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Upgrade nowCalculating Discharge Stack Sizes
Read through the material below, then test your understanding.
Module Lessons
Advanced Sanitation & Rainwater Systems
Sanitation Legislation: Parts F, G & H
BS EN 12056 & European Drainage System Types
Primary Ventilated Stack Systems
Air Admittance Valves (AAVs)
Off-Grid Drainage: Cesspools & Septic Tanks
Off-Grid Drainage: Reed Beds
Branch Pipework Design Rules
Macerators: Installation & Operation
Waste Water Lifting Stations
AAV Spacing & Fire Stop Requirements
Calculating Discharge Stack Sizes
Designing Rainwater Systems
Calculating Gutter Sizes
Air Testing Sanitation Systems
Maintaining Macerators & Lifters
Diagnosing Sanitation & Rainwater Faults
Lesson Overview
Discharge stack sizing ensures sanitary drainage systems maintain internal air pressure equilibrium and prevent trap seal depletion. Under BS EN 12056-2, stack diameters are calculated using appliance discharge units and occupancy frequency factors.
Learning Objectives
Calculate total discharge units and design flow rates for domestic and commercial buildings.
Select the appropriate frequency factor based on building type and occupancy pattern.
Determine correct stack diameters using British Standard hydraulic capacity tables and branch entry fittings.
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