Pre-action systems receive every applicable wet pipe activity plus: monthly, record supervisory, diaphragm and below-stop-valve pressures, check compressor oil and regulator, inspect and test electrical detection to Section 6, confirm the compressor starts and stops at its set pressures, check nitrogen cylinder pressure and regulator where nitrogen is used, test solenoid valves, verify low air pressure alarms and generate a local and brigade alarm test. Six-monthly, close the isolation valve above the pre-action valve where fitted, release each pre-action valve through the electrical detection subsystem, confirm alarm within 180 s and brigade signalling, then reset, restore supervisory pressure and the control unit and FIP or ASE, record gauges and secure valves as labelled. Yearly, drain condensate from the trap and compressor receiver and survey that piping and detection are secured and that protection covers the whole special hazard area. Five-yearly, renew the pre-action valve seats, seals and cover plate gasket and clean its mechanism.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.