Example 1 Calculate an appropriate pipe size for the system shown above. Use Copper Table X pipework for water at 10oC.. Answer The maximum allowable pressure drop along the length of pipe = 300,000 Pa 250,000 Pa = 50,000 Pa – Pressurised Cold Water Pipe Sizing Table 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Ref Demand Flow Estimated Measured Length of Effective Pipe Pressure Friction Pressure Pressure Pressure Final Units if Rate Pipe Dia. Pipe Run Pipe Equal Pipe Pressure Consumed loss + at Start Available Required Pipe required to Fittings Length Loss due to Static of at End of at End of Size (l/s) (mm) (m) Resistance’s Col . 5 + (Pa/m) Friction pressure Section Section Section (m) 6 From Col. 7 x 8 loss = (Pa) (mm) (m) CIBSE (Pa) Total (Pa) (Pa) Tables Pressure Consumed (Pa) A none 0.8 22 50 none 50 3500 175,000 175,000 300,000 125,000 250,000 Too small A none 0.8 28 50 none 50 1000 50,000 50,000 300,000 250,000 250,000 28 Pipe Sizing Procedure 1. Reference the pipe section - section A. 2. Calculate demand units or loading units from Tables in CIBSE guide (attached). not required, see No.3 below. –
Example 1 Calculate an appropriate pipe size for the system shown above. Use Copper Table X pipework for water at 10oC.. Answer The maximum allowable pressure drop along the length of pipe = 300,000 Pa – 250,000 Pa = 50,000 Pa Pressurised Cold Water Pipe Sizing Table 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Ref Demand Units if required Flow Rate (l/s) Estimated Pipe Dia. (mm) Measured Pipe Run (m) Length of Pipe Equal to Fittings Resistance’s (m) Effective Pipe Length Col . 5 + 6 (m) Pipe Pressure Loss (Pa/m) From CIBSE Tables Pressure Consumed due to Friction Col. 7 x 8 (Pa) Friction loss + Static pressure loss = Total Pressure Consumed (Pa) Pressure at Start of Section (Pa) Pressure Available at End of Section (Pa) Pressure Required at End of Section (Pa) Final Pipe Size (mm) A none 0.8 22 50 none 50 3500 175,000 175,000 300,000 125,000 250,000 Too small A none 0.8 28 50 none 50 1000 50,000 50,000 300,000 250,000 250,000 28 Pipe Sizing Procedure 1. Reference the pipe section - section A. 2. Calculate demand units or loading units from Tables in CIBSE guide (attached). – not required, see No.3 below.
3-pipe-sizing-2013-3.docx