Sprinklers Before- or After- Gluing CPVC Drops?

5/10/2023

When should sprinklers be installed on CPVC systems, before or after the drop is "glued" in place?

NFPA 13, 2016 Edition, Section 8.3.1.4 "Where solvent cement is used as the pipe and fittings bonding agent, sprinklers shall not be installed in the fittings prior to the fittings being cemented in place."

From my time in the trade; about 13 years I have always seen fitters "prepping" their CPVC sprinkler drops by "gluing" the sprinkler adapter on, then tightening the sprinkler into the adapter, and then sitting the drop vertically in a bucket with the sprinkler on the top.

They say that way if any glue runs down from the joint it just goes into the drop and not down in to the sprinkler itself.

That is easy enough, but what about the Tee or Elbow that the drop is going to be glued in place into?

Personally the way I did jobs while I was a foreman is we would pre make the drops, cut in a 1/2 to a whole floor and then run back through and install the sprinklers into the drops.

Personally I liked that because I only had the sprinklers on the job the day they were getting installed, no worries about getting stolen or damaged from being on site, and then no worry about glue getting into the sprinkler at all. Plus when we went around just putting sprinklers in it was extremely fast and no hold back wrench required. And it was literally just taking that process of removing the sprinkler from the box and tightening it in to a fitting and shifting it to a different day.

Plus I have personally pulled sprinklers out of CPVC systems where the head/button was filled solid with glue.

The way I read Section 8.3.1.4, I take it as all the fittings, not just the particular fitting that the head is installed in to.

But I definitely can see how it could be interpreted as only the fitting the head is installed in.

How do you other code followers see it?

Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe

5 Comments

Greg

5/10/2023 08:26:58 am

Pre-gluing drops with sprinklers installed is a bad practice due to the potential for glue clogging the sprinkler orifice and contraindicated by the manufacturer’s installation manual. If our AHJ catches this happening, drops are required to be cut out and replaced, possibly with a witnessed internal drop inspection prior to sprinkler installation.

JP link

5/10/2023 09:15:31 am

Attention to detail when gluing and installing sprinklers in a CPVC system is critical.

We did an inspection of a CPVC sprinkler system after a sprinkler failed and substantial water damage occurred. The drops were prepped in a shop then brought to the site to be installed. The drops were prepped by gluing and then standing the drops up to cure. This helped to keep glue out of the sprinkler orifice, but we noticed that where extra glue was applied, the glue would drip down the pipe away from the sprinkler head leaving a solid glue drip along the inside of the pipe. If this extra glue inside the pipe became lose, it could obstruct the orifice.

Additionally, after looking closely, we noticed cracks along the glue drip inside the pipe that could have led to the sprinkler failing. We inspected every other sprinkler in the building and noted similar glue drips and multiple other corroded sprinkler heads. We are still investigating, but at this time, we are led to believe that extra glue/cement in the inside of the pipes could increase the potential for failure in the system.

Dan Wilder

5/10/2023 09:56:41 am

The RC's upside down is only one part of the process as you indicate, the upper Tee or Ell and the potential interior glue lines running down. The glue runs also weakens the CPVC pipe walls and have replaced piping with visible exterior degradation.

Many of our local jurisdictions require that no sprinklers be installed until after both a visual and a hydro's have been completed. We test against the removable test plugs that allow the drywall to get installed and replace afterwards and just carry several bags of O-Rings to change out as needed.

Pete H

5/10/2023 11:24:40 am

It's supposed to be after.

Doing it before can cause the glue to damage the drop/pipe/orifice.

That won't stop people from doing it in the field. If not in your respective company, in every other one that is looking to cut labor costs by accepting however the fitter makes "fast" happen in a way that will pass inspection and review.

Which contributes to the thread from I believe last week where CPVC corroded before the 50 years it's supposed to last for and that happening being uncomfortably common.

Chris

5/10/2023 12:05:33 pm

I 100% agree that heads should basically be the last thing installed. Spears Flamegaurd installation book says…
“ Install sprinkler heads only after all the CPVC pipe and fittings, including the sprinkler head adapters, are solvent welded and allowed to cure for a minimum of 30 minutes.
• Do not install sprinklers in the fittings prior to the fittings being cemented in place.”

And I believe Blazemaster says essentially the same thing.

So to me it’s pretty clear-cut.

Sprinklers Before- or After- Gluing CPVC Drops?

Leave a Reply.

ALL-ACCESS

SUBSCRIBE

COMMUNITY

YOUR POST

PE EXAM

FILTERS

ARCHIVES

PE PREP SERIES