Gutter selection: Internal gutter (parapet box gutter) 400mm wide, water depth 80mm, slope 1:200 → capacity ~18 L/s per meter run. Total roof perimeter gutter length = 240m → more than adequate.
The core of the standard lies in its formulaic approach to rainfall. To design a drainage system, engineers must calculate the Rainfall Runoff ( , which is generally determined by the formula: cap Q equals r cross cap A cross cap C Rainfall Intensity (
For the overflow, use the same Q calculation but with a 100-year rainfall intensity. Example: 600 L/(s·ha) × 0.1 ha = 60 L/s. This overflow can be provided by:
NBN EN 12056-3 is a European standard that provides guidelines for the design, installation, and testing of drainage systems for buildings. The standard is part of a series of norms (EN 12056) that focus on the planning, design, and installation of drainage systems for buildings and their surroundings. nbn en 12056-3
While not strictly mandated, a fall between 1:350 and 1:600 (roughly 1.7–3 mm per metre) is recommended for efficiency.
NBN EN 12056-3 is part of a multi-part series of standards (EN 12056) that covers gravity drainage systems inside buildings. Specifically, Part 3 focuses on roof drainage
[ Q_tot = r \times C \times A ]
Q_overflow = 650 × 0.32 = 208 L/s.
The NBN EN 12056-3 standard covers several key aspects of drainage system design and installation, including:
Many people confuse NBN EN 12056-3 with siphonic systems. Let us clarify: Gutter selection: Internal gutter (parapet box gutter) 400mm
For engineers and architects, compliance with NBN EN 12056-3 offers several advantages:
Convert to mm/min: 1 L/(s·ha) = 0.006 mm/min. So 300 L/(s·ha) = 1.8 mm/min.
No. Siphonic systems have their own guidelines (e.g., EN 12566-3 or national technical approvals). However, the overflow requirement still applies. To design a drainage system, engineers must calculate