This document specifies the general principles required for the ultrasonic testing of industrial products that permit the transmission of ultrasound. The specific conditions of application and use of ultrasonic testing, which depend on the type of product to be tested, are described in documents which could include: product standards; specifications; codes; contractual documents; written procedures. Unless otherwise specified in the referencing documents the minimum requirements of this document are applicable. This document does not specify: extent of testing and scanning plans; acceptance criteria. This document describes only conventional probes, however the general principles for ultrasonic testing also apply to ultrasonic testing using array techniques. If array techniques are used then additional steps or verifications can be needed.