Help with determining appropriate pipe size

  • Thread starter Thread starter jeff3
  • Start date Start date
  • Tags Tags
    Pipe
Click For Summary
SUMMARY

The discussion focuses on determining the appropriate pipe size for connecting a city water supply to a residential fire sprinkler system, specifically using black steel pipes. With a static pressure of 48 psi and a required flow rate of at least 26 gpm, the consensus is that any standard black steel pipe can accommodate this flow due to the low pressure requirements. The critical factor is ensuring that the pressure at the sprinklers remains above 30 psi after accounting for friction loss, which is calculated to be 5.6 psi over a 100-ft length. Elevation considerations for the sprinklers also play a role in determining the necessary pipe size.

PREREQUISITES
  • Understanding of hydraulic principles, specifically pressure and flow rate.
  • Knowledge of pipe materials, particularly black steel and its pressure ratings.
  • Familiarity with friction loss calculations in piping systems.
  • Basic concepts of static head and its impact on water delivery systems.
NEXT STEPS
  • Research "Hydraulic calculations for fire sprinkler systems" to understand flow and pressure requirements.
  • Learn about "Friction loss in piping systems" to improve accuracy in calculations.
  • Investigate "Pipe sizing for fire protection systems" to determine best practices.
  • Explore "Elevation effects on water pressure" to account for vertical distance in system design.
USEFUL FOR

This discussion is beneficial for plumbing engineers, fire protection system designers, and anyone involved in the installation or maintenance of residential fire sprinkler systems.

jeff3
Messages
1
Reaction score
0
I'm trying to connect water from a city water supply to a residential fire sprinkler system. The pipe needs to be typical black steel, and hydrostatic test results show a static pressure of 48-psi. What size pipe would I need to achieve at least 26-gpm flow? I've calculated friction loss to be about 5.6-psi over a 100-ft length. Thanks in advance.
 
Engineering news on Phys.org
How have you calculated friction loss without a pipe size?

26 gpm is pretty low, as is 48 psi. You won't need very big piping to accommodate that flow. Any black steel pipe can handle 50 psi with ease.

It's not what you can "achieve", it's the pressure you need at the end, accounting for pressure drop due to pipe friction. Almost literally any pipe size can accommodate a meager 26 gpm.

For instance, if you NEED 30 psi at the sprinklers, then you need a pipe size that will not reduce the head any lower than that.

Speaking of head, is that 5.6 psi (~13 ft static head) drop accounting for the elevation of the sprinkers?
 

Similar threads

  • · Replies 8 ·
Replies
8
Views
4K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 5 ·
Replies
5
Views
3K
  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 20 ·
Replies
20
Views
11K
  • · Replies 13 ·
Replies
13
Views
4K
  • · Replies 10 ·
Replies
10
Views
6K
  • · Replies 17 ·
Replies
17
Views
4K
  • · Replies 1 ·
Replies
1
Views
3K