In the construction industry, building regulations are in place to ensure the safety, efficiency, and sustainability of new buildings and buildings undergoing major renovation or change of use.
Amongst the many regulations is Part L, which focuses on reducing carbon emissions, cutting energy costs, and improving indoor air quality while promoting environmental sustainability and corporate responsibility.
In this guide, you will find all you need to know about Part L Building Regulations Volumes 1 and 2, including its requirements, importance, and the National Calculation Methodologies (NCM) required for compliance.
Introduction to Part L Building Regulations
Part L (Approved Document L: The Conservation of Fuel and Power) is a building standard that aims to improve the energy efficiency of new and existing buildings in the UK.
It applies to both residential and commercial properties, setting out specific requirements for insulation, ventilation, heating, and other key considerations around the conservation of fuel and power.
Like all building regulations, compliance with Part L is mandatory – ensuring that all new and modified buildings are designed and constructed for optimal energy efficiency and sustainability.
Complying with Part L
Compliance with Part L of the Building Regulations requires specific calculations during design stages using the National Calculation Methodologies (NCM), SAP and SBEM.
Put simply, the Standard Assessment Procedure (SAP) is used for domestic dwellings, while the Simplified Building Energy Model (SBEM) is used for non-domestic buildings. These calculations confirm that any proposed building complies with the requirements of Part L in terms of its energy use, CO2 emissions, and fabric energy efficiency.
On completion of the project, it should be confirmed that all that was designed was built, as well as the carrying out of any “as built” tests, such as actual air leakage rate. Then an EPC (Energy Performance Certificate) can be produced and lodged with the Government register.
The EPC is an indicative banding from A (most energy efficient) to G (least energy efficient), which suggests the building’s likely running costs. An EPC on its own does not demonstrate compliance with Part L – rather, it is an output from the calculations required for Part L compliance.
Part L Volume 1: SAP Calculations
The NCM for demonstrating compliance with Part L Volume 1 for dwellings is currently SAP (Standard Assessment Procedure). This must be calculated by a certified On Construction Domestic Energy Assessor (OCDEA), who can also complete and lodge the EPC during the “as built” stage.
Within the next iteration of Part L, SAP will be replaced by a new methodology – the Home Energy Model (HEM). This introduces additional factors into the calculation, such as occupancy, location, and orientation of the dwelling, alongside heat loss from pipe runs.
Click through to read more about SAP calculations and the services available with Stroma.
Part L Volume 2: SBEM Calculations
Similarly to domestic dwellings, commercial and non-domestic buildings require assessments to demonstrate compliance with Part L Volume 2. This requires SBEM calculations, which must be carried out by a certified Non-Domestic Energy Assessor.
Visit our SBEM services page for information on SBEM calculations and how support from Stroma can help you ensure compliance for new and existing buildings.
Part L Photographic Evidence
A new requirement of Part L Volume 1 was introduced in 2021 and requires evidential photographs to be taken throughout the construction of each dwelling.
The photographs are then compiled into a BREL (Building Regulations England Part L) report for Building Control.
Stroma has partnered with AutoBrel to provide a simple management solution that streamlines Part L photographic evidence compliance processes for our clients. Click through for more details.
Benefits of Part L Compliance
Energy Efficiency & Cost Savings
Part L compliance immediately ensures that buildings are more energy efficient and thus cheaper to run by:
- Improving wall & roof insulation
- Ensuring windows & doors are sealed correctly
- Implementing energy-efficient heating systems & lighting
Certain planning requirements, particularly in London, also dictate stringent percentage improvement standards for Part L, making development in these areas even more beneficial.
Improved Air Quality
Buildings that are not adequately ventilated can have poor indoor air quality, which can adversely affect the health of occupants.
By focusing on the impact of indoor air quality, Part L compliance can help to prevent dampness and mould – ensuring a healthier, more comfortable living or working environment.
The Risks of Non-Compliance
Non-compliance with Part L means that buildings cannot be “signed off” by Building Control, thus not permitting them to be sold, let, or be subject to financial mechanisms (e.g., mortgage or warranty). In short, the building will not “legally exist” without Building Regulations sign-off.
Failure to comply with any necessary building regulations may also result in costly fines or rework, or even order the demolition of structures in more extreme cases.
How Stroma Can Help with Part L Compliance
With over 20 years of experience carrying out both Part L Volume 1 and Volume 2 calculations, Stroma is perfectly placed to assist you with not only your Part L but Part O (Risk of Overheating) compliance. This is especially important as those measures which make a building more thermally efficient may cause the same building to overheat.
For more information or to speak to a member of our team, please get in touch.