Certain fire hazards require the cooling of large hazard areas using water application. Similarly, it may be required to apply foam over a large area in some situations, instead of specific point application. This can be achieved by using oscillating monitors, as the monitor oscillates in the horizontal plane, providing coverage to a large area instead of a specific location. Oscillating Foam/ Water Monitors use gear boxes and mechanical means to oscillate the monitor in a preset angle. The power for movement can be an external power source or can be aqua powered (i.e. using a small quantity of the water supplied to the monitor). Aqua powered units are preferred as they do not require any external power source. These are also recommended where unmanned operation is necessary in view of severe fire hazards
Location of monitors is dictated by operational requirements such as type of hazard, range of the monitor, wind direction and speed, unhindered ‘view’ of the hazard, etc. When installating monitors, the following should normally be considered –
- The mounting arrangement is suitable to the back thrust from the monitor.
- Ensure that the mating flange of the hydrant post is matching to the valve inlet flange.
- Use approved gasket between flanges, and good quality nuts/ bolts.
- Ensure that full rotation of the monitor is possible, and height of the monitor handwheels are at proper height.
When tested and maintained regularly, monitors will give effective service when called upon to do so in an emergency. Monitors require minimal maintenance, however problems can occur due to entry of stones/ debris into the lines. For foam monitors, the foam solutions used (especially AFFF) are corrosive in nature, and if monitor is not flushed properly after operation, this can cause development of corrosive flakes/ pieces, which may cause problems during operation. Normal maintenance activities include –
- Periodic visual inspections (at least monthly)
- Periodic operational tests (as mandated by manufacturer/ site requirement)
- Proper flushing of foam monitors after operation.
- Greasing of swivel joints at specified intervals.
- Periodic replacement of rubber washers/ gaskets as required by site conditions.
- Periodic painting of external body (as required by site conditions).