Why is it generally not recommended to use a halide torch outside on a rooftop for leak detection?

Using a halide torch outdoors on a rooftop for leak detection presents challenges primarily due to issues with visibility and environmental conditions. One significant factor is the difficulty in detecting the color change that indicates the presence of halides, as bright outdoor lighting can overshadow the subtle color changes that signal a leak.

When using a halide torch, the detection relies heavily on observing the flame’s color change when it comes in contact with refrigerants or halide gases. In a well-lit environment like outdoors, particularly in daylight, the color variations may not be easily discernable. This can lead to misinterpretation of the results, potentially resulting in missed leaks or false confidence in the roofing system's integrity.

Other reasons for avoiding halide torches outdoors might include issues with safety, reaction with environmental factors, or limitations imposed by regulations, but these are secondary to the primary concern of visibility impacting effective detection.