Internal pipe diameter inspection
This kind of inspection is carried out on a by-order basis using a certified gauge (for sizes 40 mm and above) of the go/no go type, with both sides of the pipe subjected to measurement along the length specified in the regulatory documentation. Pipes intended for use in shock-absorbers are inspected using the special instrument called a bore gauge. Instrumental inspection of internal pipe diameter is carried out for critical pipes and relies on the use of ultrasonic equipment.
The original Russian phrase is "трубы ответственного назначения" and could be translated as "pipes used in critically important roles (applications)": when a malfunction may lead to injuries, deaths or major industrial accidents, or to the shutdown of the whole plant, with the resulting financial losses.
Is the phrase "critical pipes" a proper choice, or are there some other phrases to signal the same meaning? Would "critical duty pipes" fit?
The word-for-word of the original is "truby (pipes) otvetstvennogo (of high responsibility) naznacheniya (purpose)".