Hydronic Head Loss Calculator
Total Dynamic Head (TDH) · Darcy-Weisbach / K-factor · ASHRAE HoF 2021 Ch.22 + Crane TP-410
Project Information
System Settings
Supply 82°F: ρ=62.07 lb/ft³, ν=2.86e-7 ft²/s
Return 94°F: ρ=61.95 lb/ft³, ν=2.50e-7 ft²/s
Circuit Diagram
Circuit diagram will appear here as you add components
Index Circuit Components
#ComponentGPMPipeVel.fKHead Loss
Set starting GPM above, then add components below
Add Component (press Enter or Space to add)
Length: decimal ft (19.75) or ft-in (19-9)
Methodology & References
Pipe: Δh = f·(L/D)·(V²/2g) — ASHRAE HoF 2021 Ch.22 Eq. 2
Fittings: Δh = K·(V²/2g) — ASHRAE HoF 2021 Ch.22 Eq. 7
Friction factor: Colebrook-White (50-iteration) — ASHRAE HoF 2021 Ch.22 Eq. 4
K-factors: ASHRAE HoF 2021 Ch.22 Tables 3,4,6,7 (with velocity interpolation for Table 6 LR ells)
Large pipe K-factors (tees >16", std. elbows >12"): Crane TP-410 A-26 through A-29
Pipe dimensions: ASME B36.10M Sch.40 (Table 16) · ASTM B88 Type L (Table 17)
Temperature zones: Fluid properties computed separately at supply and return temps; components on the return side use return-side properties.
Threaded NPS<2½" · Flanged/welded NPS≥2½" · Reducer K ref. upstream velocity · K tolerance ±20–35% per ASHRAE Table 5