The Building Regulations Part O 2021 is the first of its kind and aims to tackle overheating in new residential type buildings only.

 

What is the purpose of Part O?

 

​The goal of Part O is to encourage the design and construction of buildings that limit unwanted solar gain through the summer months and ensure occupants have adequate means of removing excess heat from indoor environments. However, the measures themselves are not designed to guarantee the comfort but rather to protect the health and welfare of the building occupants.  

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What type of building does Part O cover?

 

Residential buildings within the scope of the Part O approved document can be found at Table 0.1 of the approved document and are identified below:

1. Residential (dwellings)

2. Residential (institutional)

3. Residential (other)

Please note, shared communal rooms and common spaces that contain more than one residential unit are also covered and in certain circumstances live or work units are also included, please call for clarification and assistance. 

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How is Part O calculated?

 

Part O is demonstrated if either of the following two methodologies are followed.

1. Simplified Method for limiting solar gains and means of removing heat

2. Dynamic Thermal Modelling.

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If the Simplified method is used

 

This method can be used for both high and moderate risk locations as described in the Part O approved document. Then, using the same document confirmation is gained of the dwellings risk, either high or medium. Once determined the dwelling must show "cross ventilation" which are openings on the opposite facades.

If "cross ventilation" is present guidance from the the Part O approved document table 1.1 can be followed to limit solar gain and removing excessive heat. 

Please note, there are a number of situations/scenarios that complicate this methodology. Please call for clarification and assistance.  

Where "cross ventilation is not present we would use the Part O approved document table 1.2. This table contains several targets that have been lowered to achieve compliance. 

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How is compliance with the Simplified method assessed?

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Part O approved document provides a checklist in Appendix B that we can complete and then you can provide this to building control to show compliance. 

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If the Dynamic Thermal Modelling method is used.

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This approach found in the Part O approved document is designed to provide more flexibility above those given in the simplified method.

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How is compliance with the Dynamic Thermal Modelling method assessed?

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To ensure compliance all of the following must be true:

1. CIBSE TM59 is used.

2. All TM59 limited have been used from sections 2.5 and 2.6 from Part O approved document.

3. Acceptable items have been used to reduce overheating as defined in section 2.7-2.11 of Part O  in the approved document.

Once met our assessor can provide you with a report to pass on to building control which shows pat O compliance. 

Please note, there are a number of situations/scenarios that complicate this methodology. Please call for clarification and assistance.  

 

Why Choose Us. 

 

Choosing Your Space means you get friendly, fully trained, certified and accredited assessors who work with BRE approved software packages such as JPA Designer. We keep you fully informed until the assessment is successful and our reports contain building Control required information ensuring a speedy progression of your development.