Propane Danger


 


  The majority of propane gas users are not aware that propane has different properties than natural gas.  The following may scare you and it should.

 Leaking natural gas vapors rapidly dissipate in the atmosphere and float away from their source.  Though this is dangerous, natural gas is much safer than propane. Propane gas is heavier than air and as a result it drops to the lowest level around the appliance or source of the leak and remains there permanently unless moving air blows it away. Water heaters, furnaces, and propane gas tanks when located in an enclosed area such as an under-house crawl space or basement pose a definite danger because a propane leak will collect or pocket and will explode when the appliance ignites or in some instances even when a light switch is flipped.

                                           TWO SEVERELY BURNED IN LAKE COUNTY HOUSE FIRE

                                 
Photographed by Steve Atkinson, HVLA SECURITY

 
Just before Christmas 2011, two people were critically injured in a fire that destroyed a home in  Hidden Valley Lake.  Both young men were severely burned.
 
Because of the tremendous explosion and the entire home being immediately enveloped in flames, it seems apparent it was likely the result of a propane leak somewhere in the house. The water heater was catapulted into the driveway.  In this instance a smoke detector would have been of little value, but a propane detector or perhaps a CO Detector may have prevented this mishap.You need a CO detector in the garage.
 
A qualified and competent home inspector will always check for gas leaks, carbon monoxide and improper combustion of gas fired appliances. Observations should be made to detect the clues regarding the proper air to gas ratios. Unfortunately, my experience has shown me that most inspectors do not have the experience or the equipment to perform this important task.
CONVERTING GAS APPLIANCES
 
The conversion of any gas appliance to another fuel involves not only replacing the orifices (fixed and pilot), but the replacement of appliance regulators, burners and possibly the venting as well. Appliance conversions these days are not as simple and straightforward as they used to be, if the appliances are able to be converted at all. Historically, most all appliances could be converted from natural gas to propane and vice-versa but the gas appliances manufactured today are engineered (by professional engineers) to be used with only one type of fuel as specified by the manufacturer for dedicated fuel use. In other words, most all gas appliances are built to use either propane only or natural gas only and are not designed to be converted or modified for use with another fuel.
 
The topic of converting appliances has been a problematic issue for the propane industry because of the “do it yourself” consumers who believe that switching or drilling out an orifice constitutes an appliance conversion. If an appliance is to be converted for use with another gas (natural or LP), then several other factors must be addressed including:
 
-      Appliance Regulator – Differences between natural gas and propane appliance regulators involve inlet and delivery pressures.  The wrong type of gas appliance regulator would deliver pressure either high or too low for the use of the appliance. It would be similar to watering a plant with a high pressure fire hose or watering your yard with a hose with a diameter of a guitar string. Regulators of any type should be changed, serviced or converted by a licensed professional—regulators are “hands off” in any part of a gas system.
-      Burners – Orifices on a burner function in unison with the delivery pressure supplied by the regulator and can lead to incomplete combustion if improperly sized. Burners can also damage an appliance if the conversion requires larger or smaller orifices be in place on or around the burner.
-      Burner Air Shutter – Air and gas are mixed at this point before entering the burner and are used to adjust the flame condition. With varying types of primary air shutters, this essential air/gas mixing mechanism must be of the proper type and must be adjusted properly so that complete combustion occurs.
 
Actually, it would be cheaper to buy a new appliance than to try and properly convert one that is designed for use with either propane or natural gas. Even if appliance conversion kits are available for certain equipment, the conversion should be handled by licensed technicians so that all necessary adjustments can be made prior to placing the converted appliance into operation.
 
INCOMPLETE PROPANE COMBUSTION RESULTS IN CARBON MONOXIDE
 
Carbon Monoxide is produced during the incomplete combustion of  propane. Incomplete combustion is defined as within the limits of flammability but higher or lower than the ideal ratio of 4 parts propane to 96 parts air. Incomplete propane combustion can occur in one of two ways:
 
-      Lean Burn - The ratio of propane to air is less than 4 parts propane. 2.5 parts propane to 97.5 parts air would produce a lean burn. A lean burn can be recognized when flames appear to lift away from the burner and can potentially go out.
-      Rich Burn – The ratio of propane to air is more than 4 parts propane. 8.5 parts propane to 91.5 parts air would produce a rich burn. Recognizing a rich burn is very simple as the flames are much larger than they are supposed to be and are mostly yello in color.
Several products of incomplete combustion that are easily visible and if noticed, action should be taken immediately. Visible signs of incomplete combustion include burner flame appearance (as listed above), soot collecting on appliance windows such as that of a space heater and excessive water vapors forming on windows and cool surfaces during appliance operation. Appliance service and adjustment is need if any of these visible signs of incomplete combustion are noticed.