For general components, the number of measurement areas should not be less than 10.
When the number of inspected components is greater than 30 and there is no need to provide estimated strength for a single component, or when the dimensions of the inspected components in one direction are less than 4.
5m and the dimensions in the other direction are less than 0.
3m, the number of measurement areas may be appropriately reduced, but not less than 5,.