P-Trap & J-bends observations

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shieldcracker

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So this is my first post and I would like to share some of my observations and questions on the matter.
A P-trap is a combination of two elements a J-bend and a wall arm/elbow/bend. Every factory tubular J-bend (metal or plastic) I have ever seen has a slip joint connection at the inlet and a "firm connection" at the outlet. I suppose the slip joint connection at the inlet is for installation and service convenience and the firm connection at the outlet is to insure the J-bend stays connected to trap arm keeping the seal. There are two popular types of firm connections in metal and plastic J-bends: Ground joint (no gasket, commonly found in plastic bends) and the bead joint (gasket required, commonly found in metal bends).

Is there a specific application or code provision for selecting one type of connection over the other?
 

John Gayewski

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So this is my first post and I would like to share some of my observations and questions on the matter.
A P-trap is a combination of two elements a J-bend and a wall arm/elbow/bend. Every factory tubular J-bend (metal or plastic) I have ever seen has a slip joint connection at the inlet and a "firm connection" at the outlet. I suppose the slip joint connection at the inlet is for installation and service convenience and the firm connection at the outlet is to insure the J-bend stays connected to trap arm keeping the seal. There are two popular types of firm connections in metal and plastic J-bends: Ground joint (no gasket, commonly found in plastic bends) and the bead joint (gasket required, commonly found in metal bends).

Is there a specific application or code provision for selecting one type of connection over the other?
No.

Metal traps only still exist because there are people who still buy them. People think they are better becuse they are more expensive. I replace them all the time becuse they rot. It can actually be a very tough task to replace them cause they were sometimes soldered in and can't be removed without breaking.

The reason to choose a trap isn't the method it uses to seal, they can all be made to seal as long as they are not misformed.
 

Caliber_Plumbing

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The plastic P-Traps are the least expensive of the two but are not as attractive as the metal traps. Metal traps are often the go-to, more traditional piping used by homeowners in their plumbing systems. This is because it lasts incredibly long and is generally the most durable option.
 

John Gayewski

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The plastic P-Traps are the least expensive of the two but are not as attractive as the metal traps. Metal traps are often the go-to, more traditional piping used by homeowners in their plumbing systems. This is because it lasts incredibly long and is generally the most durable option.
There are plastic "chromed" ptraps also.
 

Tuttles Revenge

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The plastic P-Traps are the least expensive of the two but are not as attractive as the metal traps. Metal traps are often the go-to, more traditional piping used by homeowners in their plumbing systems. This is because it lasts incredibly long and is generally the most durable option.
The reason a lot of plumbing companies install chrome traps isn't because they last longer, its because they are harder for homeowners to work with and prevent them from working on their own equipment. Chromed traps are more prone to corrosion both from chemicals dumped down peoples sinks and from the chemicals they store under the sink.

Plastic traps are less expensive and easier to work with both for the customer but for a professional.

We used to use only chromed traps for our commercial work because it was visible and "traditional" looking.. but that went out the door when the ADA became enforced and we ended up covering up all the traps and supplies with big rubber boots.

There still is a place and time for a nice looking trap, but under most kitchen and bathroom cabinet sinks is not that place.
 

Tuttles Revenge

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So this is my first post and I would like to share some of my observations and questions on the matter.
A P-trap is a combination of two elements a J-bend and a wall arm/elbow/bend. Every factory tubular J-bend (metal or plastic) I have ever seen has a slip joint connection at the inlet and a "firm connection" at the outlet. I suppose the slip joint connection at the inlet is for installation and service convenience and the firm connection at the outlet is to insure the J-bend stays connected to trap arm keeping the seal. There are two popular types of firm connections in metal and plastic J-bends: Ground joint (no gasket, commonly found in plastic bends) and the bead joint (gasket required, commonly found in metal bends).

Is there a specific application or code provision for selecting one type of connection over the other?
There are specific applications for certain traps. In some jurisdictions the trap must be threaded on its outlet to the wall. I believe in NYC and likely only in specific circumstances like highrises, all of the plumbing components must be metallic / non combustible.

My dad got called out on a project in the 60s where he used lead slip joint gaskets that weren't approved and he had to get them approved by the city. (i forget the whole story, he tells it better)

Some projects will call out specific materials like for federal projects where they clearly haven't updated their spec book since the 1950s and they require wrot iron traps and 3/4 stop valves for every fixture.
 

Jeff H Young

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There are specific applications for certain traps. In some jurisdictions the trap must be threaded on its outlet to the wall. I believe in NYC and likely only in specific circumstances like highrises, all of the plumbing components must be metallic / non combustible.

My dad got called out on a project in the 60s where he used lead slip joint gaskets that weren't approved and he had to get them approved by the city. (i forget the whole story, he tells it better)

Some projects will call out specific materials like for federal projects where they clearly haven't updated their spec book since the 1950s and they require wrot iron traps and 3/4 stop valves for every fixture.
right there are codes that require L.A. or NY ptraps, also job spec. come on we aret puting a plastic p trap under a sink i8n a school or hospitol
I do think there are places that need heavier duty stuff than what goes in a house or say a mobile home or RV
I also have a theory goes another step beyond making things harder for homeowners, I think the high dollar price gougers will sell thier work as being so much better than using common stuff that it helps support higher prices. So there might be guys charging 500 bucks to replace a ptrap and using a cheap plastic one might not impress the customer.
Many jobs are rel sticklers for sticking to the specs including the brand and require approval to substitute even the brand of certain items
 

shieldcracker

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Guys my OP is about the J-Bend outlet connections types, bead and ground joint, both types are available in plastic and metal J-bends.
 

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shieldcracker

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There are specific applications for certain traps. In some jurisdictions the trap must be threaded on its outlet to the wall. I believe in NYC and likely only in specific circumstances like highrises, all of the plumbing components must be metallic / non combustible.

My dad got called out on a project in the 60s where he used lead slip joint gaskets that weren't approved and he had to get them approved by the city. (i forget the whole story, he tells it better)

Some projects will call out specific materials like for federal projects where they clearly haven't updated their spec book since the 1950s and they require wrot iron traps and 3/4 stop valves for every fixture.

You are correct LA, NY, WA... have these requirements but those connections are made at the trap arm/elbow outlet. The connections I am pointing out are on the J-bend.
Evidently traps are manufactured to meet the particular requirements of a design spec and to meet code. What could possibly support these seemingly redudant joints.
 

shieldcracker

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And i/we answered you. The connection type doesn't matter and it's not any reason to pick a trap.
Only you have really answered, with a single word and then followed with a paragraph unrelated to my question which is OK, I like all posts and points of view, they are interesting. Anyway I still hope to find supporting info as to why these two connections are available if the diferentiation of using them is not code driven.
 
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