How to Read an FRP Grating Load-Span Table (Without Getting It Wrong)

A load-span table is the most important single document in a grating purchase — and the most commonly misread. Here is the four-step method.

Step 1: know your span — the real one

Span means the clear distance between supports, measured on site or from the structural drawings. If your supports are at 1.2 m centres and the bearer is 100 mm wide, your clear span is about 1.1 m — and you must read the table at 1.1 m, not 1.2. Reading at the wrong span is the number-one error: capacity falls with roughly the fourth power of span, so a 20 % span error swings allowable load by a factor of two.

Step 2: choose your load type

Tables list two families of numbers. UDL (uniformly distributed load) models crowds, stored materials, snow. Concentrated load models a wheel, a footfall at a panel edge, or a pallet corner — expressed in kN on a defined patch (usually 100 × 100 mm or 250 × 250 mm; the table states which). A deck can pass UDL and fail concentrated — check both against your reality.

Step 3: respect the deflection limit

The allowable load is tied to a deflection limit, because “not broken” is not the same as “acceptable underfoot”:

• L/180 — the standard industrial walkway criterion (a 1 m span may deflect ~5.5 mm)
• L/100 — a firmer criterion used for equipment platforms and public areas (some tables list it as a higher allowable load)
• L/250 or tighter — specified where machines or conveyors sit on the deck

A panel that “passes” at L/100 but fails L/180 will carry the load — it will just feel springy and look wrong. Specify the limit your application needs.

Step 4: confirm the table matches the panel

Generic tables describe a generic panel. Insist that the load table supplied with your quote is for the delivered panel — depth, mesh, resin and surface — and that it is signed. JINGLUE issues panel-specific tables with every quotation; that is what the specification-guide clauses are for.

For a quick check, use the interactive calculator — it applies exactly this logic.