BCO releases new guide for greener offices

The early update to its most recognised publication, ‘Guide to Specification’, responds to challenges emerging from the pandemic and the accelerating need for the built environment to address climate change. The update advises designers how to create healthier offices that support changing working patterns, while reducing carbon emissions. Recommendations include:

• Adoption of 10m² space-per-person
• Minimum sustainability target of BREEAM ‘Excellent’ and 5 Star NABERS UK target for new buildings
• Aspirational targets for operational and embodied carbon use to meet NZC (Net Zero Carbon) goals
• Increased levels of outdoor air supply
• More efficient lighting installations
• Reduced power and cooling loads
• Higher performance facades
• More flexibility in the range of structural spans for office space

The BCO has updated its guidance on space allowed for each employee when designing a speculative office building. 10m² per person is recommended as the occupancy density design standard for general workspace. The former high occupancy density allowance of 8m² per person has been redefined as a special use case for exceptional cases.

Designing for the 10 m² per person occupancy density provides greater scope for the variety of workplace settings needed to support hybrid working. It also avoids overdesign of core services, improves floorplate efficiencies, and minimises carbon emissions.

The greater use of low-powered tablets, laptops, and smart phones, plus growth of cloud computing has allowed a reduction in small power load allowances 100 W to 60 W per person. This reduces the heat generated in the office space, which in turn reduces the cooling needed.

Many developers already target BREEAM ‘Outstanding’ for new offices. Reflecting the rapid progress in the sector in adopting more demanding sustainability targets, the Guide is moving its minimum BREEAM target rating from ‘Very Good’ to ‘Excellent’, and introduces the latest building certification standard, NABERS UK – an energy performance rating relying on measured energy use. The update recommends targeting a 5-star NABERS UK rating for new building design.

Market trends have fuelled a desire to create flexible, relatively column-free, open-plan offices. However, the structural solutions needed can be carbon intensive. The 2023 update to the Guide aids the future adoption of alternative structural materials such as timber by adding smaller 6.0 and 7.5 m spans to the recommended range. This wider range provides designers with more options to minimise the embodied carbon of the structure.

The selection of high-performance facades, lighting and building services systems should also be made with net zero targets in mind, prioritising energy efficiency.

Richard Kauntze, chief executive of the BCO, said: “The BCO Guide to Specification often described as the ‘design bible’ for the office sector is an essential resource for the decision makers who invest in, develop or design millions of square feet of office space every year. The 2023 Update will drive the decarbonisation of the office sector, enacting change to help the industry deliver on the UK’s net zero by 2050 target. This new guidance for the highest-quality offices introduces more generous space standards and greater design flexibility to support wellbeing and sustainability as the office sector adapts to the world of hybrid work.”