Plumbing Contractor 633601 S.F. Valley 91605

I don't understand why you need a dye if you have an acoustic leak detector.

I'm not sure I'd foul a water line with dye, but this is not my field.

No you see not with water you can use a dye with air under P.S.I pump the line over 15 P.S.I. it will spit the dye out on the walls it will not damage the pipe.

the building is 4 story tall 12 units and a 2" line for the waterheater only

the building is $ 5.5 Mil,

This isn't about the dye damaging the pipe; but about the dye contaminating a potable water supply (if that is what the pipe actually is.) If it is a heating loop or the like, that may not be a problem.

It's a gas line

Testing for gas leaks isn't something you ask on an internet site about. You should be asking a qualified gas engineer.

I just hope you've got good public liability insurance.

I found a mention on the use of crack detecting dyes for leak detection when I conducted a search. Regular crack detecting dye on the inside and apparently it weeps out and is visible externally where there are leaks. No squirting onto walls....

I'm not sure how you would introduce this uniformly into the pipe and coat its inside totally to check its entire length.

Did your pressure test indicate a leak or is this a speculative endeavor?

Is the pipe embedded or surface mounted/hung?

Water is a very effective leak detector too...

Try a fluid that you can see with a UV lamp

Easy way is just pressurize it with air or inert gas and use an UltraSonic detector to find the leaks. Companies such as UE and SDT make great units and you should be able to find a UltraSound Technician to come in and do the testing. Very quick and efficient. 15 PSI would be sufficient but you can go higher to same pressure as the water will be under. Check the phone book under None Destructive Testing or internet the above mentioned suppliers.

Yes that would be but, in a 4 story building and the pipes are ran up in a chase

with dry wall on all of the walls a acoustic can find the leak but you have to run up from story to story. it would be faster with the dye....

by having the dye it will mark the outside of the pipe.

I know they make a dye that you can put in cars to test for leaks. Here is a link to one that works with engine oil, transmission, hydraulic, power steering, gasoline, and diesel fuel systems. The same company also sells products for testing radiators and the cooling system.

http://www.uview.com/ProductDetail.php?PartNumber=483210

You can use food grade food coloring which is commercially available almost anywhere. Check with your local cake bakery for the place where they buy theirs. Red and blue collored dye is the best for showing up, and is very easy to flush out of the pipe works.

When I was a City Engineer some years back we had a huge water main leak during a severe winter cold spell. This break was isolated in a mid-1850's era industrial/mill area and some of the water mains were that old and crossed 2 major creeks. I approach the NYS Health Dept. about their approval of using a food coloring dye in lieu of commercially available dyes (water industry standard dyes) that would have taken 2 weeks to receive. We couldn't wait that long as we were loosing about 6 MGD because of this leak. We pumped a very concentrated solution of the dye into the isolated main via a fire hydrant and put into the creeks a Police diver. We found that the 14-inch CIP water main had cracked longitudinally and was leaking into an very old stone storm sewer that emptied into one of the creeks. This storm sewer was not recorded on any of the city's as-built maps and no one in the city water, sewer dept. an my dept. knew of it's existence!

Try it....it works great and there's no chance of contamination!!!

Good luck with your project!

Putting water in a gas line in LA county, is certain to fail you your inspection if the inspector finds out. Your local building codes must be adhered to. Domestic gas is tested at 30 psi for 2 hours IIRC, but multiunit buildings might have more stringent requirements. But before you buy dye, or freon (though that is a good leak test), just pump it up to 30 psi or so of dry air, nitrogen, or CO2 with all the block valves to the branches closed. Squirt Snoop on every threaded joint and weld. The smallest leaks might take a minute or so to foam up, but they become obvious then. You will probably have to expose the entire pipe chase all the way up to permit inspection anyway. Where the fun starts is fixing the leak, which in gas screw pipe means backing out all the branches until you can turn the offending screw joint or faulty fitting. It's much easier if the leak is in a welded line, but one failed weld makes all the rest suspect. If your current plumbing contractor can't handle it, look up ua250.com, and one of the agents will hook you up.