1. A temperature of 0°C and a pressure of 1 atmospheres (760 torr). Also known as “normal temperature and pressure (NTP)”; “standard temperature and pressure (STP).” 2. According to the American Gas Association (AGA), a temperature of 60°F (1 5-5/9°C) and a pressure of 30 inches of mercury (762 mm). 3. According to the Compressed Gas Institute (CGI), a temperature of 20° C (68°F) and a pressure of 1 atmosphere.