I have a question about natural gas. In Knoxville last weekend, two teenagers were walking and one decided to light a cigarette. There was a corroded gas pipe where they'd been walking so that the air around them had enough gas in it to ignite into a fireball, buring both teenagers. One had burns over part of his body and the other was totally engulfed and was burned over 90 percent of his body.

I understood that natural gas was odorless, but had a smell put into it so that it would be detectable. You'd think the teenagers would have been able to smell the gas if there were enough in the air to ignite. Are there areas in which natural gas has no odor put in?

My first thought was that yes, smoking will kill you, but usually not that fast. I certainly hope they survive, although those kinds of injuries will most certainly be with them for the rest of their lives. How sad.

Here's a good website about the history of odorized natural gas ...
http://www.oxychem.com/products/odorants/newlondon.html

Even if gas has an odor, an individual might not notice it, say they have bad sinuses, etc, etc.

Now, propane does have an odor.

In any case, when it comes to fuels and gases, one common way to check for leaks is with a NONOIL/NONPETROLEUM based soap/water solution--just like detecting a leak in a tire or innertube. And when doing this type of work, remove anything on your person that could cause a spark--and double check your footwear! Also remove anything from the immediate area that could cause a spark! And contact the approperiate agencies (fire department, gas-electric company, etc, etc,) if the situation is serious enough.

Always remember if you do smell gas NEVER operate a light switch, the resultant spark can create an explosion.

Years ago, in Ottawa, a caretaker of a theatre smelt gas one morning, and (we deduce) turned on the light switch to the basement of the theatre to investigate the cause. It was the last thing he ever did.

The building disappeared. A set of theatre exit doors, still coupled together, buried themselves into a jewelery store across the road.

LP (propane) is heavier than air. Therefore, if you have a leak situation, you will have to get close to the ground and sniff around to find it. If you can smell it, get out of the area, fast. Turn off the gas at the tank.

I was working on a furnace in a crawl-space, dodging spiders, and critters galore. This furnace ran on LP gas. The customer had complained that the gas tank had emptied over the summer. The furnace was the only gas-fired item in the house. After checking all the gas lines for leaks using the previously mentioned soap, and seeing that the tank had just been filled, I went under the house and crawled to the furnace. I could smell a slight gas odor.

I found a bad gas valve on the furnace. Normally, when the pilot light goes out, the gas valve will shut down after about 30 seconds. It will not re-open until the pilot is re-lit, and the thermocouple heats up enough to satisfy the gas valve safety control. Well, this time, the pilot, though out, was still getting gas and it was not being burned, and was all over the floor of the crawl space. The safety control in the gas valve was faulty.

I replaced the valve. This was a good hour job. I didn't notice any gas smell anymore. So, I whipped out my trusty Bic lighter and lit the pilot.
I saw a blue flame whoosh away from me and down the grade under the house to the foundation. It happened so fast that I didn't have time to react. As quickly as it happened, it was gone.

It never occurred to me at that time that the LP was heavier than air and had pooled in the lower part of the crawlspace.

Natural gas is lighter than air, and has the rotton egg odor, too. I think that it would take alot of gas build-up to ignite when a match is lit. The fumes have to be very obvious for the concentration to be heavy enough to ignite. Thats why the smell is there. Still, get out of the area. Dont turn on anything that could cause a spark. In my case, I once had to get out of a house and shut off the gas at the meter. I called the fire department from my service truck. They told me that the house would have blown up if the gas had lingered much longer. There was a crack in a fitting on a pipe in the house that caused the problem.

Believe me when I say that I have a healthy respect for any gas, oil, gasoline, kerosene, etc. all the time.

I saw the piece on the Knoxville neighborhood on the news. The flames were really bellowing out of the hole in the ground. It must have ruptured the line in the ground.

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I was told that there was so much gas absorbed into the ground that they couldn't safely run any digging equipment. They had to "aspirate" the ground all around our yard for a whole day before they could start work. Basically, what they did was drill holes all around the yard and inserted these "T" pipes about 4 feet down into the soil. Big, industrial compressors were hooked up to one branch of the "T" and high volumes of air were pumped through them. I was told the idea was to use the venturi effect to draw as much gas out of the ground as possible to make it safe. There were about 5 or 6 of these devices all around the place and they left them running overnight. Tests were made periodically until the "LEL" readings were low enough to permit digging.

The next morning they started digging. They found a 6 inch (or something) main pipe had rusted through and was leaking pretty badly. They "jacketed" the line with this big "coupling-thingy" that looked like something out of a Frankenstein movie. When they were all done, one of the supervisors came by to make the final tests and pronnounced the area safe again. He basically told us that we were lucky that the house didn't blow up because the gas was starting to leak through the basement walls and we didn't know it. (We had to let them into the house to perform tests.)

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This story was featured in the paper, and mentioned on all of the local TV stations when it happened. It was the lead story on several. Now Evans reports the death of the burn victim.

Where's all this coverage now? I read the paper daily, and do the news on TV nightly. Not a word has been mentioned.

Life can be short.

Gas can be tricky, but I am in no way afraid of it. As long as your safety controls are functioning, you have nothing to worry about. The same goes for electric.

We had a house in 1966 that had the Total Electric medallion on the front door. The first month that we ran the heat in the fall, the bill was $350!

There are also practical considerations -- for example, lighting a gas stove generates even heat almost immediately. Starting an electric burner takes a while to heat up to maximum temperature. A pot with an uneven surface works just as well on a gas range, but loses contact area (and hence heating) on an electric burner.

If we were like France, and got 80% of our electricity from nuclear power, then perhaps the inconveniences might be worth it to reduce emissions from burning fossil fuels. However, coal-generated electricity is probably much dirtier overall than just burning gas directly in your home. And using natural-gas generated electricity in place of a natural gas stove is just silly.

There are no easy answers in the field of energy. At least, not until fusion becomes viable. Twenty more years, the scientists say. And as some people have pointed out, it was twenty years way back in the 1950s, too.

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John P. Pytlak, Senior Technical Specialist
Worldwide Technical Services, Entertainment Imaging
Eastman Kodak Company
Research Labs, Building 69, Room 7419
Rochester, New York, 14650-1922 USA
Tel: 716-477-5325 Cell: 716-781-4036 Fax: 716-722-7243
E-Mail: john.pytlak@kodak.com
Web site: http://www.kodak.com/go/motion