Firefighting systems keep pace with ship growth

Manufacturers of fire extinguishing equipment for OSVs say that demand is growing for higher capacity units for use on ever larger vessels

At least one well known manufacturer, Fire Fighting Systems (FFS) in Norway, has noticed a clear trend towards larger offshore vessels – as oil exploration moves into deeper waters – which has resulted in a parallel trend towards the installation of larger fire extinguishing systems.

“At present, FFS has many FiFi II systems, with capacities of 7,200 m3/h, on order, although the majority on order are still FiFi I systems (with capacities of 2,400 m3/h),” company spokesperson Pål Holst-Roness explained.

FFS recently introduced larger fire monitors in the form of its FFS 2400 and FFS 3600 types, which are intended for the FiFi I market, having capacities of 40,000 litres/min and 60,000 litres/min, respectively.

“Another trend is that more ships are being built with diesel-electric propulsion, which again requires different solutions for the firefighting plant, either with electrically driven pumps, or with pumps connected to the diesel engine PTO shaft via a gearbox or clutch unit,” Mr Holst-Roness explained.

Owners acquiring firefighting systems for their vessels need to know that they are capable of providing sufficient levels of performance to fight platform fires, continues Mr Holst-Roness. Equally important, such equipment needs to be able to provide sufficient water spray for the ship on which the monitors are installed, in order to protect it from radiated heat.

The image reproduced here of Tidewater’s Du Moulin Tide shows the firefighting system in operation, including water spray for the ship. “This illustration clearly shows how important the coverage of the water spray system is if it is to protect a ship from radiated heat. If well protected, a ship can go close-in to a fire, and carry out a better and more secure firefighting job,” Mr Holst-Roness explained, noting that FFS always calculates the water spray system for a vessel on a case by case basis, in order to ensure that the package will provide adequate protection.”

FFS has also recently introduced a new portable control unit for its firefighting systems. This unit has a LCD display and can be used to control all aspects of operations, thus freeing up valuable space on the bridge control desk – no additional control panel is required.

Jon Hansen at Kumera, the well known supplier of gearboxes for fire pump drives, notes that the market for firefighting gear is still booming, and that there is a growing market for standard gearboxes with a single PTO driving the fire pump. The company agrees that there is also a trend towards larger, more sophisticated ships with higher FiFi class; this demands large generators driven through a gearbox in combination with a fire pump.

Sandefjord-based Kumera has specialised in the design and manufacture of gearboxes and hydraulic clutch units for FiFi I, II and III class applications for more than 20 years, and by the end of 2007 had delivered more than 500 examples of its Norgear branded units. In Kumera’s view, the high power requirement of firefighting pumps and the operating profile of an OSV make it advantageous to utilise the capacity of the main engines through a front-end PTO drive rather than installing a dedicated diesel engine.

The conventional Norgear single input/single output design (Type 2FGC with horizontal offset shafts and Type FVC with vertical offset shafts) are the most common solutions for FiFi II installations, says the company. However, these are backed-up by models with features that help optimise engineroom layout and improve operating economics.

The Type 2FGIC/FVIC has integrated gearbox and pump assemblies for minimal overall length; the Type 4FGICC has two outputs to drive a fire pump and a thruster pump or alternator; and the Type 6FGICC is similar but with an additional idler gear to assist in fire pump selection (rotation). The NKHU is a freestanding hydraulic clutch unit which can provide a direct connection to the fire pump on high speed engines of 1,500-2,100 rpm.

At the heart of each gearbox and clutch unit is the Norgear clutch assembly, a multi-plate oil-operated type, with the standard range extending from 7,500 to 45,000Nm. The assembly is totally self-contained, with mechanical oil pump, pressure oil filter and oil cooler mounted on the housing. Cooling water can be taken from the main engine low temperature circuit or straight from the fire pump suction side.

The clutch is arranged for remote operation via an electro-hydraulic valve (24V DC or AC supply) with a local manual control to assist in initial set up and to ensure continued availability in the case of loss of power supplies. Control systems, engineered to give correct format and rate of clutch engagement, allow clutch utilisation up to full engine speed. If requested, Norgear will prove a wheelhouse clutch control and alarm panel. OSJ