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Plumbing standards & abbreviations explained

Plain-English meanings for the plumbing and water-regulation standards used across the questions.

The plumbing questions use these short names. Here is what each one means.

  • Approved Document G — the Building Regulations guidance on sanitation, hot water safety and water efficiency.
  • Approved Document H — drainage and waste disposal (above- and below-ground).
  • Approved Document L — conservation of fuel and power, including heating controls and efficiency.
  • Approved Document P — electrical safety in dwellings.
  • Water Fittings Regulations 1999 — the law preventing waste, misuse, undue consumption and contamination of the public water supply. (Scotland uses the Water Byelaws.)
  • WRAS / WaterRegsUK — bodies that approve fittings and publish guidance showing how to meet the Water Fittings Regulations.
  • Fluid categories 1–5 — the backflow risk scale: category 1 is wholesome water, category 5 is a serious health hazard. The higher the category, the stronger the backflow protection required.
  • G3 — the Building Regulations requirement for unvented hot water systems: safety controls and a safe discharge.
  • TMV — Thermostatic Mixing Valve: blends hot and cold to a safe outlet temperature to prevent scalding.
  • Level 2 / Level 3 — the core vocational plumbing and domestic-heating qualification stages.
  • CSCS — Construction Skills Certification Scheme: the card scheme for site access.

PlumbRevise is an independent revision aid — always work to the current published standards.

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