Natural gas flame and CO

You can't just \"eyeball\" the flame...

you must use combustion testing instruments to set up, service and check ANY combustion appliance. That's the ONLY way to know what the status of your system is.

Town Gas

Not only did they burn coal gas ("Town Gas") but most, if not all, of the old gas fixtures used a cloth(?) mantle of some sort. Some also had a ceramic mantle. In 1889 a gas light was invented that pointed it's flame down instead of up to compete with those new fangled electric lights. The last coal gas plant went off-line in NY in the early 70s. Between 1850 and 1960 more than 50,000 coal gas plants operated in the US.

There was also carbide gas (acetylene). This was invented in the late 1890s and by 1900 was becoming very a popular way to produce domestic gas, especially in Europe. Home owners would have a tank partially buried in the back yard where they would mix carbide crystals and water to produce acetylene - sometimes with explosive results. Another option was vaporized gasoline. In this case, there was a large contraption usually in the basement that would be filled with gasoline. There would be large counter weights that would have to be reset periodically like a grandfather clock. The weights would compress the gas and vaporize. There is one of these in the Smithsonian.

By the 1890s most towns with populations of about 10,000 or more had some means to produce town gas. As the towns grew they would interconnect there piping systems with other towns. By the 20s natural gas was starting to replace coal gas as the preferred method but the two systems operated side by side for many decades.

Greg

Its the flame

hitting the logs themselves. If you look at a well used set of logs in a gas log set youll see soot collecting on the logs. Incomplete combustion , take the logs out youll have a nice blue flame. Never had the pleasure of working on a vent free insert and dont think I want to, Ill have trouble sleeping.

luminous flame

Check out the discussion in the thread Is CO Poisonous?

The yellow tipping is a combination things. You have incomplete combustion due to cooling flames(secondary air and impingement) and less than stoichiometric combustion mixing resulting in unoxidized carbon & trash particles glowing. There are various other compounds in this gas plume including CO2, CO, NOx, aldehydes, air,unburned fuel and water vapor. When the unburned carbon atoms attach in clumps, you get "soot". As seen under polarized light microscopy(PLM), these clusters are friable and easily disperse when pressed. Compare that to the soot from long chain alkane aliphatic hydrocarbons such as diesel fuel, heating oil, cooking oil, or candle wax. These clusters have unburned fuel attached with a yellowish matrix and the whole mess does not disperse when pressed. While PLM is usually sufficient to identify the soot source, gas chromatography with mass spectrometry or gc/ms will identify the exact compounds in the soot and therefore, its source.

interesting

Bob,

thanks for the info. I had no idea about the difference in soot. How hard would it be to tell the difference in the field between the two types? There is often a "it's from candles" response to soot streaking from baseboard heaters. If you could tell the difference between types of soot in the field, it could really help this.

Also, I'm interested in the aldahyde formation. How does it form, and what are the concequences? Do the levels here compare to the long term exposure problems often discussed in IAQ talks?

jerry

Jeff, you might want to check

with the Code authorities in your area. Many locales have outlawed the use of gas lighting. I remember reading that the Lovely Lane Methodist Church in Baltimore (first one in America, for you Methodists out there) originally had a spectacular celestial display in its ceiling that was lit by gas. During a recent restoration, they had to get special permission from the Code authorities to put it back into service.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

It is my understanding...

... that the soot from diesel engines, candles, and the like will have a somewhat oily consistency, whereas soot from gas flames impinging on cold surfaces will lead to a very fine soot that is a lot like black dust. Carbon black is used in everything from tires to newsprint.

I can't remember how aldehydes form, yet I learned to smell for them when I was designing/testing the outdoor gas water heater. They're a sure sign that the combustion has gone to heck. If you can't smell the aldehydes, it's no gurantee that CO is not present... it just means that it won't be present in ridiculous amounts.

gas lights& logs

Manufactured gas contains as much as 40% CO. This is why in the old days you could turn on the stove to asphyxiate someone. The color and pattern of the flame from a oight fixture burning mfd. gas are quite different from the same fixture burning NG or LPG. I found one old conversion boiler in Philly still set up to burn mfd. gas. It was pumping out ~1,600 ppm CO and the chimney was rotten. I guess this points out why more people didn't die back in the day or in this case: The houses leaked like a sieve. The Stack Effect flushed all the nasties out fast enough to keep from killing everyone.

As for vente logs in restaurant fireplaces, this is a bad idea. I'm working on a case in Atlantic City with negative 27 Pascals of pressure. You can't hardly open the doors.Putting atmospherically vented appliances in commercial establishments with these huge exhaust only ventilation systems is really asking for it. I had another case in Wilmington, De. in a 4 star restaurant. The vented logs were installed in an old forge and vented really well horizontally out into the room until someone opened the front door. Then, they'd vent up the chimney for a moment. The chimney becomes the makeup air system for these buildings. BTW, ASHRAE 62.2-2003 would force builders to balance the houses including providing engineered makeup air where the house is less than 0.35ACH or as otherwise indicated by NFPA54 air requirements. If a builder claims his house leaks enough, 62.2 says he has to prove it with a blower door test. Now, if we could only agree on combustion spillage testing and Duct Blaster testing...