Error in city conducted flow tests. How have you handled it?

[SprinklerDesigner2]

Of course I am not allowed to perform my own test on city hydrants so they have their experts do it for me.

I like doing my own flow test because I know how to do them and my gauges are calibrated with the paperwork to go with them. I have also gotten into the habit of having someone from the fire department with me and using my phone I video tape. I don't care how pretty my drawings are if the flow test is wrong I got a pile of garbage.

ESFR system with 1,250 gpm @ 90 psi fire booster pump.

City report has 70 static, 40 residual @ 1,500 gpm (two outlets) with 1,976 gpm @ 20 psi. Sounded like we were good to go there. Nice looking report form on city letterhead and attached map showing hydrants tested. The test hydrant wasn't 100' from my fire pump.

Acceptance test yesterday and we barely made 100% @ 20 psi while running negative at 1,400 gpm. System will perform (barely) as designed as long as the 250 gpm hose stream isn't added.

Fire officials looked like a herd of deer in the headlights... test was accepted (we did get 100%) and the owner received his Certificate of Occupancy but what the heck happens if the owner wants to expand? And then the issue of the owner not getting what he paid for but I don't think I can be held accountable there.

I don't like this.

I know this has happened to everyone who has been in the game for years but just curious how others would have handled it?

 

[LCREP]

Are all valves open in the area/site? I had this happen to me, come to find out they had a water main break in the area. They opened the valves to restore service BUT one valve was not opened resulting a confirmed grid system only being a dead end system with one valve shut! I would check the water main map and ask them to confirm all valves are opened.

 

[SprinklerDesigner2]

I don't think the issue is with a closed valve.

The main in question is an 8" C=900 dead in line approximately 3,300' in length from where it ties into a 12" circulating city water main. The 12" main indicates a static of 52, a residual of 40 flowing 1,920 gpm. It's flat land (swamp area) and the 70 psi on the first test appears suspicious.

Flowing 1,500 gpm we can expect to lose 44 psi which would put us at about what we got if you assume a static of 52 and not 70.

So everyone knows this second test I got just an hour ago... how can they miss it this much? Anyone can read a static pressure and when elevation is within 2' how can you have an 18 psi difference in static?

In small towns I always insist I be there during flow tests and use my gauges.. never had an issue but I didn't do it here (kicked myself again) because it is a large metro area of over one million people.

Who would run an 8" dead end main 3,300 feet to a large industrial area???

 

[MatthewJWillis]

You already know the answer..

Unfortunately, it places us in the bad for having to tell the owner, the city messed up, we need another $250k for a tank..

I feel we do need to hold them accountable.
The question truly is how.

R/
Matt

 

[TravisMack]

Sadly, I am sure this has happened to us all. Mine wasn't as a result of city error per se. We had an issue where the hydrants were on a high pressure main but the site contractor tapped the low pressure line for the supply into the building. This wasn't found out until acceptance testing. We had to run some new mains to make it all work.

Your situation is a bit different. Adding a tank won't fix it because the pump is sized based on a certain incoming city supply. If you do a tank, then you have to replace the pump as well because it will be undersized for the pressure demands. I think it is a frank talk between the building owner, fire dept and water authority that performed the flow test. One thing I would investigate is whether your flow test and pump test were done at the same time of day. On a dead end line, you could see a significant drop if the flow test wasn't done at peak demand times, yet the pump test was. It sounds like there needs to be some procedural changes by the jurisdiction to their policies. I would hope you are in the clear as the policy in that jurisdiction is you are prohibited from doing your own flow test and have to rely on water purveyor provided data. They should have some liability to remedy the situation.

Travis Mack, SET, CWBSP, RME-G, CFPS
MFP Design, LLC

http://www.mfpdesign.com