Login or register (free and only takes a few minutes) to participate in this question.
You will also have access to many other tools and opportunities designed for those who have language-related jobs (or are passionate about them). Participation is free and the site has a strict confidentiality policy.
Sorry for the delay in grading. The client has just explained what this is and wants me to use the word 'deviations' . So, many thanks to all for your answers and comments. Sheila 4 KudoZ points were awarded for this answer
Explanation: This seems to be a rather awkward formulation in the original, but I would suggest something like, "Compliance with the wall thickness tolerances is monitored indirectly via the backpressure." Hope that works in the context.