Stainless Steel in the Built Environment

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REFLECTI NG ON M I LTON K EYNES In Spring 2022 Hot el La Tour in Milt on Keynes opened t o crit ical acclaim as one of t he most impressive archit ect ural project s complet ed over t he Covid 19 pandemic. St anding t hirt een st ories high, t he hot el is t he t allest st ruct ure in t he area and has panoramic views of bot h t he cit y and open fields and spaces. Const ruct ed from ninet y t onnes of 1.5mm 316L Ult raMarine Polished st ainless st eel t he building is st unning and reflect s t he excellent use of st ainless st eel in t he built environment .

The use of reflective stainless steel finishes is not new in an architecural setting. There are many examples from buildings clad in this finish from Dubai to Birmingham and now Milton Keynes joins them with a project that is both asthetically pleasing and providing a surface that will withstand urban contamination with the correct cleaning regime. Like all construction projects, limiting the cross contamination of ferrous on site when the building is being finished and fitted out can be a challenge. Concrete splash is also something to avoid when the infrastructure is being dug out and developed but with the quality team on site inspecting for issues such as these any affected panels were able to be either cleaned or quickly replaced. The UltraMarine finish is produced with polishing mops and compounds with a technique that minimises the mechanical mop marks for the final finish. With reflectivity measuring 63 > 70% on the 316L 2B substrate the consistency of the finish made it an ideal finish to ensure visual matchability on the structure as a whole. The machines used to polish the material were two Autopullit polishing lines which had been installed during the summer of 2019 as additional lines to expand the Bright Polishing section. Working with a rotating and oscillating polishing mop the finish of each sheet was checked on completion against a control sample piece that had been approved by the architects at the initial design stage. This continuity of finish ensured that each panel has the same degree of reflectivity and colour enabling the formation and fabrication of the panels could be in any order that suited the construction of the building.

Project managing such a large project can be time consuming and difficult. With a weekly schedule for sizes and quantities of sheets to be complete for the next stage in the project working closely together with the supply chain is essential. Overall the project was finished three months early meaning the fit out and snag stages could commence in the majority prior to opening. Keeping the finish looking its best is essesntial on such a landmark building and the use of UltraMarine on 316L stainless steel means that the surface is less than 0.05 µm which will help mitigate cross contamination of particles sitting on the surface finish and discolouring. One of the downsides to using such a reflective finish is that scratches on the surface can be ugly and very obvious and spoil the 'wow' factor particularly at eye level. If the scratches are higher up on the building then whilst the may not be visible to the naked eye they do pose a risk for streaking and discolouration if contaminates sit within the scratches and then are flushed with rain wash off. These scratches can also be subject to aqueous contamination where particles in rain, from exhaust fumes or nearby construction are depsoited. However once the structure is complete the higher panels are unlikely to be scratched or damaged and those at 'people level' usually have regular inspections as part of maintenance regimes. Cleaning the external cladding should be done with a mild washing up liquid solution and rinsed well, not rubbed, to avoid streaking and scratching.

SUSTA I NA BLE STA I NLESS Stainless Steel has an enviable position in the metals marketplace. It currently doesn't have a proven end of life-cycle as proven by the Chrysler Building in New York. From 1929 to 1960 the Nirosta stainless steel (18% chromium and 8% nickel) was inspected every five years to determine the durability of the correct type of stainless steel in architecture. In 1960 the inspections carried out by the American Society for Testing Materials were cancelled because the stainless steel panels had shown minimal sign of deterioration. Of course the life cycle will only be sustainable if the correct grade and finish are chosen for the correct application. This includes whether the building is in an urban or ultra urban environment or if it is in a coastal area and subject to salt spray. The life cycle isn't the only aspect where stainless steel is sustainable. All European stainless steel flat products are produced without using coal fired technology and the mills are working hard to measure and improve the carbon footprint . Stainless Steel is 100% recyclable and typically European Mills produce new stainless steels made with approximately 85% recyled material. This means that when planning a project to use stainless steel in the built environment, at the design stage the project can plan to fully recycle the stainless steel at the end of life for the building.

Working on a project of this size is incredibly rewarding and trips to site as the Hotel was being built enabled the Team at PPS to see their hard work realised.


Every now and then a project comes along that is incredibly special. During 2019 Craig Barnshaw from Inductaflex visited Professional Polishing Services to talk about having some 316 2B sheets polished to UltraMarine. Whilst the quantity required was quite small, just 250 sq mtrs, the actual project was fascinating and much bigger than the quantity of stainless steel. Inductaflex were making the largest and most complex bending project in the World. The huge three dimensional formed twisted aluminium profiles were formed on a bespoke machine manufactured by Inductaflex UK after hundreds of hours of engineering analysis before they produced the first bend. This structure would then be clad in the polished stainless steel.

The end result was to be an interactive stage with lights and sound to be installed in the center of AT&T?s Discovery District® in Dallas, Texas. Called the Globe, the internal structure is as stunning as the exterior use of UltraMarine finish on the stainless steel which reflects the surrounding buildings. If you venture inside the Globe there is an interactive light and sound experience. Managing Director of

Professional Polishing Services Ltd, Kirsty Davies-Chinnock visited the Globe when it was being assembled prior to shipping to Dallas to inspect the polishing finish as it was installed onto the frame. Initially polished in sheet sizes 3000 x 1500 x 6mm and 4000 x 1500 x 6mm the finish itself has a high degree of reflectivity with clean clarity suitable for the impressive design.

The design strategy of the District showcases diverse elements and is a unique redevelopment of their headquarters, making them a centre for visitors, employees and the local community. It is fitting that such a unique design serves such a unique function. AT&T describe the Discovery District® as ?A new downtown destination where tech, culture and entertainment combine to create unique experiences?. The Globe itself is 30 feet high and incorporates 300,000 LED lights as well as the most innovative bending structure and 250 sq mtrs of UltraMarine 316 Stainless Steel.


Thank you t o Lensi phot ography for t aking our phot graphs of Hot el La Tour. Thank you t o Induct aflex and AT&T Discovery Dist rict for allowing us t o feat ure you in our Case St udy Professional Polishing Services Lt d