It means following and meeting approved Standards.
The approved engineering standards must be met. If, for example, a govt. regulation requires a tighter standard, then the approved engineering standard can be presented as a means of modifying the govt. reg. However, there are cases when the govt. (e.g. military) has a tighter standard, for valid reasons, and then that tighter standard should be pursued.
Take Care,
-Dr. von Jouanne