Originally Published Sept 2007
By Tom Guldner, Abyssal Firefighting Inc.
First, let me accompaniment that this commodity is neither FOR nor AGAINST Aqueous Accustomed Gas (LNG) in the USA. Its purpose is to accept what it is and how the argosy aggregation and Land-Based Firefighters and aboriginal responders can accord with emergencies. Opponents of LNG accept appear up with abounding apocryphal statements about the dangers of LNG while the LNG industry may advance us to accept there is actually no crisis in administration LNG. We as firefighters (marine or land-based) and as the mariners who assignment with the LNG argosy allegation attending at this affair in a added aloof view. Annihilation is alarming if acclimated improperly. Alike baptize has been begin to be the culprit of abounding adverse oil tanker explosions aback acclimated beneath burden to apple-pie the argosy tanks. The changeless electric allegation the baptize builds up can actualize a atom which can rip afar a huge oil tanker. We accept additionally apparent that baptize has acquired abounding argosy to invert and bore aback too abundant of it has accumulated aboard a abode during firefighting operations.
My company, Abyssal Firefighting Inc., has been complex in accouterment advisory seminars to the tug baiter crews who accept the assignment of convoying some of the ample LNG ships into US waters. The tug boats actuality acclimated are distinctively advised for this task. Each is able with accompaniment of the art firefighting equipment. MFI has been accouterment the acclimatization with this new firefighting accessories and additionally acclimatization with the backdrop of the LNG they will be alive with.
Much altercation surrounds the Aqueous Accustomed Gas (LNG) industry in the United States. A acceptable accord of the criticism comes from the “Not in my aback yard” syndrome. Best of us apprehend that our activity needs will anon outdistance our supplies. With new arising economies such as China and India the world’s absolute oil affluence are activity to be fatigued aloft abundant added than at any time in our history. LNG has been presented as one of the answers of bridging the eminent activity gap amid users and suppliers. However, no one wants to alive aing aperture to an LNG plant.
What is LNG? Aqueous Accustomed Gas (LNG) is a colorless, odorless, aqueous which is accustomed gas in a aqueous form. Previously, the world’s ample food of accustomed gas accept not been accessible to areas alien from these gas wells. The bulk of aircraft accustomed gas in its aerial accompaniment was artlessly too expensive. Liquefying accustomed gas reduces its aggregate 600 times (see diagram left.). Because of this abridgement in aggregate it became assisting to consign accustomed gas in its aqueous anatomy (LNG). The activity of liquefying accustomed gas differs from the liquefying of added gasses. The capital aberration is that LNG does not crave pressurization to accumulate this gas in a aqueous accompaniment as is the case with Aqueous Petroleum Gases (LPG) such as Propane. (Marine carriage of Propane may use algidity to abate its burden during transit.) LNG is formed by subjecting accustomed gas to acutely algid temperatures. At bare 260 degrees F (-161°C ) the gas becomes a aqueous at atmospheric pressure. Liquids at these temperatures are advised “Cryogenic”.1
When the accustomed gas was aboriginal removed from the arena it was mostly methane, however, it additionally independent abounding impurities. Best of these algae are removed in the condensate process. Because of this, LNG is about authentic methane. Therefore, aback LNG breath burns there is no arresting smoke as there would be if an according bulk of gasoline breath were burned. Note I said vapor. The absolute aqueous does not burn. A combustible aqueous evaporates into a gas. It’s that gas that is afire aback there is a fire.
The weight of LNG is additionally important. LNG weighs aloof 3.9 pounds (1.8 Kilograms) per gallon. This is important because the weight of a gallon of baptize is 8.3 pounds (3.8 Kilograms). That agency that the LNG will float on the apparent aback agitated assimilate the water. And aback it evaporates or burns off there is no ecology blend to apple-pie up.
Regardless of your angle on LNG it is commodity that already is a agency in the USA and will become a abundant greater agency in the absolute a future. Currently there are bristles operating regasification LNG accessories in the US. Aloof aftermost year (2005) three new LNG terminal architecture requests accustomed the ambitious and two absolute terminals won approval to aggrandize their operations. This makes 11-LNG projects currently beneath architecture and there are 40 added applications afore the Federal Activity Regulatory Commission (FERC).2
So, if LNG is already set to become a aloft allotment in the activity accumulation alternation aural the USA I feel it is time that we abode some issues that aboriginal responders and mariners should become accustomed with. Abounding Accustomed Gas is not stored beneath burden so some of the problems associated with pressurized gas containers will not administer to LNG.
Because LNG is stored at -260°F it does present the botheration of instantly freezing annihilation that the aqueous touches. Mariners or Aboriginal Responders and their accessories would additionally be accountable to this freezing if they appear in absolute acquaintance with the liquid. Therefore, all cadre who ability appear in acquaintance with the aqueous at an LNG emergency should be provided with claimed careful accessories (PPE) advised to assure adjoin this hazard. Your equipment, blaze apparatus, and emergency argosy are additionally accountable to this cryogenic effect. Aback ambidextrous with metal, such as the accouter of a tug or blaze boat, that metal ability be accountable to breakable breach if the cryogenic aqueous comes in acquaintance with the deck.
As mentioned at the alpha of this article, best new LNG escort tug boats are able with Fi Fi 1 (Firefighting 1) assurance accessories (click on Diagram to the left) . To access any Fi Fi class (1, 2, or 3) the barge allegation accept a assertive akin of firefighting equipment.
At all levels of Fi Fi categories the barge allegation accept a deluge arrangement which will assure the barge and aggregation from beaming heat. This deluge arrangement is composed of a alternation of pipes all over the accouter and pilot abode of the tug boat. At several credibility sprinkler active and deluge nozzles are amid in the piping.
When baptize is started, it projects a careful blind about the apparent breadth of the tug. This baptize blind helps to assure the barge and aggregation from the furnishings of beaming heat. This would acquiesce the barge to escape the arena of a blaze in adjustment to ability an breadth of ambush or it ability accredit the barge to access an breadth of aerial calefaction to aftereffect a rescue. (See photo left.)
But this baptize deluge serves addition purpose aback it comes to LNG. The argosy accouter is continuously wet bottomward and this baptize on the accouter helps to assure the accouter from the breakable breach furnishings of the LNG. As the LNG hits the baptize apparent it is anon broiled and disbursed as a gas or done over the side.
It allegation be remembered that LNG is aloof accustomed gas in a aqueous form. Therefor, all the backdrop that we accessory with accustomed gas will be present as the LNG boils off into a gas.
The flammability ambit of a gas is the admixture of gas and air that would be appropriate for that gas to bake and burn,
Luckily this gas is usually either too affluent or too angular to burn. The LNG gas will alone bake aback it is in a absorption amid 5% and 15% aback alloyed with air.
If it’s admixture with air is beneath 5% again it is too angular to burn. If the gas and air admixture is aloft 15% again it is too affluent to burn. The analogy on the appropriate gives a clear representation of this combustible range.
If you accept anytime apparent a affirmation of an LNG discharge or aperture you will bethink seeing the white billow that forms. Abounding afield accept that this billow is the gas. Remember, we said that LNG is achromatic and odorless. You cannot see the absolute gas. What you are attractive at aback that white billow is present is baptize breath in the air that is algid by the acute algid of the LNG to anatomy a fog or alike snowflakes. It is odorless because that’s the way accustomed gas is in its accustomed state. The odor we all associated with accustomed gas aback it leaks from your affable stove at home is an odorant alleged mercaptan and/or thiophane that is added by your bounded gas account company. (This gives that rotten egg or adulteration debris smell.)
Because LNG is alone accustomed gas in a aqueous state, aback it allotment to a gas it has all the backdrop of accustomed gas. If you access the breath billow (and we now apperceive that the white blush is alone algid damp in the air) you will be subjected to the asphyxiant backdrop of the gas. All aboriginal responders should be able with and ordered to abrasion cocky independent breath accoutrement (SCBA) until the air is activated and begin safe.
Because LNG rapidly reverts aback to a gas aback heated, best baby spills will accept either evaporated and risen into the atmosphere or, if ignited, the blaze will accept captivated the LNG by the time borough aboriginal responders arrive. If it is alone a discharge with no agitation the on-scene activity is usually bound to closing valves to stop the discharge and insuring that any breath billow is broadcast with baptize aerosol and directed abroad from any antecedent of ignition. If the breath from this accessory discharge does ability a antecedent of agitation and the gas absorption is aural the 5% to 15% ambit the after blaze will bake aback to its antecedent at a slower bulk than that of gasoline or propane vapor. If the discharge is afire initially, its abasement will bake off at the antecedent until all the LNG has been vaporized. The on arena activity at this blaze will about abide of not aition the blaze until the antecedent of the aperture has been shut and the breeze stopped. Quite generally the blaze will again be accustomed to bake until all LNG has been consumed. On arena aboriginal responders will be attention any exposures which may be in crisis and possibly application fog streams to alter the breath billow and accelerate the abating of the breath so it will acceleration and blow added rapidly.
If the blaze is to be aished you do not use water. Abundant success has been able with the use of a aggregate of firefighting cream and dry actinic agents. The cream of best actuality is Hi-Expansion foam. It has been begin that the cream both separates the LNG from sources of agitation and additionally allows the controlled regasification of the LNG through arctic tunnels which anatomy in the foam. The cream allegation be activated in absolute ample quantities in a absolute abbreviate time therefor newer aerial accommodation cream generators accept been invented.
I mentioned that you do not use baptize to extinguish an LNG fire. Baptize will acknowledge berserk with the LNG and may account the blaze to blaze up and intensify. Addition achievability is that the baptize will account a Accelerated Phase Alteration (RPT) of the LNG. LNG will about-face to a gas at a accustomed bulk aback apparent to the air. Aback it comes into acquaintance with baptize this alteration from a aqueous to a gas is abundantly increased. (At times this may alike be adorable beneath controlled circumstances) However, if the alteration is accelerated up too abundant the amplification of so abundant aqueous into a gas in a baby breadth will account a RPT. “A ample bulk of activity is appear during this accelerated alteration amid phases and a concrete access can occur. While there is no combustion, this concrete access can be chancy to any adjacent being or buildings.”3
I accept done abundant analysis on LNG over the accomplished few years and I accept appear to accept that, if handled properly, LNG can be as safe if not safer than abounding of the petroleum based activity articles currently in use. The LNG industry has a arresting almanac aback it comes to the abyssal addition of Abounding Accustomed Gas. If we as Firefighters and as Mariners booty the assurance precautions actively we should be able to accumulate up the industry’s record.
This commodity is in no way advised to be a complete abstraction of LNG. Anyone who is tasked with administration LNG or responding to an LNG adventure should accept abundant advice about the LNG and about operating at LNG emergencies. Please acquaintance us for accommodation about our LNG acclimatization seminars.
Tom is a retired Lieutenant of the New York City Blaze Department’s Abyssal Division. During his 34-year administration with the FDNY he formed at structural firefighting in some of the busiest areas of New York City. In his aftermost ten years he additionally acted in the accommodation of Training Officer for the FDNY Abyssal Division. Tom captivated a US Coast Guard License as a Ships Master and has been certified as a Blaze adviser both aural New York Accompaniment and Nationally in the USA.
He is currently a accommodating affiliate of the Society of Naval Architects and Abyssal Engineers (SNAME) Fishing Barge Operations and Assurance console and additionally their Baby Alive Barge Operations and Assurance panel. Tom is additionally a Principal Affiliate of the NFPA Technical Committee on Merchant Vessels.
The Abyssal Firefighting Institute is accessible for Lectures, Seminars and Consulting. To acquisition out added CLICK HERE
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