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We also have constantly changing environments day to day in areas like the North Sea
where it is not uncommon to have heavy fog in the morning followed only a couple of
hours later by clear skies, calm seas and bright sunlight. This is evident in the
following figures which show a comparison of summer and winter conditions in
Aberdeen, Scotland for example.
Figure 1: Site in summer
Figure 2: Site in winter
As most of the flame detectors present on the market are attempting to detect similar
forms of radiation emitted from those present in our everyday environment, this can
give rise to the potential for false alarm, or desensitisation to these stimuli. An
obvious example of this would be the largest fire in our solar system, the sun. When a
flame detector is designed to detect radiation from a fire, the sun can have an
interesting impact on what we achieve from our flame detectors. This is one of the
most fundamental issues when relating to flame detection design, and one which has
very little coverage within ISA TR 84.00.07. The effects of the environment on the