Asset health and resilience are high on the agenda in the 2024 Price Review process and beyond. For a supply chain take on the issues, HUBER Technology’s International Sales Manager Andreas Heim, Safe Access Solutions explores the reasons why the technology specialist is seeing a growing level of interest and uptake of its stainless steel doors in water and wastewater applications.

Andreas Heim, HUBER Technology Safe Access Solutions division: HUBER has been a leading technology provider in the water and wastewater sector for many decades – over the years we’ve build up a considerable body of experience,  pertise, knowledge and understanding of the key operational drivers and challenges in the sector.

We know asset health in terms of longevity, maintenance and operational requirements, together with whole life costs is an increasingly important issue for water and wastewater companies worldwide.

HUBER Technology has been supplying them with specialised stainless steel products like manhole covers and pressure tight doors since the 1970s. These products play a fundamental role in protecting and maintaining the health of their many and varied assets which make up the water and wastewater networks – pumping stations, service reservoirs and biogas digesters to mention just a few.

Our customers in the German market and neighbouring countries like The Netherlands, Switzerland, Austria, Sweden and Luxembourg are already very familiar with HUBER’s range of Safe Access Solutions. HUBER started successfully manufacturing our stainless steel TT7 doors in the 1970s and since the early eighties we’ve been steadily selling about 350 to 450 of these pressure tight doors every year.

Worldwide, we now have an installed base of around 10,000 doors in place at a wide range of installations.

Recent projects where our TT7 submarine pressure-tight doors have been installed include:

• three of the biggest wastewater pumping stations in Germany in Europe’s biggest wastewater infrastructure project
• the first ozonation plant for advanced wastewater treatment in the Netherlands
• a new covered reservoir currently under construction for one of the UK's largest water companies 

So why are we now seeing a growing level of interest and uptake of our stainless steel doors in the wider water sector?

Over the years we have worked with our customers on an ongoing basis to get a close understanding of their requirements. Based on decades of experience of working with water and wastewater companies, in my view, stainless steel doors offer significant operational benefits compared to other available options on the market.

Firstly, it is quite clear that in most of the security and safety-critical applications where the doors are used, stainless steel is undoubtedly the best choice of material.

Stainless steel’s combination of high level corrosion resistance and zero maintenance delivers assets with unrivalled product life and low Whole Life Costs.

Galvanised steel has been a commonly used metal in the water sector due to its low initial cost – however, an increasing focus on long term asset resilience means we are now witnessing a shift away from using a material which at best can only offer surface resistance to corrosion. To combat this, ongoing maintenance and servicing is required, including regalvanising and painting over its average product life of around 25 years.

Over its lifetime, this inevitably results in significantly increased asset life cycle costs of an order of magnitude greater than those products engineered from stainless steel.

Image: corroded galvanised steel installation compared with corrosion-free stainless steel

In comparison, with an average life of 50 years or more, stainless steel provides considerable advantages in terms of both cost and performance. Unlike galvanized steel, it provides complete resistance throughout the metal, enabling delivery of an unrivalled product life which is completely maintenance free. HUBER doors which were first installed back in the 1970s are still in place today.

Stainless steel in concrete infrastructure stands the test of time

All our stainless steel pressure tight TT7 submarine doors and security doors are precisely engineered using state of the art production techniques and offer maximum corrosion protection for whatever application they are used in. In the majority of applications, the door is usually embedded in a concrete structure and we aim to provide a product with at minimum the same life span as the concrete structure which surrounds it.

Over the years HUBER has also significantly enhanced the doors pressure capabilities – following feedback from customers we decided in 2012 to develop a different door. Pressure requirements had reached a level where the standard door shape and design to cope with a load of up to 10 meter water column.was no longer appropriate in certain applications.

We knew from the market that this pressure resistance would not be sufficient for many future building projects where a pressure resistance of up to 30 m water column might be required, e.g. for pumping stations, pressure increasing plants in drinking water supply projects, locks or stormwater overflow tanks.

We came up with the TT7-30 – a pressure door that is absolutely watertight up to 30 m water column. Its distinctive design and appearance (see picture),offers a significantly improved resistance to high water pressures.

TT7 doors installed in infrastructure in Germany, Netherlands and UK

This new type of door can be used for applications with up to 30 m water columns - perhaps the most notable example of this is at Europe’s largest wastewater infrastructure project. HUBER’s TT7 doorshave been installed in three separate wastewater pumping stations inthe 100 kilometre long pipeline for the Emscher sewer. Once Germany’s dirtiest river, the Emscher has been completely free of sewage since 2022.

The pumping stations are the biggest in Germany and some of the deepest - Gelsenkirchen at 26 meters and Bottrop at 32 meters came into operation in September 2018, followed by Oberhausen at 42 meters in August 2021.

Photo Emschergenossenschaft: approx 40 metres deep Gelsenkirchen pumping station construction pit

Another interesting application we have recently completed is the installation of three pressure-tight TT7 door in the Netherlands' first wastewater ozonation plant in Houten. The doors, which are customised with adaptations made to the sealing and glass type to prevent corrosion by the ozone, are located seven metres underwater.

Image: wastewater ozonization plant 

In the UK, Yorkshire Water have incorporated approximately 50 of our TT7 doors at a number of their operational sites, mainly in service reservoirs. Consultants Mott MacDonald Bentley (MMB) introduced walk in access doors for three of the water company’s service reservoir replacement schemes in AMP4.

Photo: HUBER pressure-tight TT7 door inside valve house

This method was subsequently incorporated into Yorkshire Water’s Asset Standards as the required access method - the water company has since adopted walk in access services as standard practice on all its new service reservoirs. MMB has now used this walk-in access solution on 28 schemes in the UK - HUBER Technology’s TT7 pressure-tight doors have been used in all those schemes. The stainless steel doors are capable of outlasting the reservoir structures where they are installed.

To sum up, we are definitely seeing an uptick in interest in our pressure-tight TT7 doors in a number of applications – including storm water storage tanks, wastewater pumping stations, reservoirs and biogas digesters.The key feature of the pressure-tight door is of course that it is 100% watertight – with zero per cent risk of leakage irrespective of water level pressure level. In the standard TT7 door, this is watertight up to to 10 metres for a minimum of 30 years.

Flood protection for critical infrstructure 

In addition, our stainless steel doors are increasingly being used beyond the water and wastewater sector for other critical infrastructure. The growing impacts of climate change from extreme weather events like flooding are already causing significant damage to critical infrastructure running into hundreds of billions of pounds.

Photo: HUBER TT6 door in flood water 

Organisations in the wider utilities sector are particularly interested in significantly strengthening the level of flood protection they can put in place to protect their valuable and increasingly vulnerable assets.

Our flood proof TT6 door is being used by the energy generation companies, district heating providers, broadband and telecoms networks and advanced transport systems to protect their electric installations, access pipelines and internet/ broadband/ telecoms cables.

Stainless steel doors are also perfectly suited for preventing unauthorised access, accidental or deliberate damage or targeted acts of deliberate aggression and sabotage on installations and security sensitive assets. Solid stainless steel, pressure-tight doors are near impossible to drill through.

Tailoring infrastructure components to ensure maximum asset health and resilience

What we always try to demonstrate to our existing and potential customers are the benefits of early contractor involvement at the design stage of any infrastructure. So for example, when you’re doing the design work for a new tank, early contractor involvement can really help and save you time, money, additional costs, materials, resources etc at a later stage in the process.

One of the significant product advantages we offer is our ability to optimise asset strength and resilience by tailoring the thickness of the products to precisely match the thickness on-site of the structure in which it will be embedded prior toits installation. So when the customer says the depth of the structure is 30 cm – then we will make the door and its frame 30 cm deep.

Photo: concrete formwork in place for TT7 door installation

This is particularly relevant to the concrete suppliers and formwork producers that precast the concrete slabs needed in many infrastructure projects. Formwork that is made of steel and plates always has better resistance to the concrete pressure compared with any additional formwork that might be needed.

This significantly reduces the work required on the construction side and completely removes the need for any extra form work or filling out with pieces of wood – which is time-consuming, expensive and doesn’t deliver the level of pressure tightness needed compared to the concrete pressure.

In general, I would say that all the work we do is bespoke and tailored to meeting each customer’s needs. They discuss their individual requirements with HUBER and we will deliver an effective solution. So we can tailor things very precisely – but we’re also fast enough and flexible enough to provide a solution if there is a requirement that needs to be fulfilled at short notice.

Meeting required regulatory standards is a given

In terms of meeting regulatory standards, we ensure that all relevant requirements met for whatever countries and markets we are selling into This includes European and USA standards like DM174 in Italy, DVGV in Germany and NSF61 in the USA.

For potable water applications in the UK for example, we have received DWI approval for all the technical applications, materials used in our products and are now simply awaiting formal confirmation that we meet the requirements of DWI Regulation 31.

Asset resilience in PR24 and beyond

Regulatory requirements are of course key drivers in how infrastructure providers management their operational assets.

In the UK water sector, Ofwat’s thinking on cuurent asset health performance commitments for the 2024 Price Review - mains repairs, unplanned outage and sewer collapses -  is that they will incentivise companies to maintain and improve asset health.

However, alongside that its intention is to drive an even greater focus on asset stewardship for the long term via wider monitoring activities, including its proposed integrated monitoring framework for operational resilience. 

Assets deteriorating increases the risk to customers over both the short and longer term

From 2026 onwards, the UK regulator is proposing the implementation and integration of the monitoring framework to drive improvements in longer-term operational resilience.

According to Ofwat, the water sector needs to make decisions through the lens of assets, now and in the future to best serve customers, the environment and society. The regulator says it also considers “it is vitally important that companies collect, monitor, analyse and act on asset health information beyond what is reported to us.”

“Assets deteriorating increases the risk to customers over both the short and longer term. For example, if companies delay or avoid maintenance it could reduce costs but store up problems, leaving a larger maintenance bill for future customers.”

Which brings me back to my initial comments about asset health - in terms of longevity, maintenance and operational requirements, together with whole life costs these are key issues for water and wastewater companies.

Viewed through the prism of Ofwat’s requirements going forward, choosing products which are initially low cost but ultimately have a much shorter lifespan with significantly higher maintenance and replacement costs will increasingly not be an option for the companies.

Instead, in terms of asset health, they will no doubt increasingly opt for the solutions with the best Whole Life Cost and performance outcomes.

And they’ll also have the peace of mind that comes from knowing they’ve put the best solutions in place in terms of operational performance and form part of the group of assets which collectively underpin the long term asset health of their infrastructure.

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