Sprinkler Systems: 5 Year Internal Assessment

Posted by ORR Protection on Jul 29, 2020 5:37:30 PM

During the 2020 MCFP Virtual Conference, expert Matt McTyre talked through some of the most common misconceptions and questions people have around 5 year internal assessments for fire protection systems. In the video below, watch as Matt discusses  what a 5 year assessment is and what it isn't.


Video Transcript:

We are going to be discussing five-year internal assessments today. Hopefully we can clear up a few misconceptions about what it is and what it isn't. There is some confusion on what exactly is required in this assessment. We're going to discuss what gets inspected.

5 year assessment vs obstruction investigation

Is it different than an obstruction investigation? It absolutely is. There are two separate investigations. Methods of investigation; we're going to limit our discussion to the types of systems that are primarily in the sprinkler. We're not going to discuss yard mains and supplies to that degree. It's going to be wet systems, and dry pre action. Sorry we are missing yard mains, NFPA 25. Internal assessment is the minimum requirement for determining internal corrosion or blockage of the fire sprinkler system.

These occur at a five year minimum period, however, it can happen more than once within a five year period. It does not have to be set at five years. If you're doing upgrades to the system or anything like that, this can actually be your five-year assessment if the right steps are taken. So if you are having upgrades done to your system, make sure to talk to your fire sprinkler professional about taking care of the five-year assessment and make sure you document it and take pictures. The four locations that are typically done on an assessment are the system main valve, the riser itself from the top, looking down across main and branch line.

Typically on a wet system, you need to find the highest point where the air is trapped in the system to do these assessments, dry system and prediction are opposite. You go to the most remote area or the low points of the system. That's typically where the most corrosion blockage items take place and in those areas, wet systems aren't as prone for corrosion, except in the areas where the air pockets. Those do tend to collect at the high points of the wet system.

If any of these four locations show signs of any potential obstruction, a full obstruction investigation is warranted, and there are specific guidelines on exactly what an obstruction investigation is. That is part of an appendix to NFPA 25. It's actually out outside the scope of NFPA 25 and the obstruction investigation. They give guidelines and they give direction, but it is outside the scope of NFPA 25.

Fairly recently, NFPA 25 has given way to alternative nondestructive examination methods of the systems. So it's no longer just opening valves, taking off face plates, and taking pictures. There are more ways to do it now.

Bore Scoping

Bore scoping is now an approved way to do your investigation on the system. I think the bore scoping  technology is getting better every day and it is actually a less obtrusive way of examining the piping and you get a lot more information. I'm not necessarily pushing bore scoping, I'm limiting this to purely code, but bore scoping gives you a wide view of what's going on in your system and not just four points of the system.

Ultrasonic Testing

Ultrasonic testing is also being accepted, but typically that is being used to find out the width of piping that is remaining due to corrosion and not necessarily to find things that an obstruction investigation would find like gloves and organic matter. An ultrasonic for the most part should be more for corrosion situations and not just internal investigator.

Freezer Testing

This is a little off topic for most of our customers, but any freezer or cooler systems that are kept at 32 degrees or less has to be inspected on an annual basis. So you should have a way to examine and investigate for ice plugs in the entrance into the freezer or cooler itself on an annual basis.

Intake Testing

Other things that can trigger an obstruction investigation is if a fire pump intake is defective, especially if the fire pump is from a raw water source, like a pond, river or lake. If there's anything wrong with that intake system that automatically warrants an investigation of the system itself.

If there's any discharge of obstructive material like rocks, welding discs or anything like that when you're doing water testing or drains, that's an automatic red flag. We need to take a look and see if we have any obstructions in the system for other things, materials in the fire pump, materials in the water during  drain tests. Anything like that could warrant an obstruction investigation.

If you have any kind of work going on upgrades or otherwise, and you have inorganic organic material of any sort to any degree, that should be a flag too. Time to do an investigation, a full investigation of our system to see exactly where we are. I think it's overlooked if there's a new yard main put in, or if the local water supply is doing work on a system. Typically they're not always as clean and efficient as they should be. I've had several instances where new water mains are put in and I've pulled 50, 60, 70 pounds of rocks out of a system just from extra water pressure coming in, slowly getting past the clapper. You've got rocks piled up 12 feet in your sprinkler riser.

If you know roadwork is going on near your building, make sure that you have a sprinkler professional come in and at least do the minimum of the assessment. If there's no problems, it should be a quick, easy fix. It is definitely something you should keep on your radar. Any raw water supplied by FTC, from a boating area or a Marina, anything like that, if you've had any kind of situation where that's occurred, which may be rare in some of your circuit CIR circumstances, would warrant an immediate investigation to make sure there aren't any fish swimming around in your system that could potentially clog your sprinkler system.

Drain Testing

Another one, when you're doing your annual inspector's test drain, certify the system, with the test. Mark how long it takes for the water to get to the edge of the inspector's test. This should be documented and used for you all new installations. So when you do your annual test, compare those times, and if they're 50% higher, you know you have an issue with an inside diameter and C factor of your pipe. And C factors, are from friction from inside objects that are causing an obstruction.

Microbial Corrosion (MIC)

There's a lot of information out there. People confuse general corrosion with Microbial Corrosion (MIC) MIC is always discussed with five-year investigations and, you know, MIC does exist, but it is a lot rarer than people want to let on because at the beginning, everyone thought that all corrosion was MIC. We've learned through science and testing that it's actually a very small part of the problems in our sprinkler systems. So it's still there, but it is not as big an issue as we were led to believe. However, during annual testing, or if you're doing a drain test, anything like that, if any slime or a tuber cools come out of your system, they should be immediately gathered and sent off for testing. There are multiple companies out there that test these and should be done anytime that comes up during a water test and the slime should be sent off immediately.

Typically normal corrosion due to water and oxygen contact is what is causing most of the problems inside of these piping systems. Nitrogen and and ways to avoid that are discussions for another day. But that is the way that the market is going, limit the water/oxygen contact. And the best way to determine if you do have a problem is through the five year assessment. Again, annex D is part of NFPA 25, but is outside the scope. It gives a very detailed list of things to go through for a true internal assessment. It is not NFPA 25 scope. So again, it is a very detailed  step-by-step on what to do, but it is outside the scope of NFPA 25.

Just going to go over the things we've already discussed; obstruction discussed in annex D or pipe scale, all types of scale from galvanized pipe, careless installation gloves in the system, disk left from welding, those sorts of things. Raw water sources and biological growth all will trigger the annex D full investigation of your piping system.

This is a picture of a typical MIC pipe. You can tell that it's a little different than your normal corrosion, and we are actually learning some of these MIC items actually do not eat pipe. They're just there. They can cause the pipe, the water inside the pipe, to slow down, so it can affect your sprinkler system. But thankfully it's not eating the metal as quickly as we thought it was. It's just a nuisance more so than destructive for the most part.

Destructive Organism Corrosion

A destructive organism corrosion is a little different. You can see it's eating away the rust on the outside. You can see the actual wall of the pipe getting thinner and thinner and thinner. And this is a good example of when to use Sonic testing. Sonic testing can be done without shutting down the system without even getting inside the system. It's an outside scanning process, and you can see what you need to see without getting inside your sprinkler system. Especially if it's in a data center, something of that nature, it's a very unobtrusive way to get the information you need.

This is more of what you would see in obstruction case. If you come and you open up a riser and you see mud like that, possibly a glove there, and no telling what that orange thing is. That might be your trigger to say, you know, let's open up a few more spots and and see what we have cause there's a good chance if you did have a fire, that that thick mud would clog your sprinkler heads.

That's pretty much all there is for the assessment. For a further detailed view of an obstruction investigation please look at annex D   or contact me at mmctyre@orrcorp.com. I'll be happy to discuss it with you. Thank you very much.

Topics: Inspection, Testing & Maintenance, Inspection Testing and Maintenance, Leaks and Corrosion, Featured Article, Featured Blog, MCFP

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