Thickness & heat loss
Condensation & surface risk
- Condensation / Dew Point CheckCheck whether a cold surface will sweat in the air around it.
- Freeze Protection & Trace Heating CalculatorSize trace heating to stop pipes freezing in winter.
- Interstitial Condensation Risk CalculatorCheck a wall or roof build-up for hidden condensation risk.
- Surface / Touch Temperature CalculatorCheck an insulated pipe is cool enough to touch safely.
About these insulation calculators
The insulation set answers the questions that decide a specification: how thick, will it sweat, and will the surface be safe to touch.
Thickness selection follows BS 5422, the UK standard for thermal insulation of pipes, ducts and equipment, covering economic thickness, condensation control, frost protection and surface temperature limitation. Condensation and dew point checks work from the psychrometric relationship between air temperature, relative humidity and surface temperature - if the surface falls below dew point, it will condense. U-value build-up follows the standard layered resistance method and can be checked against Approved Document L and Part L targets.
They are built for insulation contractors, mechanical designers and estimators pricing or specifying thermal insulation, and for anyone who needs to demonstrate that a specified thickness is adequate rather than merely conventional.
Condensation risk is the one worth taking seriously. Adequate thickness for heat loss is not automatically adequate for condensation control - chilled and refrigerant lines routinely need more, and the dew point check is what shows it.
Frequently asked questions
What is economic insulation thickness?
The thickness at which the cost of additional insulation stops being repaid by the energy it saves over the assessment period. BS 5422 tabulates economic thicknesses by pipe size, service temperature and insulation type; the calculator applies your fuel cost, hours of operation and payback period.
How do I know if a pipe will condense?
Compare the outer surface temperature of the insulated pipe against the dew point of the surrounding air. If surface temperature is at or below dew point, condensation forms. The calculator returns both figures and the margin between them, so you can increase thickness until the surface sits clear of dew point.
Do these cover personnel protection?
Yes. The surface temperature calculator works out the outer face temperature for a given build-up, which is how you demonstrate compliance with a touch-safe limit - typically 60 °C for accessible metal surfaces.