Monthly Archives: May 2019

Rhyl Station

With its team of experts in the polycarbonate and roof glazing fields, Twinfix works on developing the best, newest and most cost-effective roof glazing products.

A family business, Twinfix has been involved in the polycarbonate roof glazing market for nearly 30 years.

Its innovative Multi-Link-Panel has been used in many markets, such as in the replacement of broken glass or failed PVC in station canopies and depot roof lights, where its patented fixing method results in incredibly quick installation times, a real bonus when working with limited possession times.

Early in 2017, Twinfix Ltd worked with structural engineers JNP Group on the design of the roof refurbishment for Rhyl Station ensuring a structure that would be in keeping with the original age, design and character of the station was specified.

The station at Rhyl is steeped in history and character. It opened in 1848 in line with the opening of the Chester & Holyhead Railway, and was later adapted as the station grew. The London & North Western Railway completed a major station enlargement in 1900 which included a new footbridge, water-powered luggage lifts and new signal boxes at each end of the station, both still standing. Rhyl railway station is on the Crewe to Holyhead North Wales Coast Line and serves the holiday resort of Rhyl, Wales.  Rhyl has long been a central hub for tourism. Once an elegant Victorian resort, families travelled across from Liverpool and Manchester after the Second World War changing the face of the town. The area had declined dramatically by 1990, but a series of regeneration projects are bringing Rhyl back to its former glory.

As part of the Railway Upgrade Plan, Network Rail is delivering £50m of investment along the North Wales Coast. The project includes rail enhancement works at Rhyl and restoration of the station, which will stand the test of time.

JNP Group agreed that the innovative Georgian Wired Multi-Link-Panel NF would be an ideal fit for the refurbishment project at Rhyl.  Georgian wired polycarbonate is a 6mm solid polycarbonate sheet from Twinfix with a dimpled surface that mimics Georgian wired glass. It’s important to retain the feel of a station, so a sympathetic restoration is crucial. However, it’s also essential to not just replace like with like, as although traditional materials may look the same there are often disadvantages associated with them. Installed at traditional 600mm centres it helps satisfy the Heritage requirements at many older stations.

Polycarbonate glazing mimics the traditional Georgian wired glass that it will be replacing, but it will not break in use. It is therefore safer to install and to use as an overhead glazing material, with no risk of glass cracking and shards of glass dust falling onto the platform below.  The Georgian wired polycarbonate is pre-glazed in a multi-link framing system which has several advantages over the old style two-part glazing bars that are put together on site to create a glazed roof.

The safety of people on roofs is of paramount importance and CDM regulations are very specific in advising designers and specifiers to design out any future possible dangers wherever possible. Specifying non-fragile rooflights helps them do that.

The HSE recommend a drop test (ACR[M]001:2014 Test For Non-Fragility of Profiled Sheeted and Large Element Roofing Assemblies) to establish whether a roofing assembly can be classified as Non-Fragile.  The Twinfix Multi-Link-Panels NF (Non-Fragile) fitted with the following glazing has been tested and they all pass this test with a ‘B’ designation.

  • 16mm and 25mm multiwall polycarbonate
  • 6mm solid polycarbonate
  • 6mm GW polycarbonate
  • In-Line Access Hatch

The Multi-Link-Panel NF passed because it consists of specially designed bars combined with a patented method of installing the polycarbonate that holds it in place when subjected to the drop test.

The multi-link system is made in the Twinfix factory in Warrington and incorporates an innovative fix and link installation feature that makes it very quick to install. So once on site there is less disruption at a station, which is important as the public needs to be serviced as normally as possible during building works. This panel system also results in fewer errors on the install as the work to get it right is carried out before it hits the site.

Vicky Evans, Managing Director at Twinfix said “The aluminium used in the Multi-Link-Panels can be powder-coated to virtually any colour and will not rust or require repainting, which helps cut down on future maintenance costs. Add this to the light weight of the polycarbonate glazing and you have rooflights that can extend the life of any existing canopy structure.”

All these advantages led to a successful roof re-glazing, providing Rhyl station with a non-fragile, virtually unbreakable and attractive roof that keeps the feel and look of this heritage station. Any hurdles that were met were overcome by the Twinfix team working closely with MPH Construction Ltd – the main contractor on site, with one joint goal in mind, completing the project successfully.  Now finished, it’s a wonderful example of the Georgian wired multi-link product and Twinfix, MPH Construction Ltd and Rhyl station can all be very proud of the refurbished premises.

Sam Buswell Senior Engineer at JNP Group commented: ‘JNP Group were approached by Network Rail to provide a refurbishment design for the Station Canopy which would be sympathetic to the heritage of the Grade II listed Station Building and Footbridge. We had the ambition of bringing the Canopy back to its original appearance by opening up the previously boarded over sky lights. We had worked with Twinfix in the past on similar rail schemes and knew their products would be ideally suited. It has been a pleasure seeing the canopies given new life by the re-introduction of these sky lights’

Evans summarised: ‘With countless years’ experience working on stations and depots across the UK, from Victoria Station in London, to Wigan Wallgate in the North West and Stafford in the Midlands the Twinfix team has developed a wealth of knowledge and expertise in the rail sector. Heritage considerations have always been important and now we can offer an even wider range of non-fragile rooflight panels that conform to these heritage requirements.’

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How safe are the school canopies you are specifying or ordering?

Non-fragile roofing should be the standard specification for the canopy roof at any educational establishment where (unauthorised) access on to the glazing is a strong possibility.

This is obviously a big safety issue. There is a misconception that polycarbonate is strong so it will not break (which is basically true) but if multiwall or solid polycarbonate is not mechanically fixed into a glazing bar system it will simply pop out of the bars when put under pressure and in these circumstances the roof glazing will always be classified as fragile. The test for non-fragility is the ACR[M]001:2014. The Twinfix roof system passes this test with a class ‘B’ designation and full test certificates are available.

The following document outlines the information that supports the case of thermoplastics only receiving a class ‘B’ to the ACR (M):001:2014

In summary;

Taken from the ACR[M]001:2014 Test For Non-Fragility of Large Element Roofing Assemblies [fifth edition] the classification of ‘Class A’ is the following:

3.4.4 On conclusion of the second drop test, the load shall be removed and the assembly examined by the competent person and if, in his opinion, the roof sheet and the assembly shows no signs of significant damage that will affect the long term strength and weatherability of the assembly –see Note 6, the assembly may be classified as a Class A non-fragile assembly.

Note 6: Any tearing at the fixings, fractures in the sheet or the assembly support structure, delamination of the sheet or damage to the surface protection which could accelerate the degradation process should be seen as sufficient to withhold a Class A rating. See also paragraph 6.1

6.1 Designers need to recognise that most economic profiled roof assemblies will not achieve Class A rating. A Class B or Class C rating is perfectly acceptable for most roofing applications in terms of being deemed to satisfy Non Fragility when new. Class A ratings can possibly be achieved but the roof sheeting and fixings specification would need to be considerably improved and at considerable cost and generally for no additional benefit.

Therefore our stance on this is a classification of a class ‘A’ is not possible for the following reason:

The type of damage referred to above e.g fractures to sheet, support structure and surface protection may not be visible however the damage will still have been caused. Other company’s may take this as ‘no significant damage’ however as we understand thermoplastic roofing materials we know this damage could have occurred therefore we know that a Class ’A’ is not achievable. It is our standpoint that most “lightweight” roofing systems (pretty much anything other than concrete) will be unable to achieve a Class A rating, the maximum will be Class B.

Class A performance can only be achieved if there is no damage to the surface protection (which could accelerate degradation), which is extremely unlikely on any plastic material. This could only be verified by microscopic analysis if at all: any slight scuff, scratch or mark on the surface would damage the very thin surface protective layer and affect long term performance, preventing Class A classification.

We have consulted with NARM (National Association of Rooflight Manufacturers) and NARMs view on the ACR test is in agreement with para 6.1 In summary, all industry guidance, including that from the National Association of Rooflight Manufacturers, strongly recommends that Class A ratings should never be claimed for any rooflights, for the same reasons already outlined.

Vicky Evans and Daniel Smith
Twinfix Limited
Lily Lane Primary 013 (Large)