Thermal Breaks

As UK cost-of-living concerns soar, is energy efficient building design a key aspect in easing the burden?

When the Office of National Statistics recently updated its Opinions and Lifestyle survey through to mid-February, over three-quarters of adults reported that their cost of living had increased – up 14% from November 2021.

Alongside the cost of food, 77% stated that this was due to an increase in gas or electricity bills, and whilst half of these people were looking to tackle this by cutting back on non-essentials, 35% of people were actively looking to cut the amount of electricity and gas they are using and 31% were driven to cutting back on spending in food and essentials.

Government action in energy efficiency

At the start of 2021, the UK’s Housing Minister announced that all new homes must be more energy-efficient and “zero-carbon ready” by 2025, and a consultation on higher performance targets for non-domestic buildings with the objective of them to be zero-carbon within the same time scale.

However, when this proposal was at the planning stage, campaigners in this area warned that this would mask the actual energy efficiency itself and that whilst this might make the building look like it is performing better, the reality is it could be worse.

This month the government has also stated that whilst they are looking at launching a boiler upgrade scheme and investing in helping to stimulate the production of ‘British heat pumps’ which can reduce demand for gas, they will not ‘impose’ measures to improve energy efficiency in existing homes. RIBA president Simon Allford said the government ‘must realise that we will not ease the burden on vulnerable households unless we improve the energy efficiency.’

Building designers, engineers and specifiers looking to go beyond the recommended standards

Whatever the minimum requirements are, the great news is that building designers, structural engineers, and specifiers are looking to exceed regulating body expectations and go beyond the recommended standards both for new builds and retrofitting older buildings.

In addition to the construction industry’s ethical commitment to reducing the amount of energy needed to power homes and businesses, the significant increase of the energy price cap, the associated jump in household bills, and the threat of further increases in autumn, are driving energy efficiency to the front of both buyers’ and renters’ minds.

New research carried out by the Home Builders Federation has shown that being ‘eco-friendly’ and ‘having a good Energy Performance Certificate’ were rated as the second and third most important factors respectively, beaten only by having ‘private outdoor space’.

Nearly three quarters of respondents stated that they are worried about the energy performance of their current home, and nearly a quarter said that energy efficiency will be a ‘crucial’ factor in their next home move.

In short, if building designers and developers want to future proof their investment and attract buyers or renters, being able to demonstrate energy efficient that doesn’t just meet legislations, but also reduces the current cost of living could be essential.

Energy efficient building design

The role of Structural Thermal Breaks in energy efficiency

Structural Thermal Breaks are widely considered to be the most efficient way to thermally separate structural connections and prevent heat loss in the building envelope. This includes external to internal structural connections, façade system connections, structural columns and exoskeleton structures, linear steel and masonry connections, roof penetrations, and concrete frame to steel connections.

With the increase in demand for private outside space, growing demand for Structural Thermal Breaks is in preventing thermal bridging where balconies are installed.

When using Structural Thermal Breaks with thermal efficiency credentials such as BRE (Building Research Establishment) and Passive House, alongside a generally proactive approach to insulation, this can ensure a significantly higher level of energy efficiency, without compromising structural integrity.

Thermal Bridging Model

Summary

Building designers, engineers, and specifiers are facing a huge challenge in taking a holistic approach to energy efficiency to help tackle climate change, but also reduce the impact of the growing cost of living due to energy prices.

For more information on integrating thermal break solutions into structural connections as part of an energy efficiency strategy, visit our Structural Thermal Break hub or one of our dedicated portals:

Architects Portal

Structural Engineers Portal

Buyers Portal

Upcoming Webinar: The significance of Structural Thermal Breaks in high rise fire design and Building energy performance

Farrat is partnering with the Institute of Structural Engineers this June to produce a new webinar on the significance of Structural Thermal Breaks in high rise fire design and building energy performance. This webinar is ideal for designers, architects, engineers, and specifiers, who are looking to go beyond the standard in fire design and energy efficiency.

Since the tragic circumstances of the Grenfell disaster, designing for fire construction material choice in all its facets has become a focus of design teams across the world. In balance, the global demand for energy efficiency and net-zero carbon pulls designers in an equally important direction.

This webinar with Farrat looks through the lens of Structural Thermal Breaks at the multi-role demands of building components to deliver best-in-class performance in sustainable credentials and building physics without compromising on fire safety.

The webinar will assist designers in understanding:

  • The latest developments in UK Fire and Building Safety regulations
  • Current requirements for specifying safety-critical building products
  • Up to date thought on the UK standards for construction material performance information
  • Current direction and time frame for Structural ‘Green’ Steel and the journey towards Net Zero
high rise fire design

Date: Tuesday 21st June

Time: 9 – 10am BST

Presenter: Chris Lister. Commercial Manager – Structural Thermal Breaks

Chris Lister is the Commercial Manager for Farrat Structural Thermal Breaks and British Construction Steel Association BCSA National Council Member. Having studied both Engineering and Architecture he has worked exclusively in the construction and building product design sector, in both senior technical and commercial roles.

At Farrat he is principal in the development of Farrat Structural Thermal Break products and facade design solutions. He’s a passionate contributor to the global discussion on fire safety in high-rise structures and building physics research and advocate for achieving the highest level of energy efficiency in building design.

Chris is a dedicated father, diehard Rugby player, and fair-weather motorcyclist.

The top 5 questions asked by engineers when specifying structural thermal breaks

The ability to transmit structural loads whilst addressing thermal performance through a building envelope has long been a difficult balance for building designers. The weight of decision has often fallen on the side of the structure, with the importance of structural integrity winning out against the impact of structural members piercing the thermal envelope.

However, as the energy demands of new and retrofit buildings have grown, so have the requirements to minimise that energy usage and the potential of issues such as thermal bridging.

This has resulted in greater levels of insulation in planar elements of a building envelope, leading to more noticeable and detrimental effects of those ‘hard to treat’ details such as structural penetrations. Add to this the need to achieve compliant critical internal temperature factors for the avoidance of unsightly or harmful mould growth and mitigating thermal bridges in a building envelope moves higher up the list of problems to solve.

Equally, the growing influence of fire design on structures has also led to the requirement for enhanced performance criteria of building materials in relation to fire that are incorporated into the building envelope. To address this imbalance, new building materials and methods of thermally breaking structural connections, such as steel beams and balcony connections, have been developed.

In the below guide, we address the most frequent questions asked by Structural Engineers when specifying Farrat Structural Thermal Breaks.

1. Which Farrat Structural Thermal Break material should I specify?

Farrat Structural Thermal Breaks take the form of flat plates of any dimensions, which provide Architects with complete design freedom and Structural Engineers the capability to design to standard codes, with a simple configuration.

Farrat offer three independently tested Structural Thermal Break materials, which are designed to balance high structural performance and low thermal conductivity:

  1. Farrat TBK (Yellow) is most specified across typical connection details, with high compressive strength (312MPa fck) and the best thermal performance in the range (0.187 W/mK).
  2. Farrat TBF (silver) is the optimum material when fire performance is a consideration, such as within high-rise buildings, due to its high compressive strength (355MPa fck) and low thermal conductivity (0.2 W/mK) performance characteristics, supported by an A2, s1,d0 Non-Combustible Classification.
  3. Farrat TBL (Black) is the favourable material when structural loadings and requirements for thermal performance are lower, and budgets are constrained, offering medium compressive strength (89MPa fck) and thermal conductivity (0.292 W/mK) performance characteristics.

2. How do I design connections incorporating Farrat Structural Thermal Breaks?

A breakdown of what to consider when designing structural steel connections is contained within the Farrat Structural Thermal Break Technical Guide and supporting SCI, Steel Construction Institute assessment document.

As an overview:

  1.  Structural Thermal Break plates should be considered as a “pack” in terms of connection design.
  2. All Shear forces need to be accommodated by the connection bolts. As a result of the multiple layers in the connection the grip length of the bolts may be significantly increased, it may also be necessary to reduce the anticipated shear resistance of the bolts in the connection.
  3. Reference should be made to BS EN 1993-3 1-8: 2005 Eurocode 3. Design of steel structures.

Example screenshots adjacent are taken from the Farrat extension for Tekla Structures that creates Farrat Structural Thermal Break connection plates. The component automatically takes the plate dimensions and holes of the plate it is fixing to.

3. Can Farrat Structural Thermal Breaks support the loads I am designing for?

The exact physical and mechanical properties for Farrat Structural Thermal Breaks are contained in the Farrat Structural Thermal Break Technical Guide.

As a quick guide:

  1. Farrat TBF and Farrat TBK materials offer compressive strength comparable with Steel.
  2. Farrat TBL has a compressive strength greater than Concrete.
  3. Structural Thermal Break plates in a connection should only be designed to resist compressive forces.
  4. Consideration should also be taken of compressive creep. Farrat materials are formulated to resist long term creep, but this element should be factored into any design.
  5. Many materials which exhibit good thermal properties have poor long term creep profiles.
  6. Reference should be made to BS EN 1993-3 1-8: 2005 Eurocode 3. Design of steel structures.

4. What is the friction coefficient for Farrat Structural Thermal Breaks?

The coefficient of friction of a thermal break plate is not a relevant property for the structural design of connections with non-pre-loaded bolts.

Whilst figures for frictional resistance of Farrat Structural Thermal Breaks can be obtained, it will differ depending on the material with which it is in contact and should be treated with caution when designing connections involving Preloaded or TCB bolts.

5. Will Farrat Structural Thermal Break plates achieve a 120-minute fire rating?

Structural steel connections that require a 120-minute fire rating will typically need to be protected with either an intumescent coating system or a fire protection board. In all situations, the Structural Thermal Breaks should receive the same level of protection as the steel.

However, Farrat TBF Structural Thermal Breaks have been tested unprotected in fire conditions, in structural steel connections, to temperatures more than 1000°C for 120 minutes and maintained structural integrity.

Different building types and legislators have differing technical and regulatory requirements for fire design, but if fire is a concern that requires addressing, then the use of non-combustible thermal breaks is one way to mitigate that risk.

Farrat TBF fire test
Farrat TBF fire test

In summary, when designing for Structural Thermal Breaks:

  1. Check that the chosen material is independently verified to resist the applied compression forces, with an appropriate safety factor applied to determine design loading.
  2. Check that any additional rotation due to compression of the thermal break plate is acceptable.
  3. Check the shear resistance of the bolts is acceptable given that there may be a reduction due to the use of packs and larger grip lengths.

If using Pre tensioned bolts:

  1. Check the slip resistance of the connection considering the coefficient of friction and the number of surfaces.
  2. Check the thermal break plate can resist the local compression forces around the bolts.

Where fire performance is concerned:

  1.  Consult with Farrat for the correct specification of fully tested and certified materials.

 


 

For more information on integrating thermal break solutions into typical, or bespoke, structural steel connections, visit our Structural Thermal Break hub or one of our dedicated portals:

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Project Showcase – Structural Thermal Breaks for energy efficiency and fire safety

Over the last few months, we have witnessed a growing public interest in energy efficiency in parallel to increasing numbers of building designers who are looking to go beyond the standard when it comes to insulating building connections in a wide range of building types. As a result, we remain busy with a large number of Structural Thermal Breaks projects as we head into Q2. Take a look at a few of our most recent thermal bridging projects below.

Primark Belfast, Northern Ireland

The Primark store in Belfast was previously based in the Bank Building in central Belfast, however, it was tragically destroyed in a fire in 2018, with firefighters taking 4 days to totally extinguish the flames.

The COVID19 outbreak also meant significant delays to the starting of the rebuild and renovation of the building, but now works are well and truly underway. Fire safety is a priority for the redevelopment project, alongside structural integrity and retrofitting the historic Grade B1-listed five-story building with modern insulation.

Farrat A2 fire- Structural Thermal Break material Farrat TBF has been selected for use across the project, to provide premium-grade protection against thermal bridging, with non-combustible properties.

Primark Belfast

Hockliffe Road Care Home, Leighton Buzzard, England

Hockliffe Road Care Home

Fire safety is often a key concern when looking to house those who would find evacuation in the instance of a fire a challenge.

Hockliffe Road Care Home is currently being constructed on the site of a former police station, and will deliver a modern 63-bedrooms development built to the highest sustainable standards using Passivhaus criteria.

The scheme will also integrate Farrat TBF Structural thermal breaks, as Passivhaus certified building components.

Golden Jubilee Hospital Clydebank, Scotland

The three-story expansion of the NHS Golden Jubilee in Clydebank, Scotland, is set to include theatre suites, orthopaedic facilities, outpatient and pre-operative spaces, a surgical admissions and recovery unit, a new endoscopy unity, and a sterilising and processing department.

Farrat is working with developers on the dramatic entrance steelwork, ensuring that structural thermal bridges are eradicated to enable the hospital to maintain its high energy efficiency.

Projections involving steel, including balconies, outside shelters, façades, and entrance features, create additional challenges when it comes to ensuring cold external temperatures do not affect the environment inside, and using Farrat Structural Thermal Breaks in this growing health facility will do that.

Energy efficiency in modern building design

Energy efficiency is front and centre in the news at the moment, with increasing utility bills creating a major concern for both individuals and businesses. Building designers are now looking to go beyond following the mandatory regulatory requirements and future proof the use of the buildings at an affordable rate.

Golden Jubilee Hospital Clydebank, Scotland

Whether buildings are using the increasingly specified steel structure or using concrete, Farrat Structural Thermal Breaks are an essential component for any energy-efficient building.

For more information on integrating thermal break solutions into structural connections, visit our Structural Thermal Break hub or one of our dedicated portals:

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The top 5 questions asked by architects when specifying structural thermal breaks

The ability to transmit structural loads whilst addressing thermal performance through a building envelope has long been a difficult balance for building designers. The weight of decision has often fallen on the side of the structure, with the importance of structural integrity winning out against the impact of structural members piercing the thermal envelope.

However, as the energy demands of new and retrofit buildings have grown, so have the requirements to minimise that energy usage and the potential of issues such as thermal bridging.

This has resulted in greater levels of insulation in planar elements of a building envelope, leading to more noticeable and detrimental effects of those ‘hard to treat’ details such as structural penetrations. Add to this the need to achieve compliant critical internal temperature factors for the avoidance of unsightly or harmful mould growth and mitigating thermal bridges in a building envelope moves higher up the list of problems to solve.

Equally, the growing influence of fire design on structures has also led to the requirement for enhanced performance criteria of building materials in relation to fire that are incorporated into the building envelope. To address this imbalance, new building materials and methods of thermally breaking structural connections, such as steel beams and balcony connections, have been developed.

In the below guide, we address the most frequent questions asked by Architects and Building Envelope specialists when specifying Farrat Structural Thermal Breaks.

1. Which Farrat Structural Thermal Break material should I specify?

Farrat Structural Thermal Breaks take the form of flat plates of any dimensions, which provide Architects with complete design freedom and Structural Engineers the capability to design to standard codes, with a simple configuration.

Farrat offer three independently tested Structural Thermal Break materials, which are designed to balance high structural performance and low thermal conductivity:

  1. Farrat TBK is most specified across typical connection details, with high compressive strength (312MPa fck) and the best thermal performance in the range (0.187 W/mK).
  2. Farrat TBF is the optimum material when fire performance is a consideration, such as within high-rise buildings, due to its high compressive strength (355MPa fck) and low thermal conductivity (0.2 W/mK) performance characteristics, supported by an A2, s1,d0 Non-Combustible Classification.
  3. Farrat TBL is the favourable material when structural loadings and requirements for thermal performance are lower, and budgets are constrained, offering medium compressive strength (89MPa fck) and thermal conductivity (0.292 W/mK) performance characteristics.

 

 

2. What thickness of thermal break should I specify?

Farrat Structural Thermal Breaks come in a range of thicknesses from 5mm t0 25mm. The only way to accurately calculate the thickness of a structural thermal break is to carry out finite element analysis on the connection and its allied components. This is not common practice due to the relative rarity of details requiring Structural Thermal Breaks and the time and cost of carrying out the thermal modeling.

However, it is possible to understand from a typical example the effects of thickness of plates on example connection.

Farrat illustrates this for their products using BRE (Building Research Establishment) certified thermal models, which show that despite achieving a lower thermal performance than the surrounding building fabric, it is possible to remove the negative effects of a cold bridge with a minimal amount of insulating material (typically a 15mm -25mm thickness). Plates may be used in multiples, but 25mm will mitigate most thermal bridge issues for dwellings and commercial office building details.

3. Do Structural Thermal Breaks need to be as thick as the surrounding wall insulation?

The primary determinate for the thickness of a Structural Thermal Break is its effect in achieving a satisfactory critical internal temperature factor on the warm side of the structural connection. It is not necessary for the Structural Thermal Break thickness to match the surrounding wall insulation thickness to be a success.

Since the thermal break is required to be a structural element, it will always be a relative weak point as an insulant.

However, as illustrated in Farrat’s latest Passive House Certified Details, this still makes it possible to achieve the highest of building performance standards.

4. Will the Structural Thermal Break meet my U value requirements?

U value calculations are the simple method of understanding the thermal performance of a build-up of construction materials in a flat plane (planar). Structural Thermal Breaks are typically used to solve problems in ‘point’ structural connections or in some case linear connections. As such their performance cannot be calculated using the U value method of calculation and require a Psi or Chi value calculations to be undertaken.

These calculations can only be undertaken using 2D or 3D finite Element Analysis (FEA) modelling.

As this is currently not common practice, Farrat utilise their typical BRE Certified Thermal Models, to provide indicative Psi and Chi values for common structural connections to allow simplified specification of structural thermal breaks where calculation models have not been created.

 

 

5. Do Structural Thermal Breaks need to be Non-combustible?

The use of non-combustible materials, particularly in high-rise buildings has become more commonplace in recent years due, in part, to high-profile building fires and subsequent investigations.

Structural Thermal Breaks are extensively used as part of the structural support in façade systems or as the main structural connection in balconies. These elements are key to the performance of the building envelope in the case of fire and the avoidance of catastrophic failure and collapse.

Farrat TBF is an A2,s1,d0 non-combustible Structural Thermal Break material that is capable of withstanding 1000°C heat and maintains its structural integrity in the event of a fire.

Different building types and legislators have differing technical and regulatory requirements for fire design, but if fire is a concern that requires addressing, then the use of non-combustible thermal breaks is one way to mitigate that risk.

Farrat TBF

For more information on integrating thermal break solutions into typical, or bespoke, structural steel connections, visit our Structural Thermal Break hub or one of our dedicated portals:

 

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The role of sustainable building materials in the race to net-zero

It has been widely shared that buildings and construction are responsible for almost 40% of global carbon emissions driving rapid climate change.

But, did you know that at the current rate of construction, the world is forecast to build more than 2 trillion square feet of floor space in the next 40 years? In their current form, a considerable proportion of these buildings will be constructed out of concrete, with cement as its main ingredient (a notorious greenhouse gas emitter).

A simple route to reducing carbon emissions in the race to net-zero is to design and build smarter. By this, we mean reducing the volume of materials required in construction, reusing/repurposing where possible, and opting for high-performance materials with superior efficiency credentials at the point of the specification.

This sentiment is echoed in a recent report published by the Royal Academy of Engineering on ‘Decarbonising Construction’, which notes that the following aspects will be vital in achieving net-zero transformation in the construction sector:

  • availability and specification of low-carbon materials,
  • reusing materials as standard,
  • and low-carbon procurement.

In our latest insight below, we further explore the role of sustainable building materials in the built environment to understand how our Structural Thermal Break solutions align with the agenda.

Utilising sustainable building materials in construction

Reduce, recycle and reuse

Structural steelwork and lightweight gauge steel can be recycled and reused multiple times. As a result, steel is increasingly selected as a reliable material for constructing robust structures that meet the low carbon demands of the future without compromising on design, practicality, or cost-efficiency.

The recovery rates from demolition sites in the UK are 99% for structural steelwork and 96% for all steel construction products – figures that far exceed those for any other construction material. And the superior strength-to-weight ratio of steel as a construction material, also means that a little goes a long way. This unique characteristic gives steel a high economic value at all stages of its life cycle.

By utilising more recyclable building materials, the industry contributes to more sustainable development by reducing waste and by saving primary resources. Recycling materials such as steel and other metals also save energy and reduce carbon emissions, since it requires less energy to re-melt scrap than it does to produce new metal from primary resources, i.e., iron ore.

The primary benefits of recycling sustainable building materials are well understood and include:

  • Reducing waste, i.e., diverting waste from landfill
  • Saving primary resources, i.e., substituting primary production
  • Saving energy and associated greenhouse gas emissions through less energy-intensive reprocessing.

Although these benefits apply to many commonly recycled materials, there are some significant differences in the properties of materials that influence the environmental benefit of recycling and particularly how these benefits are quantified.

Metals, for example, are infinitely recyclable, i.e., they can be recycled repeatedly into functionally equivalent products – this is the most environmentally beneficial form of recycling.

Other products are ‘down-cycled’ into new products that are only suitable for lower grade applications because the recycled product has different, usually lower, material properties. Although waste is diverted from landfills by down-cycling, only lower-grade primary resources are saved.

For example, crushing bricks and concrete for hardcore, sub-base, or general fill saves aggregates but does not save the resources required to make new bricks or new concrete.

BHC Steelwork - Cineworld Hounslow starts on site

BHC steelwork erection at Cineworld Hounslow in 2019

For recycling to be sustainable in the long term, it is important that the recycling process is financially viable. This is frequently the biggest hurdle to recycling, particularly for products and materials that are downcycled into lower grade, low-value applications.

Current end-of-life scenarios for three of the most common construction materials; concrete, timber and steel are shown below. The illustration describes the end-of-life outcomes of these materials against the established UK Waste Hierarchy:

end of life scenarios
Source: steelconstruction.info from the British Constructional Steelwork Association (BCSA)

Moving towards more sustainable procurement

Steel production is currently a source of greenhouse gas emissions (7% in 2020); however, the good news is that a revolution in steel production is now within reach.

The amount of energy used in steel manufacture has fallen by some 61% since the 1960s, according to World Steel Association data (2020), and further improvements are being sought from steel sector research and development investments.

In 2020, 1.8 gigatons (GT) of steel were produced, accounting for 90% of all metals globally. Major steel-producing countries, including China, Japan, the EU, and now the US, have set ambitious targets to reach net-zero economies. Achieving these demands will further advance the material efficiency of steel and the greater recycling of scrap steel.

In 2005, the British Constructional Steelwork Association (BCSA) became the first steel representative organisation in the UK to launch a Sustainability Charter. This was updated and strengthened in 2021 in response to the climate emergency. The objective of the Charter is to further advance steel as a sustainable form of construction in terms of carbon reduction, reuse and efficiency, economic viability, social progress, and environmental responsibility.

Similarly, leading manufacturers and suppliers of structural steel in the UK, British Steel, and Tata Steel, are certified under the BRE Environmental & Sustainability Standard BES 6001, a responsible sourcing certification for the UK construction market.

For these companies, sustainable procurement is part of wider corporate responsibility.

Severfield installing steel connections with Farrat TBK Structural Thermal Breaks at 22 Bishopsgate, London

Thermal efficiency in modern steel design

In respect of the energy efficiency of buildings constructed with steel, low and zero-carbon buildings, and buildings with high BREEAM ratings are readily achievable using steel construction.

Structural Thermal Breaks are commonly integrated into primary and secondary steel connections as high-performance thermal insulators that provide a robust solution to minimising energy loss in steel construction.

Performance characteristics of Farrat thermal break materials include low thermal conductivity, high compressive strength, and limited creep under load, which provides Steel Contractors and Structural Engineers with complete flexibility to modify typical structural steel details with confidence, without compromising thermal efficiency or conformance.

And unlike general thermal insulation materials on the market, Farrat Structural Thermal Breaks are suitable to mitigate against planar, linear, and point load thermal bridging whilst carrying structural loads, which means that they can be used anywhere a penetration or transition exists in a building envelope, helping Architects and designers to achieve the highest levels of building performance and energy standards.

Thermal efficiency credentials

Passive House is one of the highest standards for energy efficiency, granting certification to structures, components, and professionals who have achieved and designed the best in quality, efficiency, and sustainability. The criteria to gain the title of ‘Certified Passive House Component’ is based on two categories: living health and comfort (‘Comfort criteria’) and energy balance during practical application (‘Energy criteria’).

In 2019, Farrat’s high-strength Structural Thermal Break material Farrat TBK, was listed as a Certified Passive House Component by the Passive House Institute in recognition of its low thermal conductivity and superior energy efficiency performance.

Following this in 2020, Farrat’s A2 non-combustible fire-rated Structural Thermal Break material, Farrat TBF, was entered as an approved product into the BRE (Building Research Establishment) Certified Thermal Details and Products Scheme and was also awarded BBA (British Board of Agreement) certification.

The BRE is an international independent certification body, operating with the highest standards in the certification of fire, security, and environmental products and services, management processes, and other products and systems. Details provided within the BRE scheme are invaluable to building design professionals committed to creating energy-efficient structures and are especially useful for architects and structural engineers at the specification stage.

BRE Certified Thermal Details for both Farrat TBK and Farrat TBF thermal breaks are available online here.

“We have always placed a strong emphasis on impartial assessment and certification for our structural thermal break materials,” says Chris Lister, Commercial Manager of Structural Thermal Breaks at Farrat.

“It enables us to back up our commitment to creating cutting edge materials with practical value and sustainability, for buildings and structures of the future.”

Summary

Specifiers and contractors are responsible for addressing some of the biggest challenges facing the building construction industry in the race to net-zero.

Meeting these challenges head-on in terms of innovative energy efficiency, intelligent building design, and responsible sustainable building materials choices will be a key driver in reaching sustainability targets and safeguarding the future of the world.

For more information on integrating thermal break solutions into typical, or bespoke, structural steel connections, visit our Structural Thermal Break hub or one of our dedicated portals:

 

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What lies ahead for façades: the future of cladding connections

Façades come in a range of striking designs incorporating varying shapes, sizes, and materials, and can often be the most difficult part of a building to design.

Façades utilise cladding components that act as the principal face of a building, which must strike a balance between visual design and physical functionality, whilst meeting the most stringent of regulatory building standards. In the below insight, we explore the role of facades and cladding components in building construction today and the trends we see emerging going into 2022.

Façade or Cladding?

The expression ‘façade’ refers to the external appearance of a building. Mostly, the term is used when referring to design, style or colour and reflects the overall appearance or intent of the exterior. The terms ‘cladding,’ ‘wall cladding’ or ‘cladding component’ however, refer to the external protective layer of the building envelope.

Cladding components are attached to the primary structure of a building to form non-structural, external surfaces. This is as opposed to buildings in which the external surfaces are formed by structural elements, such as masonry walls, or applied surfaces such as render. Cladding can be made from a wide range of materials including wood, metal, brick, vinyl, and composite materials that can include aluminium, wood, blends of cement and recycled polystyrene, as well as wheat/rice straw fibres.

The primary benefits of cladding are to:

  • Create a controlled internal environment
  • Protect the building from external conditions
  • Provide privacy and security
  • Prevent the transmission of sound
  • Provide thermal insulation
  • Prevent the spread of fire
  • Provide openings for access, daylight, and ventilation
skyscraper facade

Structural and Thermal Design Considerations in Façade Design

Whilst cladding is attached to the structure of the building, it typically does not contribute to its stability. However, cladding does play a structural role by transferring wind loads, impact loads, snow loads, and its own self-weight back to the structural framework. Wind causes significant pressure on the surface of buildings and cladding must have sufficient strength and stiffness to resist this load, both in terms of the type of cladding selected and its connections back to the structure.

High-quality, well-designed, and professionally installed cladding can help maximise thermal performance, minimise air leakage, and optimise natural daylighting into a building. This can in turn help to optimise energy efficiency and lower capital and running costs. Poor design detailing or installation, however, will compromise cladding performance and can result in safety problems such as cladding collapse or cladding panels pulling away from the structure.

It is important that designers incorporate suitable thermal isolators between cladding system connections and the structural frame, to avoid thermal bridges forming and compromising the thermal integrity of the building. Farrat Structural Thermal Breaks are increasingly worked into large area rain screen cladding systems during the design stage at specification, to isolate building interior structures from excessive heating and cooling caused by thermal loads.

Fig. 1.0 Cladding to masonry connection
Fig. 1.0 Cladding to masonry connection
Fig 1.1 Cladding to masonry connection detail incorporating a Farrat Structural Thermal Break
Fig 1.1 Cladding to masonry connection detail incorporating a Farrat Structural Thermal Break

Growing Trends in Façade Design

Fire Safety

Following a series of fire-based tragedies around the world, there is now greater emphasis on ensuring that all key aspects of a building design, particularly facades and cladding components, are fire-resistant. Whilst legislation is in place, architects and specifiers are now looking to go beyond the standard when it comes to fire to ensure the highest quality safety standards and optimal occupier comfort levels.

Farrat TBF was first introduced in 2020 as the UK’s first A2 fire-rated Structural Thermal Break material. Since its introduction to the market, Farrat TBF has gained BBA certification status and underwent further exploratory tests in conjunction with Sherwin Williams, a manufacturer of fire-resistant intumescent coatings, to evaluate thermal and structural performance when integrated within a protected steel to steel connection. Findings show that as well as performing as part of an intumescent coating protected connection, Farrat TBF can resist the 1000⁰C + temperatures for 2 hours whilst maintaining a compressive structural performance of 200MPa @ 550⁰C. (29,000psi @ 392⁰F).

This unparalleled level of structural performance from a thermal break at elevated temperature, alongside its resistance to fire and insulation performance, makes Farrat TBF the thermal break material of choice for designers and engineers looking to eradicate thermal bridges in structural components where fire performance is a high-ranking consideration.

Solar Power

In line with sustainable construction targets to achieve ‘net zero by 2050’, latest research has shown that the carbon footprint of solar power is significantly lower than coal or gas, and this remains true even when accounting for emissions during manufacture, construction, and fuel supply.

This is supported by the commercial playbook recently published by a green lobby group, which aims to fill the gap left by national policy, which is not delivering change at the pace they believe is needed to meet the environmental commitments made. Some of the key guidelines published in the playbook include reducing embodied carbon & energy use throughout the construction supply chain and ensuring that low-carbon energy sources are incorporated into building design.

We foresee that façade and cladding component design that makes use of solar power, as well as façades that go beyond the standard when it comes to insulation and conservation, will play a leading role in following the suggestions made. We expect to see increasing numbers of new buildings that include facades incorporating solar panels to generate power for the building, and even provide excess power for the local area.

A recent Farrat project where this concept is utilised, is Mohammed Tower IV. Set to be the tallest building in Africa, the 55-storey development incorporates 3350 m² of photovoltaic solar panels on the South façade, thermally isolated using fire-rated Farrat TBF Structural Thermal Breaks to prevent heat transfer through steel beams where the external building aspects meet the interior.

Mohammed Tower image
rainwater harvesting facade

Rainwater Harvesting

Rainwater harvesting is a growing trend in general, using a similar principle to the antiquated garden water butts on a building wide scale, which were used to conserve water.

Façade designers have evolved this concept with the introduction of water collecting façade panels, which are both functional and thin enough to be used as facades, but also attractive. With additional technology, the panels would even be able to harvest moisture from the atmosphere using thermodynamics to cooling moist air to condense and harvest it.

Living Walls

An increasing number of new urban centre developments are integrating greenery into schemes. Living walls, or ‘vertical gardens,’ are a unique form of façade design that reduce air pollutants and urban temperatures, as well as reducing noise and providing thermal benefits to buildings.

According to a new virtual reality study, vertical greenery ‘planted’ on the exterior of buildings may even help to buffer residents against stress, creating a building design with wellbeing equally in mind – a foresight we explored earlier this year in Farrat’s ‘post-pandemic construction insight.’

living wall

Summary

Architects and specifiers are responsible for addressing some of the biggest challenges facing the world, both now and in the future. Meeting these challenges head-on can only happen if construction professionals keep up with, create and implement the latest developments in technology and ideas.

Designers are finding new and innovative ways to combine sustainable materials for energy efficiency, with increasing numbers of buildings incorporating solar arrays on the rooftop as well as double-paned windows and high-quality insulated façade designs, alongside durable exterior elements like steel panel and siding. We expect to see widespread adoption of sustainable materials and structural thermal breaks within façade design details, with energy efficiency playing a leading role.

To learn how to integrate Farrat Structural Thermal Breaks into typical connections, watch our introductory on-demand CPD module here.

For more information on Farrat Structural Thermal Break materials or specification resources for Architects or Structural Engineers, visit our Thermal Breaks Hub here or talk to our team.

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Fire regulations in the UK and beyond

In our latest insight, we explore the fire regulation landscape across Europe to understand where fire currently sits on the construction agenda.

Where it began for the UK

Fire regulations in UK construction have evolved since their original introduction following the Great Fire of London in 1666. King Charles II decreed that roads must be widened to prevent the spread of fire and that buildings should be constructed with stone instead of highly flammable materials such as wood, revolutionising the scope and possibilities of building design.

Fast forward to the UK construction industry as we know it today, and building design shapes how our communities look, function, and thrive.

Whilst there has been a significant shift in focus towards new legislation for important topics such as sustainability and environment in construction, UK regulations around fire continue to play a vital role in ensuring that buildings are principally designed for the safety of occupants.

Fire regulations across Europe

Countries across Europe adopt different approaches to fire safety regulations. UK fire regulations are categorised as ‘performance-based’, whereby the specific characteristics of the building are assessed in accordance with engineering principles and mathematical models, under the Regulatory Reform (Fire Safety) Order 2005 or ‘the Fire Safety Order’.

Sweden takes a similar approach to the UK, with the Swedish Building and Design Regulations (BBR 94 and BKR 94) following a performance-based approach. Swedish regulations also consider the proximity of surrounding buildings in the same way as in the UK – Document B stipulates material ratings in relation to boundary conditions/ proximity to other buildings.

Many countries within the European Union, however, follow a more prescriptive-based approach that allows a building to meet a pre-set standard when it comes to fire safety.

Germany operates under the National Model Building Code, which relies on prescriptive rules with additional regulations for specific types of buildings or buildings with specific uses, for example, high rise constructions or buildings used for industrial applications. Germany also has different rules on fire depending on the Federal State.

Some countries have adopted a flexible hybrid approach, such as Italy, who have an older approach of prescription and a newer approach that allows for a more ‘creative’ design, which is similar to the regulations in the UK.

In Denmark, building regulations retain performance-based requirements for complex buildings, but traditional buildings are assessed using prescriptive solutions (varies across different building types).

The building codes in Austria are specified by the governments of the 9 federal states. These building codes are referring to the OIB guidelines of the Austrian Institute of construction engineering. The OIB Guidelines are created as prescriptive fire safety design regulations, but it is also possible to use a performance-based approach if it is demonstrated by comprehensible and conclusive arguments that the required level of safety is achieved.

Beyond Europe in the US, the prescriptive approach is also favoured, with all 50 states following the ‘ICC model codes’. There are advantages and disadvantages to both approaches; a performance-based approach gives design teams increased freedom by emphasising engineering, calculation, and modelling, whereas a prescriptive-approach provides structure with fixed rules to follow and boxes to tick.

Source: RIBAJ 'How Europe regulates fire safety', 24th July 2017
Source: RIBAJ 'How Europe regulates fire safety', 24th July 2017

 

Attitudes towards fire regulations

In response to recent fire tragedies, such as the 2017 Grenfell fire in London and the 2010 Shanghai fire where a 28-storey residential building was engulfed in flames, global attitudes towards fire legislation are once again changing.

The Grenfell review, which was published by Dame Judith Hackitt following an investigation into the Grenfell fire in London, concluded that legislation regarding fire safety equipment in UK construction is not fit for purpose and needs to improve.

Several other EU countries have followed suit with a review of construction fire regulations, including Ireland, France, Belgium, The Netherlands, Greece, Denmark, Finland, and Bulgaria, all committing to roll out new initiatives.

In France, high-rise buildings are currently defined as buildings with a height of over 50 meters for residential buildings and 28 meters for other building types. France are now looking to introduce a new ‘medium-height’ of 28-50 metres for residential buildings, which will have additional fire safety requirements not currently in place. Most other countries under review are also looking to ‘plug gaps’ in fire safety in new developments.

Governments are keen to encourage people to meet fire regulations. In Holland, the 2012 Dutch Building Decree (Bouwbesluit) states that fire precautions should be taken in building, and in some cases, you will just need an all-in-one permit for physical aspects (Omgevingsvergunning). This ensures it is simple yet comprehensive.

Consistently evolving

Building regulations are frequently updated with new amendments as technology advances and attitudes towards safety adapt.

In Ireland, the amendment to building regulations in 2017 impacted a range of standards including ensuring adequate means of escape, how to prevent the spread of fire both internally and externally, and access for the emergency services.

Switzerland also updates building regulations regularly (every 10 years), to ensure that legislations are state of the art, albeit in the same format.

Over the past decades, Europe has achieved substantial improvements in fire safety thanks to the continuous adjustment and implementation of fire safety strategies. As a result of comprehensive approaches, the Modern Building Alliance report that fire fatalities have fallen by 65% in Europe over the last 30 years. However, more needs to be done as fire safety in buildings remains a major societal issue. According to recent statistics, it is estimated that around 5,000 people a year are killed due to building fires in Europe.

 

Fire resistant materials at Farrat

Recognising the need for more accessible fire-rated construction materials, Farrat developed and released the markets first A2 fire-rated Structural Thermal Break – Farrat TBF – in 2019.

Extensively researched and tested by both BRE (Building Research Establishment) and Warrington Fire, Farrat TBF is specifically engineered for use in structural steel connections and can maintain structural performance at temperatures more than 1000°C. Providing both superior structural and thermal performance to solve structural thermal bridge issues, whilst exceeding all current fire regulatory requirements for buildings above and below 18m.

 

Exceeding expectations

Farrat are on a mission to encourage building designers around the world to exceed regulations when it comes to fire safety in construction.

Exceeding regulation expectations ensures that buildings are safe, robust and fit-for-purpose for the lifetime of the building.

There is less chance of needing to retrospectively change materials, as buildings will have been designed and constructed as future-proof, and the building will be capable of meeting evolving levels of safety in an ever-changing environmental climate.

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Working with an international design team to achieve the highest energy efficiency & sustainability standards, for an exciting new high-rise tower located in Morocco’s City of Light

Set to be the tallest building in Africa at 250-metres with 55 stories, Mohammed Tower IV is a new high-rise tower designed by Rafael de la Hoz & Hakim Benjelloun to resemble a rocket on its launch pad. The striking development will be visible from 50km in all directions and forms the centre piece in the Bouregreg Valley Development Project, which plays a leading role in the development programme for Rabat, ‘the City of Light,’ in the Moroccan Capital of Culture. Once complete, the project will provide a luxury hotel, commercial offices, high-end residential apartments, and a viewing sky terrace.

The Challenge

Sustainability and energy efficiency are both primary design considerations in this project, with the client aiming to achieve LEED Gold and HQE quality standards. LEED certification provides an independent guarantee of a building’s green features, with a LEED Gold rating representing first-class leadership in resource-efficient building design, construction, operations, and maintenance.

Farrat were contacted via our export partner in the GCC region, UniGroup, to supply a high-performance, robust, and certified fire-resistant thermal break solution to mitigate against thermal bridging across façade connections for contemporary facade design company Glassline Abu Dhabi. Farrat Structural Thermal Breaks are favoured across the construction industry, as the most efficient & responsible way to thermally separate structural connections and prevent heat loss in the building envelope.

The thermal breaks would form part of a wider sustainable construction program, alongside smart energy efficiency systems such as 3350 m² of photovoltaic solar panels on the South façade, rainwater recovery and wastewater recycling systems and an internal energy recovery system to produce hot water.

Mohammed Tower image
TBF_cut

The Solution

Following a review of the connection designs, Farrat TBF was selected as the optimal structural thermal break material for extensive use across the façade connections of Mohammed Tower, to prevent heat transfer through steel beams where the external building aspects meet the interior.

Farrat TBF is an A2 rated non-combustible structural thermal break material capable of maintaining superior structural performance at temperatures more than 1000°C. Farrat TBF also provides high-level thermal performance to solve structural thermal bridge issues and exceeds all current fire regulatory requirements for buildings above (and below) 18m.

Following several high-rise fire tragedies across the globe, increasing numbers of building designers are looking to go beyond the standard when it comes to fire safety.

The Design

The inherent non-combustible composition of Farrat TBF was the solution to the fire element of the design, allowing unrestricted use in the high-rise construction. Use of the material’s remarkably high compressive force resistance allowed Farrat to assess the transmission of loads through the structural connection, sufficient to maintain performance under influence from weather stresses.

The Outcome

“In designing and securing this high-performance project, Farrat utilised the full extent of our material research & development skills and harnessed our extensive experience of thermal bridging projects in all climates and circumstances around the globe,” states Chris Lister, Commercial Manager of Structural Thermal Breaks at Farrat.

“The resulting construction details are to the highest levels of structural and fire safety performance whilst also being beautiful in their simplicity.”

Structural Thermal Breaks with Farrat

Farrat Structural Thermal Breaks are favored across the construction industry, as the most efficient & responsible way to thermally separate structural connections and prevent heat loss in the building envelope. For more information on using thermal breaks in steel construction, visit our thermal break hub.

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On a mission: to deliver sustainable construction projects with structural thermal breaks

At Farrat, we’re passionate about helping architects, engineers and fabricators to deliver sustainable structures that are flexible, fit for purpose and compliant with latest building regulations. 

In a recent interview following the announcement of this years Structural Steel Design Awards shortlist, Chief Executive Officer of the British Constructional Steelwork Association commented on the growing utilisation of steel in the drive to achieve the sustainability accolade of ‘net zero’ in the UK and Ireland.

“Structural steelwork is the original sustainable material with the ability to be recycled and re-used time and time again to deliver structures that meet the low carbon demands of clients and the climate emergency.  It is also able to deliver efficient, practical, and flexible spaces that are both beautiful and cost-effective.”

Despite the challenges of COVID-19, Brexit and the saga of ongoing supply issues in 2020/21, the constructional steelwork sector has remained buoyant and continues to provide high-quality buildings within the UK and Ireland. At Farrat, we have seen rapidly increasing numbers of enquiries over the last 24 months from architects, engineers, steel fabricators and contractors seeking suitable isolation materials capable of both reducing thermal bridging whilst transferring high loads, in a bid to meet client expectations of meeting the highest sustainability standards and certifications such as BREEAM.

Below are just a few of our most recent thermal isolation projects, where Farrat Structural Thermal Breaks have been integrated into primary and secondary steel connections to reduce energy loss and thermal transfer.

St James Quarter – new shopping centre in Edinburgh

Following five years of construction, the new St James Quarter ‘shopping mall mecca’ in Edinburgh cost £1bn to deliver and has been hailed as this generations largest development. The scheme replaces the 1960s St James Centre and the New St Andrews House office block at the east end of Princes Street and covers approximately 79,000m² of shopping premises over four storeys.

Farrat supplied Farrat TBK Structural Thermal Breaks to reduce heat loss and prevent thermal bridging between steel connections in the primary frame.

Mitigating thermal transfer was a primary concern for the design team, due to the ‘open’ building design featuring a glass roof to a central atrium. By incorporating Farrat Structural Thermal Breaks into the steel structure, the team were able to create an energy efficient and compliant building for the public to enjoy.

Edinburgh St James
Liverpool

100 Liverpool Street – office and retail centre in London

100 Liverpool Street is the first British Land building to achieve net zero carbon status, making it one of only a few in London to obtain this sustainability accolade. Built directly above the entrance to one of London’s busiest train stations, the flagship project holds 520,000 sq. ft of new office space and 80,000 sq. ft of retail alongside an exciting roof restaurant on the ninth floor with stunning panoramic views of St Pauls.

British Land’s commitment to sustainability goals meant that from the outset, a high bar was set and embedded into the early contractual obligations. Farrat were instructed to supply a high-performance thermal break solution capable of meeting a BREEAM Outstanding accreditation (achieved) and WELL Gold rating (pending).

Farrat TBK was again selected and supplied, as the optimum solution to ensure that a wide mix of environments were equally isolated to the highest standards.

Midas Oakfield – a sustainable community build in Swindon

Midas Oakfield is a new build community development incorporating 197 houses, 42 flats and a community centre in Swindon. The scheme was designed as a blueprint for future modern & sustainably built community developments in the UK.

Construction of the Oakfield development began at the start of 2020 and the first show homes will be available to view by the end of 2021. Once complete, the scheme will be one of the biggest off-gas housing developments in the country.

Farrat are currently working to supply high-strength Structural Thermal Breaks for use in steel connections across buildings in the scheme. The  thermal breaks will work as high-performance thermal insulators that prevent thermal bridging between structural building components and will reduce the risk of condensation and mould forming in the future, making lives better for residents.

Midas

Structural Thermal Breaks with Farrat

Farrat Structural Thermal Breaks are favoured across the construction industry, as the most efficient & responsible way to thermally separate structural connections and prevent heat loss in the building envelope. For more information on using thermal breaks in steel construction, visit our thermal break hub.

 

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