Building Performance Analysis and Strategy
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Air tightness requirements in buildings are becoming increasingly demanding. Consequently, it is crucial that design principles and techniques are embedded in the design and construction of buildings to ensure that air tightness levels are achieved at practical completion. We provide consultancy services that systematically work through architectural detailing and construction methods to reduce the likelihood of air leakage. During construction inspections a smoke survey can be undertaken to assess the quality of workmanship and highlight leakage paths. Interim air pressure testing with fans can also be undertaken to determine the air permeability result at a given stage in the construction process and inform the anticipated test result at practical completion.
ASHRAE energy modelling uses the ASHRAE methodology (mainly used in North America, but also Asia, Australasia and the Middle East) to determine the likely energy consumption of a building and demonstrate compliance with the ASHRAE standard and achieve LEED energy modelling credits.
Computational Fluid Dynamics (CFD) modelling is used in various situations within buildings to assess the effectiveness of ventilation strategies in achieving the desired air quality and indoor temperatures, either by natural means or forced convection. CFD is critical in assessing the effectiveness of a given system in achieving the desired air flow through zones. The modelling results inform the recommendations and guidance on thermal mass, equipment location and the optimal ventilation and mechanical services specification.
Dynamic Condensation Risk Analysis using WUFI software provides a highly detailed and accurate evaluation of the risk of interstitial condensation, mould growth, frost risk and corrosion. This hygrothermal (the interactions between heat and moisture) analysis provides the basis for recommendations on material types and thicknesses, cavity dimensions and appropriate ventilation levels to achieve best practice design standards such as EN 15026.
(Note that this analysis is now a requirement for all internally insulated external walls.)
Energy management of existing and newly occupied buildings is essential to closing the performance gap whereby buildings use multiple times more energy in operation than predicted during design. This requires a thorough audit of the building’s systems and operational strategy, subsequently, an action plan can be implemented that reduces energy consumption whilst maintaining occupant satisfaction.
Energy Performance Certificates (EPCs) estimate the amount of energy a building will consume and are the ultimate output from Part L energy modelling. They are a legal requirement for domestic and non-domestic buildings under the Energy Performance of Buildings Directive. As of 2018 landlords cannot grant new tenancies for properties with an ‘F’ or ‘G’ rating. EPCs are typically produced at project practical completion and can also be produced for existing buildings. Low EPC ratings could in part be due to poor modelling, consequently Eight Associates always ensures that all calculations are done in full detail without generic data to ensure the most accurate results.
Eight Associates works with clients from all sectors to ensure long term environmental, social and economic sustainability objectives can be embedded into operations through robust policy, plans or project strategies. A clear understanding of our client’s aspirations is paramount to adopting feasible goals and we aim to assist with ease of integration into current practices.
Establishing sustainability objectives in large organisations requires detailed planning and careful implementation. Eight Associates works with key stakeholders within an organisation to establish their priorities and provides the technical knowledge of the environment to establish the trade-offs and likely outcomes of implementing the objectives. Typically, bespoke appraisal criteria and toolkits will be produced by Eight Associates to allow the organisation to make decisions and prioritise their resources most effectively for the optimum sustainable outcome.
Glare occurs when direct light is received on an object like a screen and there is high contrast between the screen and the surrounding areas. A glare analysis highlights the areas where the glare risk is high, evaluates the daylight glare probability (DGP) for different workstations in the space, and provides recommendations and measures to reduce the glare.
An Indoor Air Quality Plan is a vital document to manage the contaminants within new and existing buildings. Eight Associates produces Indoor Air Quality Plans which contain advice on the levels of contaminants that are acceptable, measures for specifying materials with low emission levels, detailed procedures for flushing out buildings and advice on pre-completion testing to ensure acceptable levels have been met.
Condensation in building components occurs when warm moisture-laden air meets cold vapour-resistant surfaces. Condensation has two primary forms: surface condensation (visible on surface) and interstitial condensation (hidden between construction layers). A good building envelope design will have systematically designed-out the risk of condensation by performing a Condensation Risk Analysis which would highlight the potential risk and verify that the proposed design solution has mitigated that risk.
Life Cycle Assessment (LCA) is a methodology for assessing the environmental impacts of a building or material from its origin through to disposal; its entire lifecycle. The environmental impacts from the consumption of resources and emissions of substances into the environment are quantified at each point in the lifecycle, which provides a holistic summary that can be used to inform decision making and provide an accurate comparison of options, crucially on a like for like basis.
LCA is now a fundamental part of the BREEAM process and is both a cost-effective and environmentally beneficial way to achieve the required credits for Excellent and Outstanding BREEAM ratings.
Natural ventilation uses outside air movement and pressure differences to both passively cool and ventilate a building without the use of fans, which reduces installed plant costs and energy consumption. A successful natural ventilation strategy must also deliver high thermal comfort and adequate fresh air for the ventilated spaces, which requires dynamic thermal modelling to ascertain the level of effectiveness and the exact speed and volume of air flow.
Post-Occupancy Evaluation (POE) is the process of obtaining feedback on a building’s performance in use. Eight Associates’ clients are increasingly recognising the value of POE as a tool to improve poor building performance to reduce impacts on running costs, occupant well-being and business efficiency. In some instances a POE can be conducted in one day, and involves analysis of energy consumption patterns and interviews with building occupants.
Energy modelling is required for domestic and non-domestic buildings to demonstrate compliance with Part L for Building Control and CO2 emissions targets for planning. It is an essential part of the design and construction process and aims to ensure buildings are designed with energy efficiency and cost of operation in mind.
Moisture must be controlled within buildings to prevent increased risks of condensation, damage to materials, reduced thermal conductivity of insulation and associated air quality issues. Existing buildings, often constructed with moisture-permeable materials, must have appropriate strategies to avoid these risks. A structural moisture survey measures the current levels of moisture in a structure and aims to ascertain its cause. Subsequently, appropriate ventilation rates can be recommended to minimise the risks of structural moisture. This is a mandatory requirement for BREEAM Domestic Refurbishment and should be considered best practice for extensive refurbishment projects.
Karsten tube testing is conducted for existing building elements to calculate the water absorption (A-value) of materials e.g. brickwork which provides the essential data for WUFI condensation calculations to determine the interstitial condensation risk.
Thermal bridging analysis is often crucial in achieving Part L targets and is used to reduce the risk of condensation within the building fabric. Thermal bridging results where one or more building elements, that are more thermally conductive than the rest of the building envelope, meet each other. These bridges can be designed-out to reduce surface condensation risk through an iterative process of detailed psi-value calculations and careful architectural detailing.
Fenestration products have complex component geometries and material properties, which require the use of finite element analysis (FEA) in order to quantify the heat losses in thermal bridges such as frames, transoms and mullions. Calculating the heat losses of these products and systems determines the U-values than can be used for Part L energy modelling and the potential risk of surface condensation.