×
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

gravity sewage line

gravity sewage line

gravity sewage line

(OP)
Probably an over simple question for the plumbers in here but I need some clarification on any rule of thumb or thoughts on what is a reasonable length of straight run of 4" dia. PVC at 2% slope from a toilet pan to a septic tank, that is assuming there is a maximum length.
Thanks

RE: gravity sewage line

There really isn't a rule of thumb for maximum length - it all depends on the particulars of the installation.

You will have two issues;

1.  Final invert at the septic tank.
2.  Solids settling out in the pipe.

With a long run, you will have a deeper pipe connection on the septic tank the farther you run the pipe.  Septic tanks have to be pumped - and sometimes maintained - so the deeper it is - the harder it will be to maintain.

The longer your run - the more likely solids will settle out before they reach the septic tank.  Having a lot of fixtures that flow water without appreciable solids (showers, mop basins, etc.) help push the solids down the line.  Extra water closets discharging to the line also help.

A 2% slope will cause the solids to travel farther on less water - but will also cause the final pipe invert to be twice as deep as the standard 1% slope allowed for 4" pipe.

Code (at least the IPC) require cleanouts every 100 feet to help push the solids along if they start clogging the pipe.

I have seen runs as long as 1000 feet - but there were other fixtures discharging water into it, the final invert allowed for it, and there were a good quantity of cleanouts.

RE: gravity sewage line

(OP)
Thanks for the precise and useful information - a * for you.  

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