IEC TS 62788-5-2:2020 provides guidelines to assess the ability of an edge seal to prevent moisture ingress from the edges of PV modules. This document does not cover frame adhesives (sometimes colloquially referred to as edge seals) which by design do not serve to prevent moisture ingress to a meaningful degree. Edge seals should keep moisture out, remain adhered, and maintain electrically insulation from the environment. Much of the testing can be done on the material level, but given the fact that there are multiple surfaces, materials interactions, and mechanical stresses, testing on mini modules or modules is necessary. To accomplish this, this document contains three types of test sample types, materials, mini-modules, and full-size modules. It is intended that a quick evaluation and comparison can be made using materials only. This would be followed up by more rigorous tests using mini-modules where all the interfaces are correctly represented. And finally, full-size module tests are used to evaluate the actual construction process to allow unanticipated concerns to be addressed.