Woodwork
Radiator and pipe paintable area
- where
- radiator area (m²)
- faces painted
- radiator length (m)
- radiator height (m)
- pipe area (m²)
- pipe outside diameter (mm)
- length of exposed pipe (m)
- total area (m²)
Explain this equation
Works out the area of radiators and exposed pipework to paint.
A panel radiator face is length times height; front and back of one panel is two faces. A pipe's surface is its circumference, π times the diameter (converted from mm), times its length.
Rectangle areas plus the surface of a cylinder.
Sense check: a 1 m × 600 mm radiator both sides is 1.2 m²; 3 m of 15 mm pipe adds about 0.14 m².
Watch out: convector fins are not usually painted. Use radiator enamel or a heat-resistant paint.
Works out the surface of panel radiators and exposed pipes to be painted.
Enter your values to see the result.
Good to know
NRM 2 measures radiators by type (flat, panelled, column) and the area covered. A single panel is normally painted front and back (2 faces); the hidden faces and fins of double convectors cannot be reached and are usually left. Pipe area is the outside surface: π × diameter × length (15 mm copper ≈ 0.047 m² per metre). Use a radiator enamel or a primer and finish suited to heat.
Common mistake
Counting the inner faces of double-panel convectors you cannot reach, or forgetting the pipe runs, which add up on a whole house.
Limits
Flat panel faces only. Column radiators have much more surface: measure or use the manufacturer’s surface figure.
Sources
- RICS NRM 2 Detailed measurement for building works, Work section 29 Decoration (area or girth measured is that covered; frames measured edge to edge; ≤ 300 mm and > 300 mm girth; radiators by type)
- Geometry: rectangle and cylinder surface areas, prism volumes
Results are calculations from the published methods and figures shown, and depend on the data you enter. Coverage depends on the product, surface and application. Always follow the paint and wallcovering manufacturers’ data sheets and BS 6150 / BS 8000-12. Check prices and VAT with your own records and HMRC.