Code quest - dielectric unions (GrandPAH)

Dave Yates (GrandPAH)_1

The only reference I can find requiring the use of dielectric unions regards the transition from copper-to-galvanized within potable water transmission systems.

A question came up regarding copper-to-black iron piping within hydronic systems. I'm unaware of ever having seen an issue within hydronic systems (not including copper use for steam piping) or any code-required use within a hydronic system. My copies of the 1990 BOCA, ICC 03 (3rd rev) & ICC 06 (10th revision) do not mention dielectric unions in the hydronic chapters.

Kicking this notion around our morning meeting, the conversation turned to the boilers we service that have met or passed the century mark with no electrolysis between the copper feed-water line and the boiler's black iron piping.

Much too-do about nothing?

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Brad White_135

I have not seen it either

and would think it falls under "means and methods". Not sure how much a code can dictate at what level of detail beyond material and reference standards for best practices.

Disconnecting dissimilar metals is such a common practice, does the IBC mention to use means and methods to prevent dielectric corrossion at dissimilar metals?

Even screwed joints are not mentioned that I have seen, with more detail than "appropriate pipe thread compounds" (paraphrasing from BOCA). Mass. is not yet on the IBC but that is coming... forever.

Dave_4

GrandPAH

Does this help?

http://forums.invision.net/Thread.cfm?CFApp=2&&Message_ID=251638&_#Message251638


Robert O'Connor/NJ

Dave Yates (PAH)

Danged interesting!

I'll double-check tomorrow, but I didn't see that in my 90 BOCA mechanical code, or either of the 03 & 06 Uniform Code books we're currently working under. All three specifically note galvanized to copper must be dielectric, but that's it. Given the age of many steam and hot water boilers we service from the early 1900's, I'd highly doubt black to copper should be included. Maybe boiler water isn't conducive to electrolysis?

Thanks for the code tip!

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Plumdog_2

Didn't see any reference either.

That residential code is so lax as to be nearly humorous. Look at a copy of the Commentary for Residential Plumbing. There are drawings of floor drains with infinitely long distance to vents. Many of the past taboos are simply forgotten. The bar has been lowered so far now it's like doing the Limbo.

Dave Yates (GrandPAH)_1

Limbo - without the bar!

New bath with fixtures right where they were previously? No permit & no inspection needed.

Replace HVAC equipment with same size & fuel type? No permit & no inspection required. Do a heat loss/gain and install different right-sized HVAC equipment? Provide Manual-J to the codes folk, obtain a permit and get inspection(s). D'OH!

All hydronic boilers must incorporate backflow protection. Open direct systems get a wink and a nod.

HO doing the work? No permit & no inspection required - at least that's the local interpretation of our new codes.

No enforcement at all while unlicensed hacks operate in plain sight with no fear of being prosecuted.

I've lost a great deal of the respect I once had for the codes. It's nothing more than a money game today and it's being used as a bully-pulpit & only for those who are licensed.

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