About the Building

The site at 21 Moorfields is located in the northern part of the City of London. The site is bound to the east by Moorfields and to the west by Moor Lane. To the north of the site is New Union Street with Fore Street Avenue, Moor House and Moorgate Exchange to the south of the site. The existing site comprised of a 1960s office building with some retail uses. The ground floor provides car parking, servicing and a number of retail units. A mezzanine and podium level are provided above. The podium level includes the Moorfields High-walk, which is accessed via escalators from Moorgate Underground Station to the east, as well as a series of connected public spaces. The development comprised a number of interlinked buildings, which are connected at ground and mezzanine level and rise up to 5 storeys above podium level at the highest point. The majority of the office space was derelict and vacant. A number of the retail units, including the City Boot pub are currently in use. Part of the eastern building was demolished by Crossrail following its Compulsory Purchase of the land in 2010 to enable the construction of the Western Ticket Hall for the new Crossrail station at Liverpool Street.

Demolition of existing buildings and structures will make way for construction of a mixed-use development above Moorgate LUL Station, the new Crossrail station and its entrance. The proposed development will consist of one main building and a smaller annex building to the west of the site, configured around a landscaped public square at podium level. The two buildings will provide office (Class B1) space, retail (Class A1/A3/A4) space, a replacement City Walkway between Moorfields and the Barbican, a new public square, cycle parking, servicing, storage, plant, landscaping and associated works. The ground floor comprises plant, cycle storage, a loading bay, storage areas, and an office entrance for the western building. The development is to be built above Moorgate Underground Station (District & Circle Lines) and above and around the Western Ticket Hall for the new Crossrail Station at Liverpool Street, which is currently under construction.

The team aspiration is to build a building that optimises energy efficiency, low embodied carbon and health and wellbeing credentials, supported by the following Client and team goals and ambitions:

• Landsec is committed to sustainable development and have produced sustainable guidelines for all their projects which are set out in their Sustainable Development Brief (SDB). They have also produced a Low Carbon Fit Out Guide which is distributed to all tenants with the aim of encouraging them to adopt a more sustainable approach to the fit-out of their spaces.
• WilkinsonEyre believe in the power of collaboration to address sustainability. Throughout the practice’s history there has been an unashamed interest in harnessing architecture, technology and engineering. They seek to optimise the synergy between them in order to draw out the best aspects of each discipline. This ethos has driven WilkinsonEyre to achieve innovative, efficient and beautiful design solutions that embody the highest level of ethical, environmental, social and economic sustainability. They embrace the fundamental principle of “doing more with less” that inspired the High-Tech architects of the 1960s and 70s.  They recognise the role they have as a profession to mitigate future climate change and are committed to delivering the 2030 UN Sustainable Development Goals, utilising the RIBA Sustainable 2030 Outcomes. Specifically, they will target net zero operational carbon emission solutions for new buildings, supporting the UNFCCC Paris Agreement on limiting global average temperature increase to below 2°C above pre-industrial levels. WilkinsonEyre is a founding signatory of Architects Declare which is a movement working hard to put sustainability at the heart of the industry. They believe that sustainability and design quality are inexorably linked and can only be achieved through collaboration with our clients, consultants and the supply chain.

Why did the building undergo BREEAM assessment?

To enable City businesses and residents to make sustainable choices in their daily activities whilst creating a more sustainable City, adapted to the changing climate, The Greater London Authority London Plan Policy CS15 – Sustainable development and climate change requires all redevelopment proposals to demonstrate the highest feasible and viable sustainability standards in the design, construction, operation and “end of life” phases of development. Proposals for major development should aim to achieve a BREEAM rating of “Excellent” or “Outstanding”.

Green Strategy

Embodied Carbon- Embodied carbon is the carbon emissions associated with manufacturing and transporting the materials used for the building and the energy used during construction process. An ambitious embodied carbon intensity target is set by Landsec for the project, however, due to the particular nature of the building -being an over station development with a special heavy structure and the need for its appearance to respond to the corporate character of the occupier with a high end glazed cladding -is posing a significant challenge in limiting its embodied carbon. Therefore, low carbon trade-offs is being pursued to compensate for the carbon intensive elements that are deemed essential to the design.

Re-use of existing buildings: Utilisation and revamp of the existing bridges to Barbican.

Embodied Carbon in structural steel

Structural steel is a key feature of the project and also plays an important part in the embodied carbon intensity due to its large quantity (>13,000 tonnes). All steel is recyclable and is generally being highly recycled at its obsolescence as it has high commercial value. The project team is also seeking to maximise the use of low carbon steel where possible to further reduce its embodied carbon.

Steel is produced via two main routes: Blast Oxygen Furnace (BF-BOF) (c. 70% of global production) and Electric Arc Furnace (EAF) (c.29% global production). There are significant environmental advantages of the EAF production route over BOF.

BOF produces primary steel from iron ore utilising a limited amount of recycled steel scrap (up to 30%) via energy-intensive heating processes, that require coal and other fossil fuels. The furnaces used in EAF are electricity-powered using high proportions (up to 100%) of recycled steel feedstock. EAF can further benefit from the decarbonising electricity grid by the wider use of renewable energy generation.

Consequently, for a particular steel product, a higher level of recycled content means a less energy intensive process and lower embodied carbon. This is illustrated in the graph below -the range of values for a particular % recycled content represents the variations in the industrial processes and electricity-mix between different steel mills and different countries.

Benefits of Assessing to BREEAM

Based on the detailed analysis carried out for the building during the design period advises that the building use can be optimised in different scenarios with a variety of occupant profiles and typologies. The BREEAM assessment has set the standard of what a commercial building is able to achieve if operated efficiently when benchmarked against other similar type buildings. The detailed analysis carried during at every key stage of the project enable critical decision making in a very tight project programme. Total integration and early engagement have been key to the success of this project’s wider and future plans.

The NABERS/Design for Performance process and consistent with CIBSE’s TM54. NABERS modelling methodology followed with a focus on accurately predicting the operational energy use of the building:

• Baseline energy model created from detailed design stage information
• ‘Off-axis’ scenarios modelled to test the impact of unknown variables including operational scenarios
• In operation, the analysis is updated and compared to actual energy use to identify inefficiencies and reduce energy use

At 21 Moorfields, the design team embraced the importance of creating a sustainable environment on an exceptionally complex site from the outset. Their drive to achieve the highest standards in sustainable construction and their adoption of a collaborative approach, supporting environmental initiatives across disciplines, has resulted in a building design with impeccable environmental credentials. – Landsec