ASHRAE Standard 135.1 provides procedures and tools necessary to validate the interoperability of equipment claiming conformance to ASHRAE Standard 135 (BACnet). This standard defines the tools to allow a vendor to define the equipment to be tested, the language that is the grammar for the test descriptions and finally the test descriptions themselves.

ASHRAE Standard 135 (BACnet), a building automation and control networking protocol, is designed specifically to meet the communication needs of building automation and control systems for applications. BACnet is intended to provide an interoperable protocol allowing equipment from different vendors to integrate into a coherent automation and control system.