Abstract: In a connection structure for fire extinguishing system piping in which a male piping member is connected to a connection opening portion of a joint by screwing a male thread and a female thread together, the male piping member includes a joint cylinder having a protruding portion that is inserted deeper into the connection opening portion than the female thread. Each male piping member and the connection opening portion includes a step portion. The connection structure further includes an indicator that engages the step portions and in a state in which the male piping member and the connection opening portion are connected together. At least one of the male piping member and the connection opening portion includes an unmountable portion that has an outside diameter different from an inside diameter of the indicator and cannot be engaged by the indicator.

Abstract: A FIRE EXTINGUISHING EQUIPMENT includes a pump that feeds water to piping, a water flow detection device connected to the pump, a sprinkler head connected to secondary piping of the water flow detection device, and a pump start switch installed in primary piping between the pump and the water flow detection device. The primary piping is divided in correspondence with plural fire protection areas. The water flow detection device is installed in each branch of the primary piping. A relief valve provided in bypass piping that connects between the primary piping and the secondary piping not via the water flow detection device is opened when the difference between the primary-side and secondary-side pressures is equal to or more than a predetermined value. The cross-sectional area of a minimum flow passage diameter portion of the relief valve is smaller than the cross-sectional area of a nozzle outlet of the sprinkler head.

Abstract: There is provided a connection structure for fire extinguishing system piping with which stable sealing performance can be obtained, due to screw engagement, by connection work carried out even by an unskilled worker and with which secure engagement of the connection portion can be confirmed easily. In a connection structure for fire extinguishing system piping in which a male piping member is connected to a connection opening portion of a multi-port joint T by screwing a male thread and a female thread together, the male piping member includes a joint cylinder having a protruding portion that is inserted deeper into the connection opening portion than the female thread. The male piping member also includes the sealing members and that seal the engagement portion between the male thread and the female thread to prevent water leakage into the inside of the connection opening portion. The male piping member includes a step portion, and the connection opening portion includes a step portion.