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
Lawn-Boy orders for these mowers from Sears Roebuck, Gimbles, Spiegel, and other businesses. OMC then bought RPM in 1952, and changed the brand of the rotary lawn mower to the Lawn-Boy name. In the 1950s, RPM facilities were converted to production line manufacturing to meet the high number of orders from bigger retailers such as Sears Roebuck and Spiegel. Also, newer, quieter engines were introduced to reduce sound. The next couple of decades included a long period of research and development as the company continued to expand, including overseas. Riding mowers, tillers, and snow blowers were introduced, as well as a