This part of IEC 61753 contains the minimum tests, test severities and measurement requirements which a fibre management system need to meet in order to be categorised as meeting the IEC standard, category OP - Outdoor Protected environment, as defined in IEC 61753-1. This performance standard for fibre management systems defines the requirements for standard optical performance under a set of specified conditions. It contains a series or a set of tests and measurements with clearly stated conditions, severities and pass/fail criteria. The series of tests, commonly referred to as an operating service environment or performance category, is intended to be a basis to prove the product’s ability to satisfy the requirements of a specific application, market sector or user group.