Flare and radiation analysis

Before a test is started, the coordinates of the flare and the radiometers (see Chapter 6) used to measure radiation are determined by utilizing a laser range finder to measure distances to three fixed objects with known coordinates and a technique called "triangulation." Multiple radiometers are used to measure various radiant fluxes simultaneously. A photo of the radiation measurement system is shown in Figure 28.12. The measured radiant fluxes, through sophisticated mathematical analysis, are used to determine the coordinates of the effective "epicenter(s)" of the flame, and the radiant fraction, which is defined as the fraction of heat release from combustion that is emitted as thermal radiation [43]. Solar radiation is subtracted from the radiation measurements as appropriate. 

Such systems can generally recognize fires of 34,000 BTU/hr (lOkW) or greater at 33 ft (10 m) within a 90°cone of vision, and are immune to common false alarms such as hot CO2 emissions, reflections from flare radiation, black body radiation, and hot work. An added benefit is that the video image can be recorded for later analysis. 

Not all possible deficiencies are included in the above statistical analysis. There are also concerns about items such as excessive flare radiation levels, inadequate knockout drums, poorly designed quench systems, discharge of toxic fluids to atmosphere, discharge of combustible or toxic liquids and gases to atmosphere and a general lack of process safety information upon which to base a safe pressure relief system design. Therefore, it could be stated that the actual total deficiency rates reported may even be understated. 

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