Case study: Avoiding chemicaland biological disease agents

The Adam Joseph Lewis Center for Environment Studies is the teaching facility for Oberlin College’s environmental studies programme.The building is a demonstration of the commitment of David Orr, the course leader, and his team, who realised their ambition to teach in an environment consistent with their life views. They succeeded in convincing the college to support the development, gained independent funding for the project, developed a sustainable building brief and appointed an ecological architect with expertise in the field.The completed building, which includes 1,260 square metres of classrooms, offices and an atrium, is not only resource efficient, with the potential to export energy (see 3.2.8), but creates a harmonious relationship with the natural environment and a healthy indoor environment for the occupants.The building also acts as a learning tool for the students who can experience at first hand how an environmentally sound building operates.

Providing a healthy learning environment was one of the design aims for the centre. Living and working in healthy indoor environments is not only a basic human right and environmentally beneficial, but can also bring financial gains. A survey of research on the effects of office design on productivity concluded that healthy workplaces can increase staff productivity by 15 per cent (Arnold 2004). In educational environments research has shown that learning improves in naturally lit environments with good indoor air quality (Edwards 2003).

The Lewis Center’s indoor environment benefits from ample natural light, maximum fresh air through automatically openable windows, and minimal indoor pollutants through the careful selection of building materials, fixtures and fittings. Moreover, the contact with nature provides opportunities for relaxation for the building’s occupants.

To minimise sources of indoor air pollution, materials that off-gas compounds harmful to health were avoided. All paints and adhesives contain low volatile organic compounds (VOCs) (see 3.2.7).The office furniture and the auditorium chairs, designed by Design Tex, make use of an upholstery material designed by William McDonough and Partners, which is completely non-toxic, safe and biodegradable. After having removed sources of indoor air pollution, the air quality is monitored and fresh air introduced as necessary. In the classrooms, carbon monoxide monitors and motion detectors are linked to the mechanical ventilation and regulate the supply of fresh air, while maximising energy efficiency.The lecture hall ventilation is also regulated by carbon monoxide monitors, which are set at a level 20 per cent lower than recommended by ASHRAE, ensuring a high indoor air quality

Comfort levels are further enhanced by allowing individuals to control their immediate environment by opening windows in their office spaces as desired. To ensure the building retains its healthy environment, non-building sources of indoor air pollutants also need to be controlled. Cleaning materials (see 3.2.5) can be major sources of pollution. A maintenance protocol establishes cleaning products and practices to ensure the healthy environment is maintained in the long term.

The indoor air quality was also monitored by the National Institute of Standards and Technology (NIST), who used the Lewis Center as a test-bed for new methods of measuring and modelling ventilation and indoor air quality.The study showed that the very high air exchange rates could be reduced from the current 100 per cent fresh air circulated every four hours, without affecting indoor air pollution.

Creating a healthy environment has made the Lewis Center accessible to individuals with elevated chemical sensitivities and allergies. One such student was able to visit the

building, while it was being completed without suffering adverse effects. He later enrolled at the college in the knowledge that he could attend teaching activities in a healthy building.

The building has been a success in terms of creating a healthy, attractive and inspirational place to enjoy. Its role as a model has affected more than just students. In 2004 Oberlin College adopted an environmental policy that aims to reduce the college’s net CO2 emissions to zero. One of the first initiatives is to finalise agreements to purchase more than 60 per cent of the college energy consumption from ‘green’ energy sources.The policy also aims to encourage alternatives to the car and requires new buildings to be LEEDS certified (see 2.5.1). A second generation Lewis Center design may also be built some time in the future.

Site and ecology The new college building stands on apreviously used site. The external areas include anindigenous landscape, an artificial wetland, an orchard onthe partial berm on the north side of the building. and avegetable garden, which is cared for by students.Community and culture The brief was developed inconsultation with students, staff and residents and 13 designcharrettes were undertaken. The main entrance area is usedfor community occasions, such as banquets, as well ascollege activities, such as public lectures. The building isused as a learning tool for students.Health See main text.Materials Local materials were employed where possible,such as the external façade bricks. The external paving wasreclaimed from the existing 1960s building. Interfacerecyclable carpets were installed in first-floor areas. Theseare leased and not owned by the college, and will be sentback for recycling when they are worn out. Other materialswith recycled content include the steel frame, aluminiumroof, toilet partitions and tiling. All construction timber andmost of the furniture is FSC certified.Energy The building is designed to benefit from passive solarenergy with all teaching and communal spaces facing south.Exposed internal masonry acts as thermal mass. On the northside at first floor level are offices and at ground level are thekitchen, toilets and mechanical rooms. The building envelopeis well insulated with triple-glazed atrium curtain walling anddouble-glazed windows elsewhere. The north elevation ispartially bermed to provide additional insulation.Fabric U-values:Walls – 0.30 W/m2 C (R19)Roof – 0. 19 W/m2 C (R30)When external temperatures are appropriate, windowsautomatically open to allow fresh air in. In the atrium lowlevelwindows and north-facing clerestory windows openautomatically to provide natural ventilation. A closed loopgeothermal system, with 24 76-m deep wells, circulatesconstant heat ground water to heat pumps in each room to

provide heating and cooling. Additional heat is occasionallyrequired in the atrium and provided by means of a water-towaterheat pump feeding an underfloor heating system.Motion sensors, light sensors and individual controls reducethe amount of energy used for lighting. A grid-connected PVarray with 360 units, covering the 370-square metre roof,provides 45 kW of electrical energy. The buildingperformance was monitored after completion. Energy use inthe third year of occupation was measured to be:94 kWhr/m2/yr (29.8 kBtu/ft2/yr), of which 5 per cent isprovided by the PV array.Water See Chapter 6.3.Low level vents with actuators.Automatic high level vents.

Case study: Avoiding chemicaldisease agents

Timber, despite being a natural material, can have harmful effects on health. In addition, timber is often treated to protect it from fungal and insect attack, using materials that in order to achieve their purpose have to be toxic. Health hazards associated with untreated timber include dust from working the material and volatile resin vapours from some particularly odoriferous species.These are associated with skin, lung and heart disease from the dust and irritation to the nose, eyes and throat from the vapours, in susceptible individuals.The risks to health associated with timber treatments vary according to the treatment product used, and range from very low, as with boron-based treatments, to very high, as with pentachloro-phenol (PCP) (Curwell et al. 2002). Many timber treatments as well as surface finishes are dissolved in hydrocarbon solvents that affect indoor air quality, mainly during applications, but potentially also during occupation (see 3.2.5).

To avoid the need for treatment, a number of approaches can be taken.The choice of timber affects what treatment is required: hardwoods, such as oak, being generally more resistant to insect attack and water. Some softwoods, such as western red cedar, European larch and douglas fir, can also be used externally untreated. Regardless of what timber species and treatment is used, timber elements should always be detailed so the timber can dry out.This is done by detailing the timber elements to allow drainage and ventilation. Preventing the moisture content from remaining above 20 per cent for long periods of time inhibits the growth of mould. Before treating timber, it is worth considering the impact that deteriorating timber would have on the building. For example, if exterior cladding deteriorates, it can easily be replaced, with minimal impact on the building as a whole.Treatment should remain a last resort after considering all other aspects of design.

If treatment is required, one of the less dangerous treatments should be selected (see 3.2.9), such as Permethrin,ACQ, which avoids the use of arsenic and chromium, or boron, currently the solution preferred by many environmentally sensitive designers. Boron is a naturally occurring material, which is part of human and animal diet in minute amounts of 1-3 milligrams per day. In much larger amounts, 1000 milligrams, it is effective against rot and insect attack. In addition to its lower health risks, boron has other advantages, such as that it penetrates deeper into the timber, 40 millimetres compared to the typical 3-8 millimetres, and it can be used to treat dry rot in situ.

In recent years a treatment system that does not use chemicals has also been developed.ThermoWood® are timber products treated without natural or artificial chemicals.Treatment is by means of a method developed by the Finnish State Research Centre, which involves the use of heat and steam in a three-stage process. A first treatment stage, which reaches temperatures of 130°C, brings the moisture content of the timber to almost zero.This is followed by a second stage where temperatures are kept at between 185ºC and 215ºC for two to three hours, and a third stage where the temperature is lowered and the timber re-humidified to reach 4-7 per cent moisture content.The treatment changes the chemical structure of the timber by removing the timber resin on which the rot-forming bacteria and fungi grow.