactions,(I imagine hitting a hydrant would be like hitting a bollard - wreck the car (and driver), and probably damage the hydrant
#6 - allows the hydrant to be placed in a variety of locations (street, footpath/chainage, front yard) - whereas an above ground hydrant would need a branch line before it could be moved due to road widening/alignment

All that said, there are above ground hydrants in Australia here and there - they are basically a 75-150mm (3-6") pipe connected the water mains, controlled with a valve at the end, and fitted with a BIC female connector (or more than one in a manifold) immediately after the valve - the Pump truck can run a line to that and operate the same as a standard below ground hydrant. These are typically seen built into the side of large city buildings, but can also be free-standing with "protection" around them (bollards, etc) -

[nova_robotics]

can't speak for anyone else, but when I look as US above ground hydrants I see a few things different from the below ground hydrant used in parts of Australia... namely:
#1- above ground used to counteract the effects of freezing - not an issue in a lot of Australia
#2 - takes up real estate above ground (limits where people park, etc)
#3 - seems that other people can access the hydrants (movies often show kids playing in the water from hydrants) - my local council would be quite cranky if people were accessing mains pressure water free of charge
#4 - the above ground hydrant would require regular servicing at a higher level and cost than the simple valve and hook assembly of a below ground unit - the high wear component (where the hose line attaches) is carried in the truck and inspected regularly - cheap to replace, and only need 1-2 per truck, not one every x distance along every street
#5 - no above ground hazards for traffic interactions,(I imagine hitting a hydrant would be like hitting a bollard - wreck the car (and driver), and probably damage the hydrant
#6 - allows the hydrant to be placed in a variety of locations (street, footpath/chainage, front yard) - whereas an above ground hydrant would need a branch line before it could be moved due to road widening/alignment

All that said, there are above ground hydrants in Australia here and there - they are basically a 75-150mm (3-6") pipe connected the water mains, controlled with a valve at the end, and fitted with a BIC female connector (or more than one in a manifold) immediately after the valve - the Pump truck can run a line to that and operate the same as a standard below ground hydrant. These are typically seen built into the side of large city buildings, but can also be free-standing with "protection" around them (bollards, etc) -

We only have above ground hydrants here in Canada and this whole country freezes up cock stiff every winter. I don't think that's an issue.

I'm not sure about the servicing either. I don't recall seeing anyone ever service a hydrant. I'm sure it happens at some crazy long interval, but I've never witnessed it. There are some antique looking ones here in Halifax. For 3 months of the year every car on the road is white. Not because they're white, but because they're caked in road salt. I'd be much more worried about the below-asphalt ones binding up solid from a constant soaking in road salt. And the snow plows absolutely shred the asphalt. If you had to get one of those little hatches open after being hit 30 or 40 times by a snow plow blade it might be a challenge to get it open.

[desbromilow]

We only have above ground hydrants here in Canada and this whole country freezes up cock stiff every winter. I don't think that's an issue.

I'm not sure about the servicing either. I don't recall seeing anyone ever service a hydrant. I'm sure it happens at some crazy long interval, but I've never witnessed it. There are some antique looking ones here in Halifax. For 3 months of the year every car on the road is white. Not because they're white, but because they're caked in road salt. I'd be much more worried about the below-asphalt ones binding up solid from a constant soaking in road salt. And the snow plows absolutely shred the asphalt. If you had to get one of those little hatches open after being hit 30 or 40 times by a snow plow blade it might be a challenge to get it open.

as said - I can't speak for anyone, but it's my understanding that countries with freezing weather bury their water mains deeper, and so use the above ground hydrant model to bring the water up from below the frost line. Issues like road salt, and snowplows just aren't something I see here.. but would be part of the equation for countries which use them.