The Scotch Mist® dry pipe monitoring system is for use with installations to which automatic nozzles are connected.
The system will maintain a constant monitoring pressure throughout the discharge pipe network and, should this pressure fall away completely, discharge of the Scotch Mist® system will be automatically initiated.
A monitored dry pipe system therefore operates in an automatic mode whereby, under no-fire conditions, the system is quiescent and the pipework system dry but, should a conflagration cause the frangible bulb of one or more nozzles to break, the monitoring pressure will fall away, the pumps will start and the pipework system will be charged with water, enabling those nozzles that have opened to discharge.
Scotch Mist® restricted dry pipe systems are generally designed to serve up to six or nine of the total quantity of nozzles installed, but this number may be varied to suit specific requirements.
The Scotchmist compressor with receiver is a compact, self-contained air compressor designed to meet the specific needs of LPC, BS5306 and EN12845 requirements. Should a compressor become inoperative, a reservoir provides the greatest protection for dry pipe systems.
The compressor is designed for use with an air maintenance device that will automatically control the air supply into the system piping at the required volume and pressure. When used alongside an air compressor with a receiver, the air maintenance device regulates the incoming air (from the air receiver tank) and maintains the outgoing air pressure at the setting of the regulator.
The automatic air supply is directed through a restricted orifice in the Air Monitoring Device so that, when a watermist head is activated, the air supply will not interfere with the operation of the pump by continuing to supply large volumes of pressurised air to the system.
A low pressure switch is fitted to monitor the air pressure on the outgoing side and this will signal an alarm if the pressure falls below a predetermined level. Activation of a watermist head will cause the system pressure to drop to the point where a signal will be initiated, causing the system to fill with water.