304 Kim Ma Street, Ba Dinh District, Hanoi
|Type of Building:||Office Building|
|New / Refurbished:||Refurbished|
|Year of construction:||2013|
|Gross Floor Area:||7500 sq.m|
The Green One UN House is a green building project to co-locate 16 different UN organisations in Hanoi, providing shared common services to enhance effective and cost efficient program delivery. It is one important component of the “Delivering as One” reform initiatives of the UN in Viet Nam.
The 7,500-m2 renovation project involves the demolition and refurbishment of all the existing building services, finishes and walls. New construction includes two new entry buildings providing separate entrances for people, vehicles and goods, and a technical building housing mechanical and electrical equipment. Within the main building, additional workstation and office space to accommodating the growing needs of the co-located organisations will be provided by introduction of two double storey bridges on the East and West sides of the courtyard.
Construction of the project was commenced in Hanoi on January 21st, 2013 and is expected to complete during the first quarter of 2014. Successful completion will give way to acknowledgement of the Green One UN House as a flagship green project demonstrating the viability of green & sustainable buildings in Vietnam.
Key green features:
• Good passive design
• Efficient equipment to minimise energy consumption
• Reduced waste during construction and operation
• Recycling the building structure and materials
• Green roofs
Third Party Verified: No
Source of Information: UNDP
Methods of data collection: interviews with manager and data collection via email.
Design Credit: GHD One-Member Limited Liability Vietnam
(84 4) 3942 1495
Architecture, Structure, MEP
(84 4) 2221 4124
Passive Design strategies
Orientation and Shading:
The Green One UN House (Green One) is a refurbished project in which the current columns and floor slabs are to be retained. It is oriented so that the main entrance faces approximately 7o east of due south which is, fortunately, already well suited to passive design.
A solar analysis was performed which suggested overhangs of 1200mm on windows on the North and South facades was sufficient to fully shade the windows from direct solar radiation year round. The west and east facing facades however receive direct solar radiation so the strategy the design team has chosen for these facades are to:
• Minimise glazing on the east and west orientations
• Provide vertical shading fins on the East and West sides, angled towards the South
• Keep a relatively small level of Windows-to-Wall ratio (WWR) at 0.386 on average
Due to blast-proof requirements, the glazing is double glazing with 6mm toughened glass for the outer pane and 7.52mm laminated glass for the inner pane. A low-e coating facing the insulating 12mm air-gap on the inner pane to achieve a lower U-value.
Natural ventilation was considered and rejected due to a number of issues including air pollution, high humidity and security reasons.
There is an atrium over the cafeteria and the conference centre to provide not only additional space, but also daylighting. Results from daylight modelling shows that 63% of the total Net Occupied Area (NOA) has daylighting.
Active Design strategies
High efficient equipment:
The strategy is to select equipment with higher efficiency in order to minimise the energy consumption, which includes:
• HVAC: Air-cooled water chillers with capacity of 200R.ton and COP of 2.98
• Lighting: Fluorescent lamps T5/T81 with high frequency ballasts
Photovoltatics (PV) System:
The building introduces a rooftop layer of photovoltaic cells as a means of generating solar electricity on-site. The system includes 546 x Suntech 200 W mono-crystalline panels, which will account for up to 10% of the building’s annual electricity requirement.
Improvement over baseline:
Energy simulation for the proposed building shows an improvement of 22% over the baseline building.
Water efficient fixtures:
The domestic water system features water efficient fixtures. Wash hand basins use sensor taps with a flow rate of 2l/minute. These taps should also cut off water supply when the hands are removed from the under tap, or when preset timing of 30 or 60 seconds is reached. A combination of regulators and selfclosing taps can achieve significant savings.
Water efficient flushing system:
The flushing system uses dual flush low capacity flushing cisterns. Each flushing uses 4.5l of water for a full flush and 3l for a half flush compared to 6l in the baseline.
Urinals are either Waterless type or are installed with flush valves that use not more than 0.5l of water per flush.
A reduction of 47.89% m³ domestic water/year is likely to be achieved.
Water efficient landscaping:
41% of the landscape area (742 out of 1822 m2) is planted to local drought-tolerant or low water requirement plant species.
The use of drought-tolerant and low-water consumption plantings reduces the irrigation demand by 21.5% in the first year compared to a similar area planted to non-drought tolerant species. The project requires 4.26 m3 of irrigation water per day on average, while a similar area planted to nondrought resistant species require 5.43 m3 of water daily.
Reuse of materials from demolition:
Existing brick from in-fill walls of the main building will be crushed and reused as structural material in the lower terrace retaining walls, as facing material for upper terrace walls, and as crushed mulch material for the planting areas.
A minimum of 20% of materials from demolition is to be reused in the new works.
Materials prefabricated off site:
For this project as much off site prefabrication as possible is to be carried out. The objective is to achieve greater than 30% of material prefabricated off site.
Rapidly renewable materials:
The design has allowed for more than 1% of the material used in the project to be produced from all rapidly renewable resources. Joinery, doors and wall linings are made from bamboo timber veneer and the floor is finished with groove bamboo flooring.
All adhesives and sealants used in this project must have low VOC and formaldehyde content. Carpets have VOC limits as low as possible and a maximum of 0.5 mg/m2.
Soil excavated from the site which contains organic matter and supports plant life will be stockpiled and re-instated for landscaping. Although the proposed scheme requires extensive earthworks, the contractor will be required to preserve and reuse at least 40% of the sites existing topsoil.
Landscaping of the site will be carefully designed to be in keeping with the Vietnamese environment and culture, and at least 35% of the existing vegetation will be preserved or restored.
The landscape scheme features green roofs with area of up to 35% of the roof area. Green roofs are located on the entry buildings, the covered walkway and the lower level roof covering the conference centre.
Reducing the heat island effect can be achieved by maximising planting areas in relation to the total site area, and using pavers with the Solar Reflectance Index (SRI)>29. The total planting areas for Green One account for 31% of the total site area, and total paved areas with SRI>29 are up to 35% of the total site area.
Eco-Charrette is a process through which stakeholders work together to generate and target green building and sustainability goals prior to making any design decisions. The UN performs an Eco-Charrette to engage all stakeholders from the early design stage of the building.
Contractor is required to document the whole construction process to ensure the construction is in accordance with the design’s intent
Commitment from the UN:
The UN is keen on reducing the environmental footprint of the UN operations in Vietnam. The GOUNH is intended to be a “model building which demonstrates the viability of innovative sustainable buildings in rapidly urbanizing Viet Nam, maximizes the transfer of “green” technology and knowledge to Viet Nam, building local capacities whenever possible, and sets a benchmark in the region for green office design” (Source: Design Brief)
The Green One UN House Fly-Through Animation