Length of Pipe that Can Fit in Open-Web Joists?

4/26/2019

The other day there was a good discussion on pipe that can run within the open-webbing of steel joists.

Is there a good rule of thumb or any references to determine how long a pipe can be to fit within the joists?

I'm wondering if there's some tool or resource that says for 16" joists that has 2" web spaced at 4 feet, I can use only a 10.5 foot pipe length. It may not exist, just curious if it does already in some fashion.

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

4 Comments

Wayne Ammons

4/26/2019 06:45:54 am

There is an old formula and diagram for this. I could not find a website that showed it and am not sure the best way to get it to you, so I have copied an excel file to Dropbox that has the formula and diagram:

https://www.dropbox.com/sh/p4pqnz3d0tmhy1m/AABXIR6uNnXlMzLTuu0zW8vJa?dl=0

steve bahr

4/26/2019 10:24:49 am

I will look around. I have charts that show all of this. Somewhere...

James Phifer

4/26/2019 10:36:10 am

I have used a formula in the past that was created by Ed Miller from AFSA back in 1992. It's a bit conservative but at least I know the pipe will fit.

A/6 multiplied by B
where A = depth of bar joist expressed in inches
B= distance between the bar joist expressed in feet

Example: 18" bar joist spaced 4 feet on center

18/6 = 3
3*4 = 12 feet. 12 ft is the longest length of pipe that will fit.

Bobby V

5/8/2019 04:52:53 am

When I was designing, the rule of thumb was to use 10’-6” pipe lengths for exposed construction installations. For a new system installation in an existing building with hard ceilings (or lay-in), I would use 6’-0” pipe lengths. However, always consult with your installing foreman, they are the experts.

Free Signup

Subscribe and learn something new each day:

Community

Thank You to Our Top
April 2020 Contributors!

1. Mike
2. Sean
3. Franck
4. Dan W.
5. Jonathan

6. Jesse
7. Wayne
8. Jonathan J
9. James
10. Thomas

Your Post

SUBMIT A QUESTION

The Toolkit

Sprinkler Designer or Engineer?

Get all of our tools, including the Sprinkler Database, Friction Loss Calculator, Fire Pump Analyzer and more:

FREE 30-DAY TRIAL

GET THE TOOLKIT

Filters

Exam Prep

2019 PE Prep Guide
(Available Now!)

PE Prep Series
(Available Now!)

Current Leaderboard
(Click to enlarge)

PE Problems

Visit July-October for daily Fire Protection PE Exam sample questions.

Solutions are posted the day after posting.

Comment with your solutions, questions or clarifications.

Please note that questions posted are unofficial and in accordance with NCEES rules are intended to be similar to actual exam questions, not actual exam questions themselves.

RSS Feed

Home - About - Blog - Contact - Exam Prep - Store

Copyright © 2020 MeyerFire, LLC
The views, opinions, and information found on this site represent solely the author shown 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 commission for orders placed elsewhere.