Cape Town based fire protection specialists, DoseTech, have recently supplied one of the most advanced firefighting trailer mounted units to a local crude oil storage depot, for quick and effective knock-down in the event of fire at the facility.
The combined proportioner and monitor unit is fully portable and uses no external power source to deliver between 5,000 – 22,000ℓ/min of fire suppressing foam and water at distances up to 120m.
Advanced firefighting especially for oil storage depots
The unit was sourced from German based FireDos, specialists in the design, manufacture and supply of advanced firefighting equipment, especially to the giant oil storage facilities of the Middle East’s major producers. DoseTech are FireDos agents in South Africa.
“The introduction of this trailer mounted unit especially designed for the protection of fuel storage tanks is a first not only for South Africa, but a first for the continent too” says Michael Feldon, managing director of DoseTech.
“The technology is quite unique” says Feldon. “The design comprises a special foam and water monitor combined with a proportioner unit which ensures that the precise proportion of suppression foam to water – 3% - is maintained irrespective of the volume of water available from the storage depot’s fire hydrant ring main.
No external power source
“The FireDos proportioner is driven solely by the extinguishing water flow. No emergency electrical energy or engine driven prime mover is required. The purely mechanical system is made to last and is highly reliable.
“The water motor drives a specially designed pump, which delivers the foam agent into the extinguishing water flow. There is a direct linear relationship between the extinguishing water flow rate in litres per minute and the water motor’s number of revolutions.
“The more water flows through the water motor, the more foam agent is admixed. Thus, the quantitative ratio of foam agent and extinguishing water, which is referred to as the ‘proportioning rate’, always remains constant. A portion of the pressure in the extinguishing water line is used as an energy source to drive the water motor. While hydrant pressures of 10bar is usual, the unit can safely accommodate a maximum water pressure of 16bar.
“The proportioning pump that is driven by the water motor is self-priming and can deliver even extremely viscous fluorine-free and/or alcohol resistant foam agents without limits” he explained.
Radical monitor design
The design of the monitor unit is also quite radical in that unlike competitive units, the ‘oval- flat design’ virtually eliminates reactive forces which mean that no additional ballast is required to keep the trailer unit stable during operation. In this application, the monitor has 360° of horizontal movement and between 30° and 90° in the vertical plane (typically the monitors have a -90° to plus 120° vertical movement) and is fitted with a combine fog and stream nozzle for either cooling or vapour suppression applications and aim and shoot.
Easy to operate
Operating the proportioner involves opening a few ball valves to vent the proportioner in the beginning and to put it into a state ready for operation. As soon as the water flows, the water motor starts working and drives the proportioner. There are no valves that have to be actuated, which could be a source of error.
The trailer unit incorporates water and foam agent manifolds that allow connection to multiple hydrants via standard sized fire hose, while the foam agent manifold permits the coupling of more than one foam agent tank, necessary during prolonged operation.
Sturdy and made-to- last
“The FireDos unit is built to last being constructed from high-quality components and materials. All pressurized cast parts are designed for a test pressure of 64 bar, and although the unit has a mass of 4t, it can easily be pulled by the average 1t bakkie” adds Feldon.
“As these trailer systems are application and customer specific designs, options include units that can by-pass the monitor or exclude the monitor if required and can be direct coupled into a facilities tank protection pipework – a real advantage in that a fixed protection system can be designed and constructed without a separate extinguishing medium, thereby reducing system complexity and cost.
“FireDos complies with all the international certifications such as FM - Factory Mutual, NFPA - National Fire Protection Association, VdS - Loss Prevention, bvfa - German Federal Association of Technical Fire Protection and vfdb - GFPA German Fire Protection Association.
“We were really excited with the reaction from fire officers and the client when the unit was demonstrated during the site acceptance and hand over as they are confident that they now have the most advanced, easy to use, reliable firefighting unit at their disposal to combat a potentially disastrous event,” he concludes.