rdesigns

This issue is one that I have struggled with for years since I'm a code official (mechanical and plumbing.)

The International Fuel Gas Code, the Uniform Mechanical Code, as well as NFPA 54 all allow ventless heaters with certain restrictions and requirements. Some jurisdictions have amended these codes so as to prohibit ventless room heaters in residences. In the process that led to their approval,the code-writing bodies reviewed the claims of the makers of ventless appliance room heaters and fireplaces and came to the conclusion that they were safe if installed as directed by the manufacturer.

However, I have to wonder if the evidence was complete since the studies in favor of the ventlsss appliances were all paid for by the manufacturers, as far as I know. As I recall, the studies claimed that not a single death had been attributed to properly installed ventless heaters. That may still be the case, but even so, there may be cases not documented, or cases of illness resulting from low-level CO poisoning that have never come to light, and, in fact, may not even be suspected by the occupants using ventless heaters since CO poisoning mimics symptoms of common illnesses, or aggravates existing illnesses.

The safety feature of these heaters is what the manufacturers call an ODS (oxygen depletion sensor), which is nothing more than a tilted pilot flame, which, in the event that the normal oxygen level(21%)drops below 19 or 20 per cent, causes the tilted flame to pull away from the thermocouple, thereby shutting off the appliance's main gas valve.

BUT, if the reason that the oxygen level has dropped by 1 or 2 per cent is because it has been replaced with carbon monoxide, that would be fatal. (1% CO translates to 10,000 parts per million; 400 ppm can be fatal in a few hours' esposure.) Of course, if this were happening even rarely, there would be immediate outrage along with calls to ban ventless appliances, and manufacturers would pull out of the market due to the huge liability and the fact that none of them are in business with the intent to do harm to even one person. My point is that the ODS is incapable of detecting low-level CO, which might go undetected for months. Dirty burners can produce CO even in the presence of adequate oxygen levels.

It would be very useful if there were some way to verify, collect and publish any cases where ventless heaters were the cause of illness or other problems. Maybe no such cases exist, but I doubt that. I appreciate FHB's efforts to shed more light on this issue.

Nice thoughts, but I'm bound to say, if that's what we today call poetry, then carpenters I know by the dozen are poets. And not just carpenters. Farmers, ranchers, concrete finishers, etc., many of whom seem to be people who work with their hands.

They're people who, while their hands are busy with chores they no longer need to think about, have time to think. When they put their thoughts into words, the words are few and cut, dig or smash to the heart of the matter. That's poetry.

One construction supervisor I knew once said: "I like to hire those country boys because they're so godd****d stupid.
You can give them a job you know is impossible to do, and they're so stupid they'll go out and do it." That's poetry.

Jean Paul,

My fields of expertise are plumbing and mechanical. I have been the chief plmg/mech inspector for the City of Idaho Falls, Idaho, Building Department for the past 16 years. Before that, I had 27 years in the plumbing trade, mostly residential new construction and remodeling.

I served two terms on the Technical Committe for the development of the International Fuel Gas Code for the 2006 edition.

I would be in interested in responding to code questions and technical questions relating to plumbing and HVAC.

Russel Goyen
208-612-8273