House trap

[mtmprop]

Have a home built in around 1900 with the old cast sewer trap in the yard plus a vent on the house side of trap. Trap failed - must be snaked every few days. All DWV lines are updated pvc to the trap. I would like to eliminate it and add a clean out in each direction. The main stack vent is 1.5 in thru the roof.. separate 2nd bath (constructed 15yrs ago has a 2in coming out the side of house. My question is if I eliminate the house trap which I want to do, do I eliminate the vent that's on the house side of that trap? Is my current vent piping sufficient to do so.?

 

[Tuttles Revenge]

I was just reading PA plumbing code based on IPC and it specifically says not to install house traps.. but likely was legal when installed. I would rather eliminate the trap with a slightly undersized vent cross sectional than leave it.. whole hose traps are not a great idea anymore IMO.

 

[Sponsor]

 

[Jeff H Young]

I kinda wondering if its even legal to replace the house trap if he wanted to? but If I was to leave my area move away a few thousand miles where they were common Id be speaking to others in the trade and AHJ to ask if they are allowed , mandatory or optional and why I should concider keeping one . my gut says not needed , but I concider local common practices and recomendations. I know sylvan is a big proponent but he is from NYC and such a dence urban area might have needs diferant plus old antiquated systems that might not function well
looks like 1 1/2" vent might serve an entire house

 

[Reach4]

My question is if I eliminate the house trap which I want to do, do I eliminate the vent that's on the house side of that trap? Is my current vent piping sufficient to do so.?

I am pretty sure, yes.

 

[Tuttles Revenge]

I kinda wondering if its even legal to replace the house trap if he wanted to? but If I was to leave my area move away a few thousand miles where they were common Id be speaking to others in the trade and AHJ to ask if they are allowed , mandatory or optional and why I should concider keeping one . my gut says not needed , but I concider local common practices and recomendations. I know sylvan is a big proponent but he is from NYC and such a dence urban area might have needs diferant plus old antiquated systems that might not function well
looks like 1 1/2" vent might serve an entire house

1002.6 Building Traps​

Building (house) traps shall be prohibited.

 

[John Gayewski]

Leave the vent, it can only help.

 

[Jeff H Young]

Leave the vent, it can only help.

I dont have much experiance with house traps but the vent was only venting the house side leaving the vent would be open to public sewer. I cant imagine any code allows it or that it can only help, UPC it sure dont fly , but if vent goes all the way up above roof I think its a good thing.
and thanks tuttles on the info that house traps are prohibited in PA code not suprised one reason I think house traps may have played a part in plumbing systems is rain and foundation water is often going into the house drain you dont want the sewer venting back into the house might be a guess but evedently that no longer plays a part or there would be exception to the code perhaps local restriction applys . could be other changes over the decades and centurys that changed its importance

 

[John Gayewski]

I dont have much experiance with house traps but the vent was only venting the house side leaving the vent would be open to public sewer. I cant imagine any code allows it or that it can only help, UPC it sure dont fly , but if vent goes all the way up above roof I think its a good thing.
and thanks tuttles on the info that house traps are prohibited in PA code not suprised one reason I think house traps may have played a part in plumbing systems is rain and foundation water is often going into the house drain you dont want the sewer venting back into the house might be a guess but evedently that no longer plays a part or there would be exception to the code perhaps local restriction applys . could be other changes over the decades and centurys that changed its importance

More atmosphere in the piping system can only help and yes the vent should come up inside of the house and out through the roof. Or up the side of the house.

So... Leave the vent (also legal and approved under upc) and it can only help. A vent that's been there for many years isn't going to hurt anything and only help.

 

[Tuttles Revenge]

UPC requires cross sectional of the required sewer size to match the cross sectional of the venting in order to maintain a balance of the sewer system more than venting the house itself. Like where if 1 building on a property meets the required cross sectional, another building on the property is only required to meet its individual DFU venting requirements.

We get this a lot when we're installing backwater valves in Seattle. If the entire house is required to have a BWV then we have to either install a Normally Open BWV or provide a separate vent for the sewer that extends through the roof

 

[Jeff H Young]

More atmosphere in the piping system can only help and yes the vent should come up inside of the house and out through the roof. Or up the side of the house.

So... Leave the vent (also legal and approved under upc) and it can only help. A vent that's been there for many years isn't going to hurt anything and only help.

An important part is that the vent is properly terminating not down at grade like was common those vents were meant to be upstream of the trap Removing the trap and leaving a vent at ground level . I dont think thats legal to vent like that in UPC

 

[John Gayewski]

An important part is that the vent is properly terminating not down at grade like was common those vents were meant to be upstream of the trap Removing the trap and leaving a vent at ground level . I dont think thats legal to vent like that in UPC

I don't think the vents were in the yard. If they were I think yes it would be silly.