Pacific Maritime Magazine - Marine Business for the Operations Sector

LNG-powered Ships and Fire Protection: An Industry Q&A

 

Artist's rendering courtesy of NASSCO.

New vessels, including two new 3,100-TEU container ships for TOTE to be built by San Diego's NASSCO shipyard, are increasingly turning to LNG as an alternative to low sulphur diesel in emission control areas.

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.

Photo courtesy of Tyco Marine Services.

Designed for non-occupied spaces, high-pressure carbon dioxide displaces combustion-supporting oxygen by flooding the protected area.

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.

 
 

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