What Do Insulation Values Mean on a Sectional Door? U and R'w Guide
Published:
Publisher: Alkur Kapı Sistemleri A.Ş.
Two abbreviations keep appearing in technical specifications: U and R’w. Both answer the question of whether a sectional door is “insulated” — not with a single word, but with a measurable value. In this article we explain what these numbers mean in a real facility, using the certified values of the NORMTOR industrial sectional door.
U-value: How fast does heat escape?
The U-value (thermal transmittance) tells you how many watts of heat pass through one square metre of the door surface for every 1 °C difference between inside and outside. The smaller the number, the better the insulation. On the NORMTOR industrial sectional door, the standard 40 mm sandwich panel — polyurethane core at 40 kg/m³ density between two steel skins — reaches U = 0.604 W/m²K.
The practical meaning: across a wide dispatch opening, the door behaves like a continuation of the wall. The energy a heated warehouse loses through the winter, or the heat that leaks into an air-conditioned production hall in summer, is directly proportional to this coefficient. In cold-chain and climate-separation applications, the U-value is a line item in the operating cost calculation.
R’w value: How much sound stays inside?
R’w (weighted sound reduction index) expresses the acoustic insulation between the two sides of the door in decibels. The 40 mm panel’s R’w = 26 dB means forklift traffic, compressors and line noise pass towards the office side or the neighbouring plot markedly reduced. For facilities near residential areas and for shift work, this value is the quiet hero that prevents environmental noise complaints.
The structure behind the number
These values are not marketing copy; they are the result of the panel’s construction. The density of the polyurethane core, the bond of the steel skins and the tongue-and-groove edge geometry that locks the panels together all work as one. Seals are part of the equation too — if threshold and frame tightness degrades, even the best panel performs below its rating.
How much does it matter in which project?
On an internal partition door the U-value can be secondary; on an external dispatch facade or a cold-store entrance it sits at the centre of the decision. For applications requiring higher insulation, thicknesses beyond the standard 40 mm can be evaluated on request.
Not sure what these two values should say in your specification? No problem — our contact line is open for exactly this kind of question. All of the product’s certified values also live on its own page.
