a. Valves shall be installed so that their handwheels or handles are accessible and can beoperated between full open and full closed positions without obstructions.b. Valve location and orientation shall be such that a person can operate the valve handwheelor handle from a safe position and in a comfortable posture. Extensions or chain wheelsshall be provided if required.c. Valves in horizontal lines, with the exception of block valves at pressure relief valves, shallbe installed with valve stems oriented as follows, in order of preference:1. Vertically upwards2. Horizontally3. Upwards at 45d. Gate valves installed upstream and or downstream of pressure relief valves shall beinstalled with the valve spindle oriented horizontally or downwards, to prevent blockage ofthe line by a disconnected gate in the valve.