Part O building regulations
Overheating Assessments
We provide comprehensive assessments, including Simplified Overheating Method and TM59 Overheating Risk Assessments, to assist residential developments in creating comfortable and resilient indoor environments that comply with planning and regulatory requirements for thermal comfort.
The Simplified Overheating Assessments offer a quick, policy-compliant method to identify overheating risks early in the design phase, taking into account factors such as glazing ratios, orientation, ventilation, and shading. For more detailed evaluations, TM59 dynamic thermal modelling can be performed in accordance with CIBSE guidance, thoroughly analysing internal temperatures, solar gains, ventilation strategies, and occupant comfort under current and future climate scenarios.
By adopting a proactive, design-led approach, and collaborating with project teams, practical and cost-effective mitigation strategies are identified, including shading, glazing specifications, and ventilation improvements. This ensures compliance without compromising the overall design intent.
The reports provided are clear, planning-focused, and aligned with local authority requirements, facilitating smooth approvals while ensuring the development of comfortable, resilient buildings.
Simplified Method or CIBSE TM59?
The simplified method is a quick, cost-effective approach to achieving Part O Building Regulations compliance. It is suitable for straightforward developments and operates by adhering to a set of prescribed design limits and criteria. These criteria include restrictions on glazing, minimum ventilation levels, and solar shading requirements based on the building’s location, orientation, and window size. If the design remains within these established limits, it is assumed to satisfy the overheating risk assessment requirements. While this method is efficient and economical, it may not be appropriate for all projects, particularly in dense urban areas or high-risk designs.
For more complex designs or situations where limits cannot be met, a dynamic simulation model is required.
The dynamic simulation method, often referred to as TM59, offers a detailed approach for conducting an overheating risk assessment in residential buildings. This involves creating a thermal model to simulate a building’s performance over time. Utilising specialised software, the model considers factors such as CIBSE weather data, solar gains, occupancy patterns, internal heat gains, ventilation, and building materials. It predicts hourly internal temperatures, typically over a year, to identify periods when overheating may occur. The results are evaluated against the comfort criteria defined in the CIBSE TM59 methodology. If these thresholds are exceeded, mitigation measures such as enhancing shading, increasing ventilation, or reducing solar gain are necessary until acceptable conditions are reached. This method provides a more accurate and robust assessment, ensuring that dwellings are designed to remain comfortable, even during extended periods of hot weather.
What is included
How Can We Assist?
- Experienced consultancy providing practical solutions
- Advice and recommendations for appropriate mitigation measures, where necessary
- Support from early design stages through to Building Control sign-off
- Nationwide coverage
- Competitive pricing and fast turnaround times
Initial Assessment
Provide your planning drawings and specifications. A detailed review of these will determine whether the simplified method or the Dynamic Simulation Modelling approach would be best suited to your project’s needs in achieving Building Regulations compliance. For the majority of smaller projects, the more affordable simplified method should be sufficient, but where compliance cannot be achieved using this method, a CIBSE TM59 assessment may be more appropriate.
Practical & Cost Effective Solutions
Glazing ratios, façade design, and ventilation strategies, along with other key inputs such as occupancy profiles, equipment loads, and local weather data, are incorporated into a dynamic simulation model. Simulations are then conducted to evaluate temperature performance across representative spaces and orientations. If an overheating risk assessment identifies potential issues, clear and proportionate recommendations in accordance with the cooling hierarchy are provided. These may include adjustments to shading, glazing specification, ventilation design, or façade configuration.
Support From Early Stage Planning Through To Final Sign-Off.
Reports are structured for submission to Building Control or planning authorities and clearly demonstrate compliance with Part O and TM59 as required.
Related services
Supporting compliance across the project
Related services include Energy Statements for Planning, SAP and SBEM Calculations for Part L of the Building Regulations.
