Does Size Matter?

Jon Crean, Commercial Director at VIP-Polymers Ltd, manufacturers of VIPSeal® flexible couplings and adaptors, discusses the applications for flexible couplings and the questions merchants should be asking customers in the September 2018 issue of Builders Merchant News Magazine.


On first impressions, flexible couplings are relatively standard products for a standard application. Designed to join pipes of differing sizes and materials for low and non-pressurised drainage applications, the most likely question on merchants minds will be to ask the customer ‘what size pipes are you joining?’

Specifying the correct coupling is a relatively straight forward process and while size does matter with regards to selecting the correct size coupling, it is one of a number of questions merchants should be asking their customers.


Understanding the application of where it will be used is the most important piece of information when selecting the correct coupling for the customer’s needs.

The location of the pipe joint will determine which product category the coupling is selected from.

Regulations vary depending on whether the work takes place inside or outside of the building curtilage or is in a non-adopted drainage scheme. Work which takes place outside of the building curtilage and is located within an adopted area, i.e pipe system will be adopted by a Water Company requires the use of products certified to WIS 4-41-01.

This dictates that a standard coupling must be used as they have a shear band, which can withstand higher pressures, protect against shear loads / deflection and is also suitable for shear and deflection situations under a negative pressure or vacuum. E.g pumped system.

VIPSeal® Standard Coupling

As couplings with shear bands are required for adoptable schemes, a bush is required alongside a standard coupling when joining pipes with a large difference in diameter.

For applications within the building curtilage that do not require resistance against shear loads, drain couplings and adaptor couplings provide a more cost effective solution.

The medium that will be transported through the pipe and the operating temperatures are important questions as they determine which material should be selected for the coupling in order to maximise the life of the connection.

Different rubber materials have different levels of resistance to chemicals and temperatures. It is important to ask the constant working temperature (CWT) as while most rubbers have stated working temperature ranges, the upper and lower limits usually refer to intermittent exposure. Long exposure to these temperatures can severely reduce the service life of the seal.

Sealing Force Retention

A fundamental property of a gasket is what is at risk when the correct material isn’t selected for the correct application. For any seal to work it must be energised (in the case of VIPSeal®, tension bands are tightened). The industry standard BS EN681-1 stipulates the compression set and stress relaxation of a seal. VIP was the first in the industry to obtain this in 1987 and have decade’s worth of data to support the effectiveness of our materials to retain their sealing force over-time.

A seal with good compression set will recover to almost its original shape when the load is removed. When under load, the seal must retain the energy that is built up within it. Seals with good stress relaxation will retain this energy.

Material Selection

In the majority of drainage applications, foul water and sewerage will commonly travel through a drainage pipe and extreme temperatures will not be experienced.

VIPSeal® flexible couplings are manufactured from high grade, sulphur cured EPDM rubber as standard. Sulphur cured EPDM has a resistance to a relatively high range of chemicals (typically found in drainage systems) and has a service range at constant temperatures between -10°C and 60°C.

However in industrial applications where aggressive chemicals or extreme temperatures will be experienced, the correct material needs to be selected. VIPSeal’s latest addition VIPSealChem is manufactured from FKM rubber which is resistant to a wide range of chemicals and extreme temperatures (-15°C to 200°C).


VIPSealChem Flexible Couplings

For applications exposed to mineral oils, fats and greases, Nitrile rubber (NBR) becomes the preferred choice. Where temperatures rise above 60°C but the application does not require the chemical resistance of FKM, a peroxide curing stage can be applied to EPDM (CWT to 125°C) and Nitrile (CWT to 100°C) couplings, providing a more cost effective solution.

It’s not only the rubber sleeve that can be made from different materials to suite different applications. Tension and shear bands are manufactured from 1.4301 (304) grade stainless steel which provides optimum resistance in most soil conditions. For higher corrosion, contaminated ground areas, or marine environments, grade 1.4401 (316) stainless steel should be specified.

Some flexible couplings are available in flexible PVC for plumbing applications. While they can provide a low cost solution, they do not have the same compressions set and stress relaxation properties or temperature resistance (max 38°C CWT) as rubber. Therefore they should only be used for internal, above ground applications where there is access to tighten the tension bands periodically over time.

The Right Tool for the Job

The standard VIPSeal® range will be suitable for most residential drainage applications, however if merchants are aware of the factors that affect material selection, they will be better placed to advise customers on the products that are most suitable for the application, ensuring a leak free joint that will exceed the service life of the pipe.

The team at VIP are always on hand to provide advice on the best material for the application and can also provide training either at their Huntingdon HQ or in branch with merchants, giving them the confidence to deal with any drainage enquiry. So while size is important when selecting the correct flexible coupling, it’s what you’re doing with it that matters.

Discover how VIP’s patented Cast-in gasket will benefit your project at BTS 2018

VIP are looking forward to exhibiting at this year’s BTS 2018 conference and Exhibition. The biannual event is held at the Queen Elizabeth Centre, Westminster, London for two days on the 9th and 10th October.

The event which is hosted by the British Tunnelling Society combines a two day conference with the UK’s largest tunnelling and underground space exhibition. VIP will be showcasing our full range of tunnel segment gasket profiles including glued-in, hydrophilic and our patented cast-in gasket which is designed to eliminate corner point loading, often the cause of cracking and spalling of concrete segments.

The gasket has been used successfully in the Glasgow Shieldhall waste water tunnel and is being used extensively throughout the Thames Tideway project and you can learn of the benefits that it can bring your project first hand by speaking with Sales Director, Steve Casey, and Business Development Manager, Matthew Levitt who will be present throughout the event.

You can visit us on stand B22. For more information and to book your ticket, visit the BTS Conference 2018 website.

VIPSeal® Increase Overseas Potential with new Accreditation

VIP-Polymers Ltd have recently obtained two accreditations for their VIPSeal® range of flexible couplings for the Australian and New Zealand Market – AS/NZS 4327:1995 CMARK (cert no. 3018) and WaterMark (cert no. 23304).

The Water Services Association of Australia (WSAA), which covers metal banded flexible couplings and bushes for low pressure applications that utilise bands manufactured from 1.4401 (316) stainless steel, specifically for the infrastructure applications within the water utilities for Australasia.

Commenting on the new development, VIP Commercial Director Jon Crean said “we are delighted that VIPSeal® products now carry the full approval of two accreditations which will support our strategy and distributors within the Australasian market.”

Use of VIP’s Patented Tunnel Segment Gasket Increases on the Thames Tideway Project

VIP-Polymers Ltd have increased their involvement in the Thames Tideway project by winning 3 more contracts to supply their patented Cast-in gasket. These projects are in addition to the central section of the Main Wastewater Tunnel and Beckton shaft and Syphon tunnel projects VIP had already secured.

The latest contracts include the supply of Cast-in gaskets for the East section of the Main tunnel, the Greenwich Connection Tunnel and the Frogmore Connection Tunnel.

Thames Tideway Route Map

The Thames Tideway Project is required to upgrade the outdated combined sewer system that was built in the 1860’s. Originally designed for a population of 2 million, it now lacks the capacity to serve a population nearing 9 million, which continues to grow.

VIP’s patented Cast-in gasket is designed to eliminate cracking and spalling of concrete segments caused by solid corners. Solid corners result from the traditional ‘shot joining’ manufacturing process to join lengths of extruded gasket profile together to form the trapezoid gasket that encompasses the concrete segment.

As the gasket is unable to compress at the corners, higher loads are experienced which can lead to cracks and spalling. As VIP’s innovative gasket allows compression performance that is virtually uniform around the entire gasket, ensuring that loads experienced when the segments are closed together do not exceed the specification of the design.

Solid Corner GasketVIP's patented cast-in gasket corner

Caption: Cross section of a solid corner vs. VIP’s Patented gasket corner

At 8.5m in diameter (outer), the East section of the main tunnel will connect to the central section at Chambers Wharf and travel 5.5km East, terminating at Abbey Mills Pumping Station. Gaskets are being supplied to a Max Bogl / Tarmac joint venture, who will cast the gaskets directly into the segments which eliminates the need to glue them in at a later stage.

At depths between 45 and 65m, this is the deepest section of the tunnel where the ground is predominantly chalk. Due to these conditions, a 35mm profile is being used to cope with the higher water pressure at the deepest point of the tunnel.

Tideway Tunnel Depth

28mm Cast-in profile will be the gasket used by the same pre-caster for the 4.6km Greenwich Connection Tunnel. This 6.1m diameter (outer) tunnel connects to the main tunnel at the join between the Central and East section and connects to the Greenwich Pumping Station.

Commenting on the projects, Business Development Manager Matthew Levitt said, “It’s great to be involved with all sections of the project from West through Central and in to East. Collaborating with several different stakeholders from the design teams through to the contractors and precasters involved. VIP’s Cast-in system offers greater assurance to the longevity of the structure and reduction in unplanned expenditure on a project”

The final contract is the Frogmore connection Tunnel, connecting the West section of the main tunnel to the existing combined sewer overflow, Frogmore Storm Relief-Buckhold Road.

VIP’s 28mm Cast-in profile will be the gasket used in 1.1km of 3.2m diameter (outside) tunnel. VIP will be supplying gaskets to segment pre-casters FP McCann with whom they have had previous success on projects including the Glasgow Shieldhall waste water tunnel.

Continuing the working relationship with VIP for the Thames Tideway East and Greenwich tunnels is the Costain, Vinci Construction Grands Projets joint venture (CVB) who were also the contractor for the successful Glasgow Shieldhall project.

Commenting on the working relationship with VIP, Tony Parsons, Director of Engineering (Tunnelling) at Costain said “CVB selected VIP Cast-In Gaskets for waterproofing the Shieldhall Tunnel lining as they offered the best option for moderate corner compression loads and consequent avoidance of segment damage arising from ‘hard corner’ overload.

The gaskets performed extremely well in service with no related segment damage and excellent groundwater exclusion.

On the basis of their performance at Shieldhall, CVB specified VIP gaskets for the tunnels at Tideway East, and Costain specified VIP for the Tideway Overflow Tunnel at Beckton”.

Casting for the projects will begin in August.

VIP Showcase trenchless technology at No-Dig 2018

VIP will be exhibiting at No-Dig Live 2018, the go to event for anyone involved in the trenchless industry.

Held at the East of England Area and Events Centre in Peterborough, the 3 day event runs from the 18th to the 20th September and includes the UKSTT gala dinner and awards ceremony on the evening of the 19th where VIP representatives will also be present.

Throughout the event, VIP will be showcasing our VIP-Weco no-dig repair seal. Manufactured from EPDM or Nitrile rubber, VIP-Weco is available in a number of configurations which allows it to withstand internal pressures up to 20 bar and external up to 2 bar.

VIP-WECO Configuration 1

With installation times under an hour per seal, VIP-Weco is available in sizes up to DN3500 and is suitable for all pipe materials and sizes, making it the ultimate trenchless repair seal.

Alongside VIP-Weco, VIP will also be showcasing VIPSeal®, our range of flexible couplings for low and non-pressure applications including the latest addition to the range VIPSealChem for applications where extreme temperatures and high chemical resistance is required.

Visit VIP on stand 93. For more information or to book your ticket, visit the No-Dig Live website.

VIPSeal® Targets Growth with New Appointment

VIP-Polymers Ltd has increased its sales team for their VIPSeal® range of Flexible Couplings and Adaptors in the UK.

In line with VIPSeal’s growth plan, John Atkinson joins as Area Sales Manager for the North to manage the increasing number of merchant customer accounts. His role will involve developing new and existing relationships with merchants and distributors, working together with them on increasing their sales of VIPSeal® flexible couplings.

Working with merchants isn’t new to John as his sales background in light side products including PPE, workwear, fixings and consumables brought him in contact with merchants on a day to day basis.

Commenting on the job ahead, John said “I believe that the route to a successful sales portfolio is created by building and maintaining excellent relationships with customers and I’m looking forward to building on VIPSeal’s current relationships and meeting with potential future customers”.

VIP’s Commercial Director Jon Crean commented, “We welcome John to the growing team at VIP and look forward to his contribution and success in helping to develop our brand of products within the distribution market and in line with our business strategy.”

The 5 Billion Pound Super Sewer

The BBC are airing a 3 part documentary this month, focusing on the Thames Tideway Project of which VIP are supplying gaskets for sections of the project including tunnels and shafts. 

Currently in production is the central section of the main sewer tunnel for which VIP have supplied their patented cast-in gasket which eliminates cracks and spalling to concrete segments caused by corner point loading.

Other parts of the project that VIP have contributed to are cast-in gaskets for a 800m siphon tunnel and glued in gaskets for a 30m deep shaft, both of which are located at the Beckton Treatment works. Both of these gaskets were manufactured from Nitrile rubber, able to withstand the mix of chemicals that are expected to be present.

The project itself is being undertaken as the Victorian network of sewers, which was originally designed for a population of 2 million, is at bursting point.

With the overflow of sewerage being fed into the river Thames, totalling 39 million tonnes every year, the project will ensure that all of the waste and rainwater that flows into the drainage system can be treated.

With a current population of 9 million and rising, the project will ensure that it can cope with the projected population of London.

The documentary follows the people involved in building one of the largest construction projects in the UK.

For full details of the program and information on future episodes, visit the BBC website.

What is a solid corner?

Solid corners in Cast-in gaskets, caused by traditional shot joining methods contribute to cracking and spalling of concrete segments. These can be difficult to detect at an early stage as they are often on the extrados of the ring and not seen but the result, often leaks, lead to costly repairs and delays.

During our recent visit to the World Tunnel Congress in Dubai, we exhibited our latest innovation in tunnel segment gaskets.

VIP introduced a major step forward in Cast-in gasket design. The patented* compliant compressible corner technology, which is already in use on a number of projects, delivers load performance along the entire perimeter of the gasket, greatly reducing the risk of segment cracking during installation.

In our video, filmed on location at WTC2018, Sales and Technical Director, Steve Casey explains what a solid corner looks like and how they can lead to segment cracking and spalling.
*(GB2541978 – International patent pending)


Visit VIP at Singapore International Water Week

Singapore International Water Week

It’s not long to go now until this year’s Singapore International Water Week where VIP will be sharing a stand with our partner Pan Asian Holdings Ltd.

The event, held between the 8th and 12th July at the Sands Expo and Convention Centre is a global platform aimed at sharing and co-creating innovative water solutions.

Business Development Director Paul Green will be on the stand to discuss VIP’s products, services and latest innovations including:

VIPseal® – Our range of flexible couplings and adaptors for low and non-pressure pipes of any material including VIPSealChem, the latest innovation in chemical couplings.

VIP-Weco – Our No-Dig permanent pipe repair seal, suitable for potable and waste water and able to withstand internal pressures of up to 20 bar and external up to 2 bar.

Tyton-SIT Viper – The next generation of self-restrained gaskets for ductile iron pipelines to Preferred Class in sizes DN80 – DN600

Manufacturing – With in-house design, testing facilities and laboratories, along with rubber compounding and moulding capabilities, VIP have everything needed to take a product from idea through to completed item, all under one roof.

VIP will be on booth B2J32 throughout the event and look forward to meeting you. If you would like to arrange a meeting in advance, you can email Paul.

VIP achieves ISO 14001 with ‘best in class’ management system

VIP-Polymers Ltd has obtained ISO 14001 environmental certification with what the assessor described as some of the best management control systems he had seen at any manufacturer.

The global specialist rubber seals and gaskets manufacturer, based in Huntingdon, Cambridgeshire, has achieved ISO 14001:2015, the latest version of the international standard.

The assessment was based on elements of a management system, first introduced in 2016, being developed in-house by Dan Rowe, VIP’s Senior Quality Engineer, and Neil Search, the company’s Quality and Systems Manager.

This system incorporates quality, health and safety – and now the environment – in an integrated approach so VIP’s processes support each other towards a mutual goal of continual improvement.

Dan Rowe said: “The ISO assessor from BSI was very complimentary about our management system, saying we were raising the bar, and that some of its elements were the best he had ever seen at any manufacturer in the UK.
“It was very pleasing to receive such positive feedback. Passing the audit at the first attempt was a great achievement, and reflects the hard work put in by everyone involved.”

ISO 14001:2015 sets the standard for environmental management systems, taking a risk-based approach to controlling the company’s impacts on the world around it.

VIP’s management system has introduced new tools and techniques that are tailored to align perfectly with the requirements of working practices at VIP and the ISO standard.

This has included the introduction of a new form of life-cycle assessment, known as a Chi-Bi diagram, and a revolutionary new method for assessing risks across all areas of the business.

Neil Search said: “We have developed a new approach to risk management, moving from a predictive model to one based on introducing specific control processes to manage risk.

“We have also looked at every stage of how all our seals and gaskets are designed, manufactured, and then used to maximise quality, cut waste and energy use, and reduce their impact on the environment.

“Thanks to this process, which has involved every team in our organisation, our customers can be sure we are continuously improving the sustainability, quality, and value of our products.”

VIP also holds ISO 9001:2015 and has begun working towards achieving the newly published ISO 45001:2018 standard for health and safety management systems.

The company manufactures pipe seals and gaskets, and tunnel segment gaskets to many national and international standards, for major infrastructure projects around the world.

VIP has end-to-end control of the R&D and manufacturing process by compounding and mixing its own rubber, product design and testing through to the final manufacture of the products.

Download our latest ISO 14001:2015 Certificate here.