Manual fire monitors are widely used in marine, offshore, industrial andmany other corrosive environments to stop unwanted fires. Fixed Monitors spend most of their lives stationary. However when unwantedfires are perceived they can frequently be the only practical way of applyingfoam or water to distinguish fire. Although simple in principle, fire monitors are sophisticatedengineering pieces of work designed to deliver a precise performance after longperiods of inactive. Just like another engineering challenge the design of afire monitor can take many arrangements depending on the exact hazard it isanticipated to protect and the mechanism and technique of operation thedesigner uses to complete the final layout. When designing a fire monitor the designer must balance performance,operational life and ease of use bearing in mind the cost.
It is vital thus,that monitors are robust and will have a long service life, even under harshconditions. Fixed fire monitors areoften found anywhere where there are considerable Class B fire risks whereasmobile or portable fire monitors are frequently utilised to safeguard variousrisks by moving the monitors around the site. Almost all industrial firehazards are subject to fire monitor protection, however some of the more popularapplications may include; refineries, chemical plants, helicopter landing pads,fuel distribution depots and process plants etc… Although most fire monitorsare permanently secured to pipework and designed to distinguish particularinstallations, in certain circumstances monitors are mounted on trailers thatcan be moved from one fire hazard to another.
But mobile monitors need a watersupply, and usually this is delivered by hoses or portable pumps. The jetreaction force for a portable fire monitor can differ from few kg, for smallground monitor to over a tonne for larger trailer-mounted units. Portablemonitors must be secured so that it cannot move once the full water flow andpressure is applied. The design of pump pipes that make up a monitor iscritical as they serve several functions. They contain water or foam while permittingthe jet to be moved in both the vertical and horizontal planes, the pipes must havegood strength to resist pressure and reaction forces produced by the water andthey must be robust to accommodate the mounting of further items such aslevers, nozzles and hydraulic actuators etc.
; all of this must be accomplishedwith a design that is cost effective, has a tolerable pressure loss, willresist corrosion and is not heavy. The design of a monitor is a negotiationbetween cost, weight and performance.