Ashby Energy Assessors Blog and News

Future Homes Standards Consultation : Buildings other than dwellings

Thu, 10 Oct 2024 10:12:03 GMT

Energy efficiency requirements for new homes and non-domestic buildings are set by Part L (Conservation of Fuel and Power) and Part 6 of the Building Regulations 2010 (“the Building Regulations”). The consultation paves the way for achieving the Future Homes Standard and Future Buildings Standard. It explores technical proposals for changes to the Building Regulations, the associated Approved Document guidance and calculation methods.

Why is it needed on non-domestic buildings?

The UK’s built environment is responsible for around 30% of the UK’s greenhouse gas emissions. So, this consultation concentrates mostly on electrification rather than on fabric, in anticipation of a decarbonised national grid.

Methodologies to be used in non-domestic buildings –

SBEM – Simplified Building Energy Model

DSM – Dynamic Simulation Model

Some key takeaways for non-domestic buildings –

Solar PV panel coverage recommendation
Metrics to remain the same - Building Emission Rate/ Building Primary Energy Rate and Target Emission Rate/ Target Primary Energy Rate. The Emission Rate quantifies the CO2 equivalent emissions associated with the building’s use of space heating and cooling, water heating, pumps, fans, lighting and renewable generation
U-values to remain same
Improvement in Air Test score to 8
Heat pumps should follow Ecodesign Regulation which are not covered by Ecodesign regulations should have a minimum Coefficient of Performance COP of 2.5
Lightning improvement to 105 lm/W for general internal lighting, 95 lm/W for display lighting

By covering these areas, the consultation sets out to improve the maintenance of efficiency in non-domestic buildings.

We will share relevant information with our clients as soon as we receive updates on this consultation.

Air Tightness Course

Wed, 11 Sep 2024 12:08:37 GMT

Our Air Tightness Tester shares his experience at the ATTMA Air Tightness Testing Course.

Well, what a whirlwind that was! I attended the Air Tightness Level 1 course at the ATTMA training hub in High Wycombe from Monday 22nd April to Thursday 25th April 2024, culminating in 3 exams on the final day. These were a theory and practical exam, which were each an hour and a half long, followed by an envelope calculation exam which was 3 and a half hours. I have to say that Paul Carling, who runs these courses, is very patient and very knowledgeable. We went through 3 days of training where he covered every aspect required to give you the information needed to be prepared for the exams on day 4. This course was unusual for me as it was the first time I had been away from my family for quite some time, so when I was having a bit of a moment on the Tuesday night following the start of the calculation part of the course, I did spend a little while bending my wife’s ear on the phone - I’m not sure how she puts up with me! I also have to say that the other course members were really helpful and helped me get my head around what was required at night over a beer.

The course itself goes through everything you need to know to get you through the exams and Paul goes over things more than once for those needing the time for it to sink in. The training hub is also an excellent facility. We were supplied with a packed lunch each day along with all the tea and coffee you needed, as long as you allowed Ida to make it! Ida is the admin lady and she is very protective of her coffee machine!

I’m not quite sure how, but at the end of the examination day Paul came up to me and said “congratulations, you’ve passed!”. That was a big surprise to me, considering how I’d struggled with the calculations. Maybe there’s still life in me yet! The biggest help to be able to get through this course has been the team at Ashby Energy, who gave me the experience and training 2 months prior. Also, big thanks to Glenn, the owner at Ashby Energy Assessors, who saw something in me and has provided me the opportunity to become an air tightness tester.

- AH

Non-Domestic Future Homes Consultation

Wed, 21 Aug 2024 12:03:53 GMT

The government have recently closed the Future Homes and Building Standards 2023 consultation on 27 March 2024 which sets out the next steps in achieving the ultimate goal of putting buildings in a position to achieve net zero carbon.

The continuing improvement to the Part L regulations is quickly approaching its ultimate goal of getting buildings in a position to achieve net zero carbon. Non-domestic buildings, including offices, schools, hospitals, and commercial spaces, are substantial consumers of energy. They contribute significantly to greenhouse gas emissions, and improving their energy performance is crucial for achieving broader environmental goals.

Unlike the domestic regulations that will be leaving SAP behind and moving to HEM, the non-domestic assessment will be keeping with SBEM (Simplified Building Energy Model) & DSM (Dynamic Simulation Model). The non-domestic regulations will also be keeping its NCM database (National Calculation Methodology) however, despite a general tightening of the CO2 & Primary energy targets nothing fundamentally changes.

What are the new targets going to be for the notional building?

As is typical with consultation they have provided two options

· Option 1 (recommended): Solar PV panel coverage equivalent of 40% of the building’s foundation area for side-lit spaces and 75% for top-lit spaces.

· Option 2 (not recommended): Solar PV panel coverage equivalent of 20% of foundation area for side-lit spaces and 40% for top-lit spaces.

As you can see, option 1 is what the consultation is recommending and will see solar panels covering 75% of the roof space when rooflights are present and 40% if only windows are present.

How can I heat my new non-domestic building?

A heat pump for side-lit spaces and radiant electric heating in top-lit spaces. If you want to connect to a heat network, standards equivalent to a 4th-generation heat network.

What are the limiting U-values going to be?

The limiting u-values for construction remain mainly the same with an improvement to the air test score and roof u-value

What lighting efficacy do I need?

All lights fittings will required to have a average luminaire efficacy greater than 105 l/w.

Miscellaneous updates

· Carbon factors will be updated which will likely see electricity to decarbonate and the other fuels to remain the same

Labour's New Housing and Energy Pledges

Thu, 18 Jul 2024 12:13:18 GMT

The UK’s new ‘mission-led’ Labour government have set new targets in regard to housing and energy, aiming to address critical national issues and drive sustainable growth. We have highlighted some of the key housing and energy pledges that may affect your projects over the next few years:

Housing Targets

1. Affordable Housing: Labour’s Chancellor Rachel Reeves has announced plans to build 300,000 new homes annually, with more decision-making powers to be passed onto local communities. They are pushing for more ‘support’ for SME developers to begin building again and are aiming for an increase in affordable and council housing by making the Affordable Housing Programme more flexible.

2. Green Belt Protection: To balance housing expansion, Labour will prioritize building on brownfield sites and converting unused commercial properties, protecting green belt land from development. Labour announced a release of lower quality ‘grey belt’ land with ‘golden rules’ to ensure development benefits communities and nature. This increases the opportunities for housing developments, but the Conservatives say it ignores the concerns of locals.

3. Planning: 300 new planners are to be recruited to accelerate the planning process, with previously rejected planning applications to be reviewed.

Energy Targets

1. Net-Zero by 2050: Labour have announced their target of achieving net-zero greenhouse gas emissions by 2050 by focusing on decarbonizing the energy sector and investing in green technologies.

2. Great British Energy: Labour are pledging to create a new, public-owned energy production company named Great British Energy which will work alongside private sector suppliers and focus on electricity generation. This would include gas no longer being used to heat homes, but rather electric heat pumps, which will affect building costs.

3. Clean Power by 2030: Labour are pushing for a new Energy Independence Act to become enacted into law, which will double onshore wind, triple solar power, and quadruple offshore wind to achieve zero-carbon power by 2030.

These housing and energy targets reflect a bold vision for the UK’s future, emphasizing sustainability, affordability, and innovation. The collaboration between the government, private sector, and communities will be crucial to achieving these goals. Do you think these pledges are a help or a hinderance? Do you think it is impossible to achieve them in the timeframes set out? Tell us on our LinkedIn , Facebook , or Instagram page – we would love to hear from you!

In the meantime, we can assist you through these changes as they will likely affect the energy assessments that you will require. We will update you on changes as and when they happen; keep a lookout for our blogs or check out our free bespoke CPDs to learn more about how these changes might affect you.

An Introduction into Level 3 Construction Support Technician Training

Tue, 21 May 2024 15:55:23 GMT

An Introduction into Level 3 Construction Support Technician Training

Before starting my role with Ashby Energy almost a year ago I had no experience within the construction industry. Thanks to the company I have been enrolled onto and am completing an apprenticeship course all about construction to grow my personal knowledge to benefit both myself and Ashby Energy. The course is titled ‘Level 3 Construction Support Technician’, and it contains several different units that focus on different areas of methodology behind construction, as opposed to the actual physical onsite building works.

For example, Unit 7 is titled ‘Design Methods’ in which so far I have learned about some of the various equipment and methods used for construction drawing, as well as creating some construction drawings myself. I have spent time learning about manual drawing techniques and had multiple sessions on drawing boards creating my own floorplans and sections by hand. This is a massively beneficial skill for me as an air tightness tester as I know I could create plans out on site if I need them with very little equipment.

Alternatively, I have also spent time learning CAD (Computer Aided Design) techniques of drawing. The software I have been given an introduction to are called AutoCAD and Revit, both which allow the creation of 2D plans and sketches with a variety of different design elements and details. I can specify what materials I am using in a design for floors, walls, roofs, and add detail to the building such as the locations of doors and windows. I can now also expand into site plans with designing the surrounding are to show roads, flowerbeds, footpaths, or carparks to name a few.

Within Revit specifically I can also convert these 2D plans into a 3D view which brings the plans I have created to life, and this is useful to be able to present and show my ideas and work, as well as edit the plans from another angle to be more accurate to the vision of a client. Attached to this post is an image from my recent work on Revit where I’ve been designing a sports pavilion and surrounding land.

My knowledge of construction has greatly improved already from the course and I’m looking forward to getting into the second year and starting more new units. Overall the course is helping my personal development and building up my skills which will only further benefit me going forward both on my course and in my role as a Building Testing Engineer with Ashby Energy.

Part O Simplified - what is it and why do I need it?

Wed, 15 May 2024 12:48:18 GMT

Homes in the UK are at increased risk of overheating, which is worsening with climate change. This affects comfort and health of occupants, especially during night. Overheating is mainly caused by design of the houses, in particular large glazing areas and non-openable windows. To address this, Building Regulations Part O introduces two methods for compliance: Simplified Method, or comfort criteria under thermal modelling using CIBSE’s TM59 (with some additional requirements set by AD O). This blog focuses on the Simplified Method.

The Simplified Method establishes maximum limits on glazed areas and minimum free areas (openings used for ventilation). These limits vary based on:

Orientation of the most glazed façade; limits are more stringent for South and West orientations (limiting the amount of glazing in the dwelling). This is to limit solar gains that the dwelling receives during the summer.
Location – high risk locations (London and Manchester) and moderate risk locations are identified; for high-risk locations glazing and free areas are different, and shading or other strategies are required too.
Whether the new dwelling is designed to allow for cross ventilation or not (openings on opposite sides). If this is not satisfied, the glazing and free area limits are influenced.

Other considerations for Part O

Whether we choose Simplified or Dynamic method, there are number of things that we need to consider when carrying out the assessment:

Security – we need to make sure that windows utilised for ventilation, especially at night, can remain open. This generally affects ground floor and easily accessible bedrooms. When security issues are identified, the assessor needs to assume that these windows won’t be utilized for ventilation, and this often results in failure on free areas. The designer needs then to consider providing security louvres, mitigating risk, and increasing flat roof heights, or switching to dynamic simulation and providing mechanical ventilation.

Protection from falling – all windows that are identified to have risk of falling, need to either have window sills at 1.1 metres, or guarding installed. In addition, these windows are assumed to be open at 650 mm stroke length, sometimes not providing enough ventilation.

Noise & pollution – sites where noise and pollution have been identified, need to consider that some windows will not be utilised for ventilation purposes and this has to be reflected in the overheating assessment.

Windows and shading strategies need to comply with protection from entrapment criteria.

Advantages and disadvantages of Simplified Part O

Choosing the right method is crucial for cost and time savings. The Simplified Method offers cost efficiency but lacks design adjustment beyond glazing reduction and introducing openable areas; security, risk of falling and other areas are looked at too. The dynamic simulation offers much more design flexibility and will be a robust tool for dwellings that have large, glazed façades, but also large volumes achieved by vaulted ceilings. When the dwelling is past planning stage, and the external design cannot change, it also proves useful in reducing solar factors of glazing, specifying mechanical ventilation, or increasing the thermal mass.

It is also recommended that the dynamic method is chosen for dwellings where mechanical ventilation is integral to heat removal, which can’t be modelled in the Simplified Method. The Simplified Method is appropriate for ‘traditional’ dwellings, without overglazed facades, in low-risk locations.

Aspects to be mindful of

Part O compliance can not be looked at in isolation; there are many implications on other Building Regulations that need to be considered, especially:

Part B (Fire Safety) – escape windows need to have the bottom of the openable area at 1100 mm above the floor, which aligns with 1100 mm for guarding
Part F (Ventilation)
Part K (Protection from falling, collision and impact)
Part L (Conservation of fuel and power) – low G values (solar factors) will work well in dynamic overheating, but will negatively affect SAP calculations and fabric efficiency
Part M (Access to and use of buildings)
Part Q (Security)

The assessor should have some knowledge about the interaction of Part O with other Building Regulations, however, it is the client’s responsibility to make sure that all building regulations are aligned.

To summarise, the Simplified Method is not as simple as it sounds. The assessment requires expertise in a lot of areas, where solutions need to be not only aligned with removing excess heat, but also with design expectations, making sure they are usable. If you struggle to establish which method is more suitable for your dwelling, it will be best to contact one of our assessors who can take a quick look at the drawings and identify the areas that might cause some issues; sometimes by just having a chat with the architect we can establish whether the design can change to pass Simplified Method, or if it is better to switch for dynamic simulation.

Left you wanting more? Please contact kamil@ashbyenergy.co.uk or give us a call on 01476 870504 and we will help you in every way possible.

Future Homes Standards

Wed, 10 Apr 2024 13:18:03 GMT

The government have recently closed the Future Homes and Building Standards 2023 consultation on 27 March 2024. There have been two consultations into the Future Homes Standard, both of which proposed a draft of measures for new and existing homes. Most of the key takeaways from the recent consultation are in regard to new homes and non-domestic buildings. A small number of sections are also relevant to existing buildings, such as Material Change of Use buildings. The standards will build upon the recently introduced changes to Approved Document Part L 2021. This consultation provides a glimpse into what we can expect from later consultations, regarding the Future Homes Standards to be implemented in 2025.

Why was the Future Homes Standard announced?

The homes of the future in the UK are not just about luxury or aesthetic appeal; they're about sustainability, efficiency, and smart living. As we look towards the future, several key standards are set to define the next generation of UK homes. According to the Climate Change Committee, the built environment accounts for roughly 25% of UK greenhouse gas emissions, 14% of this being from 28 million homes in the UK. By introducing this new standard, the government hopes to ensure that new builds will produce 75-80% less carbon emissions, which will aid in their attempts towards the net-zero target for 2050. The government claims the following opportunities will be created for the UK as a result of the Future Homes Standards: ‘grow skills, build diverse job markets, level up across the country, reduce bills by improving efficiency, tackle fuel poverty, have warmer and better buildings, and ensure our energy system is secure and fit for the future.’ The consultation acknowledges that the changes proposed are likely to increase build costs, but argue the ‘wider benefits to local supply chains for renewable technologies and skill developments for the future’ override the negative effects felt as a result of the increased build costs. Here is an overview of the effects of the standards:

Energy Efficiency and Sustainability - one of the core aspects of future home standards in the UK is a strong emphasis on energy efficiency and sustainability. Homes will be designed to minimize their energy consumption and carbon footprint. This is likely to involve the integration of and energy-efficient windows and doors. This would prompt a drastic change in the way we build our homes, but also for homes which come into existence through Material Change of Use as they often don’t perform as well as new build in terms of energy efficiency. For domestic buildings, the government is also separately consulting on the new ‘Home Energy Model’ (HEM), which may replace the Standard Assessment Procedure (SAP) for the energy rating of new homes.

Health and Wellbeing - Homes will be designed with the health and wellbeing of occupants in mind. This includes improved indoor air quality through advanced ventilation systems, natural light optimization with smart glass technology, and the incorporation of green spaces, both indoor and outdoor, to promote mental and physical health. This is already evident in the recent Part O Approved Document 2021, with added changes becoming a possibility; standard homes created through conversions could also require Part O assessments. EV chargers will also be required, which encourages people to use more environmentally friendly modes of transport.

Will gas boilers be banned?

This is very likely. Future Homes Standards will require that all notional buildings have an efficient air source heat pump or a fourth-generation heat network that uses air source heat pumps. The standards will not allow for the installation of fossil fuel boilers while also delivering significant carbon savings, meaning that gas, hybrid heat pumps and hydrogen ready boilers will not be sufficient in meeting the standards.

Governments’ Desired Outcomes:

1. To protect occupants against high energy bills

2. To reduce energy demand of homes and non-domestic buildings by requiring high performing building fabric and building services in new buildings, thereby improving energy security.

3. To reduce total operational carbon emissions and produce buildings which are net-zero ready, by requiring low-carbon heating and increasing general electrification of buildings.

4. Create standards which are simple to understand and use by industry and provide developers with flexibility in meeting consumer preference regarding design, form and operation.

5. To consider peak electricity demand to reduce costs associated with national and local grid infrastructure upgrades.

Implementation timeline

The exact implementation timelines are yet to be confirmed, but the following is predicted:

Spring 2023 – Consultation on the proposed specification of the Future Homes Standard
2024 – Future Homes Standard implementation consultation
2025 – Future Homes Standard full implementation

Conclusively, the future home standards in the UK are set to revolutionize how we live, placing a heavy emphasis on sustainability, technology, flexibility, health, and community. If there is anything that you need help with concerning Future Homes Standards, please do not hesitate to give us a call on 01476 870504 . Our friendly team will assist you in every possible way.

To know more about the services we provide in helping the UK transition towards Net Zero please visit - https://www.ashbyenergy.co.uk/ or get in touch via email: kamil@ashbyenergy.co.uk , or phone: 01476 870504.

References:

https://www.gov.uk/government/consultations/the-future-homes-and-buildings-standards-2023-consultation/the-future-homes-and-buildings-standards-2023-consultation

https://www.homebuilding.co.uk/advice/future-homes-standard#section-what-we-know-so-far

Introducing Anthony

Mon, 25 Mar 2024 12:07:25 GMT

Our newest building tester shares his insights into his first few weeks at Ashby Energy Assessors.

My name is Anthony Howitt. I am 55 years old, I have a background of nearly 40 years in agriculture and I have decided to completely change my job and lifestyle. I am now in my 5th week working with Ashby Energy Assessors as an air tightness assessor. I have never worked in this industry before and I am quickly discovering that there is a lot of technical content to try and get my head around. My focus at the moment is to concentrate on my piece of the jigsaw, which is air tightness testing, and trying not get too distracted by everything else that is going on in a very busy office! I am working closely with the 2 other air tightness assessors, Dale Homewood and Adam Judson, who are equipping me with their expertise on the subject.

Currently, my days are filled with going out on site, helping Dale and Adam to carry out tests on multiple properties during the day and then going back to the office to complete the relevant paperwork and certificates. We travel mostly around the East Midlands to places such as Stamford, Derby, Coventry, Leicester and Nottingham, but we do travel further afield on occasion. I am gaining invaluable experience with the team ahead of my training course at the ATTMA (Air Tightness Testing and Measurement Association) Hub down in High Wycombe in April. I have also booked onto an Extractor training course in April where I hope to become qualified to test extractor fans. There is so much to learn and being a more hands on, practical person the extra computer work is taking some time to sink in, but the more I do, the more it seems to stick. The record keeping is on a whole new level to anything I’ve ever done before, but I’m now starting to understand the reasons why, and it’s a great new skill to add to my repertoire. Having the opportunity to be active in going out to sites and carrying out the tests, but also learning about the technical, desk-based side of the job allows me to enjoy both the hands-on part of the job and office life.

I really enjoy carrying out the tests on mainly new properties and learning the impact of how they are built and where the main problem areas are. I’m looking forward to gaining more experience and getting more relaxed within the different aspects of the role, a role which is crucial in achieving compliance with Building Regulations.

- Anthony

Interested in joining our team? Check out our available positions here .

The Importance of Air Tightness Testing in Dwellings

Wed, 13 Mar 2024 09:59:23 GMT

Air tightness testing plays a crucial role in ensuring energy efficiency, maintaining indoor air quality, and improving the overall occupant comfort in homes. In this blog, we will explore the importance of air-tightness testing and its implications.

The Methods of Air Tightness Testing

Air tightness testing can be performed through two methods: the blower door method and pulse testing. Commonly, the test is performed via the blower door method. This involves either depressurising or pressurising the dwelling at various pressure points to determine the air permeability of the dwelling via a specialised, calibrated fan mounted to an external door on a frame. This test is conducted after the dwelling is built and is crucial in determining the build quality, allowing for remedial work to improve the air tightness of the dwelling before occupants move in. The second and newly introduced method is pulse testing, which is a non-intrusive testing method involving short periodic blasts of air which can test small, relatively air-tight dwellings at a low pressure.

During the blower door method, air leakage areas can be identified as air is forced through penetrations in the building fabric. The leakage areas can also be visually identified through smoke testing, whereby smoke can be seen being forced through the areas under pressure. Within dwellings, these air leakage areas are typically around the penetrations for plumbing, spotlights and through poorly installed openings.

The Benefits of Air Tightness Testing

The higher the air permeability of the building, the greater the potential for loss of heat through the building fabric, leading to higher heating demand and therefore increasing the running costs and carbon emissions for the dwelling. Air leakage can also result in uneven temperature distribution, drafts and cold spots therefore compromising occupant comfort. By sealing these leaks, the building envelope becomes more thermally efficient, creating a more consistent and comfortable indoor environment regardless of external conditions.

Beyond energy efficiency and comfort, air tightness testing also helps prevent moisture intrusion and mould growth. Air leakage allows moisture to enter the building, leading to mould growth and compromising indoor air quality. Moisture-related issues can affect the lifespan of the dwelling and the effectiveness of insulation. By identifying and sealing air leaks, air tightness testing helps mitigate these risks, safeguarding the structural integrity of the building and the health of its occupants, which is particularly crucial for individuals with respiratory conditions or allergies. In order to reduce the risk of mould growth and to maintain good indoor air quality, it is crucial that a suitable and functioning ventilation system is installed. Building an air-tight dwelling also allows for better control of overall ventilation.

The History and Future of Air Tightness Testing

The current air tightness test requirements for dwellings are detailed within Approved Document Part L, Conservation of fuel and power, Volume 1: Dwellings, 2021 edition. Approved Document Part L was first introduced in 1995, and air tightness testing for new builds was first introduced in the UK in 2002 within Approved Document Part L1, Conservation of fuel and power in dwellings, 2002 edition.

While there have been multiple revisions to Building Regulations Part L, focusing on reducing carbon emissions through more efficient heating systems and increased insulation levels, air tightness testing requirements have remained relatively unchanged over the 20 years since it was introduced. However, the transition from Approved Document Part L 2016 to 2021 saw a reduction in the maximum allowed air tightness test score from 10 @ 50Pa to 8 @ 50Pa, and introduced the requirement to air test all newly built dwellings. In practice, achieving an air tightness test score of 8 @ 50 Pa necessitates building to a high specification. Most dwellings struggle to achieve compliance with an air tightness test score above 6.5 @ 50 Pa. Under the previous Building Regulations, it was possible to perform sample testing on dwellings of the same construction and layout, ignoring those dwellings that were not tested but claiming the air tightness test result achieved for these dwellings was the average air tightness score of those tested plus 2 @ 50 Pa. The requirement to test all dwellings ensures that all dwellings will achieve the air permeability requirements individually and that the carbon emissions and primary energy consumption within SAP is more accurate.

Looking ahead, the future of air tightness testing in the UK appears promising, driven by a growing emphasis on sustainability, energy efficiency and energy demand. As building regulations continue to evolve and tighten, the demand for lower air-tightness test scores is expected to increase. All new dwellings should aim to achieve an air tightness test score of 3 @ 50 Pa or below and install a continuously running ventilation system for the best performance.

Furthermore, the UK's commitment to achieving net-zero carbon emissions by 2050 will further elevate the importance of air tightness testing in the built environment. Buildings play a significant role in energy consumption and greenhouse gas emissions, making optimising their performance through air tightness testing essential for meeting ambitious climate targets.

Importance of Thermal Bridging in 2021 Part L Regulations

Thu, 18 Aug 2022 15:13:50 GMT

Thermal Bridging in 2021 Part L Regulations

From June 2022, the Government has removed the option to use the Accredited Construction Details in SAP assessments by Energy Assessors and builders on site.

The junctions will need to be constructed to another Governments approved details, or separately calculated for bespoke junctions. But why are thermal bridges important?

What is a psi value?

As we know, the heat is lost from the building through its fabric and ventilation.

We often characterize the building with U values achieved by thermal elements (floor, walls, and roof), but we also must consider the junction losses, called psi (Ѱ) values.

They are similar to U values, but instead of indicating the heat loss of planes in W/m ² K, they do that in W/mK.

How psi values and thermal bridging can affect my building?

Different materials have different thermal conductivity.

A cavity wall consists of relatively high thermal conductivity materials on both sides, while insulation with low thermal conductivity is inside.

When cavity wall creates a corner junction and the insulation layer inside is continuous, we might still expect good thermal properties of this wall and a low psi value.

However, if that layer was not continuous, or bridged with structural steel, we might expect the psi value to be high and exceed the notional dwelling in new Part L Approved Document.

It would be then very hard to achieve compliance on fabric efficiency.

It is then important to build our houses to a specific requirement advised on details by LABC or other to use certain types of cavity closers, to have continuous insulation or seal the gaps.

By doing that, we not only claim psi values to use in SAP and help us in compliance, but also build a very thermal efficient dwelling.

On new regulations, there is also a requirement for the builder to supply photographs of the construction details, therefore, it is important that we build the house according to the ones specified by SAP assessor, as the Building Control might easily verify that from pictures.

Apart from psi values in SAP, thermal bridging has also impact on condensation risk.

Badly designed junctions might be at risk of mould growth, because of temperature drop on the internal face of the junction.

Steel lintels, not continuous insulation, or lack of it might result in low inner temperature of the element and attract moisture.

New SAP requires most of the junctions to be either built to specific details, however, there are not that many of them to which our specification will suit.

Alternative will be to calculate them separately and use in SAP.

These can be then used in every future project using the same specification.

Please contact us if you require psi value calculations for SAP or have any queries in regard to thermal bridging and how to calculate the psi values .

Overheating, Air Tightness and Controlled Ventilation in Buildings

Mon, 15 Aug 2022 13:23:02 GMT

What are we considering?

Overheating is the excess accumulation of heat energy within a building, which may lead to discomfort and possibly dangerous temperature levels if not mitigated.

Air tightness of a building should be considered uncontrolled air flow through the material fabric of the building, generally leading to heat loss and uncontrolled ventilation.

Controlled ventilation such as mechanical extracts and passive vents provide fresh air to dwellings and facilitate the removal of pollutants at given and controllable rates.

How do these interact?

A balance must be maintained between the air tightness of a building, the type and qualities of its ventilation and whether it is susceptible to overheating.

To meet the net zero carbon target for the built industry, buildings will by and large need to become consistently more airtight, whilst maintaining sufficient ventilation and keeping the amount of glazing to a reasonable level such that solar gains do not make the building overwhelmingly hot.

A more airtight building will retain heat produced by the heating system, but additionally the use of electrical and mechanical services will also contribute to the internal heat gains.

It can also be expected that as buildings become more airtight the accumulation of air pollutants will also rapidly increase.

Excessive glazing will allow greater solar heat gains, which during the winter can be very advantageous, but during summer could affect the health of the occupants, with no respite by opening of windows to purge the heat from the building given the higher external air temperature such as during a heatwave.

Installing controlled ventilation solutions such as extracts, passive vents and MVHR units reduce the levels of air pollutants and should also force air changes through the property aiding in the dissipation of heat.

What can I do to reduce these issues?

A building needn’t be completely airtight as there is an appropriate design air permeability target which should facilitate the efficient operation of the buildings heat system, without being so airtight that excessive pollutant and heat accumulation can be partially avoided.

Reducing the amounts of glazing at the design stage will lower solar heat gains and calculations can be made to assess the level of glazing allowed in any building, maximising the glazing for aesthetics, and minimising the chances of overheating.

Additionally, providing external shading in front of glazing will greatly reduce solar gains, such as awnings, deeper roof overhangs and louvers.

Choosing the correct ventilation strategy, ensuring its correct planning and installation will greatly help maintain air quality whilst reducing the chances of overheating, which also includes calculating the correct window opening sizes to allow for cross ventilation and purge ventilation.

What can Ashby Energy Assessors Ltd do for you?

At design stage we can help assess your planned buildings energy efficiency, overheating risk and calculate the efficacy of the ventilation strategy you wish to implement.

When built, we can perform the air tightness and ventilation tests, and provide building regulations compliance certificates and EPCs.

Get in touch for a quote.

The Importance of Thermographic Survey in the Built Environment

Mon, 15 Aug 2022 09:52:23 GMT

What is thermography?

Thermography or thermal imaging is the process of using thermographic cameras to detect IR(infrared) radiation using an array of bolometric sensors, the data from which can be converted into an image.

These images can be interpreted to show manifestations of variance in temperatures radiating from the surfaces of objects.

Why would I have a thermographic survey?

The target of net zero carbon in the built environment is going to require more efficient thinking, planning and building if we are to achieve it.

In the built environment a persistent issue such as areas of non-contiguous insulation or high air infiltration, can be detected by observing heat loss through the material fabric of the building.

Whilst surface temperature variance can be detected, thermography however is not x-ray vision and the imagery is open to some interpretation.

Poor thermal performance of a building can be costly to the occupant and is ecologically unsound in the long term.

Thermography is a non-destructive method of surveying a building, meaning at that stage, there is no need to drill holes or dismantle material fabric to make some assessment of its efficiency.

In retrofit projects, it maybe useful to take a thermographic survey before work is undertaken, and then again afterwards to verify the improvements in insulation or air infiltration.

When should I have a thermographic survey?

It is vital that images are taken with consideration for extensive preparation, changes in environmental conditions, and image processing to ensure reasonable interpretation of the thermographic image.

For the best results, a thermographic survey is taken at night, at least 2 hours after sunset to ensure that the solar radiation has minimal effect on the results.

How are thermographic images interpreted?

It is quite normal to experience some heat loss through junctions of a building where there are intersections of construction with structural elements in contact with each other, E.g. a wall supporting the eaves of a roof.

Providing the heat loss does not affect the thermal comfort of those occupying the building and there is no major financial impact, there should be no reason to undo work done to correct small temperature variances.

If however these temperature variances will affect comfort and cost, these areas can be identified, and further investigate can be undertaken to assess what can be done to make improvements.

Who can do a thermographic survey?

A suitably qualified thermographer will have an accreditation enabling them to take images responsibly, process and interpret the images correctly to present their findings to you in an easily understandable and actionable format, should there be a need.

Thermography and the future of the built environment

Thermography can be used for building envelope inspection where massive air infiltration is occurring, moisture ingress detection such as leaking flat roofs, and direct heat loss detection through the material fabric, all being factors which may affect the energy efficiency and longevity of a building.

Looking into the future, Thermographic survey could become a staple of building pre-completion testing and would be another way to assess the quality of building stock.

Part O – Top 5.5 things you need to know!

Mon, 06 Jun 2022 13:36:32 GMT

Top 5.5 Things you need to know about Part O

Part O will come into effect on the 15th June 2022. Since the publication of Part O many have asked a variety of questions ranging from how do I fill out the paperwork, does dynamic simulations provide better results and does London have its own Part O regulations?

We are running a free Part O CPD on the 25 August 2022 @ 12:00 . Please sign up to this or if you are a larger architect practise, building control or architect society we could arrange something specific for you.

Email james@ashbyenergy.co.uk if this is you.

We have provided a top 5.5 things you need to know list all about the new part O.

1. How much glazing can I have?

If you intend to assess all your dwellings via the dynamic simulation process, then there is no limit to the amount of glazing any dwelling can have. You will still need to achieve compliance with Part O but this could be demonstrated by incorporating a mitigation strategy to prevent excess solar gain from coming into the dwelling. For example, a low g-value window.

If you want to stay with the simplified approach then yes a limit to the amount of glazing is applied. The restriction is based on the façade that has the most glazing therefore, the same house type will need different window designs based on the orientation.

For more info on the two approaches or more on the amount of glazing you allow please see our Part O page .

2. What paperwork needs to be completed for Part O?

Approved Document Part O: Overheating page 18 – 19 for the simplified approach and pages 18 & 20 for dynamic. The builder or building control office should complete page 21.

3. Does London have its own Part O Regulations?

No! London does not have its own regulations but London is defined as high-risk location so it does have its own standard to follow within Part O.

4. I’m building a glazed extension, do I need to comply with Part O?

No! Part O is specific to new build only. Glazed extension and conservatory are not covered by this regulation.

5. Do care homes and hotels require an assessment?

Yes for care homes and no for hotels! The care home is classed as a residential institution and would be covered by Part O. However, hotels are not covered, “institution or any other building containing one or more rooms for residential purposes, other than a room in a hotel”

Source:

Approved Document Part O: Overheating Page 11

5.5 Give us a call to discuss your options

Give us a call to discuss your project. We are always happy to talk about concerns you may have and provide you a quotation for the work.

Once we start the work we can provide you with numerous options for compliance to ensure everyone wins.

Please do give us a call 01476 870 504 or e-mail to james@ashbyenergy.co.uk

Retrofit Domestic Noise Reduction – A basic guide

Fri, 01 Apr 2022 12:51:10 GMT

As more rural areas are gradually urbanised and homes are increasingly surrounded by noise sources both domestic and commercial, it has become more important to consider how much noise enters a home.

What noises should be considered?

We define noise as any sound which is unwanted or dangerous.

This of course covers a huge range of sources, from road noise to dogs barking or even talking neighbours.

But should the noise be something which cannot be mitigated at the source and even if a complaint was to be made, nothing could practically be done to reduce the noise level outside, what can be done to reduce noise coming into the home.

Is noise something to worry about?

Noise can affect an occupant directly and indirectly, instantaneously or over a prolonged period of time.

A dog barking for example is a relatively short event, but repeated over days, weeks or even years, especially if the noise persists into more sensitive time periods such as during sleeping hours.

This can have a long-term detrimental effect.

Long term noise exposure has been linked to:

Annoyance
Stress
Anxiety
Depression
High blood pressure
Heart disease
Potential hearing loss high noise exposure situations

How loud is loud?

Some things to consider:

Whispers reach about 30dB, moderate conversation 60dB, heavy traffic usually 80dB and planes reaching up to 130dB.
Loudness is also subjective in that what one person finds obtrusive such as a neighbour’s loud music, is the desired effect for the neighbour playing the music, who additionally will be experiencing it at a much higher level.
A 3dB increase in noise is a doubling of acoustic energy, but a 10dB increase is required to give the effect of a doubling of perceived loudness.

All of these factors are considered when assessing how loud a noise is and if it will have a negative impact.

What can be done to reduce noise exposure at home?

This is very situational but there are a few things which apply in most situations.

1.Attempt to reduce noise at the source.

This is the best way to reduce noise exposure for the individual but for the community, but requires access to or control over the noise source which may not be possible.

2.Make a complaint to the local Environmental Health Officer at your council office.

In many cases, the local Environmental Health Officer has the power to enforce regulation or restriction on noise sources. But if for example, the new occupants of a house complain about the noise from a road adjacent to the property, given their awareness of the road prior to moving in no action may be taken.

3.Attempt to reduce the noise by retrofitting the dwelling.

What methods of noise reduction exist to retrofit a home to reduce noise?

This list doesn't cover all of the methods but from least to most invasive, and usually lowest to greatest expense, here are a few methods commonly used to reduce noise levels at home.

If the windows are modern double glazing with trickle vents, it may be beneficial to replace the vent covers with acoustic trickle vent covers.
Typically, standard trickle vent covers offer around 30-35dB noise reduction, whereas an acoustically treated trickle vent cover may offer a 40-45dB reduction when installed perfectly.

External barriers will reflect a portion of noise from the property.
This may require planning or permission from neighbours but a tall high-density fence can be very effective at reflecting road noise for example away from a property.
This can offer a reduction of between 30-35dB depending on height and distance between the road and the property, bearing in mind bushes and trees can offer some minor protection but this is more aesthetic than practical.

Upgrade the windows.
If single glazed windows are installed, consider double glazing, or if double glazed is installed, consider triple glazing.
This is a more expensive approach but the difference from single glazed to high quality acoustic double glazing can be as much as 45-50dB, and potentially more with triple glazing.

Noise from overpassing planes maybe reduced by doing a loft conversion or adding sound proofing to the loft space.
One of the best ways to stop noise from transmitting from one space to another is by adding mass to the partition. So having a loft conversion will add many layers of material to the roof and joist, alternatively there are acoustic lining which can be added to the joists in the loft.

Adding additional mass to walls and ceilings such as an extra layer of acoustic plasterboard.
By increasing the mass, variation in material and depth of a partition, the amount of directly transmitted noise can be reduced, but consultation maybe required on what board and appropriate fixing methods can be used.

Other considerations might be:

The air tightness of the façade facing the noise source or the whole property might be improved by sealing gaps or replacing window seals, reducing high frequency noise through air gaps.
The noise source maybe temporary, such as a building site which may near completion.
Some mitigation strategy may already be implemented but is either not working or is not being enforced.
Is the noise airborne or vibrational? Speech for example produces mostly mid and high frequency noise, which is easily blocked or reflected, whereas a large truck produces vibrational transmission of noise through the ground or directly through a wall. These are far more difficult to mitigate and require structural alteration to effectively remove.

All solutions are situational, and the performance will depend entirely on the quality of materials and workmanship used.

The importance of air tightness testing in the built environment

Mon, 28 Mar 2022 15:36:45 GMT

Legislation is pushing the building industry towards more sustainable carbon neutral housing and industrial complex, as such builders are required to adopt more exacting standards for air tightness to aid in regulations compliance.

Specifically Building Regulations Approved Document Part L, Conservation of Fuel and Power.

What is air tightness testing?

Air tightness testing is a process to prove the material fabric construction is sound, and to determine what proportion of the heated air from within is lost to the atmosphere.

How does air tightness testing work?

The building under assessment goes through a process of either pressurising or more commonly depressurising, forcing air through the material fabric of the building.

This is achieved by using a blower door fan method where a fan capable of maintaining a steady state pressure differential either blows the air out or draws air in through a doorway.

The air flow is measured and divided by the envelope area of the building producing the air tightness score, typically below 10 to comply with building regulations, but ideally below the design air permeability defined by a SAP or SBEM.

Recently air tightness testing can also be achieved using the pulse method, generating a more instantaneous fluctuation in the buildings internal air pressure, and measuring its duration and air tightness score can be produced.

How does the air tightness score relate to carbon efficiency?

The more airtight the building, typically the less effort is required by the heating system to maintain thermal comfort.

A leakier house will lose the heated air to the atmosphere through gaps in the material fabric and the heating system must compensate.

When does air tightness testing need to be done?

Ideally the test should be done once the building is totally completed, but this may not always be practical especially in the case of failures.

Typically, it may be preferred to test once plasterboard is up and plastered, but prior to kitchen and bathroom installation.

Perforations, incomplete boarding or dot and dab work can lead to a failed result, meaning greater time and expense on the part of the builder to gain compliance.

What buildings require an air tightness test?

Any domestic or commercial new build is required either by individual or sample testing which needs to be agreed with the Building Control Body involved with the project.

In the upcoming regulations change in June 2022, there will be no sample testing allowed and all buildings will require individual tests.

There are some exceptions, but the Building Control Body and Energy Assessor must be consulted to determine if a project is exempt.

What needs to be sealed for the test?

In short, everything, but here is a list of the most prominent areas of concern:

Around window and door frames, internally and externally
The dot and dab work should be a solid frame around the perimeter of the walls of each room
Ceiling plasterboard should be up before wall board and flush with the block or studwork behind it and then sealed
Solid dab is recommended around sockets, switches and pipe perforations
Any perforation made should ideally be sealed immediately by whomever made the perforation, be it for pipes, duct, cables or to access elements
Internal walls on all stories should be capped at top to prevent air from the roof space, being drawn down from behind plasterboard and studwork into floor voids

The only elements which may be temporarily sealed without being referred to as a test deviation are controlled ventilation, such as extracts, passive vents, trickle vents and cooker hoods.

Water traps should be filled, but if water is not available drains may be temporarily sealed in the most appropriate manor.

How will I receive the result?

The tester given enough data to prepare may be able to give an instant result on site, but a certificate will only be sent to you once the data has been submitted to the relevant accreditation body for verification.

We at Ashby Energy Assessors Ltd can give guidance, asses all your regulations compliance requirements and perform the testing offering you instantaneous results and help should you fail to pass straight away.

Get in touch for a quote.

Changes to Building Regulations Part F 2021 in Summary

Thu, 17 Mar 2022 14:42:03 GMT

Building Regulations Part F – What do I need to do to pass?

What is building regulations part F?

Building regulations Part F is changing in June 2022 and being prepared will mean that you will comply now, and after the change.

Gradual improvements in the thermal performance and air tightness of buildings has improved thermal comfort whilst, reducing energy consumption.

However, this has increased the amount of internal air pollutants within a home

Moisture (condensation / mould growth)
Carbon monoxide
Allergens (dust mites)
Odours
Carbon dioxide

All can adversely affect air quality and the occupant's health unless the correct amount of ventilation is provided.

Therefore, a greater importance is placed on:- “Build Tight – Ventilate Right”

Summery of current Part F

Part F defines four methods of ventilation

System 1, Background ventilators & intermittent extract fans
System 2, Passive stack ventilation
System 3, Continuous mechanical extract
System 4, Continuous mechanical supply and extract with heat recovery
Requirement to calculate total equivalent ventilator area via matrix

– Number of Bedrooms vs Total Floor Area

PIV (Positive Input Ventilation) is provisioned for assuming BCB certified with a BBA Certificate

Summery of key upcoming changes

Part F will reduce the ventilation strategy to a combination of:

Extract ventilation from wet rooms, be either intermittent or continuously running systems
Whole dwelling ventilation to provide fresh air to dilute pollutants, either mechanically or via background ventilators
Purge ventilation to remove high concentrations of pollutants and water vapor

This is in an effort to simplify the regs and make them easier to design and implement.

Requirement to calculate total equivalent ventilator area on a room-by-room basis
PIV (Positive Input Ventilation) is not provisioned for unless BCB certified with a BBA Certificate
Buildings which achieve an air tightness score of 3 or less, are considered highly airtight and will require a continuously running mechanical extract system

Equivalent area ventilators new matrix

Intermittent Extract Flow Rates (System 1)

Continuous Extract Flow Rates (System 3/4)

Dwelling Ventilation Targets (System 4)

Important Notes on Installation and Testing

Intermittent extracts require only a single reading to gain compliance.
Continuous extracts require two readings, and they must also comply with the whole dwelling ventilation rate which must be calculated in advance.
Mechanical Ventilation with Heat Recovery requires a full set of building calculations plus the testing and commissioning of the installed system.
Only 1.5m of flexible duct is allowed in any duct run from an axial fan, 3m for centrifugal.
Must be installed in a location that is accessible for testing and maintenance.
Insulated ducting in lofts.
Sufficient background ventilators must be installed for intermittent and continuous extract systems to comply.
It is not permissible by building regulations to mix intermittent with continuous or MVHR ventilation systems in a single dwelling.

The Testing Process

Notes are made on the number of extracts in the dwelling
A hooded vain anemometer with appropriate hood is placed over the extract
The flow rate of the extract is recorded in Litres Per Second
The duct will be inspected
The condition of the duct will be recorded
Certificates can be issued

The reality of Part F

Part F compliance has been a legal requirement since 2010
Approximately 70% of buildings fail the extract rate requirements!!!!!!!
It has been difficult to get installers out at same time as we do test
Extract rates for kitchen hoods nearly always comply if straight through walls
Utility areas are very rarely sized correctly

Most extracts fail, due to :-

Incorrect sizing of extract fan
Poor installation
Long lengths of flexible ducting

If you need any guidance or more detail on what the current and future Building Regulations Part F entails, please get in touch or attend one of our CPDs.

The impact decarbonisation of the UK national grid has on SAP assessments

Fri, 21 Jan 2022 16:13:46 GMT

The history of grid decarbonisation in the UK

At the turn of the century electricity generation was dominated by coal and gas which accounted for 71.1% of electricity generated in the UK whereas renewable sources only contributed 2.7%.

In 2010 the story was not so different. Coal and gas still dominated electricity generation in the UK (74.1%) and little progress was made with renewable sources (6.86%).

However, a decade later we are now seeing a significant increase in renewable energy sources with renewables accounting for 43.1% of electricity generation and coal and gas accounting for 37.5% in a trend that shows no sign of stopping.

The changes in carbon emission factors

The decarbonisation of the national grid has been reflected within SAP. The carbon emissions factors for electricity in the most recent version of SAP (SAP 10.2) have dropped by more than half from the previous version (SAP 2012) to 0.136kg CO2 per kWh.

The impact of decarbonisation on SAPs

For the first time electricity is now recognised as a less carbon intensive fuel source than mains gas which has remained consistent around 0.21kg CO2 per kWh.

Mains gas has traditionally been used to supply hot water and space heating for buildings, with electricity supplying lighting and auxiliaries. Now that electricity is less carbon intensive than mains gas we may see a rise in alternatives to gas boilers such as heat pumps to supply hot water and space heating via electricity or more radical techniques such as solar hot water (also known as ‘solar thermal’).

Heat pumps currently provide some benefit over gas boilers within SAP regardless of the higher carbon emissions factors of electricity versus gas due to having a higher COP (coefficient of performance). Within SAP 10.2 the higher COP and lower electricity costs while give heat pumps huge benefit over gas boilers.

This switch could be the difference between a building achieving or failing compliance with Building Regulations Part L.

Information Required to Produce a SAP for EPC

Tue, 18 Jan 2022 15:27:04 GMT

The information needed to produce a SAP and EPC for a New Build development

A Standard Assessment Procedure (SAP) is a government approved method to assess the energy performance of the new dwellings by producing an Energy Performance Certificate (EPC).

Every newly built house requires a SAP.

But what information is required to produce a SAP?

Floor plans with sections - on design stage, the most important documentation that represents the development and how the insulation will be located. With this information the assessor can establish what are the areas of the heat loss through floor, walls, and roof, as well as lengths of the various junctions of the structures that are required for thermal bridging calculations.

Specification for the dwelling – an information whether houses will be built as cavity wall, timber frame or differently, with corresponding insulation thicknesses and types. The assessor can then assess them and advise whether the dwelling will achieve compliance or advise on increasing the thermal efficiency of the buildings fabric.

U values for fenestration – If not specified by the architect, or in case they will need to improve, the assessor will include that in the report. They must be backed up by manufacturer certificates or proved by British Fenestration Rating Council on completion of the project. The assessor will also notify of possible overheating risk and possible remediation to overcome the high temperatures in summer, for example by installation of light-coloured roller blinds.

Heating, ventilation, and air conditioning – EPC represents the running costs for space heating; therefore, it is one of the most important factors to include for the SAP calculations. Often situation is that the heating system has not been specified to include the exact make and model; however, the assessor can check how would various heating systems behave and specify the efficiencies they will need to achieve, along with heating controls and additional systems reducing carbon emissions – weather compensators or flue gas heat recovery systems.

When project has been completed, it is important to send any documentation backing up the installed fenestration (u value certificates), heating (picture of the boiler) and water heating (hot water tank plate picture).

New registered address of the property – the SAP finishes with an energy rating (EPC) which is visible on the governments database. To correspond with reality and prevent unnecessary issues with mail or Council, the address on the EPC must match the new address of the property.

The list above generalises the overall information required to produce a SAP – if you are not sure whether you’ve got everything right, or would like to discuss it, please do not hesitate to contact us for more information!

Changes to Approved Document L and F 2021 Edition – Air Tightness and Ventilation

Thu, 23 Dec 2021 13:30:10 GMT

Building Regulations Part L and F are Changing

What is changing in Part L?

In line with the Future Homes Standards due for full implementation in 2025, Part L is being changed to make domestic homes “zero carbon ready” to decarbonise the energy grid.

The requirement is a 31% reduction in carbon emissions from the current regulations which will be achieved by moving to more efficiency electrically powered heating systems, and the increased inclusion of photovoltaic power sources.

This is an interim update to Part L which will be the first of many changes to come gradually turning the building industry round to a more carbon efficient design methodology.

One way to achieve this is to reduce the air tightness target to increase the efficiency of the heating system.

What is the new air tightness target?

The new maximum target for air tightness is <8m ³ /(h·m ² )@50Pa, which is a 2 point reduction from the current maximum of 10.

This more airtight target will allow for low temperature heating systems such as air source heat pumps to be viable and meet the reduced carbon emissions targets.

What is changing in Part F?

Given the tightened targets for air permeability, there is a greater emphasis on proper ventilation installation and choosing the correct method to achieve the required air changes to maintain air quality.

What are the new ventilation targets?

Within Part F it is now specified that for buildings with an as built air tightness score of 3 or below, there is a requirement for continuous mechanical ventilation which can be centralised or decentralised.

Targets air flow rates have not been changed but instead the regulations have been simplified, as it has been shown that a large proportion of new dwellings were failing due to ignorance or misinterpretation of Part F.

System 2 or Passive stack and PIV have been removed from the upcoming regulations, as well as natural ventilation without the use of mechanical extracts has been given higher targets for Equivalent Areas for background ventilators.

Bare in mind:

Intermittent extracts require only a single reading to gain compliance.

Continuous extracts require two readings, and they must also comply with the whole dwelling ventilation rate which must be calculated in advance.

Mechanical Ventilation with Heat Recovery requires a full set of building calculations plus the testing and commissioning of the installed system.

Only 1.5m of flexible duct is allowed in any duct run.

Sufficient background ventilators must be installed for intermittent and continuous extract systems to comply.

It is not permissible by building regulations to mix intermittent, continuous and MVHR ventilation systems in a single dwelling.

A reminder of the air flow targets:

Impact of Wood Log Burners in SAP

Wed, 17 Nov 2021 17:05:17 GMT

The Impact of Wood Log Burners in SAP

Did you know that installing a wood burning stove, even in new developments, can help you to achieve compliance with Part L building regulations?

A modern wood log burner, unlike open stove, can efficiently help in heating the house, minimise energy losses through the flue and ultimately improve environmental performance (if wood used is sustainably sourced, it can be seen as a renewable energy source).

Standard Assessment Procedure (SAP) works out the final Energy Performance Certificate (EPC) score by considering multiple factors, with heating systems being one of the most important ones. It calculates how much carbon emissions will be emitted to the environment, by raising the temperature to 21° in the living room and to 18°C in other areas. By installing a HETAS approved wood log burner in the living room, SAP considers this system as a heat source raising temperature from 18°C to 21° by using renewable energy, with no need for the main heating system to be turned on. This approach can greatly benefit homes with specified gas boilers and achieve even an additional 5% reduction!

The main disadvantage is the high cost of retrofitted installation in the building which does not have flues. However, if a wood burning installation is factored during the design stage of the dwelling, the overall cost for the system can be reduced significantly. Please also take caution in choosing the system – open fire in grate is not as efficient as modern wood log burners and will have negative impact on SAP. The gas-fired stoves can also help in achieve compliance, but the overall EPC score will be decreased.

An overall benefits of log burners, apart from helping in passing the building regulations are decreased bills, increased attractiveness, and environmentally friendly addition to the new homeowners. It can be also aesthetically pleasing by providing a relaxing setting in the living room!

Domestic Air Tightness Testing to Newcomers

Wed, 13 Oct 2021 16:03:19 GMT

Domestic Air Tightness Testing to Newcomers

An air test evaluates the air tightness, or air permeability, of a building. The air tightness of a building is critical to the energy efficiency of a building. The greater the permeability of a building, the greater the heat loss potential. A sufficiently airtight building helps keep the energy bills down and therefore reduces CO ² emissions.

This relatively unknown test to those outside of the industry is therefore incredibly important to evaluate future homes from both a financial and environmental perspective.

Air tightness tests were first devised in 2002 and since 2006 they have become a legal requirement under UK building regulations for all newly built buildings. The process of air testing begins with the collection of background data, including the volume and envelope area (total area of the external walls, floors and ceilings) of the building.

Once this data has been collected, an air tester can visit the site to perform an air test. As the purpose of an air tightness test is to measure the uncontrolled ventilation of a building, preparation for the test involves sealing all forms of controlled ventilation (extracts, trickle vents, cooker hoods, etc) and closing any windows or doors. One of the external doors will be sealed with a blower door and a fan.

Background readings are taken for the static pressure, the pressure differential between the outside and inside of the building and the internal and external temperature. The fan is then powered to depressurise the building after which point a minimum of 7 readings are taken across a range of pressures. These readings then determine the air tightness score of the building.

As an air tester in training, I have gained a new understanding and appreciation for how our homes are built and an insight into the complexities of the construction industry. Air tightness tests are just one of the lesser-known processes used to ensure that our homes are built to comply with CO ² carbon emissions targets, to provide good air quality and to run cost efficiently.

Noise Complaints and Assessment

Wed, 13 Oct 2021 15:58:29 GMT

Noise Complaints and Assessment

Noise complaints are rooted in assessing what sounds are acceptable in our personal space, but also what might have significant health impact.

Loud music from neighbours or nearby venues, construction noise, traffic or even dog barking can all be considered sources for noise complaint, but they are all assessed in differing ways.

Throughout the night (between 11pm – 7am) is regarded as the most sensitive period in which to be exposed to noise, as disturbed sleep can lead to a great number of significant and life-threatening conditions.

When legally enforced noise limits are exceeded, it is possible to have an investigation initiated to mitigate the noise either independently or by the council.

Usually, the first recommended step is mediation, in the form of informal agreement, which should the issue go to court, will demonstrate an attempt to act reasonably for both parties.

After attempted mediation, the complaint should be lodged with the local council or environmental health officer, who can initiate and investigation or assessment process.

The council can issue warnings, penalties or seize noise making equipment based on the impact as statutory nuisance or impact on health.

“For the noise to count as a statutory nuisance it must do one of the following:

unreasonably and substantially interfere with the use or enjoyment of a home or other premises
injure health or be likely to injure health”

(Noise nuisances: how councils deal with complaints, 2021)

At this point an environmental health officer or independent accredited noise assessor can measure the noise and report on its impact.

Periods and methods of assessment can vary based on the nature of the noise, for instance, if there is a music venue nearby, a continuous noise assessment should take place during the venues working hours outside the dwelling of the complainee. Whereas domestic nuisance noise from another dwelling must be logged, and longer-term noise records must be made so that frequency of excessive noise can be considered.

Should the complaint be about a neighbour who shares a party wall with the complainee, a sound insulation test can be carried out to asses the resistance to the passage of sound of the party wall.

The planning application procedure also considers the noise impact on the surrounding area, to reduce the impact of noise and prevent complaints during construction.

Additionally, the noise impact from a development after completion such as in the case of commercial construction will be assessed.

An assessment can be carried out on any noise which impinges on the comfort and health of any person, whether it be from commercial or domestic sources.

Citations:

GOV.UK. 2021. Noise nuisances: how councils deal with complaints. [online] Available at: < https://www.gov.uk/guidance/noise-nuisances-how-councils-deal-with-complaints > [Accessed 13 August 2021].

Which Ventilation System Should I Be Using?

Wed, 22 Sep 2021 06:45:37 GMT

There a four main system for ventilation within the UK building regulations:

System 1 – Intermittent extract with background ventilators
System 2 – Passive stack ventilation
System 3 – Continuous mechanical extract ventilation
System 4 – Continuous mechanical extract ventilation with heat recovery

Any one of these systems can be implemented into a new build but they have different design, implementation and testing requirements.

The Systems

System 1 is the most simple in terms of installation and testing.

A fan is required to be installed into the kitchen, utility, sanitary accommodation and bathrooms, each having their own compliance target to reach for air flow measured in liters per second.

Assuming the correct fan is chosen for the wet room use case, and the installation is of high quality ensuring that minimum duct is used and there is as little impedance to air flow as possible, the air flow target should be easily achieved.

Pros: this system is easy to install, provides rapid local purge extract of pollutants and has simple operation as it is linked to the usage of the room via the light switch in most cases.
Cons: this system can be more noisy, if there is provision for manual control then occupants regularly turn them off, and they are easily tampered with.

System 2 is very simple in its overarching principle but designing it into a building requires a great deal of planning.

It is required that a vertical duct be installed from any wet room, and to have it ascend through the building and out of the roof with little or no deviation from vertical to ensure the most direct airflow.

The thermal flow of warm air should rise up through the duct, and wind outside will aid in drawing the warm air out of the duct at the roof level.

Pros: No running costs, no electrical requirement and silent operation.
Cons: can be difficult to accommodate vertical runs of duct, the system is very sensitive to correct installation and the airflow can be considered to be weather dependent.

System 3 is similar to system 1 in that ideally there are single fans installed in each wet room but are continuously running on a trickle speed when there is no room occupancy, but will go into a boosted state when the lights are turned on or controlled via humidistat.

Centralized units can be installed which draw from multiple wet rooms providing there is overall speed and flow controls.

Pros: A centralized unit installation can be more simple and easy to operate.
Cons: Duct runs on centralized units can be long and reduce the efficiency of the unit to the point that it becomes ineffective, the system requires full commissioning, there are more targets which the system is require to comply with which are derived from the design of the building and with multiple fans running continuously as in decentralized installation the noise whilst generally low, is dependent on the speed required for successful commissioning, which may end up being quite loud.

System 4 is the most complex but highly rewarding system for ventilation as it can ensure sufficient supply of clean air, efficient extraction of pollutants and reduce the heating cost for the building.

Most commonly installed as a centralized unit with a single supply and extract duct connected to outside the building, along with internal ducting for supply an extract to living spaces and wet rooms.

This requires a great deal of planning to ensure that the duct runs are efficiently spaced and sized correctly to reach compliance targets. Also the unit itself must be of the correct size and power otherwise it may not be possible to gain compliance.

The unit can supply filtered air which has been heated by the extracted air via a heat exchanger, thus giving the best quality room temperature supply air possible, whilst effectively extracting humid polluted air from the wet rooms and kitchens.

Pros: Controlled preheated fresh air supplied to the whole dwelling, heat exchanger reduced the demand on the dwelling's heating source and it is possible to incorporate high quality filtration for air quality.
Cons: Initial cost for unit and installation are high with a complex planning and installation process. For optimum use, the dwelling must have a high level of air tightness and the testing and commissioning process is highly complex and involves similar targets to system 3.

Thermal Bridging and Approved Document Part L1 2021

Wed, 22 Sep 2021 06:45:12 GMT

Thermal bridging is a pathway in the building where heat transfers at a higher rate than in its surrounding. It occurs in every building, however, dwellings with reduced insulation, breaks in the insulation layer or materials with worse thermal properties might contribute to higher thermal bridging rates. Apart from reduced building’s energy efficiency, it can create a risk of condensation, moisture and eventually mold build up. It can also result in increased heat transfer from the building.

So why should we worry about the performance of the thermal bridges? As insulation in structures becomes better, the junctions between them are becoming obstacles. As heat is less likely to pass through an insulated structure, it forces its way through a thermal bridge.

The Government’s Approved Document Part L1 2013, allows us to adapt the design details set in Approved Construction Details (or recognized by the DCLG) and associated psi values for thermal bridges. However, the Government has proposed to remove the ACDs from Approved Document L, Volume 1: Dwellings, as in their opinion the ACDs are out of date and no longer work with new fabric specified for Part L 2021.

But what does it mean for builders and SAP assessors? To achieve compliance, in most cases it was necessary to use the psi values associated with ACDs, as they significantly increased the fabric efficiency and ultimately the dwelling achieved a higher SAP score on Energy Performance Certificate. With new legislation coming soon, it might be the case that the thermal bridging details will have to be independently calculated by a competent person to achieve compliance. There will also be a possibility of using the Local Authority Building Control’s Construction Details library, available on LABC website.

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SAP 10 and Hydrogens Future Role

Wed, 22 Sep 2021 06:44:40 GMT

The future of the UK new build and existing house market could see the use of hydrogen boilers playing a large part. However, despite this, the use of Hydrogen will not be a selectable option under SAP 10 and will not be selectable until the subsequent regulation is due in 2025.

Several manufacturers have announced they are working on a Hydrogen boiler, with the first few boilers expected in 2025. The initial boiler will be ‘Hydrogen ready boiler’ similar to the initial HD ready television however, these boilers could burn mains gas and eventually Hydrogen.

It is expected that as much of 35% of the UK’s energy consumption by 2050 will be Hydrogen; however, the use of Hydrogen on the existing building stock is not expected to be announced until after 2026 after the trial on the use of the fuel is concluded. If the trial proves to be a success, the government is hopeful of establishing an entirely hydrogen town by the end of 2030 to monitor the success and impact of changing people’s lives.

The hydrogen potential is also expected to be backed up with a new scrappage scheme for boilers with incentives as high as £7,000 to the homeowner to switch from mains gas to low carbon alternative, which would also include heat pumps. The new scheme will be called ‘Clean heat Grant’ and it has an initial budget of £100 million, which could be increased if required and will be launched in April 2022.

All the above items covered in the article are expected to be announced at the November’s COP26 meeting being held in Glasgow; however, these times may change. The government is also considering a complete ban on gas boilers by 2035

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Noise, Ventilation and Overheating in Domestic Properties

Tue, 07 Sep 2021 13:15:57 GMT

Noise, Ventilation and Overheating in Domestic Properties

Approved Document Part F of the building regulations is a well-established standard for the requirement of ventilation and how to measure its effectiveness, also improvements made in building air tightness and the standards of insulation have resulted in a more energy efficient home.

Consequently, the risk of overheating in buildings with poorly designed ventilation, target air tightness and insulative properties has increased.

Noise can affect what ventilation methods are used to maintain both suitable air quality and comfortable temperature, which can lead to either misuse of ventilation or dealing with greater noise levels.

Homes can be passively ventilated, simply by opening a window to equalise indoor and outdoor temperatures, or, mechanically ventilated, such as with MVHR systems or decentralised extract systems.

During periods of hot weather, it maybe undesirable to open a window for an occupant living in a busy city area for instance, allowing external noise into their dwelling, conversely, all mechanical ventilation produces some noise and is often disabled by the occupant due to their intrusive nature.

So, in either case, the occupant either must put up with greater noise, or poor ventilation.

There are no set limits for noise generated by mechanical ventilation systems as they are considered occasional noise sources, but BS8233 defines the upper limits for indoor ambient noise levels resulting from external noise sources. To assess the overheating risk of a domestic dwelling, TM59 is used which includes what ventilation systems are available, or in use, including open windows.

To satisfy both requirements whilst limiting noise exposure to the occupant, practical and possible methods must be implemented such as acoustically isolating passive ventilation panels, external window noise diffusion panels or mechanical ventilation which is of entirely non-intrusive nature.

Allowing the occupant control over their ventilation and access to the “Fresh” air outdoors means providing solutions which prevent overheating, allow for the purging of polluted air from inside the dwelling and prevent noise passing through into the dwelling.

De-carbonising Grid - Building Regulations Part LA 2021

Mon, 28 Jun 2021 14:43:44 GMT

The new Building Regulations Part LA 2021 – Future Homes Standard has provided huge insight into the future of domestic new builds. One of the major changes implemented will be accounting for the electricity generated by fuel source in UK and understanding how this will look in the future. Renewable technologies are being adopted at a huge rate and Figure 1 illustrates how this will accelerate over the next decade. In 2018 the carbon intensity generated by the UK reduced by approximately 60% since 2008 so a low carbon future is looking ever more viable. This notion is being reflected into the new regulations and electricity will now be less carbon intensive than mains gas.

With electricity now being better than gas can I install electric panel heaters as my main heating source?

No, unfortunately you cannot install electric panel heaters/electric storage heaters as your main heating source, and this is due to SAP 10 introducing a new metric for compliance:

Primary Energy Target - The Target Primary Energy Rate will consider how much energy (in kilowatt hours) is required to provide heating and hot water to a newly built dwelling. It will also include energy used by lighting, ventilation, cooling systems and showers.

The previous metrics will still need to be satisfied (C02 emissions target, fabric energy efficiency target, minimum standards) however this Primary Energy Target will now take center stage and will disallow the notion of using electric panel heaters as your main heating source.

Fuel factors will also be removed in the new build regulations , making LPG & Oil almost unreasonable from an SAP perspective. In combination all these changes are pushing the adoption of ASHP’s and this is where the future is heading for domestic dwellings, as illustrated in the draft Future Homes Specification shown in Figure 2.

Part F Domestic Ventilation Guidance

Mon, 26 Apr 2021 15:44:01 GMT

Overview

In this report an outline of the two most common and easy to install systems of ventilation will be given, with a view to guide any developer making a choice on which to install into their properties.

A broad description of the systems will be given, the pros and cons of each system will be shown for comparison and the methods of compliance will be explained with reference to Building Regulations Part F.

Systems of Ventilation

Adequate ventilation is essential in maintaining a healthy environment. It prevents the build-up of excess levels of humidity, which can lead to condensation, mould and can consequently result in health issues. Adequate ventilation also provides air for fuel-burning appliances, such as wood burners and removes cooking smells.

There are 4 main systems of ventilation with a fifth for more complex applications, but the most common two are System 1 and System 3. According to Building Regulations Part F , systems of ventilation cannot be mixed without prior consent from Building Control.

In both cases, solid duct and simple low resistance grills on the outside are always recommended as they offer lower air resistance and aid compliance. It is highly recommended that gravity shutter grills and roof tile vents are avoided as they are generally highly resistive to air flow.

System 1 Background ventilators and intermittent extract fans

System 1 is the most common type of ventilation installed with the simplest compliance targets.

As can be seen with the targets in Table 5.1a, a single fan is required in every wet room including any Utility room where there is provision for sinks, washing machine or dryers.

Where there is no cooker hood, an extractor can be fitted adjacent to the cooker which achieves 30l/s, or an extractor anywhere in the kitchen which reaches 60l/s.

There is a requirement from Building Regulations Part F for background ventilators such as trickle vents or passive ventilation sized appropriately for the size of the plots. This can be derived from table in section 5.2a of Building Regulations Part F. In most cases, trickle vents installed into each window frame will suffice.

Specifically, Decentralised Continuous mechanical extracts can be installed in a similar manner to System 1 fans, with the exception that they run continuously. These are more common in plots where the air tightness result is expected to be below 3m3/h/m2.

As shown by cross referencing Tables 5.1a and 5.1b taken from Building Regulations Part F, compliance is achieved by each individual fan reaching its “Minimum high rate”, and for the total of the low rates to be greater than the “whole dwelling ventilation rate”, which must be calculated prior to installation to ensure compliance can be reached by the fans.

Ventilation Testing and commissioning requires that the low and high rates of each fan be taken, then adjustments to be made to ensure that the flow rates are reached. This process can often lead to excessive noise from fans in situations where insufficient fans have been installed, requiring that a number of fans need to be run at higher speeds continuously.

Cooker hoods may be installed but cannot be ducted externally, instead made to recirculate the air back into the kitchen allowing a System 3 extract installed in the kitchen to remove the polluted air.

For any design air permeability, controllable background ventilators having a minimum equivalent area of 2500mm2 should be installed in each room, except wet rooms, from which air is extracted. As an alternative, where the design air permeability is leakier than 5m3/h/m2 at 50Pa, background ventilators are not necessary but see precautionary advice in paragraph 5.10 of Building Regulations Part F as this approach can lead to long term issues.

What is the dwelling emissions rate and how is it used?

Mon, 26 Apr 2021 09:09:39 GMT

The dwelling emission rate is the annual CO2 emissions from all new dwellings and is expressed in kilograms per square meter of floor area (kg/m²). The quantity is calculated in accordance with the applicable regulatory document and expressed in kilograms per unit floor area to two decimal places, is known as the Dwelling Emissions Rate, or DER. In another sense, the DER is equal to the annual CO2 emission per unit of floor area for, space heating, water heating, ventilation, and lighting less the emission that could be saved from renewable technology.

The dwelling emissions rate is used within SAP ‘ Standards Assessment Procedure ’ and will be conducted by an SAP assessor or on construction domestic energy assessor. Just so it is clear the SAP assessor and the on construction energy assessors are the same people but they can be called two different things.

The SAP will also produce a target emissions rate ‘TER’ which is also expressed kilograms per square meter of floor area (kg/m²) but uses a notional specification which is defined within the Building Regulations Part L1A documents. The DER is then compared to the TER and provided the DER is lower then the TER compliance is demonstrated.

The SAP is an independent calculation is does not take account of specific individual characteristics of a household or the specific occupiers living in the dwellings. For example,

• The household size and composition is ignored

• Ownership and efficiency of an individual particular domestic electrical appliance

• Individual heating patterns and temperatures.

Once the specific dwelling has been entered into SAP and all the relevant u-values for the floor, walls and roof, heating system, ventilation system, design air permeability score and any renewable technology this will provide the dwelling an dwelling emissions rate DER which is compared to the target emission rate TER. Provided the DER score is below the TER then compliance with Part L1A Conservation of fuel and power.

If however, the dwelling emission rate was higher than the target emission rate the SAP assessors could provide and run multiple options on ways compliance could be regained. Better u-values