Rideau Valley Conservation Authority

Public building makes a statement with energy and water savings

by Jim Taggart

The 1,600 sq.m office and conservation centre has cut the need for potable water by 70%, and passive heating, high-efficiency boilers, and heat recovery ventilators have reduced energy use by 42%. The building has become a destination to learn about LEED construction, and best practices in water conservation and on-site septic treatment.

The orientation, shape and layout of the building maximize the opportunity for passive solar exposure. The elongated, two-storey office wing provides excellent daylighting and views for the majority of staff, while the narrower wedge-shaped northern portion contains intermittently occupied spaces with less need for daylight. Integral to this is the detailing of the southern façade with large horizontal overhangs and fixed shading louvers which allow direct sun penetration only in the heating season.
The Rideau Valley Conservation Authority’s [RVCA] mandate includes: Watershed management; Source water quality control; and Septic system approval and monitoring. Therefore, the building design and siting put a particular emphasis on the collection, conservation and treatment of water. In fact the immediate site is conceived as a watershed encircling the building with the following integral features:

  • A trickle of water emerges from a boulder on the park viewing terrace symbolizing the emergence of water from a spring and the source of the watershed.
  • The stream flows around the building gathering roof runoff and being treated against acidity by flowing over limestone rocks on the stream bed.
  • At the building entry the stream has widened to a pond which is traversed by a pedestrian bridge.
  • The stream flows away from the building picking up stream runoff from the road and parking areas.
  • Water collects in a constructed wetland and pond where it is naturally treated and allowed to percolate back into the ground.

The building functions as a visitor centre for the larger Beryl Gaffey Park in which it is situated, and therefore the public atrium, meeting and boardrooms are available for community meetings and private functions. Visitors to the park and building are exposed to educational signage and displays about the park, its natural history watershed ecology and the Centre’s green building features. The site was selected because of its:

  • Adjacency to the Rideau River,
  • Centrality within the watershed management area,
  • Ease of access to major transportation routes within the region, and
  • Proximity to Ottawa [the largest population concentration within the watershed.]

The building site and pathways are integrat-ed within the larger park pathway network, while priority facilities have been provided for bike parking and carpooling activities.
The general aim of the site development work was to create a naturalized rural valley setting. The Beryl Gaffey Park consists of an abandon-ed croplands and woodlots and the building is located within one of these levelled farm fields. Renaturalisation included:

  • Restoring valley contours berms and swales to the topography,
  • Retaining the existing hedgerows where possible,
  • Planting the site using native, drought tolerant species,
  • Constructing a wetland and storm water pond to collect and treat surface runoff water, and
  • Increasing available habitat for wildlife. [Fish have now arrived in the pond thanks to nature’s own forces: the ducks.]

Accommodating the office functions in a two-storey wing elongated in the east/west direction results in 93% of interior spaces being daylighted. Extended roof overhangs and horizontal sunshades and interior operable blinds ensure that the south-facing windows remain free from glare and direct heat gain during the summer months. This plan arrangement also ensures that 92% of workstations have exterior views. Occupant adjustable thermostats permit zone by zone comfort for all users.

Water conservation and waste treatment are of particular concern to the RVCA, and they endeavoured to model an exemplary approach to these aspects of the project. In addition to low consumption fixtures and waterless urinals the building collects and treats storm water and grey water with an on-site system so that no municipal water is used for toilet flushing. Treated grey water is also used for plant watering within the building atrium.

The on-site septic system uses state-of-the art treatment tanks and filtration beds to ensure that only pure water is returned to the ground. The net result is that the building uses 70% less potable water then the Baseline.

The building shape and orientation encourage passive solar heat gain in the winter months. Concrete floor slabs provide thermal mass to store the heat. Glazed openings are not used on the north side.

High-efficiency condensing boilers with AFUE of 93% accommodate all the water and space heating needs. The building ventilation system incorporates Enthalpy Recovery Ventilators. Through these means the building achieves a 42% reduction in energy consumption over MHECB standards. Fundamental and Best Practice Building Systems Commissioning protocols [per LEED] ensured that the systems were brought into effective and efficient operation.
An emphasis was placed on using natural materials with low embodied energy. Wood was used for structure and cladding where appropriate.

The structure was selected to allow its exposure without additional cladding and finishes. These include structural steel, glulam posts and beams and galvanized acoustical steel decking for the roof. Additional acoustical ceiling tiles were provided in selected areas where it was needed to achieve acoustic damping requirements.

Exposed concrete floors were used in the public atria, circulation areas and many ancillary spaces to minimize the use of additional floor finish materials.

Low VOC paints and adhesives were used throughout. FSC wood was sourced for glulam, cabinetry and interior finished areas.
Open floor plans with demountable systems office furniture and partitions were used to accommodate planned growth of the organization by 30% over the next 8 to 10 years within the current building shell. Potential future growth of the Authority will be accommodated with an eastward expansion of the office wing. To achieve the budget limitations exterior cladding systems were selected in several categories:

  • Durable with extended life expectancy: natural stone used to clad the main Boardroom.
  • Durable with medium life expectancy: demountable panellised cement cladding system.
  • Durable with medium life expectancy and renewable finish: wood siding in protected areas, easily accessible for re-staining.

This building has a constant flow of visitors seeking regulatory approvals and information about septic systems, water quality, conservation and flood plain issues. The RVCA has chosen to make it a public demonstration project on water conservation, storm water management and septic system best practices.

Public displays and handouts about the sustainable building approaches, water conservation and waste treatment systems are provided in the public atrium.

The RVCA has commissioned a case study document to inform further LEED projects and has already started hosting tours of the building.

Jim Taggart is editor of SABMag

Credits

  • Client Rideau Valley Conservation Authority, Manotick, On
  • Architect Christopher Simmonds Architect Inc.
  • Structural Engineering Glotman Simpson, Vancouver
  • Structural Engineering [Wood Roof] Fast + Epp Partners, Vancouver
  • Electrical/Mechanical Nord Limited, Ottawa, On
  • Landscape Architect Lashley & Associates, Ottawa, On
  • General contractor M.P. Lundy Construction [Ontario] Limited, Ottawa, ON
  • Photographer Peter Fritz

Materials

  • Structure and exterior Glued-laminated timber by Western Archrib, structural steel, cement fibre board and western red cedar siding finished with Sansin Environmental Stain; Soprema Soprastar roofing membrane
  • Interior Low VOC paint on drywall by CGC;  InterfaceFLOR carpet tile;  Hubbell Lighting products, daylight photo sensors
  • HVAC and water treatment Direct Vent Condensing Boiler, inline centrifugal pumps and expansion tanks for heating system, direct vent furnaces, Mitsubishi “Mr. SLIM” condensing unit; Air-to-Air heat recovery supply fans and exhaust fans by Nu-Air, dual flush toilets, waterless urinals; on-site septic treatment by Waterloo Biofilter,  on-site wastewater treatment systems: Bionest, Ecoflo, Puraflo Peat Biofilter and Clearstream.
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