Experimental study on propane jet fire hazards: Assessment of the main geometrical features of horizontal jet flames

• Image processing of jet fires and resulting flame characteristics.
• Averaged flame width is a lot more stable than the maximum flame width.
• Horizontal flame shape is better represented using either a rectangle or a kite.
• Contours of flame are not always clearly visible using a CCD camera.
• IR camera provides improved flame visualization.

Jet fires are among the least severe fires in terms of direct effects, but are very important in terms of risk assessment due to the potential escalation of the incident by impingement or engulfment of the jet fire on the surrounding vessel, pipework or other components. This paper focuses on the determination of the main geometrical features (flame shape, length, and width) of medium-scale horizontal jet fires in air. The study is based on the experimental results of LPG jet fire released from a horizontal pipe of 1.9 cm diameter at different flow rates, with vapor flows, reaching a flame size of 1–10 m long. For each test, visible and infrared visualizations were recorded. First, the two visualization techniques are compared with each other, and with the different methods of flame shape determination available in the literature. The flame detected with each technique, both instantaneous and averaged, is then compared with basic flame shapes.