A Massachusetts plumber said it was illegal to use reducing couplings on DWV to go from smaller to bigger pipe and it called telescoping and the reducing fitting must be used and not the reducing coupling. Is this true?

????? packy ?????

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

MA plumbers seem to have to follow a lot of "ridiculous: rules, so it is possible.

when you run an 1 1/2 vent up into an attic and increase it to 2 inch because that is the minimum size allowed thru a roof, hoew you supposed to do it ??

What's the difference between a "reducing coupling" and a "reducing fitting"? A coupling is a fitting.

... just a guess ...

the code may be trying to ban bushings

? poorly worded perhaps ?

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

Around 6:45 in the video he says this fitting is illegal. He said in the comments it has to do with snaking a drain and the code was written before flex shaft was around. [www.youtube.com]

...... aaaah

i see now

one may only change a drain pipe size at a t or y fitting, not by using a reducing coupling (? or el ?)

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

The whole issue is inane and ridiculous. There is NEVER a problem with a snake going into a LARGER pipe, whether it is a bushing, reducer coupling, or fitting. Maybe they should NOT listen to a "ride along" female, who may be trying to upsell the job.

To be fair to the lady in the video, it was the plumber on the job who said the reducer fitting is not to code, not her.

There is a general principle in the piping 'industry' to ban unnecessary ADDITIONAL fittings.

There 'should' be no use in a properly designed and 'laid out' system for a reducing coupling where a different reducing fitting could be ussed.

eg. 1x1x1/2 tee is preferable to a 1x1x1 tee + a nipple + a 1x1/2 coupling



a single fitting is ALWAYS preferable to a triple 'christmas tree'




as far as the actual code ? remember the code is the MINIMUM standard !

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638



Edited 1 times.

as per my example..
if you have a washing machine set up all alone on one end of the building and the vent for that washer drain is 1 1/2 inch. you run that vent up to an attic space so you can penetrate the roof.
my code says minimum size vent thru roof is 2 inch.
or, if you run a full size 3 inch vent up into an attic and you want to increase it to 4 inch because of possible frost.. how ya gonna do that?
in fact, my code says something about if you do increase the vent you have to do it at least 12 inches below the roof.

there are long pattern fittings (or there used to be) precisely for that purpose

or, since a roof vent 'up north' should/shall/must be 4" for frost protection

perhaps a standard reducing coupling is acceptable for that purpose

[th.bing.com]




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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

I agree that less fittings and less joints is more desirable - less chance of a leak.

However I don't quite understand why they would prohibit if another configuration is equally effective even if it's one more joint. For example, I want to use a 2" santee but the vent just 1-1/2", is it better to have a 2X1-1/2X2 santee sure, but if all I have is a 2X2X2 I don't think it's that awful to use a 2X1-1/2 bushing on the top even if it's an extra fitting. I keep thinking there is another reason for the "illegal fitting" and not just that reducing coupling is an extra fitting. If only a size change is permitted at a Y or T then they wouldn't even allow a 4X3 closet elbow? Because it is a size change and there is no Y and no T.

'smooth integral bore' may be the concept


as for the WC - a 4x4 or a 4x3 = one fitting either way



sum: it is seldom good practice to 'use what's on the truck' instead of a better/simpler install

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

There is no question that less fitting is better. But as you said code is typically minimum standard not best practice.

So the fundamental question is, IF this is indeed code in MA, what does the code actually said and why?

I just have a real hard time believing that reducing the number of fitting is the context here. After all, most repair jobs involve adding couplings here and there.

The "size change only at the Y and T fittings" is from your post #8, again was a guess on what's actually prohibited.

The video said having that particular fitting there is "telescoping and is a violation in MA". I have heard of the term telescoping and usually it's in the context of going from a larger pipe to a smaller pipe which is a no no anyway except in the case of a 4x3 closet elbow.

It's still unclear to me what is actually the violation I think we are all just guessing.

yep

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

In the replies to the video, the plumber explains that, because rooter cables were not as flexible then (when reducing couplings were prohibited in instances like the one in the video) as they are now, an abrupt change in diameter makes it difficult for the cable to get to debris near the abrupt change in dia.

What’s the difference whether it reduces from an actual reducing wye or tee versus a reducing coupling in the same vertical direction in a space 2” vertical distance?

"..... smooth integral bore ....."

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638

All pvc fittings are designed with a smooth inner bore transitions

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"Measure Twice & Cut Once" - Retired U.A. Local 1 & 638