Reference Data

The defaults every sizer starts from. Edit any of them and your version is remembered on this device.

Pipe systems

Each system is a named pipe network with its own colour and default material. It carries one or more preset variants, its typical operating conditions, that any sizer can pick from. Add your own variants or tune the presets to suit your project.

Heating and cooling

LPHW

Low pressure hot water

Steel
82 / 71 °C

973.9 kg/m³ · 3.81e-7 m²/s · 4.20 kJ/kg·K

80 / 60 °C

977.8 kg/m³ · 4.13e-7 m²/s · 4.19 kJ/kg·K

55 / 45 °C

988.0 kg/m³ · 5.52e-7 m²/s · 4.18 kJ/kg·K

45 / 40 °C

991.2 kg/m³ · 6.28e-7 m²/s · 4.18 kJ/kg·K

40 / 30 °C

994.0 kg/m³ · 7.23e-7 m²/s · 4.18 kJ/kg·K

CHW

Chilled water

Steel
6 / 12 °C

999.8 kg/m³ · 1.34e-6 m²/s · 4.20 kJ/kg·K

6 / 14 °C

999.7 kg/m³ · 1.31e-6 m²/s · 4.20 kJ/kg·K

14 / 18 °C

998.9 kg/m³ · 1.11e-6 m²/s · 4.19 kJ/kg·K

6 / 12 °C · 30% PG

1029.6 kg/m³ · 4.74e-6 m²/s · 3.81 kJ/kg·K

Water services

HWS

Hot water supply

Copper
60 °C

983.2 kg/m³ · 4.73e-7 m²/s

CWS

Cold water supply

Copper
10 °C

999.7 kg/m³ · 1.31e-6 m²/s

MWS

Mains water supply

Copper
10 °C

999.7 kg/m³ · 1.31e-6 m²/s

RWS

Rainwater

Copper
10 °C

999.7 kg/m³ · 1.31e-6 m²/s

Pipe materialsroughness and size schedule
Copper schedulek = 0.0015 mm · 1.5e-6 m12 sizes
Relative sizeNominalInternal bore
15 mm13.6 mm
22 mm20.22 mm
28 mm26.22 mm
35 mm32.63 mm
42 mm39.63 mm
54 mm51.63 mm
67 mm64.27 mm
76 mm73.22 mm
108 mm105.0 mm
133 mm130.0 mm
159 mm155.0 mm
219 mm210.0 mm

Largest and smallest, to scale

210.0 mm219 nominal13.6 mm15 nominal
Nominal is a naming convention, not a measurement. For copper and the plastics the internal bore is smaller than nominal; for steel it is larger.

Bore range across materials · 0–300 mm

Copper13.6–210
Steel16.2–211.9
UPVC13–290.8
ABS13–273.4
MDPE15.4–51.4
Duct roughnessused by the duct sizer

Rectangular

Galvanised steel

Roughness k0.075 mm

7.5e-5 m

Circular

Spirally wound galvanised steel

Roughness k0.090 mm

9.0e-5 m

Max air velocity

Final1.5 m/s
Branch3.5 m/s
Riser6 m/s
Air propertiesat 20 °C
Density ρ1.2041 kg/m³
Kinematic viscosity ν1.51e-5 m²/s
Specific heat c1.025 kJ/kg·K
Loading unitsused by the simultaneous demand tool

Per outlet

WC2 LU
Urinal1 LU
Wash hand basin2 LU
Sink3 LU
Shower6 LU
Bath10 LU
Tap3 LU

The default loading units the simultaneous demand tool starts from. Edits made inside the tool apply to that job only and leave these untouched.

Diversity curve

110100100080000.1511030L/sLoading units

Probable simultaneous flow against loading units, from Graph 3 of the Institute of Plumbing's Plumbing Engineering Services Design Guide. Read for every service and interpolated piecewise linearly between the nodes below; totals of 8000 LU and above are off the published curve. This curve is not editable.

0
0.00
1
0.15
5
0.20
9
0.30
10
0.30
11
0.32
13
0.35
16
0.42
29
0.56
50
0.80
100
1.25
200
2.20
800
6.00
1000
7.00
1500
9.00
2000
11.00
5000
20.00
8000
30.00

Loading units, then probable flow in L/s.