This should be based on the Philippine Plumbing Code.
Extracted text: 1. The size of a soil stack to serve: 2-unit water closet; 2-showers; 2-lavatories and 1- residential sink (consider 4 branch intervals). 2. What diameter of soil branch will be satisfactory to serve a battery of 25 water closets? 3. The minimum number of plumbing fixtures required for an auditorium planned for a total of 5,500 people (assume 50% of each gender) 4. The minimum number of plumbing fixtures required for a restaurant planned for 250 seats (50% of each gender). 5. The minimum number of plumbing fixtures required for a higher education school building planned to laccommodate 750 students (50% of each gender).