Pipe sizing & commissioning With the increasing demand on our drinking water supply, the necessity to conserve water in our dr ying climate and the requirement to comply with the 2003 edition othe plumbing standards AS/NZS 3500, it is vitally important to pipe size the supply ocold water to all outlets correctly. Firstly , Section Three (3) oAS/NZS 3500.1:2003, which was previously removed rom legislation in Western Australia, has now been reinstated under the Water Services Licensing (Plumbers Licensing and Plumbing Standards) Regulations 2000 (the Regulations) In particular Clauses 3.3.2 (Minimum Pressure 50 kPa) & 3.3.4 (Maximum Static Pressure 500 kPa) which are now pertinent actors in the pipe sizing exercise . Secondly, the Regulations do modiy this section by deleting the second paragraph oClause 3.2.1 and the whole oClause 3.5.2. Iyou are certiying a water supply installation to AS/NZS 3500.1:2003, it is important to understand the methods osizing the system and applying the provisions oequivalent pipe sizes or materials other than copper. To pipe size correctly you will need to know the ollowing inormation: •The pipe index length The distance rom the water meter to the urthest outlet expressed in metres (m). •The highest outlet The vertical height rom the water meter to the highest outlet expressed in metres (m). •Required pressure The minimum pressure allowable at the most disadvantaged outlet expressed in metres (m). Clause 3.3.2 requires a minimum pressure o50 kPa (5m head). •Available pressure The minimum pressure that water is supplied at by the water service provider expressed in metres (m). •Flow rates and loading units Specic ow rates and loading units oxtures and appliances rom AS/NZS 3500.1:2003 Tabl es 3.1 & 3.3. Once you have the required inormation it is time to pipe size using the ollowing steps: 1 Sketch the installation, label the pipe sections & draw a table. 2 Insert loading units rom T able 3.1 into the table and onto the drawing. 3 Insert ow rates rom Table 3.1 or a single outlet and probable simultaneous ow rates rom Table 3.3 or multiple outlets into the table. 4 Determine the available pressure. 5 Determine the pressure drop. 6 Calculate the index length. 7 Using T able C1 (30m h ead) & column 40m index length rom Appendix ‘C’ pipe size each section opipework in the table. M a y 2 0 0 7 TECHNICAL NOTE Technical Advice Line 1300 360 897 Pipe Sizing and Commissioning
