Hey all Don't know if this would be the right section to post this question or not but I'm wondering what the difference in crush rating is between schedule 35 & 40 PVC vs. black dual wall plastic tile? I have a job to do for a customer - it's a septic outlet and it runs thru a farmers "hilly/ rolling" field. Some areas will only have a foot of cover :Banghead (Hence the crush rating question)
There should be published specs. What diameter are you working with?
Will most likely be 6"
The only pipes 'rated for sewer' are SDR 35 and schedule 40 PVC or ABS. You will see the latter two are approved for building use therefore the name DWV (drain waste vent). These pipes are cellular, meaning the wall is a blown material with a slick coating for the inside and outside out of the same resin but not blown. The first one, SDR35, is quite common for sewer lines and is what is used in the streets. The SDR name has to do with the way the dimensions for the size are determined. The material is not blown. Then there is pressure pipe, but the transitional fittings usually precludes this usage. See commentary at end. * In the other direction are the pipes that have no spec per se, other than the mfgs. These are the ones that say drain line but make no mention of the SDR designation or DWV designation, they could be corrugated polyethylene or a dual wall material that is constructed like a cardboard box in a similar fashion. * We never use any of the pipes other than the SDR 35 or the DWV material for a sewer line. Every time we have to look for one of these other pipes, it is always ovalled in the ground. We drill our own leach pipe since the pre-drilled stuff has no spec on the label. It doesnt take long to drill the holes. * There is definitely a technique for covering a sewer line, and a lot of folks dont have the patience or the desire or the skill to lay a drainage pipe (read sewer) with no bellies at a quarter percent. If you use one of the pipes that I mentioned, and place the soil correctly, most of the farmers vehicles are designed to minimize compacting the soil y/n?; the one foot depth (cover or depth?) is not ideal, but you probably don't have many options. If the soil moves around, you may lose you perfect install over time. But if you pick a smooth pipe as opposed to the corrugated, you could always camera it to determine where it needs to be addressed. The pressure pipe is always an option but you will likely have to avoid turns since the fittings are much tighter bends and you will have to be creative with the fittings at the transitions from one thing to another, maybe a small lathe job or a rubber hub for your transitions. Then there is slurry, ....dont forget to stake it.
Prolly will go with the 35 or 40. I just wanted other opinions. And it will only be roughly a foot of cover in a few spots thru the field. The main concerned area I have is where the outlet drains. It ties into a catch basin out by the road, then it runs under the road to a main drainage ditch. Problem is I can't put a new basin in to lower this septic outlet because the pipe running under the road is not much deeper than this outlet tile. An the county engineer will not help out with the basin because they "do not want to have to dig up their fairly new road" :beatsme
Curious, the septic outlet goes to a leach field yes? or is there some other hook up to a catch basin? then the ditch? or is this for another pipe....
No sir. This is a very old system yet. When I say old I mean from the 60/70s. No leach field at all. The tank is still in good shape, the outlet tile has just been run over by farm equipment for too many years, clay tile yet to boot :Banghead I will just be replacing this outlet
They do make Sch40 pvc in foam-core and solid. The soild core pipe is much stronger and uses the same fittings as foam-core. If you are really worried about the pipe crushing in those shallow spots they do make sch80 pvc that you could use.
Now that you say I have heard of that before. Do they make that in 6"?
At that depth you won't be below the frost line and you will have other issues...you may want to rethink some of the planning here...
For a septic outlet I would use 4'' sch 40 ,it's pretty forgiving with shallow cover.Like buckfever mentioned could still use sch 80 in the shallow areas if need be. I may have read wrong but are you replacing the whole line from the septic tank to the catch basin or just the lower section?How long is the line from the septic tank to the basin?
It has been at the same depth for 50+ years and no problems. I do understand what your saying tho cuz I brought that up to him also. Yes I'm replacing it from the tank to the basin. It's roughly 400'
I would probably just run the 4'' sch 40 pvc in that case unless there are other reasons for using 6'' pipe. I have seen old septic systems that were tied in to field tile drain lines .In that case I could see needing the 6" pipe. Dont think you will have any trouble with it freezing as its a drain line. Good luck with it KTE.
Thanks td25c!!
It's frost heave that would be a bigger problem. Unless the toilet runs...
Ya they make 6" in solid and foam core. You could also get it in sch 40 and sch 80. I think 6" is a bit overkill for a job like this but if putting it in makes both parties sleep a little better go for it.
If you are running 400 ft, my opinion would be 4" sch 40 at the minimum with that amount of cover. If it were me I would probably use 6", but it aint my job or my checkbook. Also dont forget about 3-4 cleanouts.
Good point biggrader. You should put a cleanout atleast every 100'. IMHO 50' is better so your not having to fight the snake so much if a clog ever does happen.
Many sewer services and most all solid and perforated runs on a septic system are above the frost line.Never an issue heaving as long as there is methane[heat] in the pipe.I've installed a few sewer services just under grade because of necessity without any problems.As far as bellying is concerned,it's all about proper bedding and compacting to the spring line of the pipe.
Might even be a good idea to install an effuent filter on the tank outlet if possible www.tuf-tite.com/ef4filter.html Like tuney443 mentioned , drain & leach beds are above the frost line in most cases.Come to think of it on every septic system I have installed the only part of the system that ended up below the frost line was the lower part of septic tank.I'm sure this differs in other parts of the country from job to job. From the way KTE is describing his job it almost sounds like a "lagoon system" Found this example on the Oklahoma deq site www.deq.state.ok.us/eclsnew/Fact Sheets ECLS/System Fact Sheets/Lagoon-.pdf
Most likely. Around here we get it pretty bad. I think it's a function of temp fluctuations and moisture. If you get a pocket of water underneath something and it freezes the water expands a bit over 9%. Then it thaws leaving a gap that can be filled by the next rain/snowmelt so the next freeze grows the problem by another 9%. Cycle this a bunch of times the heave becomes an issue. The clay we have around here prevents accumulated water from matriculating into the soil and dissipating. I would imagine areas with sandy soil don't have this problem to the same extent.
Thanks for all the info guys! Good tips and pointers, keep em coming
Understand what your saying Shenandoah.I havent had the heaving problem with drain pipe but I could see in other parts of the country with different climates & tempatures where it could be a problem.We would have similar based clay soil that aint the best for purking water but it works.We have been using chambers on the leach lines.Dig the ditch 24" deep X 36" wide ,chambers have about 14" cover dirt on top when backfilled. HeavyEquipmentForums In my area it allways seems to freeze the deepest where the ground is the driest.Around these septic beds & drain lines its allways pretty wet and the ground wont freeze very deep seems like. Getting back to KTE's job ,I think the drain line will work fine even with a few shallow spots of cover in places on it.The biggest problem I see happening to it is when the farmer comes in after harvest whith his "shallow pipe locating attachment" behind the tractor www.landoll.com/ag/1550/
Lol luckily this homeowner has his son as the farmer so I would say they will be working something out so that doesn't happen! It's all no-till ground around here anyway, at least for 8-10 years at a time.
For some reason that reminded me of when I was a kid and my sister decided to ride her horse home from the stables and do some riding over our leach field. They were clay tiles and the weight of the horse coupled with hooves clad in horseshoes crushed a bunch of those tiles we were sure were supposed to be a lot deeper than they turned out to be. And looking back on this thread to your comment " the outlet tile has just been run over by farm equipment for too many years, clay tile yet to boot" really hits home...
Hahah nice! Clay tile........good idea at the time..
Man I can never get my lines above the frost line no matter how much I try...most years it's about an eighth of an inch, but I have seen it nearly a half inch deep. :beatsme
To you smarter than me guys. This is probably a dumb question. But why is it referred to as "TILE". Its still pipe no matter what materiel it is made of, right? Sorry to ask, but it is just one of those things I gotta know. Like why is a whiskey and a mixer called a HI BALL????
Back in the day the leach field consisted of pipes made out of the same red clay they use to make tiles. They shaped the clay into pipes and fired them in a kiln. I guess it just stuck. That's my understanding as an old fart...
Terracotta is the correct term coming from another old fart.It's always amazing to me that when I run across it,it's usually in perfect shape compared to it's successor,the POS Orangeberg pipe.I actually collect different types of Terracotta,round,octagogonal,sizes--will make a great wine collecting display some day.
Thanks Shenandoah and turney443. That makes sense. Now........about that "HI - BALL" question!!!!!