Dezincification of Yellow Brass

Plumbing Systems in modern homes may be piped with a variety of materials, typically conventional copper water lines or now plastic pipe commonly called PEX. Each system has advantages and disadvantages, however one defect, that being dezincification of yellow brass. which can be present in a 40-story residential high rise, a mid-rise condominium complex, apartment buildings or single-family homes. The culprit is yellow brass used in fittings to join the pipes together, connect the pipes to other components of the plumbing system including shut off valves.

Yellow Brass has one essential flaw: It corrodes when exposed to water. Obviously not a prudent or proper material to use in a plumbing system. When the problem is found it’s not just in one home, but commonly all homes in the project, neighborhood and even the entire State.

The repair is remove and replace.

What is yellow brass?

Brass is a metal alloy composed primarily of copper and zinc. Lead was frequency added to facilitate machining. More on lead later.

A traditional high-quality brass is comprised of 85% copper and no more than 15% zinc by weight. If copper cost $2.10 per pound and zinc cost $1.05 per pound, obviously, fittings can be cheaper by using more zinc and less copper. These metals when used in plumbing fittings, typically have a very bright, shiny appearance, hence they’re called yellow brass. The use of more zinc and less copper has been known prior to 1905. It has proven short-sighted and is compromising the integrity of plumbing systems everywhere.

What occurs simply put, is when the cheap yellow brass fittings see water in a plumbing system they start to corrode. Once exposed to potable water the zinc reacts and is liberated from the alloy leaving behind a porous and weak metal component. Once the corrosion starts it accelerates at an exponential rate compromising the integrity of the system.

The plumbing lines also become clogged or occluded restricting the flow of water. The fittings lose their strength and castrophodically fail and cause leaks. The fittings can also slowly leak drop by drop often causing corrosion material to be evident on the outside of the fitting. Often called effloresce or a meringue. Also, of a critical nature the occlusion inside jams up the valve, the valve clogs and freezes up and leaves it inoperative when needed most when there is a toilet or sink leak. Often the water supply to whole zones or the entire building must be shut off to effectuate repairs.

Back to lead, before California and a few other states enacted lead free plumbing line requirements, (now enacted by the EPA), Plumbing lines and fittings contained up to 5% lead. As the zinc is depleted and the alloy deteriorates, the lead has the potential to pass into the water supply.
All residents may be exposed to lead in the drinking water supply including children who are most susceptible to injury.

PCA