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WRAS Approved EPDM

WRAS Approved EPDM is the core material which William Johnston & Company Limited use to manufacture the gaskets which seal the majority of flange and pipe connections in the UK potable water sector and in many other overseas markets including Europe and the Far East. These are ideal for PE to PE connections.

William Johnston & Company Limited manufacture millions of WRAS approved EPDM gaskets annually.


• Operating Temperature from -20°C to 100°C.
• EPDM is Ozone and UV stable.
• Strong chemical resistance.
• Colour Fast.
• EPDM rubber for potable water is black in colour.
• Good resistance to a wide variety of corrosive chemicals.
• Good resistance to most inorganic chemical products.
• Not recommended for use with oil or hydrocarbons.
• Limited resistance to oxidant acids.
• Offered in standard hardness of 70 (±5) Shore A.


WRAS Approved Product
Pressure Rating Working 16 Bar
Pressure Rating Hydrostatic 24 Bar

For working pressure more than 16 Bar please consult with our technical department for advice.

Shapes & Sizes

BS EN 1514-1:1997
PN6, PN10, PN16
BS 3063:1965
BS 10:2009
BS EN 12560-1:2001
ASME B16.21

• Full Face
• IBC (Ring)
• 2 Lug (or Mickey Mouse).

Gaskets are available cut to any flange standard but we limit the choice due to the pressure constraints of the selected material.

We can manufacture one off or multiple bespoke shapes or sizes according to your drawing or application using our CAD technology. Please contact us for further details.


This is ideal for use in outdoor conditions as a sealing strip and is suited to tank/lid seals on potable water tanks. Please contact us with your sizes for a quotation.



Ex-Stock sizes:

3mm thick x 1.5M x 10M
4.5mm thick x 1.6M x 10M
6.0mm thick x 1.6M X 10M

Other thicknesses by request.

Technical Support

As a manufacturer we technically support all the products that we offer which: -

• Saves time.
• Saves long term expense.
• Reduces leakage.
• Increases flange integrity.
• Decreases health & safety risk.

Whenever there is a sealing issue or technical question regarding one of our products then please get in touch on 0141 620 1666, Email us or simply fill out our online enquiry form below.

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WRAS Approved Product

WRAS Approved EPDM

Contact William Johnston & Company Limited

For more information about our WRAS Approved EPDM products that are available world wide, contact us on +44 (0)141 620 1666, Email us or simply complete our online Enquiry Form.

Please note, failure to select the correct materials or products we supply (“the Products”) may result in damage to plant, equipment or property. In some instances, it may cause death or personal injury. We are not designers and do not give advice about design related matters concerning the Products. We can help and assist with the technical specifications for the Products. In specific applications, particularly where critical conditions exist, we will try to assist you within the limitations of the services that we offer. All information supplied by us is intended as technical co-operation outlining the specifications of the different Products which we supply. To the extent permitted in law, no warranty is given in respect of any information supplied by us. The customer must satisfy themselves as to the suitability of the Products for their intended application and use. The correct fitting of Products is the responsibility of the customer. Your statutory rights remain unaffected. Save in respect of death, personal injury or fraud, our entire liability to you, however arising from the supply of Products shall be limited to the £10M indemnity amount provided by our insurers.

William Johnston Accreditation