Greening the Big Apple: how building got sustainable in the Bronx
24th September, 2010
Things are looking up in one of New York's least affluent boroughs, with the construction of the latest cutting-edge green development designed for low-income families
In 2008, in an effort to raise money in the face of a crippling budget deficit, the New York City Housing Authority announced that it would sell off several acres of public land in the South Bronx. Rather than simply giving the land to the highest bidder, however, the city prioritised developments that would incorporate sustainable design and give affordable housing a modern green face. Blue Sea Development Company was one among four firms with winning proposals, and will break ground this October on the Forest Houses development, a beacon of green building set among 15 ageing brown-brick public housing towers in the neighbourhood of Morrisania.
Morrisania isn't a place where you'd expect to find a cutting-edge green building. Like much of the South Bronx, the area is predominantly low-income, with more than 40 per cent of the population living below the poverty line.
But the Forest Houses development is just the latest of five affordable green housing developments in the area designed and built by Blue Sea. What makes these apartments 'affordable' is that they will be rented to families making $69,000 a year or less, and individuals making no more than $48,300 a year. Rents will be set at approximately 30 per cent of tenants' monthly income, in accordance with guidelines set by the city's housing department. Blue has 30 years' experience in the affordable housing business, incorporating green technologies and energy efficiency into its buildings. It designed and built the first Energy Star, LEED Silver and LEED Platinum multifamily affordable housing developments in New York State.
Raising the bar
This new building will raise the bar for New York's green building sector as a whole. Inside and out, the structure is designed to maximise efficiency and exploit green materials and techniques. Energy savings add up bit by bit throughout the building, from the smallest energy-star household appliances to the direct-drive lifts that use as much as 60 per cent less energy than conventional ones. Light fixtures throughout the common areas and apartments will be fitted with efficient LED and fluorescent bulbs, and the shower heads and kitchen and bathroom faucets are custom-made to suit the water pressure of the building, enabling designers to double the efficiency compared to low-flow fixtures without sacrificing the comfort of the residents.
But as Les Bluestone, partner at Blue Sea Development, says: 'The systems are really the focus.'
Hot water throughout the building and electricity in common areas will come from a natural-gas-powered co-generation system in the basement, and heating will be provided by natural gas boilers that are 90 to 98 per cent efficient. Computers with sensors inside and outside the structure calculate exactly how much boiler energy is needed to regulate indoor temperatures with no waste. Hot and cool air is kept in place with tight-sealed wall panels wrapped in 2in foam insulation and fibreglass-glazed windows, with additional insulation and caulk used in every nook and cranny down to the tiniest holes in the sides of electrical panels.
The building's tight seal will create a 'continuous thermal break', as architects put it, meaning no heat can pass between the inside and outside of the building. The edifice will be so leak-free, in fact, that it will cut green-building standards for maximum air change (as defined by the US LEED certifying body) in half.
Air-tight seals also line the building's interior walls, keeping temperatures, sounds and smells in common areas to a minimum, and increasing privacy and overall quality of life in the building. A noiseless and energy-efficient ventilation and filtration system removes more than 99 per cent of allergens from indoor air and controls air flow through discreet vents in the sides of the structure. Maximising air quality in this South Bronx neighbourhood is not insignificant - the area has one of the highest rates of asthma-related hospitalisation in the US.
A high level of indoor air quality is also achieved through use of green materials with low VOC (volatile organic compound) levels and zero formaldehyde. And the benefits to health and quality of life do not end with the air quality: Blue Sea has incorporated New York City's Active Design Guidelines into the building wherever possible, encouraging healthy living and physical activity among residents. Stairways will be located centrally and set behind glass walls, so that tenants are encouraged to climb rather than ride lifts. And a 10,000 sq ft outdoor area includes play structures and exercise equipment for both children and adults.
In addition to energy-saving systems and design for healthy living, the development will be a showcase of green building materials. The apartments will feature durable faux-wood flooring made from 70 per cent recycled vinyl content, common areas will be laid with recycled nylon carpet tiles and doormats made from recycled tyres, and vinyl panelling made with 53 per cent recycled content will cover interior walls.
The building's exterior walls will be made of 9ft x 40ft concrete panels that Les Bluestone explains will be assembled 'not unlike a child's building blocks.' The panels will contain recycled content such as slag and fly ash, and their pre-cast design reduces concrete waste while improving the building's air seal (because there are fewer joints between panels compared to 4in x 8in bricks from which most affordable city housing is made). Construction waste will be recycled: concrete is to be crushed and reused as filler in poured slabs or as drainage gravel, and gypsum drywall will be pulverised and used by farmers for its high lime content.
Perhaps the most interesting feature of this new development, however, is the 10,000 sq ft hydroponic greenhouse on the roof that will tie into the efficiencies of the building, utilising waste heat while insulating the top storey against heat and cold. Photovoltaic panels will supply electricity to the greenhouse and power air conditioners in the summer, cooling the greenhouse during the hottest times of the day. Additional cooling will come from passive design that maximises air flow and incorporates shade cloth and evaporative cooling pads.
The greenhouse will collect and filter rainwater to grow hydroponic vegetables year-round, yielding 10-20lb of fresh food per square foot. The rooftop structure won't be carbon-neutral, but according to Benjamin Linsley, whose firm Bright Farm Systems designed the greenhouse, the energy draw of an urban rooftop greenhouse 'is tiny compared to putting a greenhouse on the perimeter of the city', because it benefits from the rising heat that constantly radiates from below.
Set against the vast majority of New York City housing - affordable and otherwise - the Forest Houses development will be a sustainable wonder, but it is significant that the building is rising in a low-income neighbourhood. The variety, availability and price of green materials and technologies has improved dramatically over the past few decades, facilitating the expansion of a commercial green building sector that goes beyond high-end green buildings for the wealthy. 'When we started out you could count your options on one hand,' says Bluestone.
Despite how far things have come, Bluestone concedes that 'there are all different shades of green and all different levels of efficiency' - and there is always room for improvement. For example, cost constraints mean the building's co-generation system is limited to 20kW and will only provide electricity for common areas, while the bulk of the development's power will come from the electrical grid. Twenty kilowatts is nothing to scoff at, but with more funding a system could be installed to meet the building's entire energy demand. According to Bluestone, the price differential between green and conventional building materials these days is in the range of 5-6 per cent, and he recognises that the extra cost is worth the investment: 'By putting money in now we save money in the back end.'
Gwen Schantz is a freelance journalist
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