UG-39(e)(2) multiple openings in flat heads and covers
The required thickness of flat heads and covers having multiple openings is now multiplied by the factor h when the spacing between any pair of openings is less than twice, but equal to or greater than 1.25 times the average diameter of the pair.
The UG-39(e) Summary Table in flat head and cover reports provides the following information for each pair of openings, in the new and corroded conditions:
- Average diameter of the openings, dave
- 1.25 times dave
- 2 times dave
- center-to-center spacing, p
- ligament efficiency, e
- factor h
The governing h is calculated from the smallest e, unless e is greater than or equal to 0.5 for each pair of openings. [7555]