Compression fittings A or B

[mrlennie]

Alright back in college we were told that you cant use a certain type of compression fitting underground. You have to use a manipulative fitting. Now im going to be altering some MDPE for a customer and all i can find is this sort of fitting

Plasson Compression Elbow 25mm MDPE Pipe on eBay (end time 12-Jul-10 22:02:23 BST)

is this ok and why?😕

 

[WHPES]

You are getting confued with oil lines which require manipulative fittings. Water uses the standard MDPE fittings.

 

[mrlennie]

Interesting I am sure it was not oil as it was in plumbing level 1 maybe it has changed.

 

[Bernie2]

Yes it was for copper. Mostly Type B Securex drifted fittings in gunmetal. We used them with soft copper water mains.

 

[justlead1]

Hi. Type "A" above ground and type "B" below ground. A few companies made them some required a flared end on the pipe, others by using a tool which formed a swaged ring on pipe end. They are used to overcome the pulling forces placed upon fitting, due to ground moment / settlement etc. The pipe wont pull out the fitting. (Put nuts on before manipulating)
With MDPE and plasson joints make sure you use inserts at the pipe ends/ fittings as these have a similar job as manipulative for copper.

 

[tamz]

You are getting your fittings and materials mixed up.
If doing MDPE you use suitable fittings eg the plasson shown or philmacs.
With soft copper table Y or whatever en???? it is called now you use type B's for the reasons justlead said.
You can if you like, use type B's above ground ie in the house, but they are expensive.
You will come across a lot of drifted fittings in older houses like PDM's and securex as they were in common use up until the early 70's. If you strip any out keep some cones especially the 1/2". You never know when you will need one.