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Dry pipe systems

RJJ

RJJ

Co-Founder
Joined
Oct 17, 2009
Messages
2,940
Location
about 1' east of the white water
When do you all call for an excelerator and do you allow a margin of time over that called for in the code? Starting to see a number of systems fail the inspectors test both new and old. The older ones are somewhat way out and should have had one from the beginning.
 
I wouldn't allow any margin on a new system. If it is failing when you perform the test (even by a small amount) it certainly is not going to pass when the water demand is at it's highest (eg at 5am when everybody has their lawn sprinklers on). Existing systems would be case-by-case. Our water authority will furnish the historic low pressure. It only makes sense that demand will increase over time and effect the performance of the fire sprinkler. Add pump stations being turned on/off and it gets gray real quick.
 
When the system size in nfpa 13 requires it.

note to self : not all dry pipes require one
 
I agree then when it is called for then install. If you test a system and it fails by a small margin, you should estimate that after the corrosion builds in the pipe over a couple of years it will get worse.
 
based upon NFPA 13 (2002) Section 7.2.3

less than 500 gallon capacity - no requirements for either a quick opening device or need to meet 60 seconds

500 to 750 gallon capacity - either meet the 60 seconds or provide a quick opening device.

Over 750 gallon capacity - must meet the 60 second requirement. Provide a quick opening device if needed.

Or, you can utilize the calculation method in Section 11.2.3.9
 
Rjj,



Got bumped off a couple of times while researching a historical project similar to the discussion for what we had to accept. I agree with CougDad and the key is the calculation procedure as he references in the 02 standard 11.2.3.9. The 07 edition has cleared it up a bit by:



7.2.3.4 A system size of not more than 750 gal (2839 L) shall be permitted with a quick opening device and shall not be required to meet any specific water delivery requirement to the inspection test connection.



A hydraulic trip analysis and calculation procedure can be done by the designer and if it shows water can reach the test connection in the specified time threshold in the delivery time table it can be accepted by the jurisdiction. Sometimes air pressure adjustments are done so the delivery time can get close but when you have systems covering lengthy runs the delivery time can’t be met regardless, the standard accounts for that by allowing a hydraulic trip calculation/analysis to be done. I’ve reviewed two in my 26 years where necessary because they couldn’t get it dialed in without adding another remote riser. But the math worked and we had to document and accept it despite the field conditions. Glad they were both state jobs in Assisted Living Facilities and we just served as “response stakeholder” inspection guests. :(
 
I could tell you a good one about a large lumber retailer and a dry system...with an accelerator AND an exhauster...system > 750 gallons...fire pump...let's just say it's a good thing we have a 5" Storz as a FDC...
 
FM: I need to up grade to the 07! Just realized I am still on the 02. Interesting responses from all. I am aware of the sections. Just was looking for some feed back on the margins that may be ok with others. The trip analysis is ok, but I am a hands on and like to see it myself. The older systems seem to always fail and some as much as 4 1/2 minutes. Maybe I need to rephrase the question.

Do you test?

If on a 750 + system what would be considered a reasonable margin of over run?

65 sec or 70 sec? Or just a drop dead 60sec?
 
For existing systems we verify system testing by a licensed firm in accordance with NFPA 25. If the test report verifies something was wrong with the water delivery as mentioned, it could be a minor adjustment needed with the air pressure devices to get it dialed in or potential obstruction in need of investigation (in accordance with NFPA 25). If it doesn't pass or is documented as such and especially by times mentioned, the analysis/calculation is about the only thing a jurisdictional official can require…….IMHO

NFPA 25 as referenced by all codes (for existing systems) has specific testing, maintenance and corrective schedules for system components and once a QOD, air pressure devices, valves, obstructions etc. are addressed in accordance with NFPA 25 the only way to solve the delivery issue is with another control valve down stream and very doubtful that retrofit would be applicable on an existing system.

I don’t know of any jurisdictional colleagues that were able to get an additional riser/control valve to really solve what may be the real issue that was created by area growth etc. Maybe InsEng will jump in with some additional guidance......since I could be off base?

On a sadder note, I just watched an umpire (who probably won’t make it out of Detroit) make the worst call I ever saw. The Tigers pitcher Galaragga had a perfect game and made the tag for the last out but the umpire called the Indians runner safe at first. Slow motion showed he made the tag by a step and the runner was out. That’s a real crime.
 
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an other dry pipe question,,

Do you all but a level on the pipe to see if it has correct slope??????????

on the umpire question :::::: why was that not replay reviewable????????????????
 
I do use a torpedo level to make sure there is at least some slope for drainage. I have seen dry systems that froze and broke apart. Not a pretty sight.
 
Lets see if the building was in NJ the NJ IBC says 1 minute to the inspectors test regardless of the size of the system. Been that way for about 15 + years. Tyco did full scale testing in warehouse freezer applications for the Quell system about 2-3 years ago. They found if the water did not get to the hydralic remote design area in 30 seconds the fire was not controlled. Four minutes to the inspectors test, from an insurance point of view I would tell underwriting figure it as a non-sprinklered building!

As a result of the Tyco testing they stopped making exhauster's. By the way the Tyco owns Star the only mfg of exhauster's. So this will be a problem as those old Star exhauster's need parts. Tyco has just introduced a new electronic accelerator Vizor you can add to your Tyco, Gem, Star and Central valves.

Does that help???
 
Cda,

I use a level and regarding IR last night.....only runs can be reviewed (for now) after last night and some other blown calls the Comish is considering talkes on expanding replay. The Tigers handled it with class and we welcomed the ump "Joyce" with minimal boos today as he was behind the plate. Will have to catch sportscenter to see how he did today or watch the recap later on FSD.
 
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