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30 Semple Street, Edinburgh

AirScore D&O


57,000 sqft


Corran Properties on behalf of CBRE Investment Management

Soon to be Edinburgh’s “Greenest Building”, 30 Semple Street is a remarkable redevelopment combining Scotland’s leading sustainability standards with outstanding well-being facilities and exceptional flexibility.

The project, due to be completed in 2024, is a redevelopment of the original building first built in 2001 and designed by Michael Laird Architects, who have again been tasked with transforming what was formerly known as Excel House to greatly improve its sustainability in operation, occupier amenities and workplace structure to satisfy post-Covid occupier requirements.

Sustainability and wellbeing have been at the core of the redevelopment, by stripping back to the original frame, 30 Semple Street has saved 3,300 tons of CO2, more than 50% of the carbon that would have been used in the reconstruction. Spaces have also been designed with natural light and ventilation in mind with cycling storage, car charging, secure changing and great showers also put in place to support healthier people and environmentally friendly commutes. 

The redevelopment adds two floors and the inviting new roof terrace has great views over the city, including prime views of Edinburgh Castle. All new class-leading energy-efficient systems, contemporary facades, crisp aesthetics and amenities of the highest quality.

The Objective

With plans for 30 Semple Street to set the “new benchmark for net zero carbon emissions and sustainability”, there’s also been an emphasis on creating outstanding facilities for occupiers and a flexible, modern workplace.

Due to the ambitious nature of the project, the design and specification have also had building certifications in mind, targeting high performance across not only AirScore D&O, but BREEAM, NABERS and ActiveScore. Alongside this 30 Semple Street also targets EPC A performance to exceed incoming changes to EPC requirements as well as net zero carbon emissions in operation.

Conducting an AirScore D&O evaluation was a natural complement as part of their design considerations with the AirScore certifications aligning with Hea02 and Hea04 sections of the BREEAM standard. 

With the added challenge of balancing sustainability with building performance, undertaking a design & operation certification allowed 30 Semple Street to ensure their HVAC and building specification was optimal for their location and occupier requirements without compromising on energy usage.

The Outcome

After completing the evaluation by AirRated, 30 Semple Street achieved AirScore D&O Platinum, signifying best-in-class design and specification for a healthy building that will achieve outstanding indoor air quality. In doing so 30 Semple Street became the first building in Scotland to achieve a Platinum rating at design stage, providing further confirmation that the commercial space was designed with the occupier in mind.

During the review of the design specification, AirRated helped Corran Properties identify areas of the build they could optimise for Air Quality including increasing the ventilation rate to help control gases from furnishings as well as improve carbon dioxide performance.  Outdoor air quality monitors were also added to the specification to be fitted to the outside of the building. When pollution levels are high, the users will be informed and encouraged not to use their natural ventilation to ensure that their hybrid model didn’t increase the volume of pollutants entering the space.

Air quality sensors are specified to be located in the occupied zone as opposed to the typical return air duct location to give a more accurate representation of IAQ performance where the occupants are located.

Corran Properties commitment to provide fresh air within the occupied office areas at a rate of 15 litres per second per person for an occupancy density of 1 person per 8m², means 30 Semple Street significantly exceeds the new fresh air criteria bench mark set by the British Council for Offices (BCO).

To maximise the quality of the fresh supply, the intake to the central air handling plant was located at roof level, away from street level pollutants, with the exhaust at street level ensuring good separation between the intake and exhaust points. The central plant also incorporates high-quality filtration to ensure any airborne particulates are removed before reaching the occupied space.

With the building targeting all BREEAM Hea02 and Hea04 credits within their design, they scored exceptionally across both organic gas and thermal comfort with the requirements aligning with the platinum thresholds of AirScore D&O.

By achieving exceptional performance across BREEAM, NABERS, ActiveScore and their EPC rating, it’s further evidence of the stellar job their design team has done in achieving its mission of creating Edinburgh’s “Greenest Building”.

The Benefit

Achieving an AirScore D&O has not only proven the high quality of indoor air at 30 Semple Street but has also provided occupants with a greater understanding of the indoor environment.

Studies have also proven that high-quality fresh air ventilation is associated with improved health, better concentration and higher levels of satisfaction with the office environment. AirRated’s latest research shows that occupiers now prioritise the health of the building above all over features including location, amenities and sustainability.

The AirScore’s value goes beyond certification and will continue to offer a deeper awareness and understanding of indoor air quality to all who use the building. Having worked with AirRated to optimise the design specification of 30 Semple Street, Corran Properties were able to communicate the design considerations they made to ensure that the air quality was to industry-leading standards across the building to the leasing team and subsequently to prospective occupants via tours, events and leasing collateral.

Having achieved AirScore D&O platinum 30 Semple Street has a strong opportunity to go on to achieve a high AirScore, post-occupancy, and maintain excellent indoor air quality going forward for its occupants.

Find out more about 30 Semple Street here –