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A
short recap of our earlier newsletters.......
March
2000 - covered explosives, Class 1, divisions 1.1 to 1.6.
April
dealt with gases, i.e., Divisions 2.1 Flammable Gases, 2.2 Non-Flammable
Gases, and 2.3 Toxic Gases.
May
covered Division 5.1 Oxidizers coinciding with the very sad fourth anniversary
of the ValuJet accident in the Florida Everglades in the United States.
In June
we did a quick review and offered a few reminders for those who transport
dangerous goods/hazardous materials.
In July,
we examined Division 5.2, Organic Peroxides with all of the regulators'
technical information first and then tried our best to simplify those
properties as best we could, hoping that it would not only help you recognize
those chemicals but also to alert you to the risks involved in handling
this extremely dangerous hazard class and division. We extend our thanks
to those people who e-mailed comments to us about this particular division.
They shared our lack of enthusiasm for all the technical information gleamed
from the regulations and appreciated the brief description pointing out
the actual properties in understandable language. At least we hope it
was understandable.
We will be adding
monthly quizzes as a feature in our websites as well as some of our experiences
that demonstrate why dangerous goods go undeclared in transportation.
We hope that these articles will be useful to shippers, forwarders, carriers,
and less experienced persons involved in management, transportation or
enforcement.
Meanwhile, back to
the hazard classes....
This month we would
like to cover Class 3, Flammable Liquids.
Definition:
Flammable liquids are liquids that give off a flammable vapour at temperatures
of not more than 60.5 degrees Celsius (141 degrees F.) closed-cup test
or not more than 65.6 degrees Celsius (150 degrees F.) open-cup test normally
referred to as the flash point.
Even this classification
becomes somewhat confusing because of some technical terms that are misunderstood
by persons who ship or transport these liquids. Let us start with some
examples of Flammable Liquids: gasoline, ethanol,
methanol, paint, adhesives, solvents, resin solution, acetone, nail polish,
perfumes and colognes, "pump-type" hair sprays (but not
aerosols), furniture and automotive waxes and polishes, fuel additives,
ethers, flavouring extracts, aromatic extracts, home and industrial heating
oils, alcoholic beverages, cough medicine, some pesticides, medicinal
tinctures, hair tonic, drugs and medicines.
We underlined "alcoholic beverages" because that seems to get
everyone's attention during training classes. Of course, your esteemed
editor has had many years of personal experience in researching this particular
hazardous material and we are always conducting new experiments with these
products, if you know what we mean.
Now, if you can stop
laughing for just a minute, the biggest misconception about a bottle of
booze is where the manufacturer displays the "proof". The average
citizen presumes the word "proof" indicates the amount
of pure alcohol in the beverage. Actually it displays the percentage of
alcohol, times two. For example, a good brand of scotch usually indicates
that it is 80 proof. That number comes from the actual percentage of alcohol
(40%) x 2, or, 40x2=80. So, if our favorite beverage is only 40% alcohol
(actually ethyl alcohol, a.k.a. ethanol) what else is in the jug, uh,
bottle? Since ethanol is totally miscible (the ability of a liquid or
gas to dissolve uniformly in another liquid or gas) with water, distilled
water represents the highest percentage of the ingredients. Small amounts
of coloring and flavouring make up the balance of our product (hic).
In 49CFR Special Provision
24 eliminates the guesswork for alcoholic beverages. It advises that alcoholic
beverages containing more than 70% of alcohol by volume must be assigned
to Packing Group II and beverages containing more than 24% of alcohol
by volume must be assigned to Packing Group III. Alcoholic beverages containing
less than
24% alcohol are not regulated, therefore your favorite beer or wine is
not going to be regulated as a flammable liquid. The size of inner receptacles
(the bottles), percentage of alcohol, and mode of transportation may provide
for further relaxation of the regulations.
All of the international
regulations have similar rules. For example, under IATA you should refer
to the Dangerous Goods List, Section 4.2, which is very detailed, and
Special Provisions A9 and A58, in Section 4.4.
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And, now, for the
rest of the flammable liquids....
Misconception #1:
the most frequent reply to the question "what is the meaning of flash
point" is that it is the temperature at which a liquid will ignite
or explode. WRONG!
FLASH POINT is the
minimum temperature at which a liquid gives off ignitable vapors
within a test vessel. The test vessel is either an open or a closed cup
tester where the temperature of the liquid is strictly controlled. A device
at the top of the cup sets off periodic sparks as the temperature of the
liquid is increased. When the spark causes a "FLASH" you note
the temperature of the liquid and you now have the "flash point",
which should be in degrees Celsius. A closed cup test is the type of test
required by the United Nations Orange Book and most regulatory agencies
and is considered more reliable than an open cup test.
Misconception #2:
Flash point is all you need to know. WRONG!
At least three, maybe more, bits of information about the properties of
flammable liquids must be determined. BOILING POINT is vitally important.
COMPATIBILITY with the primary receptacle containing the liquid, and the
SPECIFIC GRAVITY of the liquid are also extremely important properties
to be evaluated.
BOILING POINT:
The temperature at which a liquid starts to boil. The magic number happens
to be 35°C. (95°F.) Flammable liquids that boil at that temperature
or lower are automatically assigned to Packing Group I - the most dangerous
form of a flammable liquid. Remember now, the liquid boils when it reaches
that temperature. It doesn't need your mother's stove with the flame cooking
the drum to start to boil.
As the liquid boils
it reacts similar to water boiling at 100°C. (212 °F) - it turns
to steam.
As more of the liquid turns to steam, pressure builds up in the container
causing the container to bulge and ultimately to burst with extraordinary
force.
For those of you who
physically handle dangerous goods, when the drum of a flammable liquid
is bulging on the top and the bottom you may have a very dangerous situation
unfolding. Don't ignore it!
COMPATIBILITY:
Think about the last time you needed gasoline for your lawnmower. If you
ever put the gasoline in a plastic milk bottle you have experienced compatibility
in packaging. Does the liquid "attack" the container or the
gasket in the closure? Does the container start to soften or weaken and
ultimately leak? Incompatibility leads to container failure and accidental
release of the dangerous goods. In transportation that could lead to a
catastrophe.
SPECIFIC GRAVITY:
How much does 1 litre of the flammable liquid weigh as compared to 1 litre
of water?
If the flammable liquid weighs 1.5 kg and water weighs 1.0 kg. then the
specific gravity of the flammable liquid is 1.5. Most Packing Group II
packagings are tested for a specific gravity of 1.2. In the above example,
the packaging not likely to be suitable for the flammable liquid that
is being shipped.
PACKING GROUP NUMBERS:
Packing group numbers are our way of communicating the risk involved with
most dangerous goods/hazardous materials, based upon appropriate testing.
The tests vary according to the hazard class. PG I is a great danger,
PG II is a medium danger, and PG III represents a minor danger.
For Flammable Liquids,
Class 3, the packing groups are based upon flash point and boiling point.
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Flash
Point
(closed cup test)
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Boiling
Point
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| PG
I |
-
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less
than or equal to 35°C.
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| PG
II |
less
than 23°C.
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greater
than 35°C.
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| PG
III |
equal
to or greater than 23°C.
But less than or equal to 60.5°C.
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greater
than 35°C.
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