Running Plastic Sprinkler Pipes: What You Need to Know

We have blogged about running plastic sprinkler pipes in the past but it’s so easy to get it wrong, that it warrants more information. As always, we have a story for you, but before we get to the story however please know that despite the fact that we are mentioning two manufacturers in the story, we are NOT saying one is better than the other or showing favorites in any way. These are just the facts of the story as it played out in the field for us and could for you as well.

I was doing special inspection on a wood framed project where the installer was using STI’s WF300. We find this material excellent for wood-framed projects. It offers cost-effectiveness and versatility in wood-framed construction. We had our submittals showing the listed details for each application they were using in the field. Towards the end of the project the contractor had the laborers make a supply run to finish up the final touches on the firestop. This is where our problem began.

After being in the industry for 20 years, a slight change in that iron oxide red causes one to take a closer look. The rated assembly included the plastic sprinkler pipes, which the team firestopped like the other penetrations. However, they used a slightly different material. Just barely enough to warrant a closer look, but just enough to see clearly, they used something different. Further discussion made the problem clear and rather serious.

Allow me to change gears for a moment and then we will bring these two discussions full circle.

Lubrizol developed CPVC pipes such as Flowguard, BlazeMaster, Corzan, and TempRite. Keep these two great websites handy if you work with plastic sprinkler pipes or CPVC.

This first one lists materials that have been tested and found to be compatible with these types of plastics. 

This next one lists materials that are found to be incompatible. There are a handful of firestop products on this list. One of them is 3M’s CP25WB. Again, this is not a bad product, it is just not the appropriate material in this scenario and there are plenty of other materials on the list, so 3M is not alone. The problem is that the chemical compatibility can cause splits or holes in the plastic pipes. If the sprinkler pipes don’t leak before the sprinklers are needed, the pressure change during activation will test the system. Small holes in the pipes could reduce water pressure and prevent the sprinklers from performing as intended.

Here is another blog post on this topic in case you would like additional information.

This news article is just one of several that touch on the topic of compatibility issues.

So now that you have a little more background let’s get back to the story we started, back to our jobsite. The contractor sent a laborer to a local shop to pick up the firestop material needed to complete the job. Certainly, on the shelf there was CP25WB and IC15WB. CP is red and IC is yellow.  They knew that if they showed up on site installing yellow firestop that the inspector (aka me) would ask them for new firestop submittals for this new and different material, so they went with what seemed like the easy route.

During our inspection, we noticed a color difference. When we asked the installers, they brought the tube of the material they had used.  They used CP on the CPVC pipes, which creates a problem, as shown in the links we shared. Now, the materials have made contact, and the compatibility issue persists. You can’t simply remove the sealant and replace it with the correct red or yellow material. You have to replace that section of pipe. If you don’t believe me, check with the various manufacturers or even your own corporate legal or risk management team. 

We’re unsure of the contractor’s decision, but after informing them about the issue and its potential severity, we hope they will make the right choice.