02. What is a UV block and how is it determined?

Polyfab shade cloth has been designed to block out UV (ultraviolet) light to varying degrees depending on the range.
To determine the UV block out amount, a test is required by the Australian Standard AS4174 – Synthetic Shade Cloth. This test measures the amount of UV light (290 nm – 400 nm) that is blocked by the shade cloth. This is either via reflection or absorption.
UV block is the inverse of UV transmission e.g. 95% UV block = 5% UV transmission.