Steve, Some other factors that I have noticed in these types of investigations:
1. Being from Florida, is it possible that salt spray can get blown or vented into the area and onto the pipes? We have had several cases from Hawaii where salt spray in parking garages is a factor. 2. Are there any vents that discharge moisture laden air into the area where the 90's and branches are and causes water to condense on the cooler pipes? Broken vent ducts? Any water lines or HVAC systems above the sprinklers that can drip on the fittings? 3. Have you verified that there is not an electrical or grounding issue? Something from the door lock mechanism? We often will take a volt meter and measure across the fittings, between adjacent branch lines and to other grounded metal components like a building frame or other pipes. Is it possible that there is a cathodic protection system in the jail for rebar, gas lines, water lines, piling or other buried metal items? How about large amounts of copper pipe in contact with parts of the sprinkler system? 4. I assume that the corrosion is remote from the foam around the drop so you can rule out chemical/contact issues with the particular chemistry of the foam. Because you are talking about rusting from the outside in, I would look at factors that cause water to condense on the outside of the pipe. Even if the pipes were threaded too deep or not inserted far enough into the fittings, I would expect to see the weeping cause corrosion at the joint area with the failure at the threaded area..... and the fitting fairly intact. Last and importantly, is it possible that the water chemistry or some other factor is causing pinholes selectively in the /Chinese/ fittings such as they appear to "ooze" water out the fitting? If there are enough fittings (meaning dozens or hundreds not one or two), have you considered brushing one of them off in place so that you have clean metal with the system still pressurized? You might be able to see a pin hole or rust spot that gets wet after cleaning. It can be difficult to prove that it is only the fittings that are causing the problems. What we normally would do in a situation such as this is to ask for (many) samples of the good and bad fittings/connections. Some we X-ray to look for thinness, porosity and proper thread depths and insertion. Others may be sectioned for internal analysis, visual observation, dimensional analysis of threads and chemical analysis. You have already done the water chemistry. There may be multiple factors that are causing the leaking. Michael -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Steve Kowkabany Sent: Friday, July 10, 2009 2:51 PM To: [email protected] Subject: RE: Corrosion Issues at Jail (Greg) The concrete is not touching the drops that I can tell. There is a small gap all the way around each drop through the concrete attic floor that is filled with spray in foam. (Todd) I'm not sure yet if the fittings are made in all the way yet as we haven't disassembled anything yet, and I think the drops are threadable thinwall - but then again so is the rest of the small bore piping that isn't having any trouble. It's just odd. Steve Kowkabany, P.E. Fire Protection Engineer Neptune Fire Protection Engineering LLC 616 Davis Street Neptune Beach, FL 32266 904-652-4200 Phone 904-212-0868 Fax -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Greg McGahan Sent: Friday, July 10, 2009 5:19 PM To: [email protected] Subject: RE: Corrosion Issues at Jail Is the concrete touching the drops or fitting? Threads an inch above the fitting? wow Greg McGahan Operations Manager Living Water Fire Protection 1160 McKenzie Road P.O. Box 877 Cantonment, Florida 32533 (850) 937.1850 | Fax (850) 937.1852 | Cell (850) 554.3231 [email protected] -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Steve Kowkabany Sent: Friday, July 10, 2009 3:52 PM To: [email protected] Subject: Corrosion Issues at Jail I'm trying to get my arms around a really interesting problem at a local jail where a 7 year old sprinkler system is failing at a variety of spots due to corrosion. I looked at the system this morning and here's what I found: 1) The failures are happening at 1" 90's and tee's where a drop goes down into a cell or the concrete ceiling of a common area below 2) The exterior of the fitting and the drop look horrible and are rusting off in piles of rust which are sitting at the base of the drop 3) The fittings are Chinese and the pipe is threadable thinwall - I think this might be part of the problem 4) The threads seems to extend too far outside of the fittings - over an inch in some spots 5) The water has been tested and apparently there is no MIC in the water but the water is mineral laden and fairly aggressive in this area 6) Most of the system looks perfectly fine with some light surface rust like normal - it's just maybe one in 20 drops with the corrosion issue I want to get the metallurgy of the Chinese fittings tested and a couple of the corroded pipe sections removed and tested to see what is going on. Does that scenario sound familiar to anyone. Any suggestions on labs to use for getting the pipe and water tested? This type of forensic analysis is pretty new to me. Thanks very much in advance, Steve Kowkabany, P.E. Fire Protection Engineer Neptune Fire Protection Engineering LLC 616 Davis Street Neptune Beach, FL 32266 904-652-4200 Phone 904-212-0868 Fax _______________________________________________ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field) Checked by AVG - www.avg.com Version: 8.5.387 / Virus Database: 270.13.8/2227 - Release Date: 07/10/09 07:05:00 _______________________________________________ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field) __________ Information from ESET Smart Security, version of virus signature database 4232 (20090710) __________ The message was checked by ESET Smart Security. http://www.eset.com __________ Information from ESET Smart Security, version of virus signature database 4232 (20090710) __________ The message was checked by ESET Smart Security. http://www.eset.com __________ Information from ESET Smart Security, version of virus signature database 4234 (20090711) __________ The message was checked by ESET Smart Security. http://www.eset.com _______________________________________________ Sprinklerforum mailing list http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
