Unvented Gas Fireplaces: ODS Safety Pilots Offer False Security To Consumers
May 10 '02
The Bottom Line ...the oxygen depletion pilot system was a fine invention. However, I am sure, it does not deserve the media hype the gas industry and government agencies have devoted to it.
I have written many articles about the dangers of unvented gas room heaters and fireplaces, to the point that regular readers of my reviews must think I'm obsessed with this subject. Well, here's a news flash, I am. I'm obsessed with the notion of informing consumers of the dangers of unvented gas fireplaces and making changes to national safety standards that may prevent a few thousand injuries and perhaps even save a few hundred lives each year. That's my sole motive for these reviews and until changes are made by the agencies who are responsible for these products, I intend to keep putting their feet to the fire, metaphorically speaking. Preferably, a vented fire, for their safety.
I would like to remind people, once again, that gas-fired heaters "do" injure and kill people in three different ways, through accidental fires, carbon monoxide poisoning and on rare occasions an explosion.
Injury, illness and death caused by soot, smoke, nitrogen dioxide, carbon monoxide poisoning, fire or even an explosion, are generally the price of abuse and/or neglecting the annual maintenance of a fuel burning appliance in a home. Statistically, well over 30,000 people per year, in the United States, sadly, have to agree with me.
The U.S. Consumer Product Safety Commission (CPSC) estimates that space heaters, including both fixed and portable heaters, are associated with about 21,800 residential fires every year. About 300 people die each year in fires started by these heaters.
The U.S. CPSC further estimates an average of 10,200 people per year, were treated in emergency rooms across the United States for each of the five years, 1995 through 1999, for unintentional carbon monoxide poisoning caused by consumer products. Approximately 78% of these cases were attributed to natural gas and propane heating systems.
"Nearly 300 people die each year unnecessarily from carbon monoxide (CO) poisoning, a majority because of improperly vented gas appliances.
(Note: These numbers do not include CO poisoning cases associated with automotive vehicles or those which were determined to have been caused intentionally.)
Starting with the basic premise that, most gas appliances, when installed, operated and maintained properly, are safe. Conversely, any gas appliance can cause damage, injury, illness or even death, if they are not used as intended by the manufacturer, or if they are not installed and maintained properly. These warnings may be found in any instruction manual, and are included with every gas appliance. These kinds of warnings are "required", by the standards that govern all fuel burning appliances.
Printed warnings, ignored by consumers, only serve to give the manufacturer's, of gas appliances, a plausible defense against any future lawsuits brought against them. If and when something goes wrong. According to the above government reported statistics, something is going wrong too frequently, across the United States of America.
ODS SAFETY PILOTS OFFER FALSE SECURITY:
Almost every website that promotes unvented, vent-free or ventless gas heaters and fireplaces, also prominently advertises the added safety of an ODS pilot system. The Vent-Free Gas Products Alliance which is a division of the Gas Appliance Manufacturer's Association (GAMA) advertise the ODS pilot system with descriptions, pictures and even video demonstrations on how they work.
The U.S. Environmental Protection Agency (EPA) also refers to the need to have an ODS pilot if you have an unvented gas heater. In addition to their warnings about poor indoor air quality associated with unvented gas heaters.
Even the U.S. Consumer Product Safety Commission (CPSC), (who have been in email contact with me recently), recommend an ODS pilot system and their organization takes credit for mandating them in all unvented gas heaters, in the early 1980's, as an added safety precaution.
The not so funny thing is that, statistically, the numbers of reported injuries and deaths from gas space heaters, has apparently not decreased since the introduction of the ODS safety pilot. In fact, the numbers appear to be higher than ever before, in recent years. Could this be attributed to better reporting of incidents and better records keeping? Or has the much flaunted ODS safety pilot had no impact on the safety issues surrounding unvented gas space heaters and fireplaces?
WHAT IS AN ODS PILOT?
The ODS pilot or oxygen depletion system, sometimes referred to, wrongly, as the oxygen detection sensor, was a wonderful innovation in Europe, decades ago. This pilot system is simply designed to blow itself out, if the oxygen levels, within the air in a room, fall from normal (20.9%) to an abnormal level of 18% or less. It is a very valid safeguard against having a gas appliance in a room that is depleting/burning, all of the the oxygen.
We know from tests in laboratories that a gas flame will become unstable as the oxygen levels decrease. As the oxygen levels in the air decrease, incomplete combustion of the gas increases. Incomplete combustion produces carbon monoxide.
WHY DO ODS SYSTEMS OFFER FALSE SECURITY?
1. The ODS pilot is tested under controlled lab conditions which you as a consumer will never likely encounter. Basically, they are tested on appliances in a tightly sealed, 10'X 10'X 10' cubicle (1,000 cubic foot room). How many houses are there built to those specifications? For that matter, how many homes have 10' high ceilings for the hot flue gases to collect and stratify, far above the ODS safety pilot.
2. The oxygen levels in a room do not diminish equally throughout the room. The hot combustion gases rise to the ceiling, while the cooler, oxygen rich air within the room remains on the lower level of the room. Without steady circulation of air within the room, the air quality at the level of your nose, can become much worse than the air quality at floor level, feeding the gas burner.
3. The chances of actually consuming all of the oxygen within the air of your living room are very remote. The average home allows for sufficient ambient air to infiltrate, through doors that are opening and closing, around windows and through generally accepted construction methods which specifically provide air ventilation into a home.
4. Therefore the ODS system is not going to be activated in "any" home of average construction and size.
5. A major reduction of oxygen in the room air, to the gas burner is only one of many ways to generate deadly levels of carbon monoxide. In fact, it would have to be one of the rarest ways for a gas heater to injure or kill a person.
What The ODS Pilot Does Not Protect Consumers From
Some of the more common causes of a gas heating systems producing high levels of carbon monoxide are;
A) Flame impingement. This is a particular problem with unvented gas fireplaces. The flames are designed in many to lick against artificial logs to produce a wood fire effects flame and there are ceramic fiber coals or clumps of mineral wool, laid on top of the burner ports to produce a glowing coal bed effect.
When a flame impinges on cooler surfaces the result is incomplete combustion. As the appliance warms up, the carbon monoxide levels from incomplete combustion will generally decrease to a safer level. However, if the logs or ember materials are incorrectly placed, the impingement can be so extensive that massive amounts of carbon monoxide and soot are continuously generated into the home.
Homeowners are famous for adding all kinds of strange things to the burners to make them more attractive, including; pebbles and shells from the beach, to lava rock from the barbecue. All of which will produce carbon monoxide into the room using an unvented gas fireplace.
Flame impingement can also be caused by a poorly adjusted burner which allows flames to lick off the roof of the firebox. This condition is often accompanied with soot, which will quickly cling to the moist walls of the home and leave a grey oily texture.
A good example of incomplete combustion from flame impingement is that gas barbecue. With the type that use lava rock or some other form of briquettes. With the flames intentionally licking against the artificial coals, incomplete combustion is a common trait within a gas barbecue and your backyard grill can emit massive amounts of carbon monoxide when you operate it. The safety standards for barbecues are obviously much more relaxed because the appliance is outdoors and the carbon monoxide is unlikely to harm anyone. The point is, there is no lack of oxygen on the backyard patio and yet, those appliances can produce thousands of parts per million of carbon monoxide.
B) Poorly adjusted or clogged primary air openings to the gas burner. With yellow flame unvented gas fireplaces, it is quite common for service technicians, installers or even the homeowners to fiddle with the shutter adjustment of the primary air supply. Usually these shutters are adjustable so that the burners can be used with either natural gas or propane, or they may require some adjustment when installed at higher altitudes.
Then of course, there's the dust bunny, carpet lint and cat hair syndrome. Over time these airborne particles are drawn into the gas fire and the air supply of the burner. As the burner is slowly choked of air, incomplete combustion takes place and carbon monoxide is delivered into the room.
In this case, the air within the room can be rich with oxygen, but the necessary primary air to the burner has been choked off and causes air starvation and incomplete combustion. Much in the same way it would cause incomple combustion if the oxygen were reduced through the combustion process and not restored by infiltration air.
C) Poor mixing of the gas and air in the venturi of the burner, due to misalignment of the orifice. This can happen at the point of manufacture, or by accident when a service technician has removed the burner or the orifice for service work. Misalignment of the orifice within the venturi of the burner is a common cause of carbon monoxide production and it is not very easy for a service person to diagnose.
D) Improper gas flow rates. The burner can be overfired or underfired do to the incorrect orifice drill size from the factory or from the last service technician who worked on it. The supply gas pressure can be too high, which is a particularly common complaint from those who use propane. The manifold pressure can be too high, again this can be an error from the manufacturer who is supposed to test every gas valve for proper pressures, but, doesn't always in reality.
It could also be done by the installer who is simply trying to give the consumer a bigger flame for aesthetic reasons. Either way, firing a gas appliance at an input rate that exceeds the manufacturer's certified specifications is a sure-fire way to produce high levels of carbon monoxide and to possibly cause a fire through overheating of the appliance.
E) A crack or a hole in the firebox. Especially if there is a circulation fan running that will blow the flames around in a random pattern, again causing incomplete combustion and carbon monoxide into the home. Cracks and holes in the firebox can come from the factory through poor quality control or they can develop over time with fatigue from expansion and contraction or from corrosion through condensation that forms on the firebox each time it is lit from a cold start.
F) A crack in the burner. It would not be uncommon for a gas burner to develop a crack over time and begin to burn erratically and generate carbon monoxide into the home. Some manufacturers make their own burners, which are subject to the skills of their welders and the diligence of their quality control department.
G) Plugged burner ports. Burner ports can come from the factory plugged with paint or other debris from production. Ports can also be plugged accidentally by the installing contractor as they spread the ceramic coals or mineral wool over the burners. The ports can also plug up over time from a variety of other airborne sources. Plugged burner ports can create an unbalanced burn, causing carbon monoxide. They can also cause delayed ignition and in rare cases an explosion.
Once again, simply look at an old gas barbecue, that has seen a few seasons of cooking time, to see what I am talking about here. Grease drippings and other unidentifiable foreign materials will often plug up the ports on the barbecue and cause the flames to rise on the other open ports.
H) A gas leak on the manifold side of the appliance. Again, this can happen in production, or by accident when the unit is installed or serviced. With natural gas in a vented gas fireplace, at least a small leak will be vented to the outside. With an unvented gas fireplace the leaking gas has no where else to go, but into your family room.
Read my lips, THE ODS PILOT DOES NOT REACT TO ANY OF THE ABOVE CONDITIONS.... and I've probably overlooked a few ways in which an unvented gas fireplace can place you and your family in harm's way.
Like I've said above, the oxygen depletion system was a fine invention. However, I am sure, it does not deserve the media hype the gas industry and government agencies have devoted to it. Unless you've sealed yourself into a vacuum, by taping up the gaps around the windows and doors and closed yourself into a tiny "cubicle" within the house, the ODS pilot is not going to activate in a typical home environment. Even in the tiny, hermetically sealed, cubicle we use in test labs it can take up to and hour to consume 5% of the oxygen contained in the air in the room. (Depending upon the Btu input of the appliance being tested)
The point of this entire review is, just because the ODS pilot is never activated, it does not mean you and your family will be safe with an unvented gas fireplace, for the many reasons listed, "other than" oxygen depletion.
I have to admit, that I do get tired some days. Tired of the short, auto-response emails from bureaucrats, within government agencies, who after reading my extensive submissions, refer me to yet another department within their maze. (Usually, unsigned or simply initialed.)
Worse, to receive back a dismissive email from the President of the Gas Appliance Manufacturer's Association (GAMA) who implies the best course of action is for them to ignore this old "fool" and "let this thing die."
HOW TO MAKE A DIFFERENCE
Ironically, it is apparent to me, that many government agencies, contractors, dealers, distributors and manufacturers, generally agree with my views. Most importantly, judging from the sheer numbers of encouraging emails I receive from consumers, who have read my articles and reviews, they are in agreement too. So, what does it take to make a change?
My best guess is, for all those who understand the importance of these health and safety issues, to write to the people who can make a change. Ask them politely, why they don't feel the need to answer questions about a product that is dangerous to the health and welfare of the consuming public.
We don't want more of the same rhetoric that they put in their advertisements, we would like answers to technical questions which question the very existence of a product type. Provide technical answers to technical questions, backed by up-to-date research. If they fail to do this, or refuse, I believe the answer is obvious.
Thanks for reading, please feel free to pass this message on, to those you care about, or even to those you don't, "Unvented gas fireplaces represent one of the greatest preventable and avoidable health and safety issues within the United States. Vent "any" fuel burning appliance from your home and live to enjoy it.
All the best and live safe,
Regards,
The Gasman
"Help Turn Up The Heat And Ask For Answers"
You can reach some of the key agencies and individuals at the email addresses listed below;
At the Gas Appliance Manufacturer's Association (GAMA) write:
Mr. Evan R. Gaddis, President, egaddis@gamanet.org
At the Vent-Free Gas Products Alliance write:
Ms. Mary Carson, Program Director, Mscsmitty@cs.com
At the U.S. Consumer Product Safety Commission (CPSC) write:
info@cpsc.gov
At the Environment Protection Agency (EPA) write:
James Anderson at anderson.james@epa.gov
or
Rich Lemley at lemley.rich@epa.gov
 |
|
|
|
|
|
|
Epinions.com ID:
the_gas_man
|
 - Top 200 |
|
Location: Where I Need To Be
Reviews written: 58
Trusted by: 250 members
About Me:
Still venting after all these years.
|
|
|
© 1999-2009 Shopping.com, Inc.