In the Naval sphere fire risk management is key to the operation of safety critical, high value assets. Attention is called to those in the Safety & Survivability Department or Naval Damage Control. Let’s put words into action, and create a safety culture by constantly monitoring our extinguishing systems 

Cost cutting, lack of experience, increasing risks

Although the value of the marine assets that fire systems protect is increasing rapidly, the competitiveness of the free market-places great pressure on cost cutting. Often, cheap systems only minimally comply with the regulations and, in fact, there are very few qualified engineers who may be considered experts on the subject matter. This creates an environment in which a ‘safety first’ culture remains both un-pursued and unrewarded. Routine maintenance is likely to be overlooked either because it is difficult and the crew unqualified to test or it is given insufficient attention by the owner of the system. The neglect of these fundamental continuous monitoring extinguishing systems is to the peril of the occupants of the ship and at the risk of crippling financial and reputational loss to the ship owner. It is usually the case of systems like these that they are out of sight and out of mind, and they are often located in some plant room which only the maintenance contractor visits, if at all.

Importance of Gaseous Fixed Fire Extinguishing Systems

Safety – of life at sea primarily, then of cargo and asset – is critical at sea. Fire safety is especially so, yet even in 2020, gaseous fixed fire extinguishing systems are often overlooked, and are misunderstood at all levels: owners, managers, chief engineers and crew. The reality is that gaseous systems are checked for contents annually because they are pressurised and anything that is dynamic is subject to leakage, but this fails to deal with the probability of discharge for the 364 days per annum in the interim between certification checks.

Fire Incidences

  • In July 2020, at the height of COVID19 in the USA, the USS Richard Bonhomme, an amphibious aircraft carrier, developed a 5-day fire during a maintenance interval. It injured 68 military and civil personnel. It also made “out of service” a core strategic amphibious asset of the US Navy. It was one of only four ships in the US Pacific Fleet able to handle the F-35B 5th generation aircraft.  “As tensions mount with China in the South China Sea, as well as with North Korea, the loss of this ship and her capabilities will make it more difficult for the Navy to meet all its war-fighting requirements,” said John Kirby, a CNN military analyst and former US Navy Admiral.
  • The top US Navy acquisitions official said, “Anyone who steps aboard our ships must be ever vigilant about ensuring fire safety. I urge you to use the recent fire to ensure that our work spaces are clean, that unnecessary clutter is removed, that all fire safety measures are being followed and that there is unrestricted access to firefighting and damage control equipment.” Excellent, you may think. Regardless of the reason for the fire itself, a reason that the fire became uncontrolled … was because its fire suppression system had been shutdown and its compartment doors left open. For maintenance.August 2011 – Accidental discharge of carbon dioxide on board SD Nimble resulting in serious injury to a shore-based service engineer at Her Majesty’s Naval Base Faslane (MAIB,2011).
  • September 2004 – Hong Kong – A Routine Inspection of the Fixed CO2 Fire Extinguishing System that led to the Death of Four Officers (HKSAR,n.d.)
  • February 2015 – Twentynine Palms, California – 22 US Marines Injured when a halon-containing fire extinguisher went off (Bustle,2015).
  • November 2008 – Akula II K-152 Nerpa- At least 20 people have died in an accident on a Russian nuclear submarine when a fire extinguishing system (Halon) was activated by mistake (BBC News,2008 and Red Banner Northern Fleet, 2008).

For a gaseous extinguishing system to function, whether liquefied, such as CO2, NOVEC™ 1230 or FM-200™ or non-liquefied, such as Nitrogen or Inergen, one needs two things: Firstly, sufficient contents to generate the design concentration required to extinguish the fire event, and secondly, compartmentation integrity, so that the extinguishing gas is contained within the space on actuation. Without either, the fire event risks escalation. So how can one test that either exists?

To cater for the contents, one can shut the system down, dismantle it, and weigh each cylinder of extinguishing gas. Then re-instal each of them. There can be 600 45KG cylinders on a commercial ship, 100 on an offshore platform, and 100s in a Data Centre. It takes 2 licensed fire technicians 15 minutes to do this, per cylinder. On a good day. For the compartmentation integrity, one can pressurise the compartment space, either by air or water, and see where it leaks out. Neither works when the fire technicians are away from the asset for the other 364 days per annum.

This is how our industry has worked since gaseous systems were first developed. In 1924 the Walter Kidde Company developed the first CO2 extinguisher and in the 1960’s DuPont developed the first Halon system. In the 1990’s DuPont developed FM-200™ and 3M™ NOVEC™1230 as “clean agents” to replace Halon, banned under the Montreal Protocol. After that came the use of natural un-liquefied gases. We know them today as Inergen™. What unites all of them is that they are highly pressurised. Some of them up to 300 Bar, or over 4,350 PSI. And anything that is pressurised can leak. Hence the reason why BS EN ISO 14520 was developed – to check that their contents had to be checked for content loss. If they lost more than 5% the cylinder had to be re-filled.

So it is known that anything that is pressurised can leak. That is science. Perfect physical principles. The mathematics are clear.
We need a mathematician or a physicist in our industry.

Room Integrity

The same with compartmentation. Like any ship the USS Richard Bonhomme is constructed to withstand damage. Since the principal reasons for ships loss at sea remains sinking and fire, all ships, offshore oil & gas platforms, even offshore wind turbines, understand the need for “compartmentation”. Below the waterline they are known as watertight compartment doors, and the areas between the watertight bulkheads, containing the electrical cabling that pass through every marine structure at sea, are called Cable Transit Areas. These are designed to maintain compartmentation integrity, not just to prevent water ingress and sinking, but to stop fire passing between the compartments too.

One way to test them is to fill them with water and to learn at what “head of water” the bulkhead collapses, or the watertight compartment door, bursts. But it is not very practical. Another is to pressurise the compartment by positive pressure and see where it leaks. All grand … on a cool calm day when no-one is inside the ship. Even better in a lab.

But here we are using gases for fire systems that are nearly 100, 60 and 30 years old, and we still test them inadequately. It is as if there has been no technological advancement in any field other than our own.  And the accidents keep coming. The fires keep hurting and destroying and our regulations gently modify themselves, all at a time of some of the highest-paced technological change the world has ever seen.

A dairy farmer does not check a pregnant herd by weighing them. A bat does not fly through a forest at night by sight. A whale does not communicate hundreds of miles by using morse code. Submarines rarely see their adversaries or even the sea that they glide through. The blind “see” by hearing sound and in 4 of the above examples, it is the use of sound beyond our audible range that enables them to “hear the [ultrasonic] sounds that others cannot hear”.

A cylinder containing a Clean Agent is in itself acoustic. Like a bell. A compartment is a room. Unless it is an anechoic chamber designed to completely absorb reflections of either sound or electromagnetic waves, it reflects them. And it’s leak sites let them pass through.

So just as a vet, a bat, a whale or a submarine sonar, uses ultrasound to “see the sounds that others cannot hear”, so can our fire industry use ultrasound to test both the contents of its gaseous extinguishing systems and the compartmentation integrity of the spaces that they are meant to be “held” in.

All we need are the mathematics.

Mathematics is the language of the universe. It expresses the physical principles that enable it. And it can be at the heart of our industry too. It already is by some of you reading this article.

At Coltraco Ultrasonics we share a British legacy in ultrasound that began in 1916 when the Admiralty used it to hunt enemy submarines. It is 104 years since we have had it. It has taken over 80 years for the fire industry to use it in the portable and constant monitoring of gaseous extinguishing systems, and the compartment spaces into which they actuate and protect.

To those of you who use it, I salute you.

About the Author

Carl Stephen Patrick Hunter OBE is Chairman of Coltraco Ultrasonics, the world’s leading manufacturer of ultrasonic monitoring equipment for the fire, naval, marine, offshore, wind, telecommunications and wind energy sectors. His company exports 89% of its output to 120 countries and holds the Queen’s Award for Enterprise in International Trade. Carl has strong Naval links from his Father with whom he co-founded Coltraco in 1987 who was formerly 27 years as a Royal Naval Submariner before joining Admiralty Research Laboratories among other roles in research and development.