Plastic drain line failures on pumps

[kuh shise]

Is anyone else finding failures of the plastic lines used to route drains from discharges, relief valves or intakes on older apparatus? Had two this week when performing annual pump tests.

[Chief1FF]

How old are the trucks?

Chief1ff

[ffp20]

no, none at all

[FIREDEPTMECH]

I have had some trouble with 1990 and 1993 vintage opaque/white plastic pump drain lines being brittle and cracking when moved. Have not had any fail under pressure.
Have not had any problem when DOT plastic line is used.

[kuh shise]

Chief1FF: 1992 failed on the discharge (officers side) 2 1/2" drain, but it is exposed to ehaust heat (radiation) about 8" from the point where the line split. The 2004 drain from the relief valve to the main drain manifold split when making the relay relief valve test portion of the UL procedure. Because some area hydrants are at 180 psi static, that is the set point for our relay relief valves. Our engineer (union welder/plumber) claims that the tubing being used compares to what he uses at 150 psi. We have purchased 300 psi tubing and the required fittings and will replace any failures as they appear. I understand that the NFPA calls out 250 psi tubing.

[chiefengineer11]

This thread got me to do a little checking because our newest engine uses all Synflex ( a brand name) or equivalent tubing on the drains. Also, everything that I have replaced or added on the older engine uses it also. None of it has caused us any problems.

What we have is 3/8" air brake tubing that complies with SAE J844 and 49 CFR 571.106 (FMVSS 106). The pressure is not marked on it, but I always understood it to be 150 psi. I found a chart in one on-line catalog that shows the working pressure to be 150 psi and the maximum burst pressure to be 1400 psi. So I feel OK about continuing to use it.

We too, have many high pressure hydrants, with average pressures of 185 psi. It just happens that our both of our engines have two reliefs, one on each side. I keep the one on the officer's side at 185 and the one near the pump panel at 190.

[mitchkrat]

I had one blow but it was the plastic line for the main primer from the bottom of the pump. I was pumping a long interior line and had the pressure cranked up - not sure if they slammed the nozzle on me or what but the line blew with a loud bang and then sprayed water onto the exhaust. Between the bang and the sudden cloud of steam I thought I had blown the truck engine up. Shut down and found the blown plastic line.

[Rescue101]

Is anyone else finding failures of the plastic lines used to route drains from discharges, relief valves or intakes on older apparatus? Had two this week when performing annual pump tests.

YES. In our case,like Sam,we use rated brake tubing to replace it. There are other more expensive tubing you can use but we've had good luck with the brake line.

[FIREMECH1]

YES. In our case,like Sam,we use rated brake tubing to replace it. There are other more expensive tubing you can use but we've had good luck with the brake line.

Ditto here, as well.

FM1