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Under One Roof

Canadian Roofing Reference Manual

1.3.1 Flammability

Propane is highly flammable and all that is necessary for combustion is a sufficient quantity of propane gas mixed with oxygen (air) and a source of ignition. The range of flammability are those quantities of propane that must be present in a propane/air mixture to make it combust. The range for propane is 2.4% to 9.5% of the total propane/oxygen mixture must be propane in order for it to be combustible. This means that any percentage of propane in a propane/air mixture between 2.4% and 9.5% will be sufficient for the propane to combust. If a mixture is 2% propane and 98% oxygen, there will not be combustion. If a mixture consists of 10% propane and 90% oxygen, combustion will not occur. However, an improper air/ gas mixture can produce Carbon Monoxide (CO) that is a deadly product of incomplete combustion.