Laminar Smoke Points of Wax Candles

An experimental investigation of laminar smoke points of candle flames is presented. Adjustable wicks with diameters of 1.7–7.3 mm were used to measure smoke points in quiescent air for 14 different waxes. The measured smoke points increased with wick diameter. Smoke points interpolated to a wick diameter of 4.5 mm varied from 41–80 mm and increased from commercial waxes (candelilla, carnauba, beeswax, paraffin) to normal alkanes (hexatriacontane, octacosane, tetracosane) to primary alcohols (octadecanol, docosanol, hexadecanol) to carboxylic acids (stearic, palmitic, lauric, myristic). Wax smoke points decreased with increasing carbon number. Alkane and alcohol smoke points decreased with increasing fuel C/H ratio and correlated with past measurements of liquid fuels and polymers. Soot emission was not possible for any fuel when wick diameter was below 1.7 mm or when wick length was below 5.9 mm.