Section 5 (Foul Drainage Design) 5.2.1 specifies average daily flow for gravity sewers for residential developments, in keeping with current demographics and Sewers for Adoption.   System 1 – Foul (Main Drainage Method) enables compliance. 5.2.2 design of main sewers in large developments highlights design sources including IS EN 752 & proprietary drainage software.   System 1 – Foul (Fixture Unit Method) enables compliance. Foul Design is covered in the Design Fundamentals training course.