Having personally built a number of "Pig Launchers" for PPG latex paint in cheswold DE. In the 70's I can tell you that this is a labor intensive activity, and not to be used except as a last resort. In these paint plants the pigs were launched using HP compressed air, but you could use water. The pigs were generally bullet shaped soft sponge with a plastic seat on the compressed air end only .01" smaller than the ID of the pipe. The problem is that even in these S.S. lines with full port BV the pigs occasionally became stuck. The solution is to first backpressure the pig, and when that didn't dislodge it you had to located the stoppage, and cut out that pipe section to clear the pig.
Now you're talking about doing this to underground! A PIG is hopefully a moveable obstruction and depending on your smallest interior pipe dia. Only able to remove large blockages not scale, tuberculosis or other pipe corrosion issues. Any corrosion will tend to jam a pig. Moving water at a reasonable rate has been the practice for a long time to flush underground. Yes all of us have seen some weird stuff come out of that underground during flushing. And have found weird stuff in BFP and riser checks during inspections. But that is usually from failure to flush at all, not from flushing at 8Fps or available flow. The bigger question I have before wanting to make big changes to 24 is, what is the system failure rate that would justify additional expense? What is the current failure rate? How many fires have gone unchecked because of stuff from the underground plugging heads valves or branch lines. Too often we in the industry think in absolutes. ALL, SHALL, EVERY but the insurance industry will tell you there are no absolutes! We will never be perfect, our systems will never always work. And while it is cost effective to get to 95% effective, to try and reach 96% could cost more than it did to reach 95%. Affordable effective protection is what we're after. We can save more lives and property by spreading the existing protection available to 95% of the population, than we can by improving the protection we give that small part we call our customers. Thom McMahon, SET Firetech, Inc. 2560 Copper Ridge Dr P.O. Box 882136 Steamboat Springs, CO 80488 Tel: 970-879-7952 Fax: 970-879-7926 Subject: Re: Underground flushing velocities Scott, >From Wikipedia. Pigging can just be a single shot thing also. You just drag the pig through a pipe not in use, then flush it. Pigging >From Wikipedia, the free encyclopedia _______________________________________________ Sprinklerforum mailing list Sprinklerforum@firesprinkler.org http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: supp...@firesprinkler.org To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org (Put the word unsubscribe in the subject field)
