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Dublin, Ireland

Architects: Wejchert Architects
General Contractor: John Sisk & Son Ltd.
Client: Irish Life

70 St. Stephen’s Green, a development of a brownfield site in Dublin City Centre for Irish Life Assurance Plc, results in a workplace with exceptional sustainable credentials. Accreditations for LEED Platinum, WELL Gold, and WIRED Gold were achieved as well as an attractive well-tempered workplace.

The new building location is urban, in the city center, and very attractive as it faces onto St. Stephen’s Green, which has mature trees and is a large and well-loved public park. The new multi-story office building is a careful insertion in the north elevation of St. Stephen’s Green.

The building has achieved the highest Energy and Environmental Standards: BER A3, LEED Platinum, WELL Gold, WIRED Gold, Near Zero Energy Building Standards (NZEB). To achieve these high standards, the design includes inter alia photovoltaic panels on the roof, a sedum green roof, rainwater harvesting, air to water heat pumps, and an ice bank. As is required by this accreditation, waste during construction was assessed and minimized.

Comfort / Health and Wellbeing: The floorplan is attractive. The panoramic view to St. Stephens’s Green is maximized by full glazing on that facade. The glazing to the central recess courtyards brings daylight and sunlight to the center of the floor plan. In all, 75% of the office area is no more than 5 meters from a window and daylight. Heat gain through the glass is limited by the use of glass and interstitial blinds in the south-facing facade.

The building fabric meets the WELL limits on VOC emissions. Finishes, fittings, and furniture are selected to minimize VOCs. Paint was avoided in corridors by using large format ceramic tiles. All timber products are low formaldehyde to En717-1:2004. This minimizing and monitoring of emissions applied during construction also.

Individual control over one’s working environment is achieved by providing local lighting control to over 90% of the building occupants to suit individual task needs and preferences. In addition, there is local control to multi-occupant spaces to cater to work needs and preferences.

Similar controls to heat/cooling are provided — individual comfort controls to more than 50% of occupants plus individual controls of multi-occupant spaces to enable adjustments to meet those occupants’ needs and preferences Glare from lights is managed by calculating glare, choosing appropriate light fixtures, and using shading techniques.

Reduced glare improves the visual experience for the occupants, increasing comfort and reducing the risk of fatigue and headaches.

Fabric: The material on the St. Stephen’s Green elevation is dressed stone to respect the neighboring buildings and acknowledge the urban setting for this project and it extends into the double-height entrance hall to provide continuity and inviting transparency.

The structure is reinforced concrete and includes a double basement. The mid-terrace location and the resulting high thermal mass has a good heat response, responding gently to daily and annual thermal changes, more comfortable than sharp rises or falls for occupants. The ground floor is now level with the street outside. External walls are well insulated.

Sustainability, Economy & Energy: Development is maximized by using the entire footprint, extending down by two floors, and adding a floor at roof level. The parapet level to the terrace is maintained and the vista down St. Stephens Green.

The well-insulated fabric and airtightness achieved minimize energy demand. The building is air-conditioned and has an effective airtightness value of 3W/m2/m2 @ 50Pa.

Air temperature, radiant temperature, airspeed, and humidity are included in the air-vac system and monitored in use. Fresh air with a heat recovery system is introduced to all occupant areas. MERV 13 filters are installed on the air handling units and maintained regularly.

Additional measures to ensure the system operates to the best advantage include the installation of CO2 sensors in occupant areas. Plant design includes installation of access for cooling coil inspection to check on non-interstitial condensation to assist in mold and microbe control (not always physically possible in practice).

Minimum indoor air quality performance meets section 4-7 of ASHRAE 621-2007. ASHRAE standard 55-2004.

• Regulated operational carbon emissions: (KgC02/m2/annum) BER: 15.68 kgCO2/m/yr.
• On-site renewable energy contribution: (kWh/m2): 9.62Kwh/m2.

Water: Water usage is minimized by the selection of low water usage fittings, and by water harvesting on the roof, used as greywater in WCs. The project provides fundamental water quality that meets thresholds for turbidity and coliforms for drinking and other uses and verifies standards by regular on-site tests.

Resources: The site was brownfield and is adjacent to the Luas (electric tram), and bus lines, within 500 meters of the railway line, cycle lanes, in general very well served by public transport. Parking is limited, electric charging points are provided. Bicycle parking and showering facilities are provided in the basement, a gym for fitness is included.

The building is 37% more energy efficient than an ASHRAE (US-based energy standard) baseline. 31.5% water use reduction achieved. The project offsets 1.48% of the total energy costs through renewable energy generated on-site.

Building limits disruption of natural hydrology by reducing impervious cover, increasing on-site infiltration, reducing or eliminating pollution from storm-water runoff, and eliminating contaminants.

Via placing the carpark underground and through the selection of reflective materials on the roof, the project reduces the heat island effect to minimize impacts on microclimates and human and wildlife habitats.

Maintaining the Green Standards: Innovations include improvements in plant and technical systems, but longer-lasting innovations are those that pass on the “green” message and give active encouragement to others to follow suit.

70 St. Stephen’s Green is a shell and core workplace project, and the behavior of the tenant management will have a significant effect on energy demand and CO2 emissions of the building in use, and their policies and procedures will affect the quality of the workplace for their staff.

A handbook has been prepared for the tenants. It explains the aims of WELL and LEED, describes the measures taken in the building in non-technical detail, points out how straightforward it is to build on these to achieve the same standards for the fit-out, and in general gives every encouragement to the tenant group to follow the high standards set.

Additional meters are already installed to assist in this tenant application. The Green and WELL features in the building, e.g., biophilia, art and dignity, bicycle parking, gym, information monitor in the circulation areas informing all of events and activities are available to the tenant.