Occupational Hazards

Question 1

What will be displayed on a vehicle powered by LPG?

Answer 1

Vehicles must display a red diamond on the front and rear number plates.

Question 2

What is the legal capacity for filling containers of LPG and why?

Answer 2

80% to ensure adequate vapour space above the liquid. The vapour space allows for expansion of the liquid caused by an increase in temperature.

Question 3

What is a BLEVE?

Answer 3

Boiling
Liquid
Expanding
Vapour
Explosion

Question 4

What are the properties of natural gas?

• Composition?
• Colour and odour?
• Vapour density?
• LEL?
• UEL?

Answer 4

• Predominantly methane (85-95%)
• Colourless and odourless (odorant added)
• Vapour density = 0.55 (air = 1)
• LEL = 5%
• UEL = 15%

Question 5

What is natural gas?

Answer 5

Natural gas is derived from decomposed plant and animal material that has been trapped underground. Extracted by drilling and pumped through a network of steel transmission pipes, it is used for heating buildings, heating water, cooking, drying clothes, lighting and industrial purposes.

Question 6

What is a rim fire and where should water be applied?

Answer 6

Rim fires are the most common fire to occur in a tank with a ‘floating’ roof. They are commonly caused by lightning strike. The rubber seal around the edge of the roof catches fire.

Cooling water must be applied to the outside of tank because excessive water on the roof could cause it to sink, resulting in a full surface fire.

Question 7

In relation to firefighting, what is the importance of a bund?

Answer 7

It is a no-go area for firefighters.

Question 8

Name two types of installed foam delivery systems for a flammable liquid tank.

Answer 8

• Foam pourers
• Monitors