Flex in sewerage pipe

[Vernonv]

Hi All,
I'll be buying and laying some 100mm sewerage pipe on the weekend and need some advice.

The trench that the pipe will be laid in has a slight curve to it and I was wondering if the 100mm sewerage pipe has much flex in it (I've never used it before) or if I may need an elbow joint along the curve somewhere.

I'm guess I'm really just trying to get an idea of how much flex the pipe has, or what's it's maximum bend radius is.

The pipe will be used as part of a wet stormwater system for filling rain water tanks.

[davo2310]

over a length, you will get some bend in a 100mm pipe, I would rather go for a 5 or 15 deg bend in the middle and straighten the the rest of the trench.

[Vernonv]

Thanks Davo.

Looking at the Iplex website I can find a 15 deg. bend (which is too sharp and angle), but can't find a 5 deg.

Are 5 deg. bends readily available?

[DavidG]

It bends quite a bit so, depending on the definition of slight, there should be no problems.
ps: If it is storm water then you should be using storm water pipe, not sewer.

[Vernonv]

If it is storm water then you should be using storm water pipe, not sewer.

True ... but part of the run is under a driveway and rainwater is our only source of water, so I would rather spend a little extra and use a heavier duty pipe for all underground runs.

I will be using normal 90mm pipe for all exposed work.

Better to be safe than sorry.

[bricks]

It bends quite a bit so, depending on the definition of slight, there should be no problems.
ps: If it is storm water then you should be using storm water pipe, not sewer.

I always go for sewer grade pipe, no matter what,

Yes you can use stormwater
Yes sewer is alot more expensive

But it is better

[wonderplumb]

You can buy 5 degree bends at any plumbing suppliers, I prefer to trim the trench though, and definately not flex the pipe..............

[MonkeyWrench]

Some shire councils will only let you use stormwater grade for stormwater and dwv for house drain ie Logan Qld, But I dont live there and always use dwv for its better qualities. Any plumbing merchant will have 5 degree bends in F&F and M&F.

[Vernonv]

Well I ended up getting a 5 deg elbow when I got the pipe and stuff this morning, but ended up not using it. There was easily enough flex in the 100mm pipe to allow it to follow the trench line (it's quite a sweeping curve).

Thanks all for you help and advice.

[wonderplumb]

That pipe will fatigue and eventually fail, especially at any joins that happen to be in the curve of the trench!