2.0 mm or 3.0 mm — decided by longest edge, wind exposure, circular geometry and double faces. The stiffness maths is here so you can check every row yourself.
2.0 mm 3003-H14 is the working default for regulatory panels up to about 1200 mm on the longest edge. Step up to 3.0 mm 5052-H38 when the edge runs past 1200 mm, the panel is circular and 750 mm diameter or more, the site is coastal or high-wind, or the sign is double-faced. The extra millimetre multiplies bending stiffness by about 3.4 (stiffness scales with the cube of thickness) while adding 50 % to the sheet weight and roughly 35–40 % to the panel cost.
A 900 × 600 mm panel sits squarely in the 2.0 mm band for most inland sites. The decision only flips to 3.0 mm when one of the four triggers below applies — wind exposure, panel geometry, double faces or a specification that calls for it. Every number in this article is derivable, so you can run the same check on your own size list.
Flat sheet resists bending in proportion to its section stiffness, which scales with the cube of thickness. Going from 2.0 mm to 3.0 mm multiplies stiffness by 1.5³ ≈ 3.38 — the panel feels far more solid in handling and resists oil-canning on the post better. The price is weight, which scales linearly: kg/m² = thickness in mm × density in g/cm³.
| Property | 2.0 mm 3003-H14 | 3.0 mm 5052-H38 | Ratio |
|---|---|---|---|
| Sheet density (g/cm³) | 2.73 | 2.68 | 0.98 |
| Weight per m² (kg) | 5.46 | 8.04 | 1.47 |
| Relative bending stiffness (EI) | 1.0 | 3.38 | 3.38 |
| 900 × 600 mm panel weight | 2.95 kg | 4.34 kg | 1.47 |
| Indicative panel cost step | — | +35–40 % | — |
Stiffness ratio = (3.0 / 2.0)³ = 3.375. Weight per m² = thickness × density, e.g. 2.0 × 2.73 = 5.46 kg/m². Cost step is an indicative range for the panel price, not a quotation — ask us per size list.
The fastest screen is the longest edge of the panel, then the exceptions. This is the table our own quotations are built around; if your site sits on a coast, in a typhoon corridor or at high altitude with exposed posts, move one row down.
| Panel | Standard site | Coastal / high-wind site |
|---|---|---|
| ≤ 600 mm edge | 2.0 mm 3003-H14 | 2.0 mm 3003-H14 |
| 610–1200 mm edge | 2.0 mm 3003-H14 | 3.0 mm 5052-H38 |
| > 1200 mm edge | 3.0 mm 5052-H38 | 3.0 mm 5052-H38 |
| Circular, Ø ≥ 750 mm | 3.0 mm 5052-H38 | 3.0 mm 5052-H38 |
| Double-faced panel | 3.0 mm 5052-H38 | 3.0 mm 5052-H38 |
A 900 × 600 mm regulatory sign lands in the 2.0 mm row on a standard inland site; the same panel in a Gulf coastal project is quoted at 3.0 mm.
Round panels carry their whole load through the two quadrant fixings and cannot lean on a stiff long edge, so from Ø750 mm upward our Gulf-facing specification is 3.0 mm. Gulf and coastal projects add one more layer: the back of the panel is powder-coated. Dark sun on a bare reverse heats the face unevenly and drives the film and substrate apart over the years; the coated back evens the temperature out and protects the alloy at the same time.
Double-faced signs get the same treatment for a structural reason: the second face doubles the wind-catching area and the spacing posts must clamp a thicker, stiffer panel to keep the faces true.
Most of the time. On inland regulatory and warning panels up to 1200 mm, 2.0 mm 3003-H14 meets the flatness and handling expectations of the sign shop, keeps the panel light enough for two-person mounting on 60 mm posts, and leaves budget in the order for the film grade — which, unlike thickness, is what drivers see at night. Over-thickening a small panel adds cost without adding retroreflectivity, legibility or service life.
Use it to sanity-check a bill of quantities or a tender line item before you send it for quotation. Structural design of the support — post section, foundation, gantry — belongs to the party that designs the installation; we supply the material parameters and the panel build to drawing.
Static performance requirements for fixed vertical road traffic signs — including flatness and the environmental durability expected of the panel — are set out in EN 12899-1, "Fixed, vertical road traffic signs — Part 1: Fixed signs", published by CEN (European Committee for Standardization). Sheet thickness tolerances for the delivered aluminium follow EN 485-3 (CEN); the US system equivalent is ASTM B209 from ASTM International.
Sources: CEN, Brussels · ASTM International, West Conshohocken, PA. Cited 30 October 2026.
On a standard inland site, yes — it is the default for panels up to 1200 mm on the longest edge. Move to 3.0 mm when the site is coastal or high-wind, the panel is double-faced, or the road authority's specification calls for it.
Roughly 35–40 % more per panel as an indicative range: you pay for half again the metal and a slower pass on the leveller and press. Get the exact step from a quotation against your size list — it varies with alloy and film.
Not directly. Film life is governed by the film grade, the surface condition before lamination and edge sealing. The 3.0 mm panel's contribution is stiffness — it resists oil-canning and vibration, which protects the face mechanically, not chemically.
For 5052 sheet we supply H38 as the sign temper — fully hard, flat and stiff. If your specification references another temper, send it with the drawing and we will quote to it; always write alloy plus temper, never the alloy alone.
Specification questions are answered by the same person who quotes the job.