CPCPGS3001AInstall Gas Piping Systems

Types of Gases

Work Health & Safety:

New Work Health and Safety (WHS) laws replaced the occupational health and safety (OHS) laws in NSW on 1 January 2012

• Workbook pg. 4

Gas Safety:

• PPE

• Electrical Safety

• Workbook pgs. 5 - 17

S I Units of Measure (Standard International Units of Measure)Workbook Pg. 18

S I Unit How to read it Used to measure

kPa Kilopascal Pressure

m³ Cubic metre Volume

MJ Megajoule Quantity of heat (energy)

MJ/h Megajoule per hour Heat per hour

mm Millimetre length

Combustion Principles

• Combustion is the term used for the burning of a fuel in air.

Workbook pg. 8

Combustion Principles

• 3 elements are required for combustion to take place.

Workbook pg. 8

Combustion Principles

• Fuel

• Air (the Oxygen contained in air)

• Heat (Ignition)

Workbook pg. 8

Combustion Principles

• Once ignition has taken place, the combustion process is self-sustaining providing a combustible mixture of gas and air is maintained.

See next slide

Workbook pg. 8

Combustion Principles

• Complete combustion Click to reveal

O2

O2

C3H8

CO2H2O

Heat

Combustion Principles

• Incomplete combustion Click to reveal

O2

O2

C3H8

COH2O

Heat

Combustion Principles

• Incomplete combustion produces carbon monoxide

• Carbon monoxide is a poisonous gas.

CO

Combustion Principles

Major causes of incomplete combustion

• Gas flow to high to burner• Insufficient air to burner• Blocked or restricted flue• Poor ventilation

CO

Types of Gases

Natural Gas (NG)Workbook pg. 19

• Natural gas is approximately 75 – 95 % Methane a hydrocarbon gas.

• Its molecular structure is made up of carbon and hydrogen CH4

See next slide

H

H

H

H

H

C

Natural Gas

CH4

Types of Gases

Liquefied Petroleum Gas (LPG)Workbook pg. 19

• Propane a hydrocarbon gas can be found in crude oil extraction and is also produced from crude oil refining.

• Propane is liquefied by refrigeration and pressurisation.

• Its molecular structure is made up of carbon and hydrogen C3H8

See next slide

HH

H

H

C

H

Propane (LPG)

C3H8

H

H

HHH

H

H

C C C

Characteristics and Properties of Gases

Heating Value:

• The approximate heat energy (MJ) available in a known quantity of gas.

• NG – 38 MJ /m³

• LPG – 96 MJ/m³

Workbook pg. 19

Characteristics and Properties of Gases

Relative density:

• The weight of gas compared to air.

• NG – 0.6 = lighter than air

• LPG – 1.5 = heavier than air

Workbook pg. 20

Characteristics and Properties of Gases

Ignition Temperature:

• The minimum temperature that gas will ignite.

• NG – 680 ºC

• LPG – 490 ºC

Workbook pg. 20

Characteristics and Properties of Gases

Air – Gas Ratio:

• The quantity or volume of air required for complete combustion.

• NG – 10:1 - 10 parts air to 1 part gas.

• LPG – 24:1 – 24 parts air to 1 part gas

Workbook pg. 20

Characteristics and Properties of Gases

Toxicity:

• Are fuel gases poisonous ? (toxic)

• NO …… however

Workbook pg. 22

Characteristics and Properties of Gases

Toxicity:

• Are fuel gases poisonous ? (toxic)

• NO …… however

Workbook pg. 22