34. Dangers on a Tanker (cd2-3)

C/Off: Because you are new on the tanker, let's begin this training session with the basics.

Refer to the green brochure Safety on a Tanker. Well. what kinds of dangers do

you think are lurking on a tanker? Cruz: Fire? The gas from the cmde oil could ignite and start a fire. Santos: An even worse case is an explosion. C/Off: That's right. The tanks are filled with crude-oil vapor, and when the oil is being

loaded, it could spill onto the deck. The vapor, or hydrocarbon gas, is very

dangerous. You should never carry matches or lighters while on the deck. You

may not even carry them to your cabins. Cruz: I guess that's why we should smoke only in designated areas. There are matches

there, and the ashtrays are filled with water. I smoke now, but I've made up my

mind to quit smoking. It will be better for my health, too. C/Off: What are some other dangers? Cruz: Since we use inert gas, there could be a shortage of oxygen. C/Off: Actually, there is little oxygen in the tanks. We are not too affected by inert gas on

deck except while performing specific tasks, such as gas freeing. Toxicity hazards

caused by crude oil gas are more likely to happen. Santos: I've heard that a small quantity of cmde oil gas isn't too dangerous. C/Off: That's true, but crude oil that contains a lot of hydrogen sulfide is dangerous. It

could paralyze you if you inhale it.

brochure: small booklet, pamphlet

lurking: hiding, awaiting

ignite: to catch fire

explosion: sudden, violent release of energy and substances

crude-oil vapor: vapor that forms when crude oil is contained

hydrocarbon gas: a gas of organic substances which contains carbon and hydrogen

designated areas: area marked off for a special purpose

oxygen: a gaseous substance existing in the air which is essential for breathing

gas freeing: removing unwanted gas

toxicity hazard(s): potential danger from toxic (poisonous, harmful) substances

hydrogen sulfide: colorless, poisonous gas with the smell of rotten eggs

paralyze: to make a person lose free control of movement

inhale: to breath in, to intake

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35. Tanker Fires and Explosions (cd2-4)

C/Off: Let's talk more about fire and explosions. Flammable gas, alone, doesn't cause

explosions.

Cruz: You mean there must be oxygen, too?

Santos: And also a source of ignition.

C/Off: You're right. But what is more important, however, is their concentration. What I

am about to tell you is a little advanced, but we have to discuss it so you are aware

of the dangers.

Cruz: Are you talking about LEL or UEL?

C/Off: Yes. First of all, petroleum gas consists of many different substances. Each of

these has different properties. That's why the ICS has defined UEL or UFL as a 10

percent concentration, and LEL or LFL as one percent. Santos: That means that the petroleum gas won't explode unless the gas concentration isn't

within that range. C/Off: Exactly. And an oxygen concentration of 11 percent is also necessary. Even if the

petroleum gas concentration is in the explosion range, there can be no explosion if

the oxygen concentration is less than 11 percent. Santos: So that's why the inert gas sent to the tanks has an oxygen concentration of less

than 8 percent. C/Off: The most dangerous problem with the tanks is static electricity. But if the tanks are

filled with the proper amount of inert gas, we don't have to worry about static

electricity. Cruz: Is it safe on deck? C/Off: The most important thing is to check for gas on deck when you are chipping or

welding. That's why proper maintenance and good communication between the

deck crew and the engine crew is so important.

flammable gas: a gas that catches fire easily

ignition: catching of fire, starting to bum

concentration: the amount of substance in a solution; strength

LEL: Lower Explosive Limit

UEL: Upper Explosive Limit

petroleum gas: vapor generated from petroleum or oil

substances: material(s)

properties: qualities, characteristics

ICS: International Chamber of Shipping

UFL: Upper Flammable Limit

LFL: Lower Flammable Limit

static electricity: discharge of accumulated energy, electric potential which can produce sparks

welding: joining metals by applying extreme heat

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