7 More London is one of the UK's first speculative offices to achieve a top BREEAM rating at design stage.

There is a new landmark on the banks of London’s River Thames. Alongside Tower Bridge and across the river from the Tower of London is a new office building called, modestly, 7 More London. Despite its unassuming title this conventional-looking corporate building is significant because it is one of the first major speculative office schemes in the UK to have been awarded a BREEAM Outstanding rating at design stage. It is now working to the target of following up the interim rating with a full rating post-construction.

Description

7 More London is the final and largest building to be constructed under the masterplan for the More London site. The 10 storey, 60 000 m² building incorporates 48 000m² of office space located above ground floor retail units. Construction of the building’s shell is complete; its glazed, symmetrical wings of offices open out to embrace the river revealing a hollow circular drum, housing the reception, at its core. Three curved bridges connect these two wings at levels two, five and eight, while at the rear the building’s southern elevation drops to seven storeys to respect the existing buildings along Tooley Street. Inside work is underway to fit out the offices ready for the building’s 6000 occupants, which will have moved in to their new home by May 2011.

The story of how 7 More London became one of the UK’s greenest office buildings started four years ago, when PricewaterhouseCoopers’ (PwC) decided to lease the ten storey office in order to consolidate its London operations. At the time, the building was still on the drawing board so it was regarded by PwC as having the potential to meet the firm’s sustainable vision. “We wanted this building to dispel some of the myths in the real estate world that occupiers are not interested in sustainable buildings, the so called ‘circle of blame’,” says Paul Harrington, real estate director at PwC. He says occupiers do want good sustainable buildings because “sustainability is good business practice”.

Sustainability was also seen as a differentiator between PwC and its competitors and Harrington was aware that most of the questions on the firm’s website relating to the move to new offices concerned what the organisation would be doing to enhance sustainability in its new offices. “The drive for sustainability was from the top down and the bottom up,” explains Harrington.

At the time PwC decided to lease the building it had a planning requirement to achieve a minimum environmental rating of BREEAM Very Good (2006). Accordingly, PwC pushed the developer and its design team along with PwC’s fit-out designer BDP to target the highest level of environmental performance attainable at that time, BREEAM Excellent (2006). As work on the building’s engineering design commenced, however, details began to emerge of an upgrade to BREEAM and the release of BREEAM Offices 2008. This was a major blow to PwC’s vision because the changes included the addition of a new elite rating of BREEAM Outstanding to the classification system. The result of which was that as it stood, PwC’s new building would no longer be the sustainable differentiator it wanted.

PwC upped the ante and set a target for the building to achieve BREEAM Outstanding (2008), under the revised criteria. “This is a building for the future and a building that will last us for the next 20 years so it would seem crazy not to go for the ultimate category,” says Harrington. To achieve this rating the design would have to achieve a minimum of 85 out of a possible 100 environmental points. This was uncharted territory.

To stand any chance of getting close to the threshold of 85 points, collaboration between the developer’s and tenant’s design teams was essential so that tenants and developers design teams grasp every opportunity to tease every last credit out of the scheme. “It was important that both project teams were involved, without this joint effort we would never achieve what we wanted,” Harrington says.

Learning points

“The key to attaining the Outstanding rating was to start with a good base building;” says Stephen Runicles, environmental design director at BDP. Fortunately Roger Preston and Partners’ design for the base building already included many low energy and environmentally beneficial features. This included:

· A high performance building envelope, based on an argon-filled, low transmission glazing system fitted with extensive shading to minimise solar heat gains.

· A biofuel based tri-generation system to generate heat, power and cooling using absorption chillers (CCHP). The specification of the CHP engines was enhanced to enable them to run on any biofuel including used cooking oil. The system incorporated two engines each capable of developing 385kW of electricity along with 400 kW of heating and 416 kW of cooling.

· Plate heat exchangers were added to CCHP to units to increase the use of waste heat and extend the CCHP unit’s run time to enable it to provide up to 25% of the buildings total electricity demand.

· Also included in Roger Preston’s base-build design was a solar thermal hot water supply to the core’s toilet pods and a heat recovery ventilation system.

· To squeeze every extra credit out of the design a regenerative braking system was incorporated into the building’s 16 lifts.

· PwC were helped in their task of grabbing BREEAM points by the building’s structural designers Arup, who succeeded in using 80 per cent recycled aggregate for the first time in the building’s concrete structure; an achievement which merited the award of the first ever BREEAM point for innovation.

On the office floors, the enhancements to BDP’s design to achieve BREEAM Outstanding saw:

· The office fan-coil units replaced by active chilled beams. The amount of fresh air supplied to these units is minimised by linking it to CO₂ concentration in the offices.

· The building’s electric perimeter heating was replaced by low-grade hot water heating system fed from heat recovery units added to the building’s roof-mounted chillers. The units supply low grade hot water at 45°C but the addition of the heat recovery system also improved chillers’ efficiency by 35 per cent and earned the design team another BREEAM point for innovation.

· In addition, a sophisticated control system was also developed with extensive sub metering to monitor cooling, heating, power and lighting loads on a zone by zone basis.

· The offices are also being fitted with an ultra efficient, high frequency, fully-programmable low-energy lighting system which is daylight-linked. The system is IP addressable which will allow it to be controlled by the building’s occupants via their PCs, within strict boundary conditions, and will incorporate time clock control and presence detection for out of hours working.

· In hospitality areas, restaurant, cafes and corridors BDP has opted for high efficiency LEDs to help reduce maintenance and save energy

Outcomes

“We’ve looked sensibly at what we’ve invested in,” says Harrington. As a result there were some technologies PwC did not utilise because their payback would have been over 50 years. “Some technologies have a payback of up to 15 years, but that still makes good business sense on the basis of a 20 year lease,” explains Harrington. “You have to talk commercially about sustainability; the days of windmills on roofs are gone, we now need to deliver things that are practical and cost effective,” he says.

The building has even been future-proofed to allow further environmental enhancements when these become cost effective. This includes strengthening the building’s structure in key areas to enable rainwater storage tanks to be installed in the future. There is also provision for the future installation of a solar electric array on the building’s roof – should it become cost effective for PwC to do so.

The good news for the design team was that the building succeeded in achieving a BREEAM Outstanding rating based on its design. It was also awarded an EPC A rating. According to Runicles the building will achieve “a 70% improvement in CO2 emissions over current (2006) Building Regulations Part L2.

“When we set out we wanted to demonstrate that BREEAM Outstanding could be achieved at a sensible price,” says Harrington. The good news for PwC is that the estimated cost increase of taking the building from BREEAM Excellent to BREEAM Outstanding was minimal. “We estimate it cost at £2.25 per square foot on the base price to achieve BREEAM Outstanding, which proves that good sustainable buildings need not cost that much more money if they are properly planned and specified,” he says.

Having achieved BREEAM Outstanding for the design, the next challenge is to ensure construction waste targets are met and the scheme gets an Outstanding rating under the BREEAM post-construction review. “We’re not being complacent, we’re working hard with the contractors to ensure that they meet these very challenging targets,” says BDP’s Runicles.

The design team scored 8 out of a possible maximum of 10 innovation credits to achieve BREEAM Outstanding including:

- The building becomes a learning resource by displaying environmental performance data to staff and visitors

- 80 per cent recycled aggregate used in the building’s concrete

- Exemplar performance under the Considerate Constructors Scheme

- Recovering heat from the chillers that would normally be rejected to atmosphere and using this heat in the perimeter heating system

- Water sub-metering

- Involvement of expert accredited professional BREEAM advice from pre-stage C (2 credits)

- Use of multi-fuel CHP engines