This part of ISO 13785 specifies a screening method for determining the reaction to fire performance of products and constructions of façades or claddings when exposed to heat from a simulated external fire with flames impinging directly upon a façade. It is intended for use by producers to reduce the burden of testing in Part 2 of ISO 13785 by eliminating those systems that fail the tests described in this part of ISO 13785. This test method is applicable only to façades and claddings that are not free standing and that are used as an addition to an existing external wall. This test method also is only applicable to vertical elements and is not applicable to determining the structural strength of the façade or cladding.