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Pipe Sizing by Loading Units
Size domestic water pipework from fixture loading units (BS EN 806-3 / BS 8558 / CIPHE) to design flow, velocity and pressure-drop limits.
The Ensign ToolboxPipe Sizing by Loading UnitsSize domestic water pipework from fixture loading units (BS EN 806-3 / BS 8558 / CIPHE) to design flow, velocity and pressure-drop limits.
Fixtures
no.
15mm sep taps · 2 LU each (medium)
no.
2×8mm mixer · 1 LU each (medium)
no.
15mm sep/mix tap · 5 LU each (medium)
no.
15mm sep/mix tap · 8 LU each (medium)
no.
6-litre cistern · 2 LU each (medium)
no.
15mm head · 3 LU each (medium)
no.
Domestic, cold feed · 2 LU each (medium)
no.
Domestic · 2 LU each (medium)
Frequency of use
CIPHE Design Guide Table 15 — same band applies to every fixture
Pipe & limits
m
m/s
CIPHE Design Guide: ≤1.5 m/s avoids noise risk
Pa/m
CIBSE Guide B1 life-cycle criterion (≤200 Pa/m)
Check input values (whole fixture counts, limits > 0)