Just in case anyone needs a Canada to US translation, I believe the reference is to Toronto Hydro Electric utility poles.
Just in case anyone needs a Canada to US translation, I believe the reference is to Toronto Hydro Electric utility poles.
Oops yes I'm from Canada, I'm not from TO but we use the same terminology.
Bill beat me to the "hydro pole" reference. In British Columbia, Ontario, Quebec, and Labrador most of the electricity is from hydro-electric dams, and so everything power company related is referred to as "hydro-" this and that. 23 years after leaving B.C. my Canadian wife still refers to it as the "hydro bill".?ÿ
As far as checking into local benchmarks - it is frequently more important to report elevations relative to a nearby agency benchmark than it is to report them relative to a national datum. For site development purposes the idea is to coordinate with GIS and other record data.?ÿ
I agree, the top nut tightens down in a different place every time; but a quick and light "X" chisel on a bonnet bolt works. Fire Hydrant don't move up and down, most have a huge concrete thrust block underground.
I agree, the top nut tightens down in a different place every time; but a quick and light "X" chisel on a bonnet bolt works. Fire Hydrant don't move up and down, most have a huge concrete thrust block underground.
I agree, the top nut tightens down in a different place every time; but a quick and light "X" chisel on a bonnet bolt works. Fire Hydrant don't move up and down, most have a huge concrete thrust block underground.
A couple of things copied from firefighter's forums
"Always open and close the nozzle slowly. One time when I was training I shut the nozzle too quickly and got yelled at by my chief. Apparently in the next department over someone caused a water hammer once and it ripped the hydrant out of the ground."
"I have myself stood next to a hydrant that a person was opening and closing to fast and the ground was literally vibrating like godzilla was coming out of the ground. I?ÿhave a coworker who broke a water main by slamming a blitz gun on or off. The truck took the hit fine but the water main under it didn't."
Water is essentially incompressible .... water hammers from shutting valves down too quickly is the cause of thousands of municipal water main breaks a year.?ÿ Thrust blocks are designed for the normal pressure and conditions.?ÿ If shut down fast enough you can get five times the normal pressure flowing backwards into the system.?ÿ If that force can rupture ductile iron mains, it can move hydrants.
It's not common, but it's certainly possible?ÿ?ÿ
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I've seen them used, but always with care.?ÿ ?ÿWe would chisel a square or leave another bench within easy sight so that you always had a two point check to make sure you were on the right pair and the hydrant had not moved.?ÿ?ÿ
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I've also see them really screw up a project when a crew uses the top of the hydrant instead of a chiseled x on a flange bolt... then closed back to the same wrong point.?ÿ Lots of blame to go around on that one, but the dirt guys caught it before the big pipe was dropped in.?ÿ ?ÿ
Notmyrealname says "Anyway, I always check into two bench marks before beginning work. Who uses only one bench mark?"
I do!?ÿ I have used one benchmark many times within my survey career.?ÿ Benchmark by definition is the starting point, like the initial point in the plss.?ÿ When I perform a topographical survey my elevations are based on something and that something is the bm.?ÿ If I am also verifying elevations shown on improvement plans or other sources and I'm not matching +- expectations then I may further investigate.?ÿ A benchmark should also be a well defined point such as the 3" brass disc stamped xxx in the top north east corner of bridge wing wall, but sometimes you have to take what is available which may require one to verify by checking to another if available........?ÿ Jp
First LS boss said Never Ever use a fire hydrant for a BM no matter how temporary. There was an accompanying story ab0ut the fire hydrant BM that went up and down 0.3' in the course of a day depending on the water pressure and the finger-pointing festival that went on until they figured it out.
I have done several urban water line upgrade project surveys for Whitman,?ÿRequardt.?ÿ One of their engineers told me hydrants are bad for BMs because even if they aren't replaced they can (and usually do) surge vertically because of water hammer when the system is exercised.?ÿ Food for thought.
