Dynamic Overheating Assessment Part O, TM59 and TM52 Compliance
Innervision Design has qualified dynamic thermal simulation modellers and consultants, and can offer clients a range of dynamic overheating modelling and assessment reports including Part O, TM59 and TM52 compliance. We strive to provide a service with competitive rates and quick turnaround time; as well as offer our clients with cost-effective and practicable solutions.
1. Why use dynamic thermal modelling for overheating risk analysis
As our globe continues to warm up, and modern buildings are constructed with enlarged glazing and high air tightness, overheating is becoming an important issue in the UK homes and buildings.
The newly released Building Regulations Approved Document O (Part O), which will come into effect on 15 June 2022 in England, outlines and provides guidance on the legal and technical obligations for newly constructed residential buildings to comply with overheating standards.
Part O of the Building Regulations stipulates two methods for overheating analysis.
- The first method, called the simplified method, prescribes maximum areas of glazing and minimum free areas of openings allowed in rooms and buildings, in order to limit solar gains and remove excess heat.
- The second method, the dynamic thermal modelling method in accordance with CIBSE TM59, will allow greater design flexibility and provide more accurate overheating risk analysis.
Some planning authorities, for example, the Greater London Authority, was demanding dynamic overheating analysis a few years ago.
Dynamic thermal modelling is an advanced computer algorithm, and allows accurate predictions of thermal and other building related performances. It takes into account a wide range of design parameters (e.g. hourly weather files and detailed occupancy schedules and internal gains), and analyses them at short time intervals (e.g. sub-hourly analysis). Consequently, the results derived from dynamic thermal modelling are a more accurate reflection of a building's performance, in comparison with other static methods.
We use industry leading software, DesignBuilder dynamic simulation software, to construct 3D models and analyse overheating risk.
2. Part O and TM59 dynamic overheating assessment for dwellings and residential institutions, to comply with the Building Regulations and local planning policies
Part O requires new dwellings and new residential institutions to comply with CIBSE TM59 dynamic thermal standards.
CIBSE TM59:2017 (Design methodology for the assessment of overheating risk in homes) defines an industry standardised approach to predicting overheating risk for residential buildings using dynamic thermal analysis.
Residential buildings include dwellings and other residential institutions (e.g., student accommodation, care homes and prisons etc).
3. CIBSE TM52 dynamic overheating assessment for non-residential buildings, to comply with local planning policies
CIBSE guide TM52, 2013 (The Limits of Thermal Comfort: Avoiding Overheating in European Buildings’), defines an industry standardised approach to predicting overheating risk for non-residential buildings using dynamic thermal analysis.
CIBSE TM52 is required by some local planning authorities (for example, the Greater London Authority). However, Part O of the Building Regulations will not apply to non-residential buildings.
4. Innervision Design Part O, TM59 and TM52 dynamic overheating assessment services include:
- Construction of detailed 3D model of your buildings
- Comprehensive data input (e.g. u-values, thermal mass, external shading, HVAC, openings and free areas)
- Dynamic simulation modelling using various DSY1, DSY2, DSY3 weather files if required
- Guidance on overheating mitigation strategy based on cooling hierarchy to ensure compliance. Passive measures will be prioritised (e.g. shading, low-g windows)
- A detailed and easy to read report for your submission to Building Control Body or related planning authorities.
5. Part O compliance checking using the simplified method if dynamic overheating analysis is not required.
The Part O Simplified Method prescribes maximum areas of glazing and minimum free areas of openings allowed in rooms and buildings, in order to limit solar gains and remove excess heat. Therefore, Part O will have a significant impact on conceptual design as areas of glazing and free areas of openings are important design elements which need to be carefully thought over. Architects may need to incorporate an overheating mitigation strategy at the planning stage; otherwise, the approved schemes may be subject to costly and time-consuming changes in order to comply with Part O 2021 at the later Building Regs technical design stage.
For Part O compliance, it would be ideal if you can get in touch with us as early as possible, preferably at the pre-planning stage for a preliminary Part O compliance service, using the Simplified Method. We will check your conceptual plans thoroughly and ensure the size of glazing and free areas of openings are compliant. If projects fail the Simplified Method, we will guide you on a cost-effective solution to comply with this method. Not every project will be suitable for the use of Part O Simplified Method. We will advise you on Dynamic Overheating Modelling if required, which can normally be taken at the Building Regulation compliance stage.