The part of a sentence "has been normal practice" is correct and usable in written English.
You can use this phrase in instances where something has continued and become commonplace over time. For example, "Making sure to follow safety protocols has been normal practice for the construction team."
For example, where a caesarean section would have been normal practice, vacuum extraction is now considered.
As Trump and his advisers have argued, it is normal practice in our society to pay as little in taxes as possible.
Although it has been the normal practice of the Russian special forces to storm any bus, train or helicopter full of hostages, any such attempt in Budyonnovsk could mean death for hundreds of people who are patients in the hospital.
Once a radiosynthesis has been developed, it is normal practice to perform a number of runs (3 5) to demonstrate the robustness and reproducibility of the manufacturing process and prove that the radiopharmaceutical is pure, sterile, isotonic, apyrogenic, stable and of suitable pH.
We made no attempt to randomise the magazines but had them shuffled, as was normal practice in the waiting room.
United have not said if contract talks have begun, although it would be normal practice as the deal is about to enter its final 18 months.
The programme controller of Capital Radio Group, which then owned Xfm, described the false report as an "unfortunate incident", adding: "The caller sounded genuinely distressed, but Bob has been reminded that it is normal practice to check whether a story is true before making any announcement".
"It's normal practice to have turnover year to year on waiting lists," said Bernie Mullin, a senior vice president of the N.B.A. But, he added, "The vast majority of teams don't have waiting lists".
