Gentlemen, I am looking at a large diameter sewer project that bids this month. There is around a mile of 30" main to be laid between 20-27 vf deep. I have two choices: Heavy Wall SDR-26 PVC or Vitrified Clay Pipe with the new fiberglass reinforced hubs and the no-lube gasket system. Before you make up your mind, there is one more kicker. The PVC has to be mandrel tested (3% deflection-would have to have a custom mandrel made) at 3 & 11 months, this means sanitize the lines, bypass the up & running system, etc., and if the mandrel fails, you have deep well dewatering and point repairs versus a low pressure air test (one time) with the VCP. Okay, what would you choose? ZAXIS
As much as I like the plastic I would go with the clay. I have seen it in use up here and it takes a beating. Plus you only have to test it & forget it! Use a little extra bedding!
pvc heavy wall with NO hesitation...just adhere religiously to manufacturer's bedding specs. i hate freakin clay tile, nothing but a headache. you can get flow thru mandrels
Thanks camara & dayexco, I appreciate the comments-still havent made up my mind yet.
Ive never personally put clay pipe in the ground. Ive see it done, and it doesnt look like its fun. Was on one job where we had to run under a clay pipe. It held, until we had finished putting our pipe in, the it promptly broke. You look at clay pipe the wrong way and it breaks. Ive never really had a big problem with pvc. Take your time, bed and compact properly, you should have no problems. You also should check and see if your area will allow resizing the pipe if your madrel doesnt pass. I worked for a company in Ohio that put some serious footage in the ground every year. Very rarely did we have an issue. If we did, most of the time we resized the pipe, which basically moved it back to the proper place. We even did one job where the inspector, lets just say had other priorities. We were supposed to dig the job up and redo it, but we just built a pipe resizer to work with a porta power and sized it back into place.
Just for clarification if it's Hobas Pipe I'd use it. If it's regular clay then I'd use the plastic with a little extra bedding.
something you may want to consider is the length of you pipe. Most clay pipe is shorter and since you mentioned about dewatering and with the total depth it may be easier to lay shorter lengths of pipe. Also with the depth that your at you could possibly get by with shorter trench boxes. Being that deep shorter trench boxes are better in the the tab data respect.
Thanks For All The Advise-it Helps To Have All The "in House" Experience This Forum Has. Zaxis
I agree with Pipeguy 100%
camara, I can use a can-clay vcp with the fiberglass reinforced hubs(much stronger) and the no-lube gasket system. I really don't think that this is the best application for pvc, due to the possibility of deflection, and the cost to correct it. ZAXIS