LDH and the FDC

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Permalink Reply by Mark Lee on May 9, 2008 at 4:27pm

Good idea. I will see maybe if Salka can get me contact info on that. Thanks for the help, brother.

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Permalink Reply by Stan Mettinger Jr. on May 11, 2008 at 7:58pm

Our jurisdiction had discussed requiring 5" storz FDC for new construction with Sprinklers or Standpipe. Excess pressures (200+) should not be an issue for us because an ordinance prohibits buildings from being over 4 stories. My thoughts on the 5" to the FDC is that you can lay one line and get all the water you need.

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Permalink Reply by John Norman on May 13, 2008 at 3:30pm

Tom, can I ask what type hi rises they are, residential or commercial?
At 16 stories high, you need to be pumping in the vicinity of 250 psi at the FDC inlet with that arrangement.

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Permalink Reply by Thomas Horne on May 14, 2008 at 11:58am

They are residential. The need for attack line pressures was the entire point of my submission to the safety office. I see were are you are getting 250# from? With a hundred PSI nozzle the stand pipe pack needs 150 PSI, the standpipe needs 25, add seventy five for the fifteen floors above the inlet which brings you to 250 PSI at the inlet. That's why we changed to the fixed gallonage 150 GPM 50 PSI nozzle. That way the pack only needs 100 PSI to give you the 150 GPM. Also if the pressure is inadequate it will be obvious when you test the nozzle for pressure and pattern before you make entry. One of the concerns I had was that an automatic nozzle would make any flow over fifty GPM look good. With the fixed gallonage nozzle you know if the flow is inadequate. I didn't want the lads and lasses duck walking into a concrete oven with only a good looking fifty gallon per minute stream for protection. That still leaves me with the problem that a lot of our LDH is relay & supply hose with an annual test pressure fifteen pounds less then that needed pressure. If we really want to be ready for "the big one" we would have to use 100 GPM nozzles for the initial attack line to match the old law requirement for 65 PSI at the top of the standpipe riser. The problem with that is that we would then need 2&1/2 inch standpipe packs for our back up lines and you can't deploy that kind of stream with two person hose teams. Heaven forbid that one of the nations ten most wealthy counties should have to pay to have four or even five firefighters on the engine. Why that might mean that we cannot put video monitors in the bus stops to tell those who cannot read a schedule when the next buss will be there. Don't get me started. Hell this county doesn't even have a policy on what is the annual test pressure for attack rated hose. Most of the fire departments that I'm familiar with test at 300# thus providing a fifty pound margin over a 250 # operational limit. But I know that several of the companies here test only to 250#.
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Permalink Reply by Thomas Horne on May 14, 2008 at 12:04pm

And when a civilian in a minivan takes out your "one line" do you still have all you need?
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Permalink Reply by Mark Lee on May 14, 2008 at 1:28pm

With low rise structures, you are correct; the pressure may not be such an issue. Just remember that 185 psi is the max working pressure for 5" supply hose.
And as stated many times, do we want to rely on one line, or maybe the twin 3's could provide a back up.
Another issue that we have had come up recently is now people are stealing the 5" storz caps for the scrap aluminum value. Ever seen how big of an item you can throw away in a 5" storz FDC?
This is going to be another issue...

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Permalink Reply by Stan Mettinger Jr. on May 14, 2008 at 2:24pm

We are using 5" Neidner Supply line. It has a higher factory test pressure and therefore a higher working pressure, although exceeding 185 PSI would not be an issue in buildings 4 stories and under.

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Permalink Reply by Greg cousler on August 23, 2008 at 10:25pm

I would like to understand more about your 50psi safety margin. We use 5" hose that has a service test pressure of 225psi. Opperating pressure is 10% less than test pressure. The burst pressure is twice that of the service test pressure. We have never tried 5" hose to supply a standpipe. However we do use it to supply one of our ladder trucks that does not have it's own pump. We have always been comfortable with the " opperating pressure". Perhaps we are missing something. With regard to the weight we always connect 5" hose to the hose testing machine with a short section of 3" hose to avoid the weight hanging off the machine's outlets.

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Permalink Reply by Thomas Horne on August 24, 2008 at 9:24am

The only test pressure that matters after the first year in service is the annual test pressure. Once it has been service tested it should never be used at a pressure closer then fifty pounds below that test pressure. I noticed that someone said that ten percent was their safety margin. That seems awfully thin to me. Just closing a nozzle will run your pressure up higher then twenty to twenty five over the flowing pressure. I am a belt and suspenders kind of guy when it comes to safety of the crew. The job is dangerous enough without going that close to the annual test pressure. Keep in mind that the hose may get quite a beating just on one incident let alone on a years worth of incidents.
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Tom

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Permalink Reply by Bob Franklin on August 24, 2008 at 3:31pm

Hey Mark,
We ran into this problem with using 5 LDH to supply our aerials. Our 5 inch LDH was "supply" hose which has a burst pressure at 200 p.s.i. We found that there is a 5 inch "attack" hose that has burst pressure of 300 p.s.i. We have purchased some 5 attack hose and it appears to be working fine for our application.

Take care,
Bob Franklin

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