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

10-2 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e Pipe installations Must be carried out by an authorised installer. Basic standards for the design and location of pipes and materials to be used are governed by an Australian Standard (AS 5601). AS 5601 covers installation of appliances for use with natural gas, LPG, SNG or TLP. Administrative, gas supply and metering requirements are determined by the local authority. The installer must obtain all relevant information before commencing work.

Purging of gas services Purging is the replacement within a vessel of one medium with another. For gas fitting this is either replacing air (or inert gas) with gas on new lines, or replacing the gas with air or inert gas on existing lines Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e

Testing of gas services It is important for every joint on a gas service to be tested for soundness prior to charging with gas and/or lighting an appliance. New pipework is tested using air or inert gas to a minimum pressure and time limit—refer to AS The minimum test time is determined by the volume of the piping. Existing installations are tested for soundness prior to lighting an appliance Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e

Pipe-sizing installations Consideration must be given to the factors that affect the flow of gas through pipes. 1. Length of pipe. 2. Number of fittings used. 3. Specific gravity of the gas. 4. Material type of the pipe or tube. 5. Nominal size of pipe Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e

Determining pipe size Information required a) The type of gas. b) The gas rate in megajoules of each appliance to be used on the installation (consideration of future needs). c) Pipe configuration, lengths of each section, number and type of fittings. d) The static pressure of the installation. e) Meter outlet pressure and/or allowable pressure loss of installation. f) Diversity factors Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e

Adding appliances to existing installations Check the meter, regulator and inlet service are capable of meeting the additional load. Pipe-size existing installations to determine adequate capacity for carrying the additional load Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e

Pipe-sizing Gas type Material Index length Appliance loads Pressure drop 10-8 Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e Note: Letters marked at branches and appliances.

Pipe-sizing two-stage installations Two-stage installations use the same principles as single-stage installations, except that each stage is sized using tables applicable to the pressure rating of each section. As the pressure setting of the first-stage regulator is relatively high a much higher pressure drop is used, which results in smaller pipe sizes than lower pressure regulators Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e

Two-stage piping index length The index length for the first-stage section is from the regulator to the most disadvantaged (furthest) second- stage regulator. The index length for the second stage is from the second-stage regulator to the furthest appliance it serves Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e

Pipe installation—Summary Installation of piping to comply with AS Pipe size factors –Gas type –Gas load for installation –Piping configuration –Pressure loss for installation –Material –Diversity factors Testing and purging is part of the installation of piping Copyright  2010 McGraw-Hill Australia Pty Ltd PowerPoint slides to accompany Puffett, Hossack, Stone, Burn & Miles, Gasfitting 2e