Carl Brahe
It’s common to hear about explosions from gas leaks in homes, businesses and pipe lines, but most leaks are so small that enough gas to explode doesn’t accumulate. In the Boston city gas distribution system it’s estimated that $40 million in natural gas a year escapes. That amounts to 9 billion cubic feet a year coming out of mainly leaks too small to reach explosive mass . The city’s policy is to ignore the leaks that pose no danger for explosion. Rather than repair leaking sections they are systematically replacing the entire system with more flexible, longer lasting pipe.
In homes and businesses small leaks may occur from appliances with standing pilot lights. Most appliances have replaced pilot lights that burn constantly leaking gas into the air if they go out, with igniters that light the gas as needed. Igniters are common in furnaces, gas ranges and gas clothes dryers. Standing pilot lights are still common in water heaters and gas fireplaces. The amount of gas leaking from unlit pilot lights is too small to cause an explosion but may cause a rotten egg like odor. If you have a small gas leak you may not be able to smell it because of physical conditions that restrict smell, other odors that mask the smell or just because we get used to smells and cannot smell our own homes.
A gas leak that is too small to cause an explosion may have other less obvious dangers.
“Small gas leaks accumulate over time, and add a significant amount of pollutants to your home that can stress your immune system. A severe leak can reduce the amount of available oxygen resulting in dizziness, fatigue, nausea and headache. Lower concentrations can cause symptoms such as pneumonia, nausea, vomiting, irregular breathing, memory loss, and sinus pain. Some other adverse effects of gas exposure include flatulence, diarrhea, constipation, depression, pain in hands and legs.” - Read more -
Gas leaks in homes and businesses usually occur when a change is made that affects the gas lines. If a gas clothes dryer is moved to install a new washer or just to retrieve a lost sock, damage may occur to the gas line that feeds the dryer. Flexible gas lines can be crimped and develop leaks. Gas lines made from improper materials may become brittle or even corrode away. Improper installation may be the source of present or future leaks. Gas lines buried, or embedded in concrete, can break with shifting soil or corrode causing gas leaks under your foundation that may or may not explode. An area of dying vegetation may indicate an underground leak. Gas leaks are common in earthquakes, tornados, hurricanes, tsunami, mud slides and other events of nature.
If you smell a gas leak or detect a leak in any other way leave immediately. Don’t use any electronic devices, electrical switches or outlets. These can spark igniting gas. When you are away from the building call the fire department. You may not smell a leak, for various reasons, but you may be able to see or hear it. If work, moving or other activity disturbs gas appliances in any way check all the gas connections and joints. If you think you have found a leak it can be confirmed by spritzing the connections and joints with a soapy water solution. If a leak is present it will create soap bubbles that are easily seen. If you observe dirt or water being blown into the air or hear a whistling, hissing or roaring sounds, get away immediately and call the fire department.
In researching this article I discovered that the gas meter on our house is not properly bonded and grounded. We live in a rural area and when we first moved in our gas supplied by a tank in the back yard. About 10 years ago an underground gas system was put in and we switched. They came out and buried bright yellow, flexible gas lines (Corrugated Stainless Steel Tubing CSST). At the time bonding and grounding were not required. This requirement was added in 2009 after it was discovered that CSST can spring a leak if hit by lightning if not properly bonded and grounded.
From one of the gas utilities regarding the loose wire where the gas line comes out of the ground. This is a tracer wire and should not be tampered with. It allows location of underground piping.
"There is a wire wrapped around the gas meter. It is not attached to anything. Is it supposed to be there? If it is not supposed to be there, what should I do? And if it is supposed to be there, what is it for?
Yes, the wire is supposed to be there. It is a tracer wire and allows the location and route of service to be tracked from the meter to the main. Please do not tamper with this wire."