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!

*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.

Jobs

Calculating capacity of vertical overflow pipe in box gutter sump (example attached)

Calculating capacity of vertical overflow pipe in box gutter sump (example attached)

Calculating capacity of vertical overflow pipe in box gutter sump (example attached)

(OP)
Hello,

I have a situation where we are installing a new gutter on an existing roof which was previously leaking and had no overflow provision. I have attached a detail of our proposal.

My question is...how do I go about calculating the capacity of the vertical overflow pipe in this situation? We have a 150mm deep sump with the overflow rising 184mm above the bottom of the sump (so 34mm above the bottom of the gutter).

Australian Standard AS3500.3 Section 3.7.5.2 states that "A vertical pipe overflow that projects through the floor of the sump, is a possible alternative where a high capacity device is not required. No equations, graphs or examples are provided for vertical pipe overflow devices due to a lack of appropriate research data."

Anyone haev any ideas? I'm guessing this would this would either be solved with:

(a) Circular weir equation? If so, what formula should be used? Or,
(b) Orifice equation?

Also, how would you determine what H value to use?

Thank you in advance,

Alex

RE: Calculating capacity of vertical overflow pipe in box gutter sump (example attached)

I would use the orifice equation, with the head being the distance from the top of the overflow pipe to the WSE in the gutter.

For low-head conditions you could compare this to weir flow, using the sharp-crested weir equation based on the perimeter of the orifice.

Peter Smart
HydroCAD Software
www.hydrocad.net

RE: Calculating capacity of vertical overflow pipe in box gutter sump (example attached)

for self-venting (2-phase) flow in a vertical pipe, capacity may be less that that predicted by the orifice equation. And if there is any debris in the pipe, that will limit capacity also.

http://www.eng-tips.com/viewthread.cfm?qid=409750

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


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close