1-1 Chapter 1 GAS TYPES MARKETED IN AUSTRALIA Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e

1-2 Gas types Marketed in Australia for gas appliances: Natural gas (NG) Liquified petroleum gas (LPG) Tempered liquified petroleum gas (TLP) Simulated natural gas (SNG) Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e

Natural gas Formed by: –decaying organic matter –compressed by sediment layers –build-up of pressure and heat converted to:  gas  oil Gas production –Exploration –Drilling –Production wells –Treatment –Delivery 1-3 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e

Formation of natural gas 1-4 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e

Liquified petroleum gas (LPG) Types of LPG –Propane –Butane –Autofuel Produced by: –by-product of natural gas wells –oil refineries Stored in cylinders by moderate pressure. 1-5 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e

Tempered liquified petroleum gas (TLP) Developed to replace towns gas in small provincial cities. Towns gas substitute produced by using propane or butane as a feedstock and mixing it with precise amounts of air. 1-6 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e

Simulated natural gas (SNG) Used where natural gas is expected to become available. –Produced by using propane or butane as a feedstock and mixing it with precise amounts of air. –When natural gas arrives installations and appliances can be connected with minor adjustments. 1-7 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e

Other gases TOWNS GAS –Produced from coal. –Later produced from oil. –Gas contained condensate (tail pipes required). –Toxic gas. PROCESSED NATURAL GAS –Produced from natural gas to produce simulated towns gas until converted to natural gas. These gases no longer available in Australia. 1-8 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e

Properties of gases 1-9 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e

Characteristics of gases 1-10 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e

Heating value This is the measurement of the amount of energy liberated when one cubic metre of gas is completely burnt in air under standard test conditions. Measured by the number of megajoules (MJ) in a m³. Natural gas38 MJ/m³ LPG (propane)96 MJ/m³ 1-11 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e

Relative density This is the weight of gas relative to the weight of air. Air = 1 Natural gasRD0.6 (lighter) LPG (Propane)RD1.5 (heavier) 1-12 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e

Burning velocity (also known as flame propagation) This is the speed at which the flame can consume the gas. Natural gas 400 mm/second 1-13 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e

Air requirements Air must be available for complete combustion to take place. Air to gas ratio = natural gas9.5:1 (gas) LPG (propane)24:1 (gas) 1-14 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e

Ignition temperatures The air–gas mixture must be ignited by sufficient ignition temperature. Natural gas680°C LPG (propane)490°C 1-15 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e

Flammability limits (Also known as explosive limits) Not all air–gas mixtures are combustible. Lower explosive limits(LEL) This is the minimum percentage of gas mixed in air that will burn or explodee.g. NG 5% Upper explosive limits(UEL) This is the maximum percentage of gas mixed in air that will burn or explodee.g. NG 14% 1-16 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e

Toxicity This is whether gas is toxic or non-toxic (poisonous). Natural gas non-toxic LPGnon-toxic Towns gastoxic Note: Although some gases are non-toxic, it must be remembered that an escape of gas can result in fire, explosion and asphyxiation Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e

Odourants All gases have odour added before distribution to the customer. Odour is added to gas sufficient to be detected at one fifth LEL by smell Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e

Gas types—Summary Natural gas and LPG (propane) are the most common types of gas available in Australia for appliance installations. Consideration of gas types is an important part of installation, appliance design and operation. Installers must understand how the different gas types work to ensure the installation and appliance operate safely. Safe work practices must be followed while working around gas Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e