Fire Sprinkler Pipe Corrosion

[TECMSC]

We've had several pin hole leaks develope in a dry pipe system. Unfortunetly, there are several uneven spots where we needed to add drip legs to get the standing water out. A failure analysis was performed and the result: failures were the result of MIC mostly at the seam welds in the piping. I've been tasked with finding a solution to slow down or stop the corrosion.

I've come across one item at par-guard.com and was wondering if anyone has heard of it and can comment or has other solutions.

Essentially, they take their foam product and mix it with a patented chemical(enviro. safe and citrus base) and inject into the fire sprinkler system. The chemically infused foam dissolves the "metallic type" corrosion and kills the MIC. Once the chemical process is complete the dissolved corrosion byproduct remains suspended in the foam. Next step is the pipes are flushed and foam is disposed of via 50 gal drums.

To inhibit the corrosion, another chemical(not sure if seperate treatment) creates an ionic bond coating the interior surface of the pipes. I believe the pipe/iron is positively charged and the chemical is negatively charged and results in a protective layer guarding against metal and MIC type corrosion.

One item that gives pause is that the Warranty section on the website is under construction! Additonally, I spoke to a rep the other day and still haven't heard back--potential customer service concern. Also, still need to investigate the maintenance costs and application.

additional thoughts or concerns welcome.
Thanks

 

[unclesyd]

Here is the WHI website and the press release concerning Par-Gard in 2001. Their guarantee is very simple.
I have not seen Par-Gard in use or talked to anyone who has, but have observed their test kits in operation. Their test kits worked as advertised with very few problems.

If it can really remediate an already infested sprinkler piping system as described they certainly have an equal to sliced bread. I would talk to WHI and see if you they will give you a reference to a user, not a new user, preferably one with a onsite metallurgical/analytical group.

http://www.mic-testing.com/press-releases.htm

As far as I'm concerned successful solutions to an established MIC problem of this nature are few and far between. Once they build the condominiums they are very hard to evict.

 

[TECMSC]

I had missed the WHI website and this guarantee. The guarantee is for the test kit only and not on the MIC abatement. The test kit might save a few bucks over hiring a consultant to tell us we have a MIC problem at other sites. Good to hear it works.

I had requested a reference and video about 10 days ago and have not heard back. Maybe he forgot about me and got a little busy, but I will try again to find a "user". I got the impression from the wesite they would also like to sell sprinkler pipe with the "special" coating...hmmm.

From what I've read the solution is to stop hydrostatically testing the sprinkler systems as often as current codes require, thus no more food/oxygen for the established colonists to eat and they die off. This solution dosen't appear likely.

I'll post if I come across something interesting or a revolutionary solution! Thanks for your reply.

 

[chicopee]

Is the piping steel or copper? from what is suggested it seems to be copper. Also when was the sprinkler system installed and what were the specs on the metal.

 

[TECMSC]

The existing piping is SCH 10 galvanized. I believe there was a cost trade off in substituting SCH 10 galv for SCH 40 during the original construction. Installation has been in use about 5-6 years.

I did notice the copper pipe from WHI. I believe they call it Eddy Guard. The "Eddy Guard", from what I've read is a "Dynamic Biostatic" coating. It is a somewhat water soluable coating that is equally concentrated throughout the system via "ionic-diffusion" The coating can be measured in the sprinkler system water. when the concentration becomes low, a maintenance canister can be added to boost the level. Usually increased once a year. (paraphrased from a couple of different articles...sounds believeable but maybe a little too much like sliced bread!, or maybe the application is so new it hasn't caught on...I don't know, which is why I'm bring it up )
TC

 

[chicopee]

My Kent engineering handbook does not show schedule 10 pipe thicknesses for nominal pipe size fom 3/4" to 3" normally used for sprinkler branch and trunk lines hydraulically calculated but that does not mean that they do not exist. Obviously replacement of leaking pipes is in order, then correct any non leaking but sagging segment. Since pitting from zinc depletion seems to be the problem due to standing water in sagging segemnt during annual or biennual trip tests think about cathodic production of the entire system. Water supply could be corrosive.
Also do some research on pipe specs. to see if you have compliance on steel quality. Junk steel from overseas from such places as CHINA and JAPAN have been problematic in many applications. Buy USA.

 

[TECMSC]

From my research Sch 80 would have been typically installed 50-60 years ago and lighter schedule 40 has been used since around the 1970's. Over the past 20 years sch 40 has oftern been replaced with sch 10.

I should mention the system in question is a dry pipe type. Apparently, the water left behind after testing produces a moisture and oxygen saturated environment that is more aggressive against steel pipe than a completly water filled system! Our report indicated that an incomplete zinc coating actually increased the rate of corrosion as well. I have a few inquiries out regarding cathodic protection for above ground sprinkler pipe.

Thanks for reminding me about steel quality. Procuring good quality steel from a known and reliable source will be considered. One note:according to my research,
once MIC starts in a clamped joint system it is nearly impossible to correct.
Thanks

 

[chicopee]

For cathodic protection, Natural Gas Co's use impressed current; DOT's use sacrificial zinc bars for H piles driven into corrosive soils; Propane UST's will also be protected with sacrificial zin bars.

 

[0707]

For pipe sprinklers materials comparison.go to

http://fire.nist.gov/bfrlpubs/fire94/art022.html

 

[TECMSC]

FYI...heard back from a cathodic protection firm...You cannot apply cathodic protection within an above grade pipe. Geometry and cost work against you.
I'm getting some interesting info on chemical cleaning and protection and will post once it is put together.

Thanks to all for your replys, I have used the info in one way or another!

 

[chicopee]

TECMSC-The firm that you spoke of has not been in contact with hot water tank manufacturers and distributors who will supply sacrificial anodes that are inserted into the tanks during installation. I would think that similar method of arrangement would work (although unusual)pn your dry sprinkler system. Of course it is preferred to find the cause of pitting because your situation is unusual. Check your water quality and also determine if there is stray current that could cause your problem. Obviously remedy the sagging pipe problem.