Friction Loss for Roll-Grooved Couplings?

9/12/2019

I had always thought that couplings didn't need to be calculated under NFPA 13, but I'm reviewing a set of calculations which show 1-foot of schedule 40 equivalent for each coupling. This is for a 4-inch main with roll-groove couplings. Any ideas?

Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe

4 Comments

Names.R.Hard

9/12/2019 10:46:44 am

Hmmmm, it looks like it was an old FM requirement from datasheet 2-8N, which seems to no longer be used. I couldn't find any record of it in the FM 2-0 or 3-0..

Looks in 2010 they updated their datasheets.
https://www.sfpe.org/page/2012_Q2_4

It might still be in a current datasheet somewhere, hopefully somebody who knows more can chime in

Max link

9/12/2019 11:49:50 am

Victaulic has a data sheet on roll grooved pipe.

Wayne Ammons

9/13/2019 09:38:09 am

This is no longer a requirement in FM Data Sheets. I spoke with Victaulic concerning their data sheet 26.08 for Roll Grooved Pipe, which references the now obsolete FMDS 2-8N, and was informed that their data sheet has not been updated to reflect this.

Section 2.5.3.4 Grooved Pipe Connections of FMDS 2-0 does not require a friction loss across the roll groove pipe connection like Section 2-5.3.1 of FMDS 2-8N.

Since section 27.2.4.8.1 (1) of NFPA 13, 2019 Edition requires friction loss to be calculated for "pipe, fittings, devices...", I wonder if it is the intent of the committee that the words "pipe" and "fittings" be inclusive of any friction losses created by the joining method?

Wayne Ammons

9/13/2019 11:05:29 am

I posed the question to NFSA's Expert of the Day and here is the response:

Question: Is it the intent of NFPA 13-2019 section 27.2.4.8.1(1) to require any friction losses in hydraulic calculations created by rolled grooves themselves and/or grooved couplings?

The answer to your question is, “No. Like flows through a tee on the run, while there is turbulence in flow, the friction loss is negligible and can be disregarded in the hydraulic calculations.”

If a product has a friction loss equivalent length significantly different than those shown in NFPA 13, it should be documented on the product’s data sheet and that value should be used in the calculations.

(copied with permission)

Leave a Reply.

Home - About - Blog - Forum - PE Exam - The Toolkit - MeyerFire University - Login - Pricing - Contact Us

MeyerFire.com is a startup community built to help fire protection professionals shine.
Our goal is to improve fire protection practices worldwide. We promote the industry by creating helpful tools and resources, and by bringing together industry professionals to share their expertise.

MeyerFire, LLC is an International Code Council Preferred Education Provider.
All text, images, and media Copyright © 2021 MeyerFire, LLC

The views, opinions, and information found on this site represent solely the author and do not represent the opinions of any other party, nor does the presented material assume responsibility for its use. Fire protection and life safety systems constitute a critical component for public health and safety and you should consult with a licensed professional for proper design and code adherence. Some (not all) outbound links on this website, such as Amazon links, are affiliate-based where we receive a small commission for orders placed elsewhere.

Friction Loss for Roll-Grooved Couplings?

Leave a Reply.

ALL-ACCESS

SUBSCRIBE

COMMUNITY

YOUR POST

PE EXAM

FILTERS

ARCHIVES

PE PREP SERIES