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Read through the material below, then test your understanding.
Module Lessons
Cold Water Systems: Planning & Design
Water Industry Legislation
Notification, Part G & Certification
Multi-Storey Boosting Systems
Large-Scale Cisterns: Design & Materials
Cistern Filling & Control Components
Private Water Supplies: Sources & Storage
Private Water Treatment & Disinfection
Private Supply Pumping
Specialist Cold Water Taps
Shower Pumps & Pressure Control
Fluid Categories & Contamination Risk
Backflow Protection Strategies
Non-Mechanical Backflow Devices
Mechanical Backflow Devices
Backflow Regulations & Guidance
Design Information Sources
Assessing Demand: Flow Rate & Pressure
Pipe Sizing: The Tabular Method
Pipe Sizing: BS EN 806 & Thomas Box Formula
Cistern Capacity & Pump Power Calculations
Accumulator Sizing & Presenting Designs
Fault Diagnosis: Booster Pumps & Backflow Devices
Corrosion Faults: Electrolytic & Blue Water
Commissioning Standards & Regulations
Soundness Testing: Planning & Preparation
Disinfection: Types, Process & Capacity
Disinfection: Testing & Flushing
Commissioning Records, Defects & Certification
Maintenance Types & Legionella Control
Lesson Overview
Mechanical backflow devices provide a physical barrier to prevent back pressure and back siphonage where air gaps are impractical. Understanding their mechanical operation, ratings, and fluid category suitability is essential for regulatory compliance.
Learning Objectives
Identify the key mechanical backflow prevention devices from Type BA to Type HC.
State the permitted fluid risk categories for back pressure and back siphonage for each mechanical device.
Explain the operating principles, testing requirements, and installation rules for verifiable and non-verifiable units.
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