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Radiator Odors


Dan Holohan
July 16, 2009
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How's your nose? You bothered by odors? How about someone in your family? Anyone have asthma? You worried that out-gassing from new materials such as paint might make you sick? You like that new-car smell? That smell is out-gassing you know. I hear that it's not very good for you. You got a good lawyer?

Here's an e-mail that came to me recently. Read it over and consider the new perils that you face nowadays in our Age of Information, when everyone is concerned about everything, and there's a growing realization that life causes death.

"I'm e-mailing you because I've read a few of your articles at and I can see that you're very knowledgeable when it comes to radiators. There's a problem we're having with ours that I hope you can possibly shed some light on.

“Here's the situation: I'm staying in a grad residence at a university. The building has about 400 rooms, 190 of which are occupied. A steam radiator heats each room, and about 25-30% of the people can smell an unpleasant odor coming from their radiators. Some describe the smell as 'a burning odor," or 'a burning iron,' or 'burning plastic,' others just call it 'an unpleasant smell.'

"I first smelled this odor when I moved in back in March of '05. I'm asthmatic and I noticed every night around nine or 10 pm that I would smell this burning smell and I'd start to have difficulty breathing. So over the course of a week or so I figured out that if I turned the radiator control valve down (0 = the lowest setting, and 8 = the highest) the odor was less and the difficulty breathing would lessen. But even with the control knob at 0, or off, there was still a little bit of this smell.

"At first I thought this smell might be from the old lead-based paint on the radiator and the pipes because even with the control knob at 0 the inlet pipe would still be hot and you could still smell a little of this odor. Last summer all the radiators were taken out, sandblasted and repainted with a heat resistant paint: Sherwin Williams Direct-to-Metal Alkyd Enamel. A couple of mistakes were made with regard to the pipes, though. First, they were not chemically stripped of the old lead-based paint; and secondly, a non-heat-resistant paint, Sherwin Williams Pro Mar 200, was used on them.

"When the radiators were turned back on last October it was absolutely awful. The paint fumes combined with the previous burning odor made anywhere from 35-50% of the residents here sick. People suffered from nausea, dizziness, vomiting, headaches and shortness of breath. This lasted for two months, and several residents actually moved out.

"Personally, I sealed off the section of my room where the radiator was and this made it a little better. By now, though, the paint fumes have died down. But the previous problem (the burning odor from the radiators) is still here, and at least 25-30% of the residents can smell it in their rooms. But there are some rooms where you can smell nothing at all, neither the burning odor nor the new paint. Initially we thought heating the radiators up, and heating the old paint, was the source of the problem. But recently, several residents have noticed that even with the control valves completely off, they can still smell this odor.

"The steam for the building is generated in a plant about a block away. This plant also supplies steam to all of the buildings on campus that use radiators. An industrial hygienist from the university's Environmental Affairs Department has come to test, but has not pinned down the problem. Another dorm on campus has the same problem, and I've smelled this odor once before in an old hotel heated by radiators.

"My questions are these: Have you ever encountered a situation like this before? Could the source for this be a gas leak? Or does this sound like it's coming from the old paint? Is this possibly corrosion in the radiators and pipes? Is this just from the heat of the steam, or is this possibly the result of control valves that leak? Could this be from the chemicals used in the plant where they generate the steam? Are there any published studies on this type of problem? And lastly, if you've seen or heard of this type of problem before, do you know the composition of this ‘burning odor,’ i.e. carbonic acid, carbon dioxide, etc.?

"Sorry about writing such a long e-mail but I thought you'd need the info to answer my questions."

So spend a bit of time with Google and learn about Volatile Organic Compounds (VOCs), and where the limits are, and what happens when you heat paint, and how very sensitive some people can be to odors. The guy who wrote me the e-mail says that 25-30% of the people in the building can smell the radiators. Which means that 70-75% of the people in the building can’t smell the radiators.

How sensitive is your nose?

And I'm not even sure if it's the paint in this guy's case. It could be boiler chemicals. It's tough to tell from his description whether he has a one- or two-pipe steam system. If it's one-pipe, whatever chemicals they add to the boiler will cause an odor upstairs. If it's two-pipe there shouldn't be any air vents on the radiators. But once radiator traps begin to fail they cause backpressure in the returns. The backpressure holds the air in the radiators, and where there is air, there won't be steam. At this point, some knucklehead will add a one-pipe steam air vent to the two-pipe steam radiator, which is the dopiest thing you can do with steam heating because it works. It makes that radiator hot, but the condensate won't be able to drain, so it will also make the vent squirt. And whatever is in the boiler will wind up in the room.

The Dead Men once used vinegar to lower the pH of their boiler water to prevent foaming (which is one of the causes of water carrying over into the system). They also used baking soda to raise the pH to prevent corrosion. Either of those smells will wind up in the rooms upstairs, and nowadays some people think that the smell of vinegar might cause death, so be careful what you put in any boiler because the lawyers are lining up to take the cases.

There was this job where the superintendent in a building filled with filthy-rich people didn't get what he thought were appropriate tips during the holiday season. So he got even by saving his urine in a big Maxwell House coffee can. He drank coffee all day long and saved every drop of pee that he could muster. And at the end of each day he unscrewed the boiler's relief valve, poured in the contents of his Maxwell House can, replaced the relief valve, and sent the odor wafting upstairs to the rich folks.

Score one for Little Stinky.