BS 6920 Suitability of Non-Metallic Products for Use in Contact with Water for Human Consumption, with Respect to Their Effects on Water Quality

Broadly speaking, the BS 6920 series of standards was developed to protect the public from non-metallic products that come into contact with drinking water and their effects on taste, odour and microbial growth. These standards help ensure compliance with both UK and European Union regulations.

The standard “BS 6920 Suitability of non-metallic products for use in contact with water for human consumption in terms of their effects on water quality” developed by the British Standards Institution (BSI) consists of the following subsections published under the same title:

• The "BS 6920-1 Specification" standard specifies the requirements for the suitability of non-metallic products, including water fittings and components, pipes, and materials used for coating, protecting, lining, joining, sealing, and lubricating, for use in contact with hot or cold water intended for human consumption, and their effects on water quality. In some cases, relevant national authorities or regulators may require specific additional tests to be performed on extracts from certain types of these materials. The interpretation of the results of the additional tests is the responsibility of the requesting organization.
• BS 6920-2.1 Test methods - Test samples" describes the preparation of test samples for all types of non-metallic (including cementitious) materials and products, including water fittings and components, pipes, and materials used for coating, protecting, lining, joining, sealing, and lubricating, to determine their suitability for use in contact with water intended for human consumption, with respect to their effects on water quality. This standard does not cover metallic materials and products unless they are used in conjunction with a non-metallic material (e.g., a coating). National authorities or regulators may require specific additional tests on extracts from certain types of materials. The interpretation of these results is the responsibility of the requesting organization.
• BS 6920-2.2.1 Test methods - Odour and flavour of water - General test method describes a method designed to assess the ability of a product to impart a discernible odour or taste to water intended for human consumption. This method is applicable to most types of non-metallic products that come into contact with drinking water. However, the standard does not apply to testing the following types of products:
  • Multilayer pipes and hoses, barrier pipes and reinforced flexible hoses, the outer material of which is different from the inner (water contact) material (these are BS 6920-(Scoped with the 2.2.2 standard)
  • Hoses (reinforced or non-reinforced) used in food and beverage equipment (these comply with BS 6920-It is within the scope of the 2.2.3 standard).

Procedures for testing the odors and tastes imparted to water by flexible hoses (reinforced or unreinforced) in their final state (i.e., before assembly) and by flexible hoses (reinforced or unreinforced) intended for use in food and beverage preparation equipment are set out in BS 6920-2.2.2 and BS 6920-2.2.3 , respectively.

• BS 6920-2.2.2 Odour and aroma of water. Method of test for odour and aroma imparted to water by hoses and composite pipes and tubes. A method is described for assessing the ability of multilayer hoses (including reinforcements) and tubes to impart a discernible odour or taste to water intended for human consumption. A modified test for use with hoses intended for conveying water in food and drink preparation is provided in BS 6920.-Defined in the 2.2.3 standard.
• BS 6920-2.2.3 Test methods - Odour and aroma of water. Method of testing the taste imparted by hoses used to transport water used in food and beverage preparation. A method is described for assessing the ability of flexible hoses (including reinforcements) to impart a discernible odour or taste to water intended for use in food and beverage preparation. This method is only applicable to testing hoses intended for installation on equipment used in food and beverage preparation.
• BS 6920-2.3 Test methods - Appearance of water describes a method designed to assess the ability of flexible hoses (including reinforcements) to impart a discernible odor or taste to water intended for use in food and beverage preparation. This method is only applicable to testing hoses intended for installation in equipment used in food and beverage preparation.
• BS 6920-2.4 Test methods - Aquatic microorganism growth test" describes a method for assessing a product's ability to promote the growth of aerobic aquatic microorganisms in water intended for human consumption. This method is applicable to all non-metallic products used in contact with water intended for human consumption.
• The standard "BS 6920-2.5 Test methods - Extraction of substances of potential public health concern" describes a screening procedure (simple cytotoxicity test) using a mammalian cell line and leachate from a product. The results of this procedure aid in the toxicological assessment of the product for use in contact with water intended for human consumption. The procedure outlined in this standard is suitable for all non-metallic materials intended for use in contact with water intended for human consumption.
• The standard "BS 6920-2.6 Test methods - Extraction of metals" describes a test procedure for assessing the leachability of metals from non-metallic products when used in contact with water intended for human consumption. Given the type of product tested and the amounts of additives present, it is unlikely that a specific solubility level (saturation) will be achieved in the extract water. The detection limit and sensitivity of the method vary depending on the specific metal being analyzed.
• BS 6920-3 Tests at High Temperatures describes methods designed to assess the ability of a non-metallic product to impart a discernible odor or taste, or any discernible color or turbidity, to hot or boiling water intended for human consumption. It is also applicable to assessing the leaching of metals from non-metallic products into hot or boiling water and to extract substances of public health concern from these products. However, this standard does not apply to testing for the growth of aquatic microorganisms (BS 6920-2.4 applies). Products used solely in industrial or steam services are excluded.

In short, BS 6920 standards play a crucial role in public health and infrastructure safety. Their primary purpose is to determine the safety of non-metallic materials (such as plastics, rubbers, coatings, sealants, hoses, and gaskets) for use in drinking water systems. These materials must have the following properties:

• It should not impart taste or odor to water.
• Should not support microbial growth
• Must not release harmful substances such as toxic chemicals or metals
• Must not affect the appearance of the water (e.g. cause discoloration)
• It should not increase the pH value of the water beyond acceptable limits.

These standards apply to all non-metallic components that come into contact with drinking water:

• Water treatment plants
• Storage and distribution systems
• Domestic installations and appliances

To ensure compliance, materials are subjected to a series of laboratory tests, including:

• Smell and aroma evaluation
• Appearance evaluation (changes in color or turbidity)
• Cytotoxicity testing (to check for harmful biological effects)
• Growth of water microorganisms
• Extraction of harmful substances (including heavy metals and organic substances)

Test results must show that the material is chemically stable and biologically inert in prolonged contact with water.

BS 6920 standards are recognised in the UK under water supply (water fittings) regulations, and compliance with these standards is a legal requirement for manufacturers and suppliers of plumbing products. Failure to comply can lead to regulatory action, product recalls, and reputational damage.

Compliance with BS 6920 standards is required for:

• Manufacturers of plumbing fixtures and fittings
• Water distribution companies
• Importers and distributors of water system components
• Construction and plumbing professionals

Materials that pass the BS 6920 test can receive a certificate showing they are suitable for use in drinking water systems.

Consequently, BS 6920 standards are critical for ensuring the safety and integrity of drinking water infrastructure. They protect consumers by ensuring that materials in contact with water do not compromise water quality. As water safety regulations tighten, compliance with BS 6920 standards is not just good practice; it's essential.

Our organization, which has been operating for many years and meticulously follows global developments in science and technology, employs a skilled team and extensive infrastructure to conduct testing, measurement, and analysis in a wide range of areas for businesses across all sectors. In this context, we also provide testing services in accordance with the BS 6920 standard, "Suitable for use in contact with water intended for human consumption, with respect to their effects on water quality."