This part of IEC 62788 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. This moisture ingress pathway can be restricted by using a low-diffusivity material around the perimeter of a module between the impermeable front-and backsheets. Alternatively, it can be desirable to use a low-diffusivity encapsulant, which may significantly reduce moisture ingress over the lifetime of the module, and to evaluate it in a similar way to an edge seal material.

In addition to restricting moisture ingress, edge seal materials also provide electrical insulation. To perform these functions, edge seal materials are relied upon to adhere well.

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. It is not required that all of these tests be performed, but that if these measurements are made that they be performed as outlined here.