When selecting couplings, valves, hose assemblies and other components for water applications, terms such as Regulation 4 compliant, WRAS approved, BS 6920 compliant and Regulation 31 approved are frequently encountered.
They are related, but they do not mean the same thing.
Understanding the distinction is particularly important when specifying components for potable water, building services, food production and other systems connected to the UK public water supply.
What is UK Regulation 4?
In England and Wales, Regulation 4 forms part of the Water Supply (Water Fittings) Regulations 1999.
At its simplest, Regulation 4 requires a water fitting to:
-
be of an appropriate quality and standard; and
-
be suitable for the circumstances in which it is used.
The Regulations apply to water fittings connected to the public water supply and are intended to protect water supplies against contamination, waste, misuse and undue consumption.
This means compliance is not simply a question of whether a coupling physically fits the pipework or can withstand the operating pressure. The materials, construction and suitability of the fitting for the particular installation also need to be considered.
Similar requirements apply under separate legislation in Scotland and Northern Ireland.
What does “Reg 4 compliant” mean?
Reg 4 compliant is a statement about compliance with the applicable water fittings regulations. It is not the name of a product certification scheme.
This distinction is important.
A manufacturer or specifier needs appropriate evidence that a water fitting meets the requirements applicable to it. Regulation 4 recognises routes including conformity with an appropriate British Standard or a specification approved by the regulator.
Independent product approval schemes can also provide a recognised means of demonstrating that relevant requirements have been satisfied.
What is WRAS approval?
WRAS stands for the Water Regulations Approval Scheme.
WRAS operates independent certification schemes for water fittings and materials. A WRAS Product Approval is a recognised way of demonstrating that a fitting is of an appropriate quality and standard for the purposes of Regulation 4.
WRAS approval is therefore not another name for Regulation 4.
A useful distinction is:
Regulation 4 = regulatory requirement
WRAS = product/material certification scheme used to demonstrate compliance with relevant requirements
WRAS Product Approval is a voluntary certification route rather than the legislation itself.
Importantly, WRAS states that its Product Approval demonstrates compliance with the appropriate quality and standard requirement. It does not remove the requirement for the fitting to be suitable for the particular circumstances in which it is installed.
Correct product selection and installation therefore remain important.
WRAS Product Approval vs WRAS Material Approval
There is also an important distinction between a WRAS Product Approval and a WRAS Material Approval.
WRAS Product Approval
Product approval relates to the complete water fitting covered by the approval.
Depending on the product, assessment can include mechanical performance and water quality requirements.
An approval applies specifically to the products and models identified within the approval documentation. It should not automatically be assumed to cover similar products, different configurations or rebranded versions.
WRAS Material Approval
Material approval concerns the effect that a non-metallic material or component may have on water quality.
Examples include:
-
elastomer seals
-
O-rings
-
rubber materials
-
plastics
-
other non-metallic wetted components
A component containing a WRAS-approved material is therefore not automatically a WRAS-approved product.
This is particularly relevant to quick-release couplings, where an approved seal material may form only one part of the complete coupling assembly.
What is BS 6920?
BS 6920 concerns the suitability of non-metallic products for use in contact with water intended for human consumption, particularly their effect on water quality.
Testing can assess characteristics such as effects on the taste or odour of water and the ability of materials to support microbial growth.
BS 6920 is therefore principally concerned with materials in contact with drinking water.
It should not be confused with approval of the complete fitting.
For example, an elastomer used for the seals within a coupling may have successfully undergone the appropriate BS 6920 testing. That does not by itself establish that the complete coupling is WRAS Product Approved or suitable for every potable-water installation.
What is Regulation 31?
Regulation 31 is different again.
It concerns products and substances used by water undertakers in the treatment and distribution of public drinking water supplies.
In broad terms, the distinction is:
Regulation 31 – products used by water companies in the treatment and distribution of public water supplies.
Water Fittings Regulations / Regulation 4 – water fittings used after the point of supply within premises and installations connected to the public supply.
A Regulation 31 approval should therefore not automatically be treated as equivalent to WRAS Product Approval or general Regulation 4 compliance.
The correct requirement depends on where and how the product is being used.
Does stainless steel mean a coupling is suitable for potable water?
Not automatically.
Material selection is only one part of determining suitability.
For a quick-release coupling, consideration may need to include:
-
coupling body material
-
plug material
-
plating or surface treatment
-
valve components
-
springs and locking components
-
elastomer seals
-
lubricants
-
operating temperature
-
pressure
-
fluid contact time
-
installation arrangement
A stainless-steel coupling may offer excellent corrosion resistance, but the material of the body alone does not establish regulatory compliance of the complete assembly.
The same principle applies to brass and other metallic materials.
Does a WRAS-approved seal make the complete coupling WRAS approved?
No.
This is an important distinction when specifying industrial fluid-transfer components.
A coupling could incorporate a non-metallic component or seal with an appropriate WRAS Material Approval or BS 6920 test evidence without the complete coupling assembly holding WRAS Product Approval.
Product and material approval should therefore be identified separately within technical specifications.
What should engineers specify?
Rather than simply requesting a “water coupling”, identify the regulatory and application requirements at the specification stage.
Useful information includes:
| Requirement | Information to establish |
|---|---|
| Medium | Potable water, process water, cooling water, etc. |
| Installation | Public water supply, internal system, process equipment, water treatment/distribution |
| Regulatory requirement | Regulation 4, WRAS Product Approval, Regulation 31 or other requirement |
| Material | Brass, stainless steel or other specified material |
| Seal | Required elastomer and water-contact approval |
| Temperature | Minimum and maximum operating temperature |
| Pressure | Normal and maximum system pressure |
| Connection | BSPP, BSPT, hose tail, tube connection, etc. |
| Coupling function | Straight-through, single shut-off or double shut-off |
This avoids selecting a product solely because it has been described broadly as suitable for “water”.
Quick Reference
| Term | What it means |
|---|---|
| Regulation 4 | Regulatory requirements concerning the quality, standard and suitability of water fittings |
| WRAS Product Approval | Independent certification of specified complete water fittings against relevant requirements |
| WRAS Material Approval | Approval relating to specified non-metallic materials/components and their effect on water quality |
| BS 6920 | Testing relating to the effect of non-metallic materials/products on water intended for human consumption |
| Regulation 31 | Requirements concerning products and substances used by water undertakers in treatment and distribution of public water supplies |
| Potable water suitable | An application description; it should not be assumed to constitute a particular regulatory approval |
Selecting Quick-Release Couplings for Water Applications
Kee Connections supplies quick-release couplings and fluid-transfer components for a wide range of industrial water applications.
The correct coupling should be selected against the requirements of the complete application, including the medium, pressure, temperature, materials, seals, connection type and any regulatory or approval requirements.
Where a project specification calls for Regulation 4 compliance, WRAS approval, BS 6920-tested materials, Regulation 31 approval or another water-industry requirement, this should be identified when enquiring so that the required documentation and product specification can be checked.
Do not assume that suitability for general water service establishes suitability for potable water or compliance with a particular regulatory requirement.
Contact Kee Connections with your application requirements, operating conditions and required approvals to discuss the appropriate coupling or fluid-transfer solution.
