Sustainability Report

Life cycle assessment

A full Life Cycle Assessment was conducted using OneClickLCA and assessed in accordance with EN 15978. The assessment covers environmental impacts across material production, construction, in-use, and end-of-life phases.

The calculation was made as part of the BREEAM assessment, in line with the BREEAM International New Construction 2016 standard, over a standard 60-year lifecycle. 

The recorded carbon figures are:

• Upfront embodied carbon (A1–A5): 1,628 tCO2e / 201 kgCO2e/m²
• In-use replacement (B4–B5): 966 tCO2e / 119 kgCO2e/m²
• End of life (C2–C4): 215 tCO2e / 27 kgCO2e/m²

Material efficiency and structural coordination

• The building’s sustainability ambitions are embedded in its structure and section, not only in its systems. The primary frame consists of precast reinforced concrete columns, beams, and hollow-core slabs, with spans dimensioned to achieve a structurally and materially efficient geometry.
• Structural, facade, and planning elements are coordinated to a strict 1.35-metre module. This provides the underlying discipline connecting the efficiency of the precast frame, the sizing of the bespoke facade extrusions, and the flexibility of the floorplate.
• Precast construction reduces on-site waste and allows tighter quality control of concrete mix and reinforcement, minimising material use relative to equivalent cast-in-situ construction. The span sizing was developed specifically to reduce the quantity of material in the structure, with a direct reduction in embodied carbon as a result.
• Multiple project-specific extrusion profiles were developed for the repetitive aluminium elements across the facade. Rather than adapting standard off-the-shelf sections, each profile was sized to suit its precise structural and dimensional role, avoiding the excess material associated with generic sections designed for a broader range of applications. Across a facade of this scale, with a high degree of repetition in the fins, cladding profiles, and spandrel elements, this approach reduces the total aluminium tonnage in the building.
• The mechanical and electrical strategy was brought into the design process at the earliest stages, rather than being resolved around an established building section. Developing the services strategy in parallel with the structural and spatial design allowed the building section, core placement, and floor-to-floor height to be optimised around services distribution efficiency. This reduced duct and pipe run lengths and associated material quantities throughout.
• As a direct consequence of the core arrangement and facade design, the building does not require a sprinkler system, avoiding the embodied carbon associated with pipework, storage tanks, and suppression infrastructure extending through the full building height.

Operational emissions overview

• Emerald achieved a BREEAM International New Construction 2016 Final Certificate at Excellent level, with an overall score of 75.7 percent. The certification was awarded in February 2025. 
• The building is pursuing WELL v2 Core Gold certification, with the remaining performance tests currently being carried out to finalise the award.
• Beyond BREEAM and WELL, the project has been independently assessed for alignment with the EU Taxonomy, covering climate change mitigation, climate change adaptation, and the transition to a circular economy. A CRREM pathway analysis completed by PwC Luxembourg confirms that the building’s operational carbon trajectory is aligned with the Paris Agreement 1.5°C decarbonisation path.
• The building’s as-built Energy Performance Certificate records an estimated energy consumption of 85 kWh/m²/year. The CRREM analysis confirms this places Emerald within the 1.5°C-aligned decarbonisation pathway for Luxembourg office buildings, with compliance projected through to 2047. This takes into account the expected decarbonisation of the Luxembourg grid and district heating network over that period.
• Emerald is connected entirely to district heating, supplied via the Cloche d’Or district energy network. This network is sourced from the combustion of municipal household waste, making it a locally recovered energy source. There is no gas boiler on site.
• Conditioning throughout the building is delivered via an Interalu climate ceiling system. This radiant approach operates at lower water temperatures than conventional forced-air systems, improving the efficiency of heat and cooling delivery. It also works efficiently with district heating supply temperatures and contributes to the stable thermal environment required for WELL certification.
• The cooling system specifies refrigerant R-1234ze, with a Global Warming Potential of 7 and zero Ozone Depletion Potential.
• The facade is the building’s primary environmental control strategy. At ground-floor level, a full-height Schüco FWS 60 SG SI structural glazing curtain wall provides the main envelope, with a bespoke extruded aluminium rainscreen cladding system concealing the insulated solid zones.
• Above, the upper floors are enclosed by a continuous ribbon of Schüco AWS 90 Si windows, triple glazed throughout, with alternating fixed and tilt-turn opening lights set into recessed spandrel panels in matching PPC finish.
• The facade’s deep vertical and horizontal fins, projecting up to 580 millimetres from the face, provide passive solar shading across all orientations and seasons. The vertical fins are angled in alternating directions, shifting the shading geometry across the day and year.
• A fully automated solar blind system, Model System Italia Modelpak FX 80 M, is integrated within the fin assembly, with blind guides and head boxes concealed within the fin depth. The combination of fixed shading geometry and responsive dynamic blinds allows the facade to manage solar gain while maintaining daylight and views.
• The double-layer motorised entrance, based on a KONE sliding door system, operates in sequence to reduce thermal infiltration at the lobby. This supports both the building’s WELL thermal comfort criteria and its overall envelope performance.

• All office surfaces are equipped with raised floors and false ceilings, maintaining flexibility for services reconfiguration without structural intervention throughout the building’s life.