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Why opt for Dynamic Thermal Modelling in Assessing Overheating Risks?

As global temperatures rise and contemporary building design features larger windows and high-efficiency materials, overheating has emerged as a significant concern in UK homes and buildings.

The introduction of Building Regulations Approved Document O (Part O), effective from 15 June 2022 in England, sets forth legal and technical requirements for new residential buildings to meet overheating standards.

Part O offers two approaches for achieving compliance with overheating criteria. The first, a simplified method, limits the maximum glazing area and dictates minimum ventilation through window openings to manage solar heat gain and dissipate excess warmth. The second approach involves dynamic thermal modelling as per CIBSE TM59 guidelines, offering more design flexibility and delivering a precise assessment of overheating risks.

Notably, some planning bodies, like the Greater London Authority, had already mandated dynamic overheating analyses in recent years.

Dynamic thermal modelling employs sophisticated computer algorithms to forecast the thermal behaviour and other performance aspects of buildings with high accuracy.

This method considers an array of design variables, such as hourly weather conditions, detailed occupancy patterns, and internal heat sources, performing analyses in short intervals (e.g., sub-hourly). Thus, outcomes from dynamic thermal modelling provide a more faithful representation of a building's thermal performance compared to static approaches.

To evaluate overheating risks, we utilise the leading DesignBuilder dynamic simulation software, which enables us to create detailed 3D models for thorough analysis.

Dynamic overheating assessment under Part O and TM59 for homes and residential institutions, ensuring compliance with Building Regulations and local planning guidelines.

Part O of the Building Regulations specify that new residential buildings must adhere to the dynamic thermal standards of CIBSE TM59 assessment. The aim is to ensure new dwellings meet a high standard of thermal comfort and energy efficiency, mitigating the risk of overheating for occupants.

The guidelines outlined in CIBSE TM59 overheating assessment enable professionals to consider a variety of factors affecting a building's thermal environment, such as insulation, ventilation, and material thermal mass.

This comprehensive approach ensures accurate assessments of thermal performance, helping to minimize overheating risks and contribute to the creation of more liveable and energy-efficient residential spaces.

QSMK Design offers services for dynamic overheating assessment, encompassing Part O, TM59, and TM52 evaluations:

• Development of intricate 3D models for your structures
• Extensive incorporation of data, including u-values, thermal properties, external shade, HVAC systems, and ventilation specifics
• Utilization of dynamic simulation modeling with DSY1, DSY2, DSY3 weather files as needed
• Advice on strategies to mitigate overheating, adhering to a cooling hierarchy that emphasizes passive interventions first, such as shading and low-g windows
• Preparation of a clear, comprehensive report for submission to the Building Control Body or relevant planning departments.
  

Verification of Part O compliance through the simplified method when dynamic overheating analysis isn't necessary.

The Simplified Method under Part O sets limits on the maximum glazing area and the minimum required ventilation openings in rooms and buildings to control solar gains and facilitate excess heat removal. This aspect of Part O significantly influences the early stages of design, as the dimensions of glazing and ventilation openings are critical design elements that require careful consideration.

Architects are advised to integrate strategies for mitigating overheating early in the design process to avoid the need for potentially expensive and time-consuming modifications later on, specifically during the technical design phase of Building Regulations compliance for Part O 2021.

For ensuring compliance with Part O, engaging with our preliminary compliance service at the planning phase is highly recommended. Through the Simplified Method, we will meticulously review your initial designs to ensure that the specifications for glazing and ventilation openings meet the required standards. Should your design not pass the Simplified Method, we will assist you in finding a cost-effective way to achieve compliance.

It's important to note that the Simplified Method under Part O may not be suitable for every project. In such cases, we will recommend Dynamic Overheating Modelling, typically carried out at the stage of complying with Building Regulations.