Tilbagestrømningssikring af vandforsyningssystemer - Rørcenter-anvisning 015 Overview
Rørcenter-anvisning 015, titled Tilbagestrømningssikring af vandforsyningssystemer, was published in October 2009 by Rørcentret at the Danish Technological Institute (Teknologisk Institut). This guidance was prepared for the Danish Enterprise and Construction Authority (Erhvervs- og Byggestyrelsen) and serves as a technical reference for protecting drinking water systems from pollution caused by backflow. It establishes a framework for compliance with the Danish Building Act (Byggeloven), the Water Supply Act (Vandforsyningsloven), and the Authorization Act (Autorisationsloven).
The scope of the document includes the categorization of fluids based on health risks, the selection of appropriate backflow prevention devices, and guidelines for installation, operation, and maintenance. It references the European standard DS/EN 1717 and the Danish standard DS 439 (Norm for vandinstallationer). The guidance defines five distinct medium categories (Mediumkategori 1-5) and specifies technical solutions such as air gaps (AA, AB, AD), controllable reduced pressure zone valves (BA), and various check valve configurations (EA, EB, EC).
This technical document provides the parameters for risk analysis and identifies specific requirements for installations with high-risk profiles, including chemical plants, food production facilities, and agricultural buildings. It outlines the legal responsibilities for authorized plumbers, consultants, and property owners regarding the implementation and verification of backflow prevention measures.
Categorization of Fluids and Medium Categories
The document categorizes fluids according to the level of risk they pose to human health, aligning with DS/EN 1717. These categories determine the minimum level of protection required at connection points.
- Mediumkategori 1: Water intended for human consumption from the distribution network.
- Mediumkategori 2: Fluids that do not pose a health risk but may have changed in taste, odor, color, or temperature.
- Mediumkategori 3: Fluids posing a health risk due to the presence of harmful substances.
- Mediumkategori 4: Fluids posing a health risk due to toxic, radioactive, mutagenic, or carcinogenic substances.
- Mediumkategori 5: Fluids posing a health risk due to the presence of microbiological elements or viruses.
Types of Backflow Prevention Devices
Different technical devices are specified for each medium category. The document details the functional requirements and installation criteria for various 'families' of prevention units.
- Family A (Air Gaps): Includes Type AA (Free air gap) and Type AB (Air gap with non-circular overflow), used primarily for Category 5 protection.
- Family B (Controllable Reduced Pressure Zone): Includes Type BA (TBS valve), required for Category 4 risks.
- Family E (Check Valves): Includes Type EA (Controllable check valve) for Category 2 and Type EB (Non-controllable check valve) for specific residential uses.
- Family L (High-pressure Vacuum Valves): Used for protection against back-siphonage in various installations.
Legal Framework and Responsibilities
The document defines the obligations of different parties involved in construction and maintenance under Danish law.
- Authorized Plumbers (VVS-installatør): Responsible for ensuring installations meet functional requirements and notifying owners of dangerous conditions.
- Property Owners (Ejer): Legally responsible for maintaining installations in a safe condition and ensuring backflow preventers are inspected.
- Municipalities (Myndighed): Duty to react if illegal conditions are discovered and the authority to issue enforcement orders (påbud).
- Water Suppliers (Forsyning): Have the right to demand control documentation and maintenance of backflow prevention at the property boundary.
Operation and Maintenance Procedures
All backflow prevention devices require regular maintenance and inspection to function correctly. Rørcenter-anvisning 015 specifies the recommended frequency for these actions.
- Type AA (Air Gap): Inspection and maintenance every 6 months.
- Type BA (TBS Valve): Inspection every 6 months and maintenance once per year.
- Type EA (Controllable Check Valve): Inspection and maintenance once per year.
- Type EB (Non-controllable Check Valve): Inspection once per year and replacement every 10 years.
Frequently Asked Questions
What is the difference between DS 439 and DS/EN 1717 regarding backflow?
DS 439 uses five levels of pollution degrees (forureningsgrader), while DS/EN 1717 uses five medium categories (mediumkategorier), with the numbering systems being inversely related.
When is a Type BA valve required in Denmark?
A Type BA valve is required for Category 4 fluids, such as in chemical laboratories, industrial kitchens, or professional laundries where toxic substances may be present.
Are property owners responsible for backflow preventer maintenance?
Yes, according to Byggeloven § 14, the owner must keep the building in a safe condition, which includes ensuring that backflow preventers are functional and maintained.
Can a check valve replace an air gap for Category 5 risks?
No, for Category 5 risks involving microbiological elements or viruses, an air gap (luftgab) is required and cannot be replaced by a check or vacuum valve.
How often should a TBS valve (Type BA) be tested?
The guidance recommends a visual inspection every 6 months and full maintenance, including pressure zone testing, once per year.
What documentation is required for technical installations in small buildings?
For buildings of limited complexity since 2009, owners must sign a declaration stating the installation complies with Bygningsreglementet and Byggeloven.
Is backflow protection required at the property boundary?
Yes, BR08 Kapitel 8 requires a backflow preventer to be installed on the distribution line immediately after the water meter and before any branching.
What constitutes a 'significant change' requiring updated backflow protection?
Significant changes include moving the installation, changing the volume or type of water usage, or installing components like rainwater systems or industrial process units.
