(L) Boilers with a rated evaporation greater than 0.5 t / h shall be fitted with at least two safety valves: a boiler with a rated evaporation less than or equal to 0.5 t / h and at least one safety valve. Separable economizer outlet, steam superheater outlet must be installed safety valve. (2) Safety valve should be installed vertically in the pot, the highest position of the header. Between safety valve and drum or header, there shall be no steam outlet pipe and valve. (3) Lever safety valve to prevent movement of the hammer to move the device and limit the lever over the guide rails, spring-loaded safety valve to have to enhance the handle and prevent accidentally twist the adjustment screw device. (4) For boilers with rated steam pressure less than or equal to 3.82MPa, the throat diameter of safety valve shall not be less than 25mm. For boilers with rated steam pressure greater than 3.82MPa, the throat diameter of safety valve shall not be less than 20mm. (5) safety valve and the boiler connection pipe, the cross-sectional area of ​​not less than the safety valve inlet cross-sectional area. If several safety valves are installed together on a short tube connected directly to the drum, the cross-sectional area of ​​the short tube should not be 1.25 times the discharge area of ​​all safety valves. (6) safety valve should be installed generally exhaust pipe, exhaust pipe should be through a safe place, and have sufficient cross-sectional area to ensure that the exhaust gas flow. Safety valve exhaust pipe should be installed at the bottom of the positon has received a safe place of the hydrophobic pipe, the exhaust pipe and the hydrophobic pipe are not allowed to install the valve. This article Keywords: safety valve