IEC 62788-5-1:2020 provides procedures for standardized test methods for evaluating the properties of materials designed to be used as edge seals. When modules are constructed with impermeable (or extremely low permeability) front- and backsheets designed to protect moisture-sensitive photovoltaic (PV) materials, there is still the possibility for moisture to get in from the sides. The test methods described in this document are intended to be used to standardize the way edge seals are evaluated. Only some of these tests are applied for IEC 61215 and IEC 61730, and that status depends on the specific design.