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TOHU, la Cité des arts du cirques, houses the international headquarters of

Cirque du Soleil. It has landmarked Montreal as a world leader of the circus arts. It unites

the idea of creativity, materiality and production into a single unit and incorporates

history with modern. The Tohu organization is actively involved in the Saint-Michael

Environmental Complex (CESM – second largest urban landfill site in North America)

revitalization and development program. Designed by architect, Jacque Plante and

scheme consultants, Jodoin Lamarre Pratte and Associates, the pavilion was opened to

the public, June 21, 2004. It contains Canada’s first circular performance hall and is

praised for its state of the art “green” architecture; achieving Gold certification from

LEED (Leadership in Energy and Environmental Design).

In the early 20th century, the 192-hectare site that Tohu is situated upon was a

limestone quarry. Later on, the site was sold to Miron and turned into a landfill site. In

1988, the City of Montreal acquired the landfill site and surrounding areas and turned it

into a waste sorting and elimination center. Eventually, the site became the Saint-Michael

Environmental Complex and, “the focus of the most extensive environmental

rehabilitation project ever undertaken by the City.”1 Tohu has been given the

responsibility of running the cultural and educational programming of the complex. Its

sustainable design incorporates innovative methods of heating, cooling, ventilating, and

construction.

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The pavilion is

primarily constructed out of

concrete, steel and glass

(Fig. 1). The elephant skin-

like, prefabricated

architectural concrete panels

were designed by Saramac.

These revolutionary panels

are low cost, malleable, easy to install, more fire resistant, and are more effective for

sound-proofing. In fact, they are so efficient they barely require any type of maintenance

at all and are expected to have a long life expectancy. Usually the structure of a building

holds up its cladding panels. However, in Tohu, the opposite occurs and the panels are

used to retain the structure. An increased number of fasteners were attached between the

panels. This method of design allows the panels to directly handle wind loads. Structural

design and construction is an important part of sustainable design. Careful “detailed

attention was given to the bearing capacities of columns located in the openings of the

ground floor. Moreover, one method of very precise installation had to be established so

that the installation of the panels [was] sedentary.”2 The construction and materiality of

Tohu is an integration of history and transformation. Many of the structural components

are recycled including: the steel beams from the old Angus factory (Fig.2), the grand

stairway made from old La Round bumper cars, rusted CP rails, pieces from an

abandoned crane, and metal panels from Expo ’67. The use of aged and recycled

Fig. 1: Materiality S A Lorenzo Martoni Cyry Assoc ppt

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materials, “symbolize the metropolitan industrial heritage.”3 It also reduces the amount of

waste generated from demolition, and lowers cost.

The cost of heating is 20% lower than

that of conventional heating methods due to

Tohu’s co-generating, hot water heating system.

The fermentation of waste from a CESM

excavation site annually produces a lot of

biogas. Gazmont, a local company, extracts this

biogas from the subsoil and converts it into

energy. This combustion of biogas is used to

boil water, which then transforms into steam,

which then turns a large turbine in order to

generate electricity. The steam must then be cooled and when this process occurs, part of

the hot water is routed to the Tohu pavilion. The water then circulates throughout a

network of ducts embedded in the floor of the building. This method of heating not only

reduces cost, but it avoids the production of any greenhouse effect gases, which benefits

not only the building itself, but the overall environment.

Passive geothermics not only regulates heating, but also cooling. Under the Tohu

site, in what is known as the “Canadian Well,”4 lies a massive ice-tray accumulating up to

20 000 pounds of ice. The ice tray is used “primarily as a reserve of freshness for the

periods of keen demands….”5 Passive geothermics has lowered the mechanical

Fig. 2: Steel beams from the Angus factory TOHU - Développement durable.pdf

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equipment capacity necessary for ventilation. Tohu uses natural ventilation by convection

and huge amounts of ice for air conditioning. “This system uses the funnel effect of the

theatre to diffuse the air with a low velocity system rather than traditional ventilation.”6

The stack effect is assisted by two chimneys and the sun. During the summer, when

overheating occurs due to sunlight, hot air rises and collects in a vortex near the ceiling.

The hot air is then forced out the two 1.2m diameter chimneys located 0.6m apart while a

system of ventilation ducts and air supply points near the ground circulate cool air. Two

ducts allow for operation flexibility customization to the office’s needs. Twenty-six

supply outlets behind the top row of seats can supply a total of 8000-9500 liters of

air/sec., six supply outlets backstage can supply 1000-2000 liters of air/sec., while supply

from under the seats and diffusion throughout the seats can supply 2000-3000 liters of

air/sec. With no interior gains, this natural movement of air cools and heats the building,

maintaining the interior environment at approximately twenty-three degrees Celsius (Fig

3). This continual process “consumes seventy percent less energy than a conventional

system while producing no greenhouse effect.”7

Fig. 3: Movement of warm and cool air.

By Dr. Andreas K. Athienitis, ing

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Another method used to reduce the need for heating in the theatre space is the

construction of a Trombe wall. The wall is made out of transparent insulation (1 RSI

min.), air cavity and approximately 20-30cm of concrete. “It is sized to contribute in

practically reducing heating required to almost nil on a clear February day.”8 The wall is

sufficient enough to accommodate most of the theatre’s heating needs and only during

shows on cold nights will additional heating be needed. The addition of this wall will lead

to an annual energy savings of about 38000kW/hr.

Not only does Tohu address internal comfort, but much effort was put into

creating an attractive external environment. Currently a park is underway as well as a

green roof. A green roof will not only reduce the building’s heat gain during the summer,

but it will enhance the city’s air quality. A large basin beside the administration side of

the building is used to collect rain water, creating also a nice focal point. The basin

ensures that there is gradual drainage towards the Ville de Montréal sewers. Due to the

basin, “Tohu has a natural system, eliminating the need to construct a traditional

underground retention system of massive concrete ducts.”9 This both conserves material

and energy. Energy is also conserved with the site’s external lighting system which uses

thousands of LED bulbs, reducing light pollution (Fig. 4). This type of light bulb can last

for several decades before they need to be replaced.

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The Tohu building makes effective use of daylighting by minimizing solar heat

gain in the summer and maximizing solar gain in the winter. The south facing rectangular

volume consists of mainly solid walls with few window openings. The walls block out

unwanted sunlight in the summer (Fig. 5) and the horizontal windows on the east

elevation let in low-angle sunlight in the winter (Fig. 6).

Fig. 4: LED bulbs reduce light pollution TOHU - Développement durable.pdf

Fig. 5 Fig. 6

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Conversely, the volumes to the north of the cylindrical theater have a significant

amount of glazing. They are situated in the shadow cast by the cylinder for the majority

of the year (Fig. 7). Therefore, the large amount of glazing is used to collect the

maximum amount of light throughout the year. Floor-to-ceiling windows oriented west in

this portion of the building admits a great deal of solar heat from the winter sunrays (Fig.

8).

Fig. 8

Fig. 7

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The cylindrical theatre does not apply strategies for daylighting because it uses

electrical lights for its specific purposes.

Due to its careful and innovative design, Tohu is one of the first buildings in

Canada to receive Gold certification from LEED. “The decision to build new circus

infrastructures near an old dumpsite and to take charge of the CESM programming

demonstrates [their] commitment to participate in the renewal of a district that was once a

victim of environmental shortsightedness.”10 Scoring a total of 44 points under the LEED

evaluation system (Fig. 9), Tohu conforms to a strict grid of criterias. There are six main

categories which include: sustainable sites, water efficiency, energy and atmosphere,

materials and resources, indoor environmental quality, and innovation and design

process.

Fig. 9: LEED Scorecard

TOHU - Développement durable.pdf

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Eight points were accredited to Tohu for its use of sustainable sites (Table 1).

Tohu is accessible by alternative means of transportation (e.g. Bikes, public

transportation, etc.). By choosing to build on an existing landfill, the building has reduced

its environmental disturbance and has avoided development on an inappropriate location.

In fact, Tohu encourages the rehabilitation and redevelopment of its surrounding areas in

the Saint-Michaels District.

Water efficiency is achieved through landscaping (the large basin which collects

rainwater) and reduced water consumption (recycling hot water for heating). Tohu

received four out of the possible five points from LEED in this category (Table 2).

8 Sustainable Sites 14 possible points Y Prereq 1 Erosion and Sedimentation Control 1 Credit 1 Site Selection 1 Credit 4.1 Alternative Transportation: Public

transportation access 1 Credit 4.2 Alternative Transportation: Bicycle

storage & changing rooms 1 Credit 4.4 Alternative Transportation: Parking

capacity 1 Credit 5.1 Reduced Site Disturbance: Protect or

restore open space 1 Credit 5.2 Reduced Site Disturbance: Development

Footprint 1 Credit 6.2 Stormwater Management: Treatment 1 Credit 8 Light Pollution Reduction

Table 1: Sustainable Sites score

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4 Water Efficiency 5 possible points 1 Credit 1.1 Water Efficient Landscaping: Reduce by

50% 1 Credit 1.2 Water Efficient Landscaping: No potable

use or no irrigation 1 Credit 3.1 Water Use Reduction: 20% reduction 1 Credit 3.2 Water Use Reduction: 30% reduction

The combination of heating by passive geothermics and natural ventilation has

significantly reduced the energy consumption needed in order for the building to

function. Not only is energy intake reduced, but the output of harmful greenhouse gases

is also lowered. This makes Tohu more environmentally friendly and less responsible for

the depletion of the ozone layer. Its high energy performance and sustainable networking

method has obtained fourteen points in the energy and atmosphere category (Table 3).

14 Energy & Atmosphere 17 possible points Y Prereq 1 Fundamental Building Systems

Commissioning Y Prereq 2 Minimum Energy Performance Y Prereq 3 CFC Reduction in HVAC&R Equipment 2 Credit 1.1 Optimize Energy Performance: 20% New

/ 10% Existing 2 Credit 1.2 Optimize Energy Performance: 30% New

/ 20% Existing 2 Credit 1.3 Optimize Energy Performance: 40% New

/ 30% Existing 2 Credit 1.4 Optimize Energy Performance: 50% New

/ 40% Existing 2 Credit 1.5 Optimize Energy Performance: 60% New

/ 50% Existing 1 Credit 2.1 Renewable Energy: 5% 1 Credit 2.2 Renewable Energy: 10% 1 Credit 2.3 Renewable Energy: 20% 1 Credit 4 Ozone Depletion

Table 2: Water Efficiency score

Table 3: Energy and Atmosphere score

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When designing, it is important to account for materials and resources. Much of

Tohu is comprised of recycled material received directly from local sites. This reduces

construction waste and the demand for virgin materials. The use of local materials also

reduces the impact of transportation on the environment. Three points were awarded by

LEED in the materials and resources category (Table 4).

3 Materials & Resources 13 possible points Y Prereq 1 Storage & Collection of Recyclables 1 Credit 2.1 Construction Waste Management: Divert

50% 1 Credit 5.1 Local/Regional Materials: 20%

manufactured locally 1 Credit 5.2 Local/Regional Materials: of 20% above,

50% harvested locally

Under the category of indoor environmental quality, a possible fifteen points may

be received. Tohu was rewarded ten points (Table 5).

10 Indoor Environmental Quality 15 possible points Y Prereq 1 Minimum IAQ Performance Y Prereq 2 Environmental Tobacco Smoke Control 1 Credit 1 Carbon Dioxide Monitoring 1 Credit 2 Increase Ventilation Effectiveness 1 Credit 3.1 Construction IAQ Management Plan:

During construction 1 Credit 3.2 Construction IAQ Management Plan:

Before occupancy 1 Credit 4.3 Low-Emitting Materials: Composite wood 1 Credit 5 Indoor Chemical & Pollutant Source

Control 1 Credit 7.1 Thermal Comfort: Comply with ASHRAE S5-

1992 1 Credit 7.2 Thermal Comfort: Permanent monitoring

system 1 Credit 8.1 Daylight & Views: Daylight 75% of spaces 1 Credit 8.2 Daylight & Views: View for 90% of spaces

Table 4: Materials & Resources score

Table 5: Indoor Environmental Quality score

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The building satisfies the two prerequisites of having minimum IAQ performance

and environmental tobacco smoke control. It also provides an effective distribution of air

in order to ensure health and comfort of the occupants, reduces the quantity of potentially

irritating contaminants, and allows for freedom of control of comfort through the

systems of heating, ventilation, and lighting.

From its use of passive geothermics to the Trombe wall, it is without a doubt that

Tohu is a leader in green architecture innovation. The building has been rewarded five

points in the category of innovation and design process; the highest number in that LEED

category (Table 6 ). Tohu aspires to reach exceptional performances that go beyond the

LEED given requirements.

5 Innovation & Design Process 5 possible points 1 Credit 1.1 Innovation in Design: Hybrid ventilation &

displacement 1 Credit 1.2 Innovation in Design: Passive geothermics 1 Credit 1.3 Innovation in Design: Diffusion 1 Credit 1.4 Innovation in Design: Gazmont energy 1 Credit 2 LEED™ Accredited Professional

Many of the concepts embedded in the Tohu pavilion have made Tohu a

remarkable leader in sustainable design. The first of its kind in Canada, it not only

educates by example, but it sets a standard for which future architecture should follow.

“Entering the TOHU pavilion is like entering a universe where environmental concern

permeates every space and every experience on the site. In fact, the pavilion is green not

Table 6: Innovation & Design Process score

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only in spirit but in body.”11 The term Tohu is “derived from the expression ‘tohu-bohu’,

which means ‘confusion’”.12 When looking at its design, it is obvious that there should be

no confusion as to whether or not Tohu should be rewarded for its environmental

diligence. Presently, Tohu is trying to push its way up in the rankings of LEED Platinum.

Until then, LEED gold more than suffices. Bravo.

1 To actively participate in the revitalization of the Saint-Michael Environmental Complex http://www.tohu.ca 2 Concrete panels which revolutionize construction http://www.infrastructures.com/1003/saramac.htm 3 Camille, Begin. "RE: pavilion." Attachment: CP Green Architecture (ENG).pdf. E-mail to Sarah Khalid. 15 Nov 2004. 4 The house of the TOHU: an ecological project in “gold” for Montreal http://www.guidesperrier.com/architecture/tohu/tohu_pavillon.html 5 The house of the TOHU: an ecological project in “gold” for Montreal http://www.guidesperrier.com/architecture/tohu/tohu_pavillon.html 6 Camille, Begin. "RE: pavilion." Attachment: CP Green Architecture (ENG).pdf. E-mail to Sarah Khalid. 15 Nov 2004. 7 To actively participate in the revitalization of the Saint-Michael Environmental Complex http://www.tohu.ca 8 Athienits, Dr. Andreas K., “Cité des arts du cirque: Simulation study of design options.” Quebec, 2003. 9 Camille, Begin. "RE: pavilion." Attachment: CP Green Architecture (ENG).pdf. E-mail to Sarah Khalid. 15 Nov 2004. 10 To actively participate in the revitalization of the Saint-Michael Environmental Complex http://www.tohu.ca 11 Camille, Begin. "RE: pavilion." Attachment: CP Green Architecture (ENG).pdf. E-mail to Sarah Khalid. 15 Nov 2004. 12 Urban miracle in green http://www.usgbc.org/News/usgbcinthenews_details.asp?ID=1120