Gas service technicians work on the installation, maintenance and repair of all gas appliances in domestic and commercial premises. This involves installing the appliances and preparing them for the customer to use, the subsequent maintenance of the appliances to ensure their continued efficient running and safety, and also repairing equipment that has developed a problem. The normal working week is 40 hours and the majority of the work is conducted indoors, but sometimes outdoor work is also necessary. Gas service technicians may work for large manufacturing companies or other large organisations such as British Gas.