After seeing the gas explosion in Springfield, Maine last week, I thought that I would camp on this subject this week. Many of us have gas appliances, whether they are furnaces, hot water heaters, dryers or supplemental heating systems, such as gas fireplaces or gas logs. The gas used for your device might be natural gas or LPG (liquefied propane gas). There are differences in these two fuel sources. Some of the major differences are: 1. Vapor density- Natural gas is lighter than air, and therefore goes to the highest part of a room first when a leak has occurred. LPG, on the other hand, is heavier than air and will be found near the floor, or the lowest part of a building when a leak occurs. 2. Natural gas is distributed as a gas, whereas, LPG is transported and stored as a liquid. Once LPG is released from its container, it becomes a gas, with a liquid to gas expansion ratio of 270 to 1. 3. Natural gas and LPG are colorless and odorless, therefore an odorant, usually Mercaptan, is added so that a leak can be detected in its smallest quantity.
What should you do if you smell the odorant? If you know where the leak is, shut off the gas to the appliance. If the leak is in the main line and you have a propane tank, shut off the tank. If you have a natural gas leak in the main line, then it will have to be shut off by the fire department or the gas company at the meter. Remember, if the main gas gets shut off, then all of the pilot lights to all of your gas-supplied appliances will need to be relit, unless you have automatically lighting pilots, when the gas line is repaired and service is restored. Since it is hard to determine gas levels without proper monitoring devices, the best way to insure safety is to call 9-1-1, and have the fire service check levels, and insure that the gas has been shut off. Keep in mind, if I heard the story correctly, firefighters and the gas company had been on scene for an hour when the explosion occurred in Massachusetts last week. Thankfully, no one was killed. If there is any doubt of what you should do, evacuate and call 9-1-1. Evacuate in this case will mean more than getting out of the building. The Massachusetts explosion damaged approximately 65 other buildings in what looked to be about a city block.
Can natural gas or propane hurt me by inhaling it? The quick answer is yes. Once these gases permeate a space, they displace oxygen. The flammability and explosive characteristics are the greater hazard, but low oxygen can injure or kill you as well. Another hazard associated with a propane leak is that it can cause freeze burns. One detection device that I would recommend to anyone that uses gas-fueled appliances is a carbon monoxide detector. Carbon monoxide is again colorless and odorless. The greatest danger is that your body has a 200 time greater affinity for CO than for oxygen. In other words, if there is oxygen and CO present, your hemoglobin will accept the CO first. CO exposure results in headaches, reddened skin, nausea & vomiting, loss of consciousness and death. The treatment for severe CO poisoning is a hyperbaric chamber.
Whether you have natural gas or propane really doesn’t matter that much to you, as long as no problem exists. Once a leak occurs, you will need to understand some of the characteristics, so that you can take the right steps. Knowing how to shut off gas to appliances or knowing who to call will help when a leak occurs. Gas explosions do not happen often, but when they do, it usually makes the news. I leave you with this. When I was on the Hazardous Materials Team, we used to talk about a BLEVE (Boiling Liquid Expanding Vapor Explosion). The results of these are catastrophic, and the ingredients exist in Chesterfield County for one to occur. What we need to do is prevent the right ingredients from coming together. Take care of leaks while they are small.