In June, new building regulations were introduced in England including a brand new Part O. Part O has been implemented in a bid to reduce the risk of buildings overheating. Existing energy efficiency requirements mean that new build and refurbished homes in the UK tend to be very well insulated to prevent heat loss in the colder months, but this is leading to homes overheating in the summer, particularly in towns and cities. The new legislation attempts to address this issue.
Guidance on how to comply can be found in the new Approved Document O. As well as domestic dwellings, the new regulations also apply to buildings such as care homes and student accommodation.
Part O Simplified Method
There are two methods to demonstrate compliance with the new rules. The first is known as the Simplified Method. This is where you will be expected to limit solar gains and maximise natural ventilation potential through window sizing and window design.
Under the Simplified Method, you need to limit the amount of glazing on the south, west and east facades whilst ensuring there is sufficient openable window area. Details about the glazed area and opening area of every single window are required to complete the calculations.
To pass, the total glazed area within the dwelling must not exceed a limit based on the floor area and orientation of the most glazed facade and the total area in the most glazed room should not exceed a percentage limit which is based on the floor area of that room.
Factors such as the possibility of cross ventilation will affect the allowable glazed area and Approved Document O also takes into account the differences between dwellings in urban locations and more rural dwellings.
Part O Dynamic Thermal Modelling Method
If you are unable to achieve compliance with the Simplified Method, you will need to use the Dynamic Thermal Modelling Method. This is based on CIBSE’s TM59 design methodology and can provide more flexibility than the Simplified Method.
Under this method, the building will be modelled using the standard set of data inputs from TM59. This model can then be used to show compliance.
At C80 Solutions, our team of experts is well versed in the new regulations and we can help you carry out both the Simplified Method and Dynamic Thermal Modelling Method for Part O compliance. Get in touch with us today.