Session 10: Tanker introduction

Question 1

What safety guide do oil tankers use?

Answer 1

International Safety Guide of Oil Tankers and Terminals(ISGOTT): Comprehensive guide that provides best practices and safety recommendations for ships carrying oil and the terminals where they load or discharge the oil.

Question 2

What does auto ignition mean?

Answer 2

Temperature at which a substance will catch fire without an external ignition source, like a flame or spark.

Question 3

What is spontaneous combustion?

Answer 3

Material catches fire as a result of a chemical reaction that occurs internally, producing enough heat to ignite the material.

Question 4

What’s the difference between “Auto ignition” and “Spontaneous combustion”?

Answer 4

“Auto ignition” is when something catches fire at a certain temperature by itself, while “spontaneous combustion” is when something catches fire because of its own internal chemical reactions.

Question 5

What is bonding in oil tanker operation?

Answer 5

connecting together of metal parts to ensure electrical continuity

Question 6

What is sludge?

Answer 6

oil remaining on the wall of a pipe or on the surfaces of tank interiors after bulk of the oil has been removed

Question 7

What is flashpoint?

Answer 7

lowest temperatures at which liquid petroleum gives off flammable vapor

Question 8

what is volatile petroleum?

Answer 8

petroleum having a flashpoint below 60 °C as determined by the closed up method of testing

Question 9

what is loading rate?

Answer 9

volume of liquid loaded within given period of time

Question 10

What is flammable range?

Answer 10

range of hydrocarbon gas concentration in air between lower and upper flammable limit

Question 11

what is inert gas?

Answer 11

a gas or a mixture of gases, such as flue gas, containing insufficient oxygen to support combustion of hydrocarbons.

Question 12

What’s the purpose of inert gas?

Answer 12

In oil tankers, the purpose of inert gas is to prevent explosions or fires. By filling the empty spaces in the tanks with inert gas, it reduces the amount of oxygen, making it harder for flammable oil vapors to ignite.

In simple terms, it’s a safety measure to keep the air inside the tanks from catching fire.

Question 13

What is purging?

Answer 13

Introduction of inert gas into an inerted tank to either reduce oxygen% or hydrocarbon%.

This refers to the act of flushing out or replacing one gas with another. In the context of oil tankers, it could mean flushing out hydrocarbon vapors with inert gas to ensure safety.

Question 14

What is topping-up?

Answer 14

introduction of inert gas in the inerted tank to maintain required tank pressure

Question 15

What is ullage?

Answer 15

Space above the liquid in a tank

Question 16

what is referred to “measuring the depth of a liquid inside a tank”

Answer 16

sounding

Question 17

what is this referred to : ullage + sounding

Answer 17

total cargo capacity

Question 18

what is meant by topping off?

Answer 18

loading cargo at required ullage

Question 19

What are some hazards of petroleum?

Answer 19

-flammability
-toxicity: short term and long term danger because of inhalation of petroleum vapors ex; marine pollutant
-corrosive: final operation in pumping bulk liquid from a tank or pipeline

Question 20

what does the fire triangle consist of?

Answer 20

Oxygen
Heat
Fuel

Question 21

from the fire triangle what should be avoided in zone A, B, C, D

Answer 21

zone A: Fuel (accommodation, engine room)
zone B: Heat (Main deck)
zone C: oxygen (cargo hold)
zone D: Depends (bow, foremast)

Question 22

What is static electricity?

Answer 22

Static electricity is the build-up of electric charge on a surface, usually caused by rubbing two objects together.

Question 23

What causes static electricity when loading oil?

Answer 23

When oil flows through pipes or is being loaded or unloaded, it can generate static electricity. If there’s a build-up of this static charge and it’s not properly dispersed, it could spark and cause a fire or explosion, especially because the environment is filled with flammable vapors.

Question 24

Causes and prevention of static electricity on board a tanker?

Answer 24

Causes: flow of water, oil and air through cargo pipelines

Prevention: start loading cargo at minimum rate, checking the bonding of portable cargo and tank cleaning hoses, stop cargo operations during lightning near the ship

Question 25

Between what percentage on the explosive range diagram does the mixture of hydrocarbon gas and oxygen is considered flammable?

Answer 25

The leftmost point of this area (point G on the diagram) is at an oxygen percentage just below 5%, and the rightmost point (point A) is at an oxygen percentage just above 20.9%. Between these two extremes, any mixture of hydrocarbon gas and oxygen that falls within the blue lines is considered flammable.