The heat is on for the industry to upgrade marine vessel
fleets from traditional fuels to liquefied natural gas (LNG). While there is a
lot of talk about this switch, there are still many questions ship owners,
builders and operators must consider when thinking about transitioning or
building for LNG propulsion.
Interested in discovering the most important issues to the
shipping industry, Tyco Marine Services spoke with decision-makers at the 2013
International WorkBoat Show to learn what the industry wants to know about
LNG-powered ships and fire protection.
What is the current state of LNG-powered vessels in
the industry and what is the expected growth rate for the
construction/conversion of these ships?
Currently there are approximately 40 LNG-powered vessels in
operation globally with roughly 40 new builds on order. Twelve of the vessels
in operation are Offshore Supply Vessels (OSV).
With the number for new orders and interest in retrofits
continuing to grow, LNG as a fuel source will continue to shape the maritime
industry as the next generation of ships.
What are the dangers presented by LNG-fueled ships?
As the momentum to use LNG as a propellant gains speed, it's
important to maintain the safe track record of LNG. Regulations and standards
are evolving with industry trends; by knowing hazards and installing proper
fire protection systems, the dangers of working with LNG can be minimized.
In LNG vessels, fire hazards are primarily present when
transference of the fuel creates a spill or when a vapor leak occurs.
Containment of materials is key when transferring LNG and
the potential for a spill is higher. While a fire hazard during the exchange is
low, since LNG is refrigerated at -160˙C (-260˙F), structural damage to the
vessel can be a larger concern. Methane (which makes up 90 percent of LNG) is
lighter than air, making it unlikely that a high enough concentration of
methane can gather at the same time an ignition source is present. This is
assuming the bunkering takes place outdoors, which is standard for most
operations.
Engine rooms have all the ingredients for a potential fire
hazard. Typically, LNG is in a gaseous state in an engine room and potential
ignition sources, such as exhaust manifolds and turbo chargers make the
opportunity for fire high.
Additionally, LNG burns very clean – almost invisible –
making early detection of a fire a challenge. Gas detection is crucial in
preventing a major fire event.
What are the current regulations and what's coming
that will impact LNG-powered ships?
One of the greatest challenges for the industry will be
meeting stringent emission requirements for vessels operating within the
200-mile perimeter known as the Exclusive Economic Zone (EEZ). The EEZ is the
area beyond and adjacent to the territorial sea of the coastal State.
EEZ requirements help minimize environmental effects of
potential contaminants such as methane slips, or methane that does not burn
during combustion. Currently, most diesel-powered vessels do not meet the
minimum EEZ requirements. As a result, engine manufacturers are looking to
produce LNG-fueled engines with minimal methane slip.
With respect to fire protection for the marine industry,
there are a variety of regulations and standards being reviewed – all of which
have the potential to change to adapt to the emergence of LNG-powered vessels.
The International Maritime Organization (IMO), American Bureau of Shipping
(ABS) and the United States Coast Guard (USCG) will all play major roles to
update and enforce important regulatory standards related to fire protection on
LNG ships.
For example, one recent regulation proposed by the USCG,
known as CFR-46 Subchapter M, intends to promote a safer work environment on
towing vessels. One of the newly proposed measures within CFR-46 Subchapter M
may require fire protection for all vessels that qualify for a certificate of
inspection (COI).
It will be important for ship owners and builders to work
with a fire protection service that has the experience and knowledge to stay
ahead of regulation changes and industry needs.
What makes fire suppression for LNG-powered ships
different from that for traditional fuels?
LNG powered vessels present additional fire hazards compared
to legacy diesel-powered vessels, and thus, require additional fire protection.
For instance, while a traditional fuel vessel requires fire protection
primarily for the engine room, LNG vessels require protection in the engine
room as well as at bunkering stations, gas valve areas (GVA), and the LNG tank
space.
When choosing fire suppression solutions for engine rooms
and machinery spaces, it is important to consider clean agents that provide total
flooding capabilities, while still offering complete suppression for valuable
equipment. The following agents are waterless gases with limited ozone
depletion potential. Each requires very little cleanup post-discharge,
providing minimum downtime for operators.
• High-pressure carbon dioxide – Designed for non-occupied
spaces, this agent displaces combustion supporting oxygen by flooding the
protected area. Stored in individual cylinders, the system can be discharged
remotely or locally at the system.
• FM-200 – Recommended as a Halon alternative, this agent is
safe for areas where people may be present and works by removing heat from fire
hazards.
• Novec 1230 – Stored at low vapor pressure and a liquid at
room temperature, Novec 1230 enables ease of handling and system recharging.
• Inert Gases – Made of naturally occurring gases, this
non-synthetic agent is safe for people and does not produce a fog, ensuring
escape routes to remain visible.
Bunkering stations require the benefits of dry chemical powder
agents to suppress fire incidents.
• ABC multipurpose agent – Comprised of a mix of
monoammonium phosphate and ammonium sulfate, this agent interferes with the
chain reaction of Class B – flammable liquids or gas fires.
• Purple K (PKP) – Developed to suppress Class B fires from
two fronts, PKP smothers fires in addition to breaking the chemical reaction of
the source.
If we want to retrofit a boat for LNG-propulsion, do
we need to change our fire protection system?
Vessels fueled by LNG need fire protection systems that are
flexible and accommodate the spaces inherent to these ships, including the
engine room, machinery spaces and bunkering system areas. As outlined above,
each area requires a fire suppression system that dispenses the correct agent for
the potential hazards of each.
It is always best to work with a fire protection engineer
early in the retrofit process to ensure current fire protection regulations and
standards are met. Additionally, ship owners and operators can gain peace of
mind knowing people and assets are protected.
How do you address space constraints with LNG fire
protection systems?
The layout of an LNG-powered ship can vary considerably and
identifying the right fire suppression system depends on whether a ship is a
newbuild or a retrofit job. The engine, machinery and mechanisms involved in
powering an LNG ship use more valuable deck space than hydrocarbon-fueled
ships. With square footage at a premium, it is critical that deck space be used
well.
When choosing fire suppression solutions for engine rooms
and machinery spaces, it is important to consider clean agents that provide
total flooding capabilities, while still offering complete suppression for
valuable equipment.
Typically, the fire protection systems required in
LNG-fueled ships need more deck space because the holding tanks have a much
larger footprint than those of traditional fuels, but there is a fire
suppression option to suit every need.
When the footprint of the system is important, clean agents
such as Novec 1230 and FM-200 may be the best choice as the overall system is
smaller and maximizes the space available. High-pressure carbon dioxide systems
require multiple cylinders, which take up more deck space, but also offer
configuration options. Ultimately, a system engineer can help design the best
option to provide total fire protection, while considering costs and space
constraints.
Fire protection in the new LNG normal
As the maritime industry continues to shift and move toward
increasing the number of LNG-powered vessels in operation, fire protection must
remain top-of-mind for ship owners, operators and builders. Companies like Tyco
Marine Services can help offer expertise and insight to design total system
solutions that help address potential hazards and protect lives, and limit
downtime and damage to property, if a fire occurs.
Steve Pelletier, business development manager, Tyco
Marine Services, is a former member of the United States Coast Guard, and holds
associate degrees in science and electronics engineering. He has worked in the
fire protection industry since 1996.
