Storm Sewer < 90 degrees

[Poster formally known as dannybobber]

what are your thoughts on a storm sewer design where there are junctions that have less than a 90 degree change of direction. obvioulsy there are HGL implications, but other than that...any reason to avoid?

 

[Capt Worley PE]

There's only one man who can truly answer this question with the gravity it demands. He's not here.

 

[Guest]

Normally, avoid this. But if the site condition has constriants, it's still ok for me if the angel is not too sharp, otherwise, you can just use blind connection.

 

[EM_PS]

^ Sharp angels will tear you up!

Less than a 90 degree change in direction is great actually! Or are you meaning to say an angular junction with angle sharper (less) than 90 (meaning a greater than 90 degree change in flow direction)? :huh:

 

[TranspoVA]

The HGL implications come from the energy losses associated with the sharp change in flow direction...Although this can be worked out mathematically the to function correctly the bigger reason is construction, Trying to put 2 pipes together in a manhole with a sharp angle is next to impossible, that or you are upsizing your manhole which is really expensive. Check out your states standards they give guidance on entry and exit angles of pipes and dont forget to account for Inlet shaping.

 

[Chucktown PE]

Where in the hell is EB.com's resident stormwater expert?

 

[squishles10]

you can do it. ive done it. just watch out for water jumping out of the ground. if you also have high velocities it gets nasty bc of the erosion potential in the pipe at the back of the bend. but if you have high velocities you probably wont be doing this. we had a pipe like this 17 ft underground but hey, you gotta do what you gotta do i think that was a 30 degree turn. might want to make sure and use water-tight joints even if they arent required, *just in case*.