Pipe Insulation Calculator

Pipe & Fluid

Outer diameter. Common: 15-25 mm domestic, 50-150 mm commercial
Total run including bends and risers
Select for default temperature

Temperatures

Operating temperature. Auto-set by fluid type
Indoor: 20°C. Outdoor winter: -10 to 5°C

Insulation

Mineral wool: cheap, 60-200°C. PIR: -50 to 120°C
Economic: 30-80 mm. High perf: 100-150 mm

Installation & Surface

Affects surface heat transfer coefficient
Still air: 0-1. Moderate: 2-5. Strong: 5-10
Aluminum: 0.2-0.4. Painted: 0.85-0.95

Economics

Natural gas: 0.08-0.15. Electricity: 0.15-0.30
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Pipe Insulation Design

Pipe insulation is essential for energy efficiency, condensation control, and personnel protection. This calculator uses cylindrical heat transfer equations to determine heat flow through the pipe wall, insulation layer, and outer surface. The total thermal resistance is the sum of pipe resistance (usually negligible for metal), insulation resistance (dominant factor), and surface resistance (convection + radiation). For cold pipes, the surface temperature must stay above the dew point to prevent condensation and corrosion. For hot pipes, surface temperature must stay below 50°C for personnel protection (EN ISO 12241). Optimal thickness balances insulation cost against energy savings over the system lifetime.

Key Points:
  • Heat transfer: Q = 2πL × ΔT / (R_pipe + R_insulation + R_surface)
  • Insulation resistance: R_ins = ln(r3/r2) / (2π × k_insulation) - dominant factor
  • Surface resistance: R_surf = 1 / (h × 2π × r3) - h = 8-10 indoor, 15-25 outdoor, 30-50 windy
  • Condensation risk: T_surface < T_dewpoint → water vapor condenses → corrosion, mold
  • Personnel protection: EN ISO 12241 requires T_surface < 50°C for hot pipes
  • Economic thickness: payback period 3-5 years typical, NPV over 20-year lifetime
  • Mineral wool λ: 0.035-0.045 W/(m·K) | PIR λ: 0.022-0.026 | Aerogel λ: 0.015-0.020
  • Steam pipes: high temp requires calcium silicate or mineral wool (PIR degrades >120°C)
Calculation Steps:
  1. Enter all required parameters
  2. Click "Update Calculation"
  3. Review results and analysis
Formula Variables:
Q Heat Loss/Gain (W)
q Heat Loss per Meter (W/m)
T_fluid Fluid Temperature (°C)
T_ambient Ambient Temperature (°C)
T_surface Surface Temperature (°C)
R_pipe Pipe Thermal Resistance ((m·K)/W)
R_insul Insulation Resistance ((m·K)/W)
R_surface Surface Resistance ((m·K)/W)
k_insul Insulation Conductivity (W/(m·K))
h Heat Transfer Coefficient (W/(m²·K))
r1 Pipe Inner Radius (m)
r2 Pipe Outer Radius (m)
r3 Insulation Outer Radius (m)