Canadian Consulting Engineer

6 Case Studies

HVAC SYSTEMS

December 1, 2007   Canadian Consulting Engineer

HVAC SYSTEMS

Abbotsford Regional Hospital and Cancer Centre, B.C.

Stantec Consulting, mechanical engineers

The new 63,000-sq.m, $355-million, Abbotsford Regional Hospital and Cancer Centre is a high profile, public-private-partnership (P3) project in B.C. It is also Canada’s first P3 hospital. The 300-bed hospital is due to open in 2008.

The P3 partnership is between the Ministry of Health Services, Fraser Health, the Provincial Health Services Authority, the BC Cancer Agency, the Fraser Valley Regional Hospital District, Partnerships BC and a consortium of companies known as Access Health Abbotsford. Access Health Abbotsford is responsible for the design, construction, financing and maintenance of the new hospital.

Stantec was hired by the P3 project architect, Musson Cattell Mackey Partnership/Silver Thomas Hanley, to provide full mechanical consulting services. In this role Stantec not only had to design the HVAC systems, but also has to help the construction team ensure the systems meet certain performance and operational requirements as stipulated in the P3 contract.

The owner’s project scoping documents stipulated, for example, that the hospital must qualify for a LEED Silver green building certification, with at least three energy credits. It also had to qualify for NRCan’s CBIP rebate, meeting strict energy efficiency targets.

To meet the contractual requirements for sustainability, the project had to be designed using an integrated design process, engaging the full design and construction team. The integrated design process started at the conceptual design stage and continued throughout the design and construction process.

The energy targets for the building were possibly the most difficult targets to meet. It was necessary to rethink typical hospital design practice and come up with cost effective solutions that were acceptable to the contractors. Literally hundreds of possible energy saving strategies were analyzed, using sophisticated simulation software, with the help of EnerSys Analytics.

The following measures were adopted for the building’s design:

* High-efficiency gas fired hot water boilers are used for building heating; two 4,900-kW and one 2,000-kW 85% efficient hot water boilers are located in the hospital’s central power plant.

* A flue gas heat recovery system, using heat exchangers located in the combined boiler breeching, recover up to 700 kW of energy that would normally be wasted. The recovered energy is used for heating the building and domestic hot water.

* A high-efficiency chilled water generation system is used for air-conditioning portions of the building; two 900-ton chillers are piped in counter-flow configuration with a chilled water temperature reset control to optimize energy efficiency; the chillers consume a maximum 0.5 kW/ton of cooling. Also a condenser water heat recovery system recovers up to 980 kW of energy that would normally be wasted. The recovered energy is used for pre-heating the hospital’s domestic hot water.

* An exhaust air heat recovery system recovers energy from all significant exhaust air systems; the recovered energy is used to reduce the energy impact of the large 100% outside air systems serving the operating rooms, laboratory and intensive care areas.

* Variable speed control is used on all significant fans and circulating pumps. For example, the chilled water circulating pumps and the secondary heating water pumps have variable flow control to reduce energy consumption at non-peak operating times.

* Bypass control on all heat recovery and cooling coils reduces standby energy losses. For example, automatic bypass dampers open when the heat recovery coil is not recovering energy.

* Demand ventilation control is used; carbon dioxide and occupancy sensors control the amount of ventilation air supplied into non-critical areas of the hospital.

* Low flow plumbing fixtures reduce the energy required to heat the domestic hot water.

* Energy efficient lighting systems have a power density of 8.9 W/sq.m.; a typical hospital has a lighting power density of 15.3 W/sq.m..

* The high performance-building envelope has low-e glazing, with selective shading coefficients for control of building heating and cooling loads.

The hospital is expected to consume approximately 38% less energy compared to a code compliant hospital. The savings in carbon dioxide emissions will be approximately 3,120 tons a year. The energy operating cost savings will be about $480,000 year — money that can be redirected into providing healthcare.

Mechanical engineering: Stantec Consulting, Vancouver (Paul Marmion, P.Eng.). Energy simulation: EnerSys Analytics

Client: Access Health Abbotsford (AHA)/John Laing Investments (project management), ABN AMRO Bank N.V. (finance), PCL Constructors Westcoast (design-build), Musson Cattell Mackey Partnership/Silver Thomas Hanley (design), Johnson Controls and Sodexho (facility management)

HVAC SYSTEMS

Cottonwood Lodge, Coquitlam, B.C.

Cobalt Engineering, mechanical engineers

Cottonwood Lodge is a mental health residential care facility owned by the Fraser Health Authority. It was developed as a prototype long-term residence to enable mental health patients to live more independently.

Completed in 2006, it provides accommodation for 24 residents on two levels totalling 1,387 square metres in area.

Cobalt provided mechanical engineering design services to assist this healthcare facility achieve LEED Gold certification for sustainability. Cottonwood Lodge is the first Leed Gold Certified long-term care facility in Canada.

Energy savings were realized through the use of a concrete mass structure and an embedded radiant heating and cooling system in the concrete slab. The radiant heat and cooling system is fed from a water-to-water heat pump plant. During heating seasons, condensing boilers used for the domestic hot water system add additional heat to the loop, thus eliminating the expense and use of a ground geo-exchanger.

The radiant heating and cooling is coupled with a displacement ventilation system, which introduces fresh air at the ground level, resulting in significantly reduced operational loads.

The two systems work well together as the radiant system provides space temperature control, and the ventilation system introduces fresh air and removes contaminants from the air.

Improved indoor environmental quality was achieved through the use of 100% outdoor supply air and the selection of low emitting indoor materials. Waste heat is recovered through the use of heat recovery ventilation equipment located in an attic fan room.

The building was thoughtfully oriented to maximize opportunities for daylighting and reduce the need for artificial lights. Daylighting also benefits the psychological health of occupants. Motion sensors to control the lighting gave further energy savings.

Overall, the building’s energy performance is an improvement of 40% compared to the standard in Canada’s Model National Energy Code for Buildings.

Water efficient plumbing fixtures were used to reduce potable water consumption by 42% annually.

Mechanical engineers: Cobalt Engineering, Vancouver (S.K. Lai, P.Eng.). Architect: CJP Architects. Structural: Bush, Bohlman & Partners. Electrical: Acumen Engineering Engineering. Owner: Fraser Health Authority

HVAC SYSTEMS

CFB Kingston Primary Care Centre, Kingston, Ontario

Cohos Evamy integratedesign, architect, structural, mechanical & electrical engineer

CFB Kingston Primary Care Centre is a 5,900-sq.m facility that provides both health and dental services for military personnel.

The design implements sustainable features to enable LEED Silver certification.

To achieve this sustainability target and an energy saving of 50% over the Model National Energy Code of Canada, the team was challenged to come up with innovative solutions. Cohos Evamy integratedesign provided a comprehensive set of services for the project, including architecture, structural, mechanical and electrical engineering.

First, the building has a hybrid natural ventilation system. Manually operable windows can be opened to allow natural ventilation when the outdoor air temperature is suitable. In order to ensure that open windows draw air into the building, two solar powered ventilation chimneys create a negative air pressure in the building when required.

Two central rooftop ventilation units reclaim heat from the exhaust air. High-pressure steam generated from the central base steam plant supplies heat to the building, using dual heat exchangers, a pumped hot water loop and perimeter radiant ceiling panels. Domestic hot water is generated with a gas-fired condensing hot water heater.

The building also uses an underfloor air delivery system — an uncommon feature in healthcare facilities. The raised floor system to allows future changes to the power and data systems. The underfloor air delivery was chosen for:

* thermal comfort, ventilation efficiency, indoor air quality

* reduced energy use

* acoustic superiority

* reduced life-cycle building cost

* reduced size of building envelope due to lower floor-to-floor heights

* reduced labour costs due to 30-40% savings to install utilities under floor vs. above ceilings

Floor air diffusers with adjustable volume dampers are installed throughout. In speciality room, such as treatment or procedure rooms where there has to be seamless flooring to protect from spills, sidewall diffusers are located just above the baseboard level. Return air is routed back to the main air-handling units through the ceiling plenum.

The facility has been configured to enable a large portion of the floor plate to be lit with natural daylight. Daylight occupancy controls ensure that when daylight is available, or when areas are unoccupied, the lights remain off.

Architect, structural, mechanical & electrical engineer: Cohos Evamy integratedesign (Tim McGinn, P. Eng., lead mechanical engineer) Owner: Department of National Defence

HVAC & LIGHTING

Alberta Children’s Hospital, Calgary

Wiebe Forest Engineering mechanical and electrical engineer

Located on the University of Calgary campus and opened in 2006, the $253-million Alberta Children’s Hospital is the hub of the Alberta Children’s Healthcare Network, serving southern Alberta, southern Saskatchewan and southeastern British Columbia.

The building covers 70,000 square metres of space on five levels, with an exterior designed as a series of large colourful blocks and window units. The design by Kasian Architecture is intended to make the building look smaller than it is, after feedback from children during the design stage indicated they were afraid of big buildings.

Wiebe Forest did mechanical and electrical engineering, together with Hemisphere Engineering for mechanical work, and Stebnicki + Partners for electrical engineering.

Ventilation is of great importance to a modern health care facility, and the Alberta Children’s Hospital provides high indoor air quality while reducing energy use. The majority of the hospital uses the air system for both heating and cooling, with radiant heating provided in the office areas.

A sophisticated electronic building management system (BMS) controls over 10,000 points in the facility.

The HVAC systems use a variable air volume (VAV) approach, with over 100 variable speed drives installed. All patient care areas of the hospital receive 100% outside air, using total energy heat recovery to minimize the energy used for heating in winter and cooling in summer.

Electronic air volume boxes regulate the amount of air supplied and returned from each room to control the room pressurization and mitigate airborne infection. The ventilation control sequences allow the building operators to isolate patient wings in the case of large outbreaks of airborne infections.

Infection prevention and water conservation were key drivers in the design of the plumbing systems. All examination and patient rooms are equipped with touchless hand-wash sinks that use low water consumption faucets. The domestic hot water systems employ a unique recirculation design that ensures there are no stagnant piping zones. As well, all domestic water is treated with ultra-violet light sterilizers to kill any micro-organisms.

In the public and staff areas are a total of more than 3,000 motion activated occupancy sensors. The sensors not only control lighting, but also are connected to the VAV boxes, so that air flow to a room is reduced when it is unoccupied. In the corridors and public areas that have abundant windows the lighting is also controlled by sun sensors.

The light fixtures in patient areas have flat hinged lenses installed below conventional fixtures so that they can be readily cleaned for infection control, while minimizing an institutional look.

Most of the lighting uses T8 fluorescent and electronic ballasts, with T5HO, compact fluorescent and LED lighting in specific applications. Incandescent lighting is used only where dimming is required in clinical applications. The lighting density for the facility is 1.2 watts per square foot, well below the Model National Energy Code of Canada limit for hospital facilities.

Mechanical: Wiebe Forest Engineering (Marc Kadziolka, P.Eng.)/ Hemisphere Engineering (Dale Way, P.Eng.). Electrical: Stebnicki + Partners (Gerry Stebnicki, P.Eng.)/ Wiebe Forest Engineering (Jeff Bannard, P.Eng.). Architect: Kasian Architecture Interior Design and Planning. Structural: Stantec Consulting

PROJECT DELIVERY

Upper River Valley Hospital, Waterville, New Brunswick

ADI Group, project manager, construction manager, prime architect, structural, civil engineer

The province of New Brunswick chose an unusual method of delivery for the Upper River Valley Hospital, a new 70-bed hospital scheduled to open this November. The $85-million hospital is the largest capital building project undertaken in the province in recent years.

ADI Group of Fredericton was engaged by the N.B. Department of Supply and Services to provide project-management, design-build delivery services for the 17,000-sq.m facility. ADI provided a lump-sum price for all labour and expenses related to these services. The province bore the capital cost for construction and equipment.

With a team of specialist consultants, ADI’s scope of work went well beyond the engineers’ traditional role. ADI acted as prime architect and as structural and civil engineer. The company provided project and construction management. It also oversaw the procurement of furniture, fittings and equipment, and organized occupancy planning for the relocation of staff and equipment from existing facilities. It managed the approvals process, undertook the commissioning of building systems, and carried out operator training.

The 70-bed hospital is 17,000 square metres in area, located on a 30-hectare site overlooking the St. John River. Built on three-levels, it has four wings surrounding a sunlit atrium, a configuration that gives patients the maximum exposure to windows. The structure is clad in reflective glass, with brick and masonry components at entry points. It is designed for LEED silver certification.

Construction was carried out in a compressed schedule, and began in the spring of 2005 while detailed design was still continuing. Using sequential tendering, there were approximately 30 trade contracts
issued during construction.

Project manager, construction manager, prime architect, structural, civil engineering: ADI Group, Fredericton, N.B. (David Beattie, P.Eng.). Associate architects: Parkin Architects, Steen Knorr, Soucy & Ellis. Mechanical: John MacLean Management. Electrical: TEK Consultants. Other: Enermodal (LEED), R.J. Bartlett (fire protection), Lummis & Co (foodservice), Seawood solutions (commissioning), Equipment Planning Associates (FF&E), Quest Health Care Solutions (occupancy planning) Owner: River Valley Health Authority

STRUCTURES

Carlo Fidani Peel Regional Cancer Centre, Credit Valley Hospital, Mississauga, Ontario

Halsall Associates, structural engineer

In 2005, a 37,150-sq.m new cancer treatment centre was added to the Credit Valley Hospital in Mississauga, Ontario. The new addition is a four-storey structure, plus penthouse and basement.

A new entrance lobby was built to link the cancer treatment centre with the adjacent building. This large atrium is constructed using four large tree-like supports. The glue-laminated timber “trees” have embedded steel connections, and they support a steel deck roof and linear skylights.

When compared to conventional steel, the cost of the wood structure was notably less, and despite the complexity of the structure, the project was tendered under budget.

As wood is a combustible material, one of the design team’s challenges was meeting the Ontario Building Code requirements for fire and life safety.

By working directly with the Ontario Building Code staff and the Ontario Fire Marshal, the team developed technologies so that the structure complied with the code requirements. A unique fogging, or mist, fire suppression system was specified since conventional sprinklers could not adequately protect the large amount of shielded surface on the curving beams. The mist heads are concealed in custom-designed light standards at the base of each “tree,” and are used together with infrared detection devices. The mist system is an environmentally responsible alternative to ozone depleting fire suppression chemicals.

The authorities approved the fire protection system only after the National Research Council in Ottawa had tested a full-scale mock-up of one of the trees.

The cancer centre houses three complete radiation treatment bunkers, and space for three additional bunkers. The treatment bunkers were constructed with high density Hematite concrete to provide radiation shielding, while minimizing the bunker’s footprint. The project also included a new parking structure on nine split levels.

Structure and cladding: Halsall Associates, Toronto (Michael Jelicic, P.Eng.). Architect: Farrow Partnership. Mechanical & electrical: Rybka Smith and Ginsler. (Richard Armstrong, P. Eng.) Builder: PCL Constructors. Timber Structures: Timber Systems. Fire suppression: Marioff Owner: Credit Valley Hospital


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