Pipesize                  Water temperature     °C   (typically 10°C for Chilled, 75°C for LTHW)
Mass flow kg/s    or Volume flow     l/s or Heating/Cooling load     kW
    Delta T     °C

Pipe Material / Diameter:
Steel - Medium black BS EN 10255 Steel - Heavy black BS EN 10255 Steel - Heavy galv. BS1387
Steel - large dia BS3600  Seamless Steel BS EN 10220  Ductile Iron BS EN 545 Class 40 
Copper - Table X   Copper - Table Y   Copper - Table Z  
Cast Iron  BS1211  Mapress Carbon Steel  Mapress Copper 
UPVC - Class C  BS3505 UPVC - Class E  BS3505 Aquasystem PPR  
  Hep2o   PB and PE-X  BS7291/2871 Instaflex   PB & PE-X  BS7291/5556 MDPE PE80 (SDR11)
 Friatherm  PVC-C  BS7291 PVC-C  DIN16968   HPPE PE100 (SDR11)
    Or specify:           Internal Diameter mm   and   Roughness  k  mm     See CIBSE C guide table 4.1 for k - eg  rusty pipes k = 2.5 

 Results:                                                                    

Pressure drop per unit length   Pa / m   typically 250-400 Equivalent length le  m  (length for pressure drop of 1 velocity pressure)
Velocity Pressure Pa Velocity  m/s   typically aim between 0.75 and 1.5 (or < 3 for larger pipes)
Density  kg/m3 Reynolds Number