How will the changes to Approved Document L, F and O, due June 2022, affect commercial buildings?

Darren Evans
July 1, 2022

In December 2021, the government introduced a range of changes to Building Regulations that will affect new and existing commercial buildings. These interim updates to Approved Document L and F of the Building Regulations, more often called Part L and Part F, aim to prepare the industry for a shift toward the Future Buildings Standard.

The overarching goal of these changes is the design of highly efficient non-domestic buildings that won’t require retrofitting in the future. These will also be zero carbon ready as our grid continues to decarbonise. Implementation of low carbon HVAC (heating, ventilation, and air conditioning) solutions and improvements to the building fabric are the two main areas to help deliver future electrified commercial buildings.

The updated regulations will come to force on the 15th of June 2022 and will be subject to new ‘plot-by-plot’ transitional arrangements. For the first time, the work on each individual building will need to have been started by the 15th of June 2023. This marks a departure from traditional transitional arrangements and is likely to affect large, multistage non-domestic developments. If work on a building has not commenced, it may be subject to redesign to comply with the new regulations.

What do the interim changes to Part L mean for HVAC solutions in non-domestic buildings?

The key performance metrics that will need to be met are:

  • CO2 emission target
  • Primary energy target
  • Minimum standards for fabric and fixed building services

The expectation will be for each non-domestic building to deliver on average 27% less CO2 emissions when compared to the current Part L standard. This is the more ambitious of the two options proposed in the original Future Buildings Standard consultation. The other proposed option was a 22% CO2 emissions reduction.

The introduction of a primary energy target is a new concept for the industry, albeit one Darren Evans have supported for some time. The primary energy target will drive increased energy efficiency by considering the amount of energy (or fuel) required by all the services in our buildings and the amount of energy needed to produce and deliver that fuel. This is pivotal to the success of built environment decarbonisation and should help drive the specification of highly efficient low carbon solutions to significantly reduce the amount of energy required to deliver heating, cooling, and hot water to commercial buildings.

Minimum efficiency standards for the fabric of the buildings have been uplifted to include lower U-values of thermal elements. TM23 by CIBSE will be the single methodology approved for air testing. A new minimum standard will also be introduced for wet space heating systems in new buildings. This will require a design that will enable such systems to operate at a maximum flow temperature of 55°C to ensure system efficiency. Building automation and control systems (BACS) will be required in all commercial buildings with heating or air conditioning systems over 180kW. This is instead of the 290KW suggested in the initial Future Buildings Standard Consultation.

Controls must be included for all space heating and hot water systems in existing commercial buildings. As in new buildings, BACS must not exceed the 55°C maximum flow temperature. Should the replacement fixed building service require a fuel switch, the new service must not produce more CO2 emissions or have higher primary energy demand than the service it replaces.

How do the interim changes to Part F affect commercial buildings?

The updated Part F aims to ensure the installation of appropriate ventilation systems and the provision of adequate indoor air quality in all commercial buildings with a highly efficient building fabric. The new approach that targets the ingress of external pollutants will allow the design of performance-based ventilation systems that focus on individual volatile organic compounds (VOC) as opposed to the current strategies that target a total VOC level.

A new requirement will be introduced to install CO2 monitors in offices and high-risk areas of a commercial building to reduce airborne infection risks. The minimum air supply rate in mechanically ventilated offices and common spaces will be set at 0.5 l/s per m2. This Part F update has not adopted ventilation capacity increases.

Filtration or air cleaning systems will be required for all recirculating ventilation systems that aren’t set up to prevent air recirculation within a space or between different rooms or zones in office buildings.

To help support you through the upcoming changes, or to offer a refresher on Part L, our on-demand video CPD “Part L Changes 2021 and Future Homes Standards” is available to watch at your convenience, or alternatively, you can book our CPD for an in-person delivery by one of our expert team.

If you’d prefer you can also contact the team at Darren Evans for support on your next project and to discuss the changes to Part L and F and the new Part O in greater detail.


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