Canadian Consulting Engineer

Feature

A Calgary Icon

 





 

The Talisman Centre is an integral part of the Calgary community. Formerly known as the Lindsay Park Sports Centre, this huge complex is located near the Calgary Stampede grounds on MacLeod Trail, accessible from downtown by the C-Train.

The centre was originally constructed for the 1983 Western Canada Summer Games, when it brought together thousands of athletes from across Canada in a “celebration of youth, sport, culture, and community.”

The centre has two Olympic-sized swimming pools, an Olympic dive tank, five full-sized gymnasiums, a 200-metre running track, 2,300 square metres of cardio and weight training space, a steam room, locker rooms, and a 20-person hot tub – all situated under the main building with its dramatic fabric roof. Access leads to a separate annex added in 2003 that has two additional Olympic-sized swimming pools. A separate entrance on the north side of the facility is used to access the 1,300-sq. m LifeMark Physiotherapy and Sports Medicine Clinic.

Owned by the city of Calgary and operated by Lindsay Park Sports Society, the Talisman Centre is one of the largest multi-sports facility in North America. It has millions of patrons and visitors each year, hosting both amateur and professional sporting events. It is also one of only three recreation facilities in Canada capable of holding international swim competitions.

In 2007, the city of Calgary retained Williams Engineering Canada to investigate the existing building to determine an appropriate strategy for replacing the 25-year old roof and to advise on other environmental and lighting energy efficiency upgrades.

The renovations were then organized to be completed in two concurrent phases with Williams Engineering Canada as prime consultant, a role that included structural, mechanical-electrical, and building envelope engineering. Roger Miller was project manager with Williams Engineering.

Throughout the renovations, access to the adjacent buildings had to be maintained. As well, various building components were shut down, which posed interesting challenges to the engineers as the different building elements were linked to the same building automation network. The project was completed in February this year and opened to patrons shortly after.

Replacing the roof

The first thing anyone notices about the Talisman Centre is its striking white fabric roof. A sculpted, tent-like form, the roof descends in a series of panel ridges from a large arched spine. It measures approximately 48,770 square metres in area.

The problem with the original roof was that temperatures inside the building could be scorching in summer, while in winter the building suffered from cold and condensation.

The solution was to replace the original Teflon-coated fibreglass roof with one that looks similar, but which has much better thermal and acoustic properties. The roof was replaced as a design-build project by Birdair with Geiger Engineers.

They provided a Tensotherm roof system that has layers of Nanogel impregnated fleece insulation within a Teflon-coated fabric. The technical name for the fabric is Polytetrafluoroethylene (PTFE). The nanogel can insulate four times more efficiently than fibreglass or foam and is hydrophobic moisture resistant. It has an R-value of 11 and a U-value equal to 0.7 per 25 mm thickness.

The fabric also has acoustic benefits. According to Cabot Corporation who manufactures the nanogel, its fine pore structure slows down the speed of sound, especially in the lower ranges, which is a definite bonus for a large recreational facility. The fabric’s coating is flame-resistant and it acts like a filter and neutralizes airborne impurities and odours. It also has self-cleaning attributes.

Each custom-designed new roof panel was installed individually using a new lifting device and two tower cranes. A life safety system for the arch was also developed to allow for the roof to be properly serviced over its expected 30-year lifespan.

When the old fabric roof was disassembled, it was rolled up and sent to the City of Calgary Parks Department, who used the material for the roof of a new storage shelter for equipment.

On the north and south entrances to the main building, the existing curtain wall had run its service life. As part of the renovation, the entire system was replaced with one that has fibreglass insulation and is translucent. The system admits natural light, but also provides glare protection.

The ring beam is a major structural element of the main building. It is located at the circumference above grade level, connecting all the roof valley, ridge and lateral cables. When modeling indicated that excessive heat loss was escaping through the exposed concrete beam, the beam was faced on the exterior with an R12 exterior insulation finishing system

Mechanical systems within the roof arch

The new mechanical systems were primarily adopted to prevent condensation from building up on the underside of the roof. Before the renovation, conditions under the roof during severe cold weather could become so wet they produced “raining” inside the centre.

The building’s original HVAC equipment in the basement was upgraded and left in place, but substantial new systems needed to be added. To save on valuable floor space, it was decided that the new HVAC system should be placed into the roof arch. Fitting the mechanical systems into the arch presented the greatest challenge.

Because the building is oval, the engineers needed a duct that would handle the curved geometries. To do this with a fixed aluminum or steel duct would have been exceedingly difficult, so a fabric duct system was specified. A fabric duct is more flexible and can be built off-site. Also, the centre has an open concept design, so care was taken to create a lightweight, harmonious design so that the exposed ducts would not interfere with the building aesthetics.

Various types of duct fabric were researched and a Danish supplier was identified to supply a patented system of fabric ducts and jet-throw nozzles. The nozzles are attached to the ends of the fabric ducts and direct air to the underside of the roof in a complex and specific pattern.

The mechanical system for the 1.8-m diameter fabric duct supply and return air system is unprecedented and may be the only one of its kind in the world.

Two 45,000-cfm fans were installed in the arch and required additional structural support for positioning into the architectural elements of the building. Supporting the massive equipment and preventing vibrations within the steel framing was a significant feat of engineering.

It was not a matter of simply installing new fans. The fans have to consistently operate at 800 rpm and they are designed to run 24/7. Therefore, prior to any work being undertaken, subconsultants reviewed the existing structure and did modelling tests to determine how to minimize the transfer of vibrations onto the structure. After construction was complete, an acoustic and vibrations consultant was hired to ensure the facility was operating within the design guidelines.

The high-efficiency 45,000-cfm fans produced excessive noise, so two-stage, upstream and downstream silencers were custom designed to dissipate the sound. The silencers are approximately the size of an apartment kitchen. Not only do the fans have enclosures of their own to muffle the sound of the vibrations, but also the fans have a silencer on the supply and return air.

Since a prime goal was to ensure condensation does not build up on the underside of the roof, during the design phase special data logging was done to monitor and gather information about the temperature and humidity of in-situ conditions over different seasons.

The models for the ductwork in the new design showed some potential dead spots in the building itself. Glycol heat and thin tube radiato
rs were installed on the ring beam to heat up those areas that lacked air movement. By simple heat conduction they prevent the accumulation of condensation.

Dehumidifiers were installed to reclaim heat and moisture out of the air and displace it directly into the swimming pools. This approach provides additional cooling benefits.

To ensure the remainder of the building is not contaminated with impure air, a filter wall was custom-built to allow the return air to flow through. These return air walls are wide open as opposed to being partially enclosed by grates, which provides additional benefits. During events, large banners and balloons occasionally float up into the ceiling space. Instead of blocking air flow and being expelled into the fans, the balloons and the banners are sucked into the return air and taken back down to the filter wall where they are trapped and can be retrieved.

The motors that run the fans were upgraded to be VFD (varying frequency drive) compatible, which is an unconventional motor and fan combination for a facility of this nature. The VFD motors can reduce the vent fan speed during low activity times to conserve additional energy. All existing chillers and fans were replaced with VFD-compatible motors and controls to reduce energy consumption.

During the renovations, the entire spine of the building was exposed. Air quality testing was done to mitigate any issues that might arise from the steel deteriorating due to the high levels of chlorine emissions from the swimming pools. These tests also helped to ascertain the type of materials that were required to build the equipment enclosures.

Fire protection, lighting, electrical design

To ensure that the fire suppression, fire alarm, and smoke evacuation systems continue to work during an emergency, the renovations added a custom built damper system within both the filter system and within the filter wall. The fire protection system is designed so that in the event of a fire, the fabric duct system would shut down and the damper would open and allow the infrastructure to continue to function as the smoke escaped.

Comprehensive 3D modeling was created to establish the lighting design. Overall the upgrades changed the lighting from 300 lux lighting levels to 600 lux levels.

One of the changes was to exchange the existing exterior flood lights for new interior direct and indirect lighting. The new lighting glows up through the new nanogel fabric roof, making the Talisman Centre a dramatic visual symbol at night.

Existing pendant lights that were over the pool had presented maintenance difficulties. These were removed and instead indirect metal halide and fluorescent lights have been added around the ring beam within the mechanical systems. The lights were installed on brackets that provide structural support to the mechanical equipment where they can be easily accessed.

As well, fluorescent strip lights are hidden up in between the large fabric duct and the walls. They render a cove lighting effect that blends with the architectural and building systems. The strip lighting also eases shadow effects caused by the large fabric ducts. Since the ducts are so large, they would have caused noticeable dark spots by the perimeter of the building if the strip lights weren’t installed.

Thanks to the new upgrades both to the roof and the mechanical-electrical systems, the Talisman Centre is vastly improved and will continue to be an important venue for the city of Calgary and its residents. cce

Lana Winterfield is communications coordinator with Williams Engineering Canada, based in Edmonton.

 

Client:

City of Calgary & Lindsay Park Sports Society with the Talisman Centre

Prime consultant, structural (except roof), mechanical-electrical, building envelope:

Williams Engineering Canada (Roger Miller, John McKay, P.Eng., Randy Smith, P.Eng., Wayne Yan, P.Eng., Winssy Lo, P.Eng., Stoyan Atanasov, P.Eng.)

Subconsultants:

AJ Technical (review existing mechanical components); Comtec Associates (public address and sound system), Golder Associates (indoor air quality), Leber Rubes (fire protection and codes), Neil Jaud Architect (locker room, gym floor, EIFS ), RWDI (air flow and vibration modelling), Todd Busch (acoustic and vibration testing)

Roofing design-builders:

Birdair, Geiger Engineers

General contractor:

Stuart Olson Dominion Construction