Massachusetts lead solder ban

Background to the fire-watch case. 1978 ban triggered the cascade.

Let me give you the one other externality, that I didn't even know about until they redid my office a couple of years ago. Usually when you put copper pipe in a building — for a heating system or a water system — you would solder it. Then in 1978 you couldn't use lead-tin solder. You had to get the lead out, and you had to start using tin-silver solders, tin-silver-antimony solders. They're okay, but they tend to leak a little bit more. The real problem, the thing that got expensive, is that over time they had enough plumbers burn down buildings while they were soldering things, that they started saying, you have to have a fire watch.

Massachusetts Commonwealth plumbing code change forced transition from lead-tin to tin-silver and then tin-antimony solders for potable water. Sets up Tom's argument that the tin-base replacements don't bridge plumbing-clearance gaps the way lead-tin did.

They first got the lead out of plumbing. I think it was 1978, the Commonwealth of Massachusetts changed the plumbing code, and you could not use lead-based solders in your plumbing for your household potable water. They first went to tin-silver — and you can see why they did — and it was pricey, but it's only 5% silver, and silver wasn't quite as expensive back then as it is now. Then they went to tin-antimony, which has anywhere from 3 to 10%. Some of them are tin-antimony-copper — you put a little copper in there, raises the melting point a little bit. But there's a problem with that. If you talk to a plumber — and soldering, remember, is not just the way we make electrical connections; it's the way we make plumbing joints.

Brief reference — 1978 Massachusetts ban on lead solder in plumbing.

They have to have something to eat. In this case some bugs will reduce sulfur compounds and that's what they eat. Don't ask me, I'm not a biologist, but they call them SRBs — sulfur-reducing bacteria. It wasn't something we thought about in the corrosion literature until about 40, 45 years ago, when we saw the stuff in nuclear reactors. Now you read a report on corrosion in a tank, and half the metallurgists in the world say, oh it must be MIC. So now everything is MIC. In fact I had a case once that someone said was MIC on copper. Well wait a second — copper actually kills bugs. If you had a copper-hull ship — in 1836 Humphrey Davy made a copper-hull ship for the British Navy to get rid of all the barnacles that would grow on there. Copper kills organic things at very low concentration. So copper is toxic — you shouldn't be eating lots of copper, but there's not enough copper in copper water pipes; it doesn't corrode fast enough. They worry about the lead in the pipes from the solder. They took lead out of solder in Massachusetts in 1978. But copper is not a problem.