×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Conflict in NFPA #14?

Conflict in NFPA #14?

Conflict in NFPA #14?

(OP)
From NFPA 14 "Standard for the Installation of Standpipe, Private Hydrant, and Hose Systems" 2000 Editio

Section 5-9.1 requires the system designed for 500 gpm at the most remote standpipe:

5-9.1 Class I and Class III Systems.
5-9.1.1* Minimum Flow Rate.
For Class I and Class III systems, the minimum flow rate for the hydraulically most remote standpipe shall be 500 gpm (1893 L/min). The minimum flow rate for additional standpipes shall be 250 gpm (946 L/min) per standpipe, with the total not to exceed 1250 gpm (4731 L/min).

But right below it the calculation procedures call for each standpipe to be designed for 250 gpm.

5-9.1.2* Hydraulic Calculation Procedure.
Hydraulic calculations and pipe sizes for each standpipe shall be based on providing 250 gpm (946 L/min) at the two hydraulically most remote hose connections on the standpipe and at the topmost outlet of each of the other standpipes at the minimum residual pressure required by Section 5-7. Common supply piping shall be calculated and sized to provide the required flow rate for all standpipes connected to such supply piping, with the total not to exceed 1250 gpm (4731 L/min).

Seems to me if you design each standpipe at 250 gpm, per 5-9.1.2, you will never get the system to pass acceptance test which requires 500 gpm be flowing from the top outlet.

In the past I've always calcualted each standpipe to deliver 500 gpm wich 250 from each additional standpipe and I will continue to do so.  The problem is I am helping a friend pass NICET for testing.

RE: Conflict in NFPA #14?

Typically, the most remote system is going to have a roof manifold for testing.  That will require 2 outlets at the roof.  That is where I place each of the 250 gpm demands for the remote standpipe.  So, you are carrying 500 gpm down the most remote standpipe.  You then add 250 gpm at the split for each additional standpipe to the max req'd flow.

Even if you don't have the roof manifold at the remote, you will be carrying a total of 500 gpm down the most remote standpipe.  You just have to provide 250 gpm at each of the top 2 outlets.

T

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources