EVALUATION OF MANIFOLD METER CONNECTOR DESIGNS
FR0156

JAN 1991

To investigate domestic water meter concentric connectors with respect to their basic design, jointing components and materials used, and to explore possible alternatives.

Concern has been expressed within the Water Industry about possible shortcomings in the concentric meter connections, particularly regarding the possibility of internal bypassing of the meter and the suitability of the metal thread form when used in plastic manifolds.

III CONCLUSIONS

• The critical dimensions of manifold connectors vary between both meter and manifold manufacturers since they are not built to a common standard. This will lead to internal leakage in some instances.
• The connectors use O-rings which seal by screw down compression. This is not one of the recommended methods for using O-rings.
• The O-rings may easily become dislodged or misplaced during installation, causing internal leakage.
• The plastic thread used in some manifolds is considered inadequate.
• Given these shortcomings of the current connector, a modified design is required.

• The proposed alternative meter/manifold connector design given in this report should be circulated to the Water Industry and existing meter and manifold manufacturers for comment.
• Prototype connectors should be developed and evaluated.
• A Water Industry Standard (WIS) should be prepared.
• British Standards committees should be asked to include the design in the relevant British and European standards.
• Manufacturers should implement Quality Assurance testing for connector dimensions.

Up to 100,000 boundary boxes a year are currently being installed at new properties and where new service pipes are fitted. The Water Industry has identified some technical problems in the operation of the connector between the boundary box manifold and the water meter. Problems of internal leakage and those associated with plastic thread forms are identified. A comparison of the connector design from manufacturers commonly supplying the industry is made. An alternative design has been proposed for consideration by the Water Industry and manufacturers. Suggestions have also been made on the way forward to develop a Water Industry Specification and for Quality Assurance Testing.

Copies of the Report are available from FWR, price £15.00 less 20% to FWR Members