I have previously discussed the concept of odor fade in association with the use of propane. Likewise, in natural gas, odor fade occurs. Odor fade is a term that is used to describe the process by which the odorant selected by the natural gas industry fails to serve as an effective warning in the event of a gas leak. The reasons for odor fade occurring in natural gas are many of the same reasons that apply to propane gas. Natural gas is odorless, colorless, and invisible. This means you cannot see, taste, touch or smell natural gas. It is extremely flammable and explosive and any leak of natural gas in a home or building is very dangerous.
The warning odor will not awaken sleeping persons. This means for a sleeping family there is no warning in the event of a gas leak. Contact with concrete walls, masonry, soil, building blocks, furniture, fabric, drapes and other materials likewise can strip the odorant from natural gas thereby reducing or eliminating the odor. The odor stays with the propane. This means that unless the consumer’s nose is in the concentration of gas there is no possibility of being warned by odor alone. Indeed propane gas can leak in an adjacent room of a home and the occupant still will not be warned.
The human nose is a poor gas detector. The reason for this is that there are physiological limitations to using an odor warning including olfactory fatigue. By this method one can be exposed to the odorant before it reaches a detectable level and by the time the odorant is detectable the nose has become desensitized such that it cannot detect the odor.
Odor masking can occur. Such common smells as cooking odors are known to cover up or mask the odor warning. The strength of smell is a factor. Studies have shown that persons normally associate a weak odor as not being dangerous while a strong odor is considered dangerous. Colds, age, sex, smoking and distractions all factor into whether a person will be warned by the odor warning system. The distraction a person is under plays a significant role concerning the effectiveness of the odor warning. If a person is in a directed mode attempting to smell for natural gas especially at floor level and told to smell for natural gas there is a far greater chance the occupant or consumer will be able to detect escaped natural gas. However when a person in a building has no expectation or knowledge that there might be leaked natural gas, there is a 50-50 chance that the odor will not warn anyone.
There is however a device that natural gas users must have to provide protection for themselves and their families. This is a natural gas detector. It is a device that works similarly to smoke detectors in that it will sound an audible alarm when natural gas is detected. These devices are relatively inexpensive and easy to install. Natural gas detectors can be purchased in any major hardware store. Please purchase and install one or more natural gas detectors in your home.
Donald G. Beattie