# Pressure

2 replies to this topic

### #1 Calixico

Calixico

Project Engineer

• Senior Member
• 56 posts
• Discipline:Civil

Posted 30 March 2012 - 02:38 AM

I was working problems and come acorss the solution to this one and I'm stumped. Can someone please explain to me where the (500/449) coming from. I know they are using the Hazen William Head loss equation and that those values represent the flow rate (but how?). I'm just confused where this is coming from.

Thank you!

### #2 mrt406

mrt406

Project Engineer

• Senior Member
• 80 posts
• Discipline:Civil

Posted 30 March 2012 - 02:14 PM

The equation states there are 500 connections at 1 gpm/connection. This gives you 500 gpm. However, the Hazen Williams equation utilizes cfs (rather than gpm), which is where the 449 comes from. It's a conversion factor (7.48 gallons/cubic foot x 60 sec/min).

Hope this helps!

### #3 Calixico

Calixico

Project Engineer

• Senior Member
• 56 posts
• Discipline:Civil

Posted 30 March 2012 - 06:48 PM

The equation states there are 500 connections at 1 gpm/connection. This gives you 500 gpm. However, the Hazen Williams equation utilizes cfs (rather than gpm), which is where the 449 comes from. It's a conversion factor (7.48 gallons/cubic foot x 60 sec/min).

Hope this helps!

Thank you!

#### 0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users

=