venting drain to septic tank

[raisadan]

Hello All!
I'm building a log house in the countryside near Kazan, Russia. I have a plumbing question. Underneith the floor is the horizonrtal 5" drain line that goes to the septic tank. In the kitchen a small sink/basin and (low water volumn) washing machine empty into this drain. In the adjoining room is the bathroom, into this portion or the drain pipe are fed the toilet, basin and bath tub. CanI put the vertical 3" vent between these 2 rooms? It will be a real low use system. In the rural areas here the work is very slipshod, they don't even know about venting. Will the one vertical vent be adequate for all the above fixtures? The big drain pipe is about 20' long and is a straight run. Any input wou ld be much appreciated.
Thanks!
Dan
Kazan, Russia
(originally from Olympic Peninsula,WA. state.

[rreidnauer]

I don't know if we have any plumbers on here or not, and I'm not one myself, however, I'm pretty good at visualizing a situation.

By "between" what do you mean? Both rooms vent to a single vertical vent that connects where? Tees off the lateral drain line? (as in, it goes up inside a wall between rooms) Or, have individual vents from both rooms culminating together for a single vertical vent?
If it is the former, I see problems of of the tub or toilet sucking air through the basin trap. (as water flowing before reaching the vent in the lateral will still draw a vacuum) If there are no ways to properly vent basins and such, you could place studor vents to alleviate siphoning problems.
If the latter, I see no problems.

[raisadan]

Hi!
Thanks for your reply. Yes, the kitchen (basin and washer) as well as the bathroom fixtures all drain into a aingle (horizontal 5" pvc.It will run under the floor and all the fixtures will empty into it.
In the middle of this is a T which the upper portion vents to the roof. At this junction, the 'T' cpntinues downward past (through) the drain and empties into the septic system 1.5 meters deep. So it really isn't so much a "T" but more like a big cross, sort of. The veint will be 3-4" pvc and the big drain will be 4"-5" pvc, whatever I can get here in Russia. Do you think I'd have any vacuum problems with this?
Thanks!
Dan

[raisadan]

Do STUDOR vents need to be placed for each fixture that empties into the drain? And if I use STUDOR vents, do I still need a roof vent for the system?
Thanks,Dan

[rreidnauer]

Whether you'll have vacuum problems or not will depend a lot on how far your smaller fixture drain lines are from the "big" drain. If it's an immediate drop right into the big drain, then it will probably work fine, but say you got the tub and basin drain lines plumbed together, and they run a few meters to the big drain, you'll likely have issues. Imagine what would occur when you drain the tub. The water fills the drain line, and as it does, it will pull a vacuum, no differently than siphoning fuel out of a gas can. You can imagine, it would easily pull the water from the basin's trap.

I don't think you'd need to fit a studor vent to each fixture. In the above example, if you had just one on the basin's line, the tub wouldn't siphon the basin's trap. I don't recommend using studor vent except as a last resort, because the can be problematic. (they may stick open and allow sewer gas into the home) If using just studor vents, you *could* omit the roof vent, but I don't think that is a good decision.

[rocklock]

Dan;
These are a few guideline that I have learned.
Horizontal pipes must have 1/4 inch per foot drop. I taped a one inch block on the end of a 4 foot level to measure this angle,
The amount going into the septic must be vented. In other words, My septic is 3 (ID) inches, I must have the equivalent of 3 inches going out the roof. Either one 3 inch or 2 two inch and another 1 and 1/2 inch... I know its confusing...
Here they do not allow wet venting so there will be a maximum protection for the "P" traps. This means the fixture drain then the "P" trap then the vent then the drain. This is a real PITA.
Do not use ABS (the black stuff) and PVC in the same system unless separated by a rubber pressure fitting.
Then there are more stuff like not putting a santi T on its back unless its in a venting situation... I could go on but it would probably be more confusing...
Note; I am not a plummer nor do I play one on TV...
Best of luck

[raisadan]

Thanks everyone for all the great information.....guess I'll have to punt!

[raisadan]

All the fixtures will be connected no less than 2 feet (probably less) into the main (wet vent) drain then to the septic. The main drain will run directly under all the fixtures. Could this work? Wish I could post my diagram here.

[StressMan79]

just put it in photobucket and past the '[img ]' tag here. Then this site finds the pic and shows it.
-Peter