Need Fire Hydrant Help ASAP

[jeb6294]

Long story short, they do everything backwards here. They put in the water loop around the base and then put in the perimeter road. The road ended up being wider and higher than the original so several of the fire hydrants are about 1-ft off the EOP and half buried. I am trying to do an estimate for the cost of moving the hydrants back about 2 meters which would get them off the EOP and bring them up to a proper elevation.

The whole contract is a big mess so in the interest of being EXTREMELY conservative I just looked up the cost of a fire hydrant install and subtracted the cost of a hydrant since they are just moving them. Apparently that's not good enough for our friendly native contractor so now I'm going to do a realistic estimate. So, is there any reason they couldn't just yank out the pipe between the valve and the tee and put in a piece that is 2 meters longer reusing everything else? I'll have to check in the morning, but I believe it is HDPE pipe which I'm not as familiar with. If you can't reuse the joints once they've been installed, could they just cut the pipe and insert a 2 meter piece in there, i.e. coupler->2m pipe->coupler?

Thanks for the help.

 

[Dexman PE]

So the firehydrants need to be both raised and moved? Easiest way to do this would be at the point of the firehydrants. Excavate down to where the 90 is, splice on a 2' horizontal extension, add a new 90, then add an appropriate vertical extension to raise the FH to grade. This way you maximize the amount of materials re-used/kept in place as well as minimizing the excavation. Obviously the thrust-block would need to be demo'ed and re-installed (hence the need to replace the 90, assuming they have thrust-blocks).

 

[jeb6294]

With the slope of the shoulder, if they move it away from the road about 2 meters to enough horizontal clearance then the vertical clearance should take care of itself. But it sounds like you're saying they could just extend what they got.

 

[Dexman PE]

You would just need to confirm that any coupling is rated for the pressures, but I don't think a horizontal extension would be a problem

 

[Yakfish PE PS]

"in the interest of being EXTREMELY conservative I just looked up the cost of a fire hydrant install and subtracted the cost of a hydrant since they are just moving them. Apparently that's not good enough for our friendly native contractor"

The savings you think you should get for reusing the material is going to be offset by the additional labor and equipment needed to salvage it. The work involved in salvaging the pipe and fittings would be slower and more complex than installation of a hydrant only. First there is the extra care required to safely excavate around the pipes, jack hammering out the concrete thrust blocks, removing all of the poly wrap, tracer wire and cathodic protection, then dewatering and unbolting the pipes and fittings. Fire hydrant pipe is typically ductile iron pipe from the main to the hydrant but can be PVC, I doubt it would be HDPE, either way it will have mechanically restrained joints with lots of bolts. You should Google mega lugs, these have lots of bolt heads that break off after reaching a certain torque, these would have to be cut off the pipe with a demo saw. You have to do all of this work without damaging anything before you can begin lengthening the pipe and reinstalling the hydrant.

Can you see why just subtracting out the cost of a new hydrant assembly from the original cost to install a new hydrant would not make your contractor happy. You are basically trying to screw them. In some situations the extra work involved in salvaging materials actually costs more than what the material cost when new. Something to consider.

If you can't reach a reasonable agreement you can always try the old time and material method. Just make sure that you have an experienced inspector on site to observe and document the work.

 

[Capt Worley PE]

Does NFPA 24 allow for HDPE? I think they are more specific than that but have to wait til I get back to the office to confirm.

 

[jeb6294]

...there is the extra care required to safely excavate around the pipes, jack hammering out the concrete thrust blocks, removing all of the poly wrap, tracer wire and cathodic protection, then dewatering and unbolting the pipes and fittings...

We're in Afghanistan. All of this is going to be done with about 8 guys with shovels who are being paid about $8 a day.

Does NFPA 24 allow for HDPE? I think they are more specific than that but have to wait til I get back to the office to confirm.

The only thing being referenced is AWWA C600 which is for installation of ductile iron mains. There is a section for installation of hydrants but it only says that 6" has to be used, it doesn't specify a material and the way these guys are, if it doesn't specifically say then they are going to use what they've got which would be HDPE. Unfortunately I was not here when they were installed so I'm not really sure how these things were installed, but I've been told it's all HDPE.

 

[wilheldp_PE]

We're in Afghanistan.

Then why the bloody hell do you care if it's done up to code?

 

[Dexman PE]

We're in Afghanistan.

Then why the bloody hell do you care if it's done up to code?

Professional integrity. At least that's why I would do it.

 

[wilheldp_PE]

It must be our government paying for these projects. If it was the Afghanis, they'd just do it the cheap and quick way.

 

[IlPadrino]

We're in Afghanistan.

Then why the bloody hell do you care if it's done up to code?

So that it works as required (firefighters like them to work when needed) and has the right life-cycle costs?