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Cold Water

Exam revision materials for Plumbing Level 2&3 and ACS Gas Safety test

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Cold Water Storage Cistern

Installation Requirements

Cold Water Cistern Requirements

cold water storage cistern installation requirements
  • Water Regulation Guide G16.13
  • Protected Cistern By Law 30 Kit
  • 350 mm - MIN space above cistern (maintenance puprpose)
  • 25 mm - MIN height from bottom for side outlets (connections from the bottom of the cistern are preferred)
  • 0.65 mm - MAX mesh size opening for Air Vent and Screen
  • Should withstand 500 hours of boiling water
  • Use Hole Saw ONLY to cut the holes for pipe connections
  • 20°C - MAX temperature of stored cold water (25°C at outlets)
  • Plastic Washer MUST be used for connections (Oil-based paste of any description should not be used)
  • Made of:
    • Now: polyethylene, polypropylene, polyvinyl chloride
    • Past: galvanised low carbon steel
    • Produced in black to prevent Algae Growth
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Base of the Cistern Requirements

  • MUST be fully supported with Moisture Resistant 25 mm Chipboard approved by National House-Building Council
  • 150 mm MIN overlap of a baseboard from each side
  • 3 Timber Bearers required for a typical domestic cistern
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Legionella Bacteria

  • Document L8 - Guidance for the control of legionella bacteria in water systems
  • Store water above 60°C or below 20°C
  • The water in the taps should be below 20°C after 2 minutes
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  • 115L  - MIN size of CWSC or at least equal to HWSC (for direct systems)
  • 230L - recommended by BS 6700 for for indirect systems or = 2 x HWSC (if it also supplies a feed to a hot water cylinder)
  • 230LMIN size of CWSC (for industrial installations)
  • 80L – per bedroom
  • 130L per bedroom (refilling at night)
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Overflow Pipe

  • Must be screened
  • MIN Ø19mm
  • MIN Ø25mm for CWSC >1000L
  • MIN termination - 25mm above water line
    • 50mm if CWSC capacity is > 1000L
  • Should be always greater in size than Feed Pipe
  • NO flexible parts
  • MUST be separate with F&E overflow pipe
  • Separate Warning Pipe is fitted 25mm below Overflow Pipe for CWSC > 1000L
Byelaw 30 Type Kit
Byelaw 30 type
  • Dip Tube - 50mm "Dipped Feed"
  • Screened warning pipe elbow
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