Mark Fletcher looks at turbines as alternatives to reciprocating engines. Primarily seeing use in marine fire fighting, turbine-based powerplants do, in fact, offer capabilities that will make them incredibly attractive to other fire-fighting scenarios.
Next year, the diesel engine will celebrate its 120th birthday. Developed in 1893 by Rudolf Diesel, its general all-round capabilities have made it the powerplant of choice for a huge variety of applications and industries – including multiple instances in the world of fire fighting.
In the marine sector specifically, dedicated fire-fighting boats and tenders often employ multiple diesel engines for both propulsion – increasingly coupled to generators and electric motors – and for powering fire-fighting pumps using take-off units attached to the propulsion engines.
For all its popularity, the diesel engine does have drawbacks, primarily down to its size and weight. But with no significantly viable alternatives coming onto the scene in the last century, it has been sitting pretty at the top of the fire fighting powerplant pile… until now that is.
The turbine concept has been around for even longer than the diesel engine, with early steam derivatives appearing in the 1840s. Like the diesel engine, turbines have made their way into multiple applications, including marine powerplants, but it is only relatively recently that they have been deployed as powerplants for fire-fighting equipment.
"The initial request came from a customer 15 years ago," explains Ted McIntyre II, president of US-based Marine Turbine Technologies (MTT). "Our customer had bought a tugboat and needed more power, but they did not have room for bigger diesel. The question came up, ‘can you put a turbine on a fire pump? You’ve put turbines on other things’."
From this initial request, the adoption of turbines as fire-fighting powerplants began to snowball. One thing to provide significant impetus was the steady worldwide adoption of the Fire Fighter (FiFi) standards originally developed for the oil and gas industry in the North Sea. The standards define the fire fighting capability (based on equipment and performance) for vessels deployed in oil and gas fields. As well as fire fighting equipment features such as the number of pumps, the capacity and the throw length, the FiFi standards also look at position keeping and self protection.
"Until the FiFi standards were introduced it used to be ‘anything goes’, but since their introduction customers around the world increasingly ask for boats defined by their class," McIntyre explains. "To cater for these needs, we have created a FiFi package based on a 1,400hp, 300Kg turbine, supplied in a modular package.
"The majority of our products have been FiFi 2 – four pumps, four enclosures and four monitors." McIntyre elaborates. "They are designed to go on the deck of an offshore supply vessel and can be up and going within just a few minutes. All unit have local panel and a remote panel in the bridge so the vessel’s captain can maintain station (DP2 or 3), this is particularly important with our pumps as each one of our pumps has a reactionary force of 5,000 pounds… we can generate 6 knots just from the force of cannons."
The particular advantage that turbines offer over diesels is their power to size/weight ratio. Most modular diesel powered fire fighting modules are based on a standard shipping container in order to house an engine big enough to offer enough power. McIntyre’s turbine packages, however, can offer the same performance in a 6 x 13ft envelope. "We can get three of our pumps in the same footprint as diesel unit," McIntyre explains.
Another attractive facet of these smaller, modular packages is the fact that many vessels were built before the standards were introduced, and it is very difficult to swap out their existing diesel-electric or get suitable amounts of power from diesel take off. Reliability is also paramount. The turbines are based on engines used in the Eurocoptor, so they are capable of running at extremely high rpm for up to 10,000 hours, something a diesel wouldn’t be able to do without regular remedial maintenance.
"We ‘marineise’ the engines," McIntyre explains, "primarily to protect them from salt water. We have developed a solution where our engine is in an enclosure using filtered air. We have kit that has been working for 10 years. The original 22 units are still in operation."
When quizzed, McIntyre does admit to a turbine’s known downside, in that it consumes more fuel, typically 30% more. But it doesn’t demand any special fuel requirements – running on ordinary number 2 marine diesel.
MTT has evolved its turbine offering and is releasing what it calls a FiFi Rig Pack, which will be used to create a curtain of water to prevent gas flare-off flames blowing back onto the rig. The company is also looking to evolve its offering into other markets, exploiting the ability to draw water from 20m down and still deliver significant (1,200m3/hour) performance. Already believed to be a record, the company will be going for 30m in the near future.
"It is these capabilities that lead us to believe that we can make a real difference elsewhere," McIntyre explains. "One idea we have had is to site a turbine module on top of buildings in built-up areas. With the power of our pumps, coupled to the elevation, I could see fire fighters shooting water huge distances to fight fires on neighbouring buildings. The military is also looking at them as non-lethal deterrents, as are some of the major shipping companies to deal with the escalating problems of piracy in the seas around Somalia. The ships being targeted are often extremely large and need a solution capable of pumping water from far below."
The turbine-based solutions are no more complicated than their diesel peers; indeed MTT has gone out of its way to make sure that they are as user friendly as possible. Full training can be offered by MTT and both new users and maintenance personnel can be trained within a day.
Turbines will not sound the death knell for diesels, but what they will do is finally offer engineers a choice of powerplants for demanding applications. Although they are relatively more expensive and consume more fuel, their aerospace reliability coupled to their amazing performance, has the ability to offer the necessary payback where it really counts.