September 12th, 2021. In the Working Group Warm Edge of the BF, for the collective project on the usability of warm edge systems, spacers were divided into five categories based on EN 1279-1, Section 3, Figure 2 (see also ift guideline VE-17/1) :

Category A = fully metallic hollow profiles (e.g. profiles made of aluminum, galvanized steel or stainless steel)
Category B = non-fully metallic hollow profiles, with a metallic adhesion surface* to the sealants (e.g. profiles made of plastic with stainless steel as a diffusion barrier)
Category C = non-fully metallic hollow profiles, with non-metallic adhesion surface* to the sealants (e.g. profiles made of glass fiber reinforced plastic with composite foils as a diffusion barrier)
Category D = Hot applied flexible spacers (thermoplastic material)
Category E = prefabricated flexible spacers (foamed spacers from the roll)

* According to Section 3.24 of EN 1279-1, the adhesion surface of a spacer is considered to be “metallic” if it is made of rolled or extruded aluminum, galvanised steel, stainless steel, without organic surface treatment. According to Note 1 to the term, organic surface treatments are painting, organic coating, organic film or organic overspray.