prBAS CEN/TS 17217:2025

This document covers physical properties and manufacturing requirements for envelopes having an address window and the flap on the front side once the flap has been sealed, hereafter the flap side. It covers the main design features of the reverse envelope, notably of the flap and address window, and the materials used for the manufacturing thereof. It applies to reverse envelopes with advertising or communication printed on the plain side, eventually on its entire surface. This document covers empty envelopes, but also finished mailpieces that have been properly inserted, addressed and franked (reverse mailpieces) and are submitted to Postal Operators. In particular, reverse mailpieces will be compliant with relevant Postal standards applicable in the member states. By extension, these requirements also apply to non-window envelopes used for reverse mailpieces and having the address printed on the flap side. This document does not apply to: - envelopes with a large window on the plain side (opposite to the flap) as these are already common and widely accepted, - paper requirements to ensure print quality (except for the postage mark and address) and notably colour rendering.