VIP’s tunnel segment gaskets are manufactured in our Cambridgeshire headquarters in the UK, which is certified by The British Standards Institute to ISO 9001, using the latest manufacturing equipment and processes.
VIP compounds its own rubber at our on-site mixing facility to proven formulations developed by VIP’s rubber technologists. The compounds used meet WRAS and other internationally recognised standards where required.
Predominantly EPDM is the rubber of choice for tunnel segment gaskets as it provides the sealing and material qualities required. However in instances where resistance to more aggressive chemicals is required, VIP can compound and manufacture using NBR (Nitrile).
A study carried out by Loughborough University in the UK on behalf of VIP concludes that one of the major elements affecting the gaskets’ long term sealing ability is ‘Stress-Relaxation’. This is the measurement of the force that a compressed gasket exerts over time which is crucial to the sealing performance.
The research also revealed that with correctly formulated and processed rubber, as supplied by VIP, the life expectancy of our gaskets is in excess of 120 years.
To begin the manufacturing process, VIP’s gasket profiles are extruded through one of the most modern microwave curing lines. This manufacturing technique creates the profile length by forcing the rubber through a die prior to curing. This is then cut to lengths determined by the segment requirements.
All VIP’s corner joints can be manufactured in obtuse, acute and 90° angles to perfectly fit with the corresponding segments.
Using the latest laser guided cutting technology enables virtually any joint angle to be achieved and their design ensures that the sealing properties and closure forces match the extruded gasket section.
In order to ensure the final product meets the high standards set by VIP, physical checks are made by our quality team both during the manufacture process and on final completed gaskets against:
Profile Size – to ensure a consistent profile shape during the extrusion process
Joint Integrity – to check the strength of moulded joints
Geometric Requirements – to check the shape of the finished gasket meets the segment design requirements
VIP can recommend a number of approved adhesive suppliers for the application of glued-in gaskets onto the segment. If required, we can also arrange the supply of the adhesive.
VIP recommends applying lubricant to the surface of the gasket during segment installation to assist the segments sliding into place.
This process reduces the friction between gaskets, ensuring corner positioning and reducing the risk of gaskets moving or pinching during installation which can potentially affect their performance. We can recommend and supply an appropriate WRC-approved lubricant.
TSGs should be stored in the same conditions as for most elastomeric products and ideally in accordance with ISO 2230:2002 (rubber products guidelines for storage). VIP can supply details upon request.
VIP operates a quality system, which is approved to ISO 9001 standard and certified by BSi. We are renowned in the seal and gasket industry for the high quality of all of our products, and our approach to quality extends to TSGs.
Available to download, VIP have created a new product brochure specifically for the tunnel segment gasket product group. The brochure includes details of our gasket corner jointing system which eliminates corner point loading during installation – often the cause of cracked and damaged concrete segments.