NHBC Issues New Chapter – 4.6 Engineered Fill

NHBC Issues New Chapter – 4.6 Engineered Fill

NHBC Issues New Chapter – 4.6 Engineered Fill

In January of this year the NHBC rolled out their newest chapter – 4.6 Engineered Fill.

Amongst a number of additional updates, this new chapter covers guidance on meeting their Technical Requirements for engineered fill along with recommendations for developments where buildings are founded in engineered fill, or where fill is used to support external works and roads or pavements etc.

Mark Russell, Standards & Policy Manager at NHBC commented, “Our standards team is committed to continuous improvement and revising the Standards annually to ensure they remain current and relevant. I am proud to be part of such a robust process that continues to support the ongoing advancement of build quality and helps builders and developers to keep raising standards in house building.”

The launch of this chapter and the dates for roll out are interesting as, whilst on the surface there appears to be quite an addition, and potentially a welcome one, in many cases it will be business as usual, particularly with regard to founding within engineered fill.

In our experience, our developer clients have long avoided this particular route which, as geotechnical and environmental consultants, can be inwardly frustrating when we see the value that can be gained through good earthworks design and construction. Too often we see trenchblock/reduce level digs/over designed rafts or piles being adopted in order to get through newly placed fill. The environmental and financial cost of this is significantly higher when compared to a traditional shallow foundation within the engineered fill.

reusing soil on site
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Why is it avoided? Historically, we have found this to be a knock on effect of a lack of confidence from the warranty providers themselves, which is likely down to bad experience and increased risk of excessive settlement or heave resulting from poorly designed and controlled earthworks, possibly resulting through the absence of a set of technical standards to follow!

The thing is, a robust and well considered earthworks design, based on a full and detailed high quality ground investigation, constructed under the supervision of an experienced engineer can usually mitigate this type of concern. This approach is often demonstrated in the commercial non-warranted world as well as in the public sector with earth structures and highways.

You’ve probably driven on a road or motorway constructed on engineered fill in the past week, walked along a footpath on a constructed embankment with a retaining wall set in or travelled on a train that runs along an embankment constructed with engineered fill.

How useful will this chapter really be?

Whilst this new set of conditions may give rise to concerns over ‘another load of hoops to jump through’ or similar, it could, and arguably should, be welcomed and used to add value back into certain schemes where practicable. Although the initial investigation, testing and design costs, and timescales, may seem higher than some clients are used to, they should be considered alongside the alternate options and their costs to realise the benefit.

Founding in engineered fill can not only reduce the project costs with regards to foundation options, but can also reduce the requirement to dispose of material off-site. Through a well thought out cut and fill model, and use of the CL:AIRE DoWCOP Materials Management Plan (where suitable and applicable), the majority of soils can be kept on-site. This not only leads to cost savings, but importantly is a more sustainable option, ensuring valuable soil resources are re-used rather than disposed of, and limits that amount of truck movements to and from the site.

Omnia have been pushing this approach with engineered fill, where practical and of value, for a few years now and have demonstrable experience of successful schemes. Tying together the Ground Investigation, Testing, Geotechnical Design, Material Management Plan, Supervision, QA and sign off can be a challenge but those of us that have been practicing this for a number of years should have no issue in fitting neatly into this NHBC Condition 4.6 for Engineered Fill and assist our clients in delivering more sustainable value engineered projects.

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Odour Assessments for Planning Permission

Odour Assessments for Planning Permission

Odour Assessments for Planning Permission

The sense of smell plays a crucial role in our daily lives, influencing our emotions, memories, and overall well-being. Odour, in its various forms, can either be pleasant or unpleasant, let’s suppose you walked past a fish and chip store or restaurant and found yourself captivated by the mouthwatering aromas emanating from within. While pleasant, these scents can sometimes be inconvenient for those living nearby. But have you ever wondered what exactly defines Odour? I will try to delve into the concept of Odour, its units of measurement, the different types of Odours, and the best time to measure and analyse them.

What is Odour?

Odour, commonly referred to as smell or fragrance, is the perception of certain molecules in the air that stimulate the olfactory system. Our olfactory receptors, located in the nose, detect these molecules and send signals to the brain, resulting in the recognition and interpretation of specific scents. Odour is a complex sensory experience that can evoke various emotions, trigger memories, and even impact our behaviour.

Units of Odour Measurement:

To quantify and measure Odour, specific units and methods have been developed. One commonly used unit is the “Odour unit” (OU), which represents the concentration of a particular Odorant in the air. This unit is typically measured using instruments such as olfactometers, which assess the intensity of Odour perception.

Types of Odour:

Odours can be classified into different categories based on their origin and characteristics. Here are some common types of Odours:

1. Aromatic Odour: Aromatic Odours are typically pleasant and often associated with natural substances like flowers, fruits, and spices. These Odours are frequently used in perfumes and aromatherapy due to their positive effects on mood and well-being

2. Putrid Odour: Putrid Odours are highly unpleasant and often associated with decaying organic matter, sewage, or rotten food. These Odours serve as a warning sign of potential health hazards and are generally avoided.

3. Chemical Odour: Chemical Odours arise from various man-made substances and may have distinct characteristics. Some chemical Odours are harmless, while others may indicate the presence of toxic or hazardous materials.

4. Metallic Odour: Metallic Odours are often described as a metallic, tangy scent and can be associated with blood, certain minerals, or metallic substances. These Odours can sometimes be indicative of a medical condition or environmental factor.

    When is the Best Time to Measure Odour?

    The perception and measurement of Odour can vary depending on several factors, including time of day and environmental conditions. To obtain accurate measurements for an Odour Assessment, it is generally recommended to measure Odours during stable weather conditions when wind speed, wind direction, temperature etc. Early morning or late evening hours are often considered ideal due to reduced activities and traffic that can influence the dispersion of Odours.

    Why Might You Need an Odour Assessment for Planning Permission?

    Odour Assessments are often required for planning permission applications, particularly in industries that may produce substantial odour emissions, such as restaurants, livestock farms, and chemical facilities etc. The primary purpose is to evaluate the potential impact on the surrounding environment and nearby communities. By conducting an Odour Assessment, applicants can demonstrate their commitment to environmental sustainability and ensure compliance with local regulations. This assessment helps identify mitigation measures to minimize or eliminate odour nuisance to protect the quality of life for residents.

    Conclusion:

    Understanding the nature of Odour, its units of measurement, and the different types of Odours can enhance our awareness and appreciation of the olfactory experience. Whether it’s enjoying the pleasant fragrance of flowers or identifying potential hazards through unpleasant Odours, our sense of smell plays a significant role in our daily lives. By recognizing the best time to measure and analyse Odours, we can gather valuable information that contributes to improving air quality, health, and overall well-being.

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    Nutrient Neutrality

    Nutrient Neutrality

    Nutrient Neutrality

    Olivia Maxwell: July 2023

    What is Nutrient Neutrality?

    Nutrient Assessments refer to a future developments NET Nutrient load on the surrounding environment. For a development to be Nutrient Neutral, it will not have a nutrient load that is greater than the nutrient load prior to the development.

    The nutrients referred to are Nitrogen, Phosphorus or both.

    In June 2019, guidance was issued to Planning Authorities in the Solent Region by Natural England giving advice on how to achieve nitrate neutrality in The Solent Region (Advice on Achieving Nutrient Neutrality for New Development in the Solent Region, Natural England, June 2019), which has subsequently been updated in March 2022 to cover multiple areas of the country (Advice for development proposals with the potential to affect water quality resulting in adverse nutrient impacts on habitats sites, Natural England, March 2022).

    This guidance followed two rulings in the European Court of Justice which deemed that regulatory authorities in the Netherlands had not undertaken sufficient checks to ensure that proposed developments would not cause a significant harm to European Natura 2000 sites.

    Natura 2000 classifications include SSSI, SAC, SPA & Ramsar sites.

    Whilst the majority of nitrates entering water bodies are derived from current and historical agricultural sources, new developments have been deemed to result in an increased load on existing Wastewater Treatment Works (WwTWs) resulting in increased nitrates being discharged into the watercourses.

    The new guidance by Natural England has resulted in certain local authorities requiring nitrate neutrality calculations and reports to be produced for all new developments.

    Why is Nutrient Neutrality important?

    An increase in the concentration of Nitrogen and Phosphorous in surrounding water bodies can cause eutrophication. A eutrophic water body will be high in nutrients, turbid and green from dense phytoplankton growth.

    Due to this dense algae growth, the light penetrating into the water column will be low, and there will be a low species diversity, and low oxygen, making it difficult for aquatic insects or fish to survive, in turn removing a food source from the food chain.

    Where is Nutrient Neutrality an issue and Who is affected?

    Natural England (https://publications.naturalengland.org.uk/publication/4792131352002560) have highlighted areas of the country where development proposals could have an adverse impact on designated habitats, and nutrient neutrality has been identified as a potential mitigation solution.

    Nutrient Neutrality is a national concern with approximately 74 Local Authorities falling within areas of concern.

    Affected areas include:

    1. The Solent
    2. Cheshire East,
    3. Lake District National Park;
    4. River Avon SAC;
    5. River Camel SAC;
    6. Broadland and South Norfolk;
    7. Peak District National Park,
    8. Folkestone and Hythe;
    9. Carlisle;
    10. Stodmarsh SAC/Ramsar;
    11. River Wye SAC;
    12. Stockton-on-Tees;
    13. Somerset Levels and Moors Ramsar

    All developments that propose overnight accommodation are affected by this guidance, including new housing developments, hotels and camping sites.

    Each council within an affected area has released its own guidance on how to move forward with Nutrient Neutrality, and many have produced their own calculators.

    How are Nutrient Neutrality assessments completed?

    The nutrient balance of a development needs to be considered early, as mitigation measures may need to be designed on-site, or off-site mitigation measures may need to be arranged, which can cause delays to the proposed development planning approval.

    Omnia can help you to produce Nutrient Neutrality assessments. In order to complete a nutrient neutrality assessment we will assess the nutrient load of the current site based on its uses, and compare it with the nutrient load of the proposed development.

    The sites future nutrient load will be dependent on the proposed development, the future population of the site, the water usage of the development and any mitigating factors, such as proposed wetlands.

    What happens next?

    Following completion of a nutrient neutrality assessment, it may be determined that your proposed site will have a higher nutrient load than the existing site, and therefore mitigation measures may be required.

    Mitigation can be on-site, through the construction of wetlands, land use changes, or implementing SUDs  for example, or off-site by off setting the nutrient load against another parcel of land, in agreement with another site, or through purchasing credits. A lot of mitigation options are available and early consultation with the Local Planning Authority and Natural England is advised.

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    Clean Air Day 2023

    Clean Air Day 2023

    Clean Air Day 2023

    On 15th June 2023, we are celebrating Clean Air Day, the UK’s largest air pollution campaign. We are aiming to spread knowledge and understanding of the impact of air pollution and to take steps in improving air quality.

    Clean Air Day is an exceptional opportunity to raise awareness of the critical role clean air plays in our well-being and the health of the planet. It serves as a call to action, urging us to raise awareness and take positive steps towards creating a healthier environment. Clean air is essential for our respiratory health, cognitive function, and overall well-being. However, the global issue of air pollution threatens these vital aspects of our lives, leading to respiratory diseases, allergies, premature deaths, and ecological damage.

    The tragedy of nine-year-old Ella Kissi-Debrah, who passed away due to complications of asthma caused by illegal levels of nitrogen dioxide around her home in December 2013, reminds us of the pressing need to take action and protect our children and future generations from the harmful effects of air pollution.

    The Chief Medical Officer’s 2022 Annual Report focused on air pollution, stating that “we can and should go further to reduce air pollution”. 

    What is Air Pollution?

    Common key pollutants in the UK are NO2 and Particulate Matter (PM). PM is the broad term for microscopic particles suspended in the air originating from a range of human-made and natural sources. PM is classified by size range, named according to upper-limit diameter in micrometres, and comprises coarse particles (PM10-2.5), fine particles (PM2.5) and ultrafine particles (PM0.1).

    NO2 is one of a group of gases called nitrogen oxides (NOx) but is the most harmful to human health. O3 gas is not directly emitted but formed in the air. Ground-level (tropospheric) O3 can be formed by photochemical reactions (driven by sunlight) of NOx and non-methane volatile organic compounds (NMVOCs) from various natural and human-made sources.

    Industries’ Role in Air Pollution Reduction: Industries have a crucial role to play in combatting air pollution. By implementing technologies that reduce emissions, promote energy efficiency, and adopt sustainable practices, they can significantly minimize pollution. Embracing eco-friendly policies and legislation within industries helps create a cleaner environment for all.

    Green Spaces and Advocacy for Stricter Regulations: Creating green spaces in urban areas and planting trees can absorb pollutants and improve air quality. By advocating for stricter air quality regulations and sustainable practices, we can drive positive change on a broader scale. Encouraging collaboration between policymakers, businesses, and communities is vital for achieving cleaner air.

    Our Air Quality Services

    Through our range of air quality services, we aim to reduce the impact that developments, no matter how big or small, have on air quality. We regularly undertake Air Quality Assessments, often required for planning permission, to determine whether a proposed development could have an adverse effect on existing and future residents.

    We offer Air Quality Assessments and Monitoring across several sectors including residential, commercial and industrial. Our Air Quality Consultants carry out our assessments, before, during and after construction, depending on the project.

    Clean Air Day 2023

    We recognise the importance of clean air in maintaining our health, ecosystems, and the future of our planet. It is a day to celebrate and take action. We can create a positive change if we recognize the impact of air pollution and take concrete steps to reduce our contribution. We should adopt sustainable practices, support clean technologies, and advocate for policies that prioritize clean air. Together, we can make a difference and ensure that future generations breathe in a healthier and more sustainable world.

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    Sound Insulation Testing

    Sound Insulation Testing

    Sound Insulation Testing 

    What is Sound Insulation Testing?

    Also known as ‘Sound or Acoustic Testing’, the Sound Insulation Tests measure and quantify how much noise travels through party floors, walls and ceilings. Sound Insulation testing is required for the construction of all new dwellings, as well as for any construction that modifies a freestanding (previously single) dwelling for multiple living uses. It is also required when converting previously commercial space into dwellings, such as offices into flats for example. Tests are carried out to meet the requirements of Approved Document E of the Building Regulations. The chief aim is to minimise sound transmission with a view to reducing the impact of nuisance noise on homeowners and improving their quality of life.

    How Do Sound Insulation Tests Work?

    There are two types of sound insulation testing that are undertaken: Airbourne and Impact Testing.

    • Airbourne Testing BS EN ISO 140-4 (Airborne)

    Airborne floor sound insulation tests are carried out with a large dodecahedron speaker, using a white noise generator to create the source sound. A sound level meter is then used to take noise measurements within the source room and the receiver room (room directly adjacent to the source room). The background noise level is also measured. The higher the background noise then the higher the source noise will need to be set, since the resulting noise level in the receiver room needs to be 10dB higher than the background noise at all measured frequencies.

    • Impact Testing BS EN ISO 140-7 (Impact)

    When undertaking impact sound testing the tapping machine is placed in the upper apartment or flat and the noise level is measured in the lower apartment or flat in the room under the tapping machine. In all cases the room to be tested should be habitable in nature, i.e. bedrooms or living rooms.

    airborne and impact

    Part E Requirements for Sound Insulation Testing

    In order to meet resistance to the passage of sound standards, the test elements must meet values outlined in Building Regulations Part E. This document presents the following criteria to be met:

    Sound Insulation

    When Should Sound Insulation Testing be Undertaken?

    Sound Insulation tests should be carried out as early as possible. If minimum noise attenuation levels are not met during the test, changes can be made to insulation measures with less difficulty and expense that if these were to be carried out after the construction is fully completed.

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    Changes to UK Radon Maps

    Changes to UK Radon Maps

    Changes to UK Radon Maps – what it means for your development

    Radon is formed from the decay of Uranium and Thorium in rocks and soils, and is a radioactive gas. Inhalation of high concentrations of Radon has been strongly linked to lung cancer, and Radon is considered to be the second-most frequent cause of lung cancer after cigarette smoking.

    The radon level is very low outdoors but can accumulate indoors due to the high density of Radon gas in comparison with air.

    How Do We Mitigate Radon?

    The Radon Potential data classifies areas based on their likelihood of a property having a radon level at or above the Action Level. The Radon Action Level is currently set at 200 Bq/m3. The Radon Potential data is presented as a percentage of properties affected by Radon and are:

    • Less than 1% of properties affected
    • Between 1% and 3% of properties affected
    • Between 3% and 5% of properties affected
    • Between 5% and 10% of properties affected
    • Between 10% and 30% of properties affected
    • Greater than 30% of properties affected

    The levels at which protection measures are required varies across the UK, with initial trigger levels split between England & Wales and Scotland. 

    In England and Wales: 

    At a level of 3% or less mitigation measures are not required. At a level of >3%Building Regulations require Basic Radon Protection measures to be installed. At a level of 10% or more, Full Radon Protection is required. 

    In Scotland:

    At a level of 1% or less mitigation measures are not required. At a level of >1%Building Regulations require Basic Radon Protection measures to be installed. At a level of 10% or more, Full Radon Protection is required. 

    Contrary to guidance in England and Wales, properties in Scotland in the range 1-3% require Basic Radon Protection Measures.

    Basic Radon Protection will comprise the installation of a Radon Protection Membrane across the floor slab, depending on the foundation construction type adopted.

    Where Full Radon Protection measures are required, this will likely comprise the installation of a Radon Protection Membrane across the floor slab and ventilation measures, depending on the foundation construction type adopted.

    Any protection measures required will need to be set out in a site-specific standalone document, by a qualified Environmental Consultant.

    Map showing Radon protection areas

    Radon Map – Recent Update

    The UK HSA launched a new radon map on 01/12/2022.  The new map has resulted in Radon classifications in some areas changing to a level where Radon protection is required where previously it was not, or to a higher level of Radon protection being required.

    You can check whether the Radon Classification for site has changed by checking on the UKRadon website and entering the site postcode, however this search is only suitable for single dwellings (no larger than 25m in size) UKradon – UK maps of radon

    If the site/land is for redevelopment, a GeoReport provide by the BGS should be obtained BGS Shop · Radon : England and Wales GeoReport.

    NHBC Radon Requirements 

    From the 1st December 2022 onwards, all sites registered with the NHBC will have been assessed against the updated radon maps. If you’re site was assessed by an environmental consultant prior to 1st December 2022, the Radon Risk may have changed, and this will need to be reassessed.

    From 1st February 2023 plots commencing construction with the NHBC will be required to have radon protection measures installed in accordance with the updated mapping.

    The NHBC recommends that developments that have already commenced prior to the publication of updated mapping should discuss with the NHBC how best to comply with the higher level of protection that may be needed. To know if you’re site has been affected, order a BGS Map from BGS Shop · Radon : England and Wales GeoReport, or contact us for further advice and information.

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