Gas detector in industrial refrigeration processes and biological degradation processes, including exhaled breath. Depending on the required sensitivity, different types of sensors are used (e.g., flame ionization detector, semiconductor, electrochemical, photonic membranes). Detectors usually operate near the lower exposure limit of 25ppm; however, ammonia detection for industrial safety requires continuous monitoring above the fatal exposure limit of 0.1%. There are several different sensors that can be installed to detect hazardous gases in a residence. Carbon monoxide is a very dangerous, but odorless, colorless gas, making it difficult for humans to detect. Carbon monoxide detectors can be purchased for around US$20–60. Many local
Chainsaws in popular culture Chainsaws in popular culture Chainsaws, the common logging and woodworking tool, are also a common sight in popular culture. Chainsaws have appeared in countless films being used for their intended purpose, but this rarely if ever is given a prominent role in the plot. More prominent however is portrayals of chainsaws as weapons or torture devices. Despite chainsaws having been around since the 1930s, they were not seen used as a weapon in film until the 1960s, possibly due to Hays Code censorship restrictions on portrayals of graphic violence. Among the earliest films to portray chainsaws as weapons are "Dark