The first phase of the Centre Hospitalier de l'Université de Montréal (CHUM)  is almost complete. The structural and mechanical-electrical engineers describe the challenges of designing for this massive P3 construction project on a tight urban site.

MECHANICAL AND ELECTRICAL DESIGN

By Nick Stark, P.Eng., Vice President
HH Angus & Associates
The mechanical engineering design for CHUM had to meet many challenges, not the least of which was the sheer magnitude of the project on a congested urban site. There was also a strict energy target, along with request-for-proposal (RFP) requirements that drove alternative approaches.

In spite of the challenges presented by its sheer size, the project design was completed in Revit, enabling enhanced coordination of more than 2,500 building services drawings. Over 60 MEP models had to be maintained and data driven processes were developed to manage the information. Online collaboration sessions were essential for coordinating the work between HH Angus in Toronto, the project office in Montreal, and Cannon Design offices across the U.S.

Locating the plant. Locating the heating, cooling and emergency generator plants for an urban hospital complex presents a challenge. Traditionally a plant of this size would be located at grade in a separate building where it could be isolated from the clinical functions of the hospital. However such space did not exist on the CHUM site. The initial schemes positioned the plant below grade, but the real estate proved too valuable and was needed for clinical functions.

HH Angus developed a scheme to locate the plant 80 metres in the air above the ambulatory block. The boilers and chiller share one level, and the generators and cooling towers share another. These floors sit on top of an air handling plant room, forming a volume 30 metres high, fully enclosed with louvres. With this location, the design had to overcome challenges for the mitigation of noise and vibration.

The central plant consists of six dual fuel hot water heating boilers with a total output capacity of 30,900 kW, six dual fuel steam boilers and one electric boiler totalling 47,000 kg/hr. In addition to serving the needs of CHUM, the heating plant also supplies CRCHUM, the adjacent research centre, with steam and hot water. The cooling capacity is 9,000 tons in two multistage process chillers, two centrifugal heat recovery chillers and five conventional chillers.

  • Energy saving systems. The client mandated an energy consumption target of 40% less than the ASHRAE 90.1-1999 baseline — a very aggressive target for an urban acute care hospital. Every system that consumes energy was strategically assessed against possible alternative solutions.
    The modelling target was achieved using a multi-pronged approach that incorporated:
  • space by space control of air volumes (supply and exhaust)
  • enthalpy heat recovery wheels on virtually all air handling systems
  • reduced fan energy by reducing air velocity through air handling units and ductwork
  • process cooling and chiller heat recovery systems as the primary source of low temperature reheat water
  • a condensing boiler stack economiser
  • lighting power reductions coupled with occupancy and daylighting controls
  • control strategies including supply air temperature reset.
  • In terms of environmental and energy design, the building is targeted for LEED Silver designation, with a potential for LEED Gold.

Ventilation systems and heat recovery. Ventilation in a hospital is the system that requires the most plant space, not only in terms of plant room floor area, but also for vertical shafts and ceiling space. The RFP imposed a number of requirements, including HEPA filters on all systems serving clinical areas, no air recirculation between departments, and a high level of redundancy – all with a limited air handling unit size. To meet these requirements would have required two full intermediate mechanical floors and at the same time would have severely compromised the system’s future flexibility. HH Angus worked with CHUM to develop an alternative approach.

Where the RFP required a distinct air handling unit for each department, we proposed the use of 100% outdoor air units serving multiple floors where the occupancy was similar, and demonstrated to the hospital the merits of this approach from the perspective of infection control and future flexibility.

To mitigate the energy penalty of 100% fresh air systems, we proposed enthalpy heat recovery wheels. The RFP initially prohibited these wheels, but we used our 25+ years of successful experience with the technology to demonstrate to CHUM and their compliance team that their infection control concerns could be successfully mitigated with the right components and controls. The RFP was then modified accordingly.
The RFP also mandated a standby air handling unit for each unit serving a critical care space. This solution would have required much higher capital and operating costs over the life of the building, as well as more space. We developed an alternative approach by combining a number of air handling units together into one duct system to share the redundant capacity. This solution considerably increased the overall reliability of the systems while reducing operating costs.

Lastly we demonstrated that the restriction on air handling unit size could be raised to 33,000 l/s without any practical impact. Even so, 46 air handling units are required for a total supply volume of 1,300,000 l/s.

Combining these alternative approaches in the ventilation system design resulted in many benefits, including the ability to modify the occupancy of the spaces and enable future renovations. The net result was that additional clinical floors could be constructed under the zoning height restriction, which was a key factor in developing a successful bid.

Operating suites. The 39 operating rooms (ORs) had to be spread over two floors, even with a floor plate the size of two football fields. HH Angus located a main air handling plant room on the floor immediately above to enable direct servicing of the ORs. The supply and return terminal boxes as well as the terminal humidifier for each OR is located in the plant room, reducing the need for maintenance personnel to enter the ceiling space of the sterile area.

Plumbing and medical gas. The domestic water supply in a typical hospital may consist of one or possibly two pressure zones. For CHUM, with a difference in height of 120 metres from the lowest mechanical room five floors below grade to the roof, five separate pressure zones had to be created. The scale of the medical gas system is unprecedented: over 11,000 outlets.

Electrical distribution. The project required understanding the crucial demands placed on a hospital’s electrical system and knowledge of the intent and intricacies of codes and standards. Our team designed an electrical system that is robust, reliable and resilient, and one that met the owner’s RFP requirements in a cost-effective manner.
The high voltage distribution system includes 25kV and 4160V switchgear, with four incoming Hydro Québec lines totalling 36MVA. The emergency power generation system for the CHUM complex consists of four 2.5 MW diesel generators, generating at 600V, with four 2.5 MW back-up generators producing 4160V.

Lighting, fire protection and security systems. Lighting layouts were designed to balance the aggressive LEED requirements with CHUM’s stringent requirements for light levels. To provide an atmosphere that is elder-friendly efforts were taken to ensure even illumination, with gradual changes between adjacent spaces. The lighting is controlled by a building-wide lighting control system.

The addressable two-stage fire alarm system is combined with the public address system. Two complete CACF (central alarm and control facility) rooms were provided.
The security systems include CCTV, card access, intercom, and a real-time locating system. The card access system and CCTV system are IP based using POE (power over ethernet), which minimizes the risk of down time by using a centralized UPS system.

Published in Candian consulting engineer magazine - December 2015 edition (page 10)

Click to read complete article 

Congratulations to HH Angus’ long-term client, Cadillac Fairview, on a very notable achievement: All 6 towers of Canada’s iconic Toronto Dominion Centre have been certified LEED EB: O&M Platinum.

This is a significant achievement in sustainability. The TD Centre’s capital investment, operating capabilities, and green initiative helps to lessen the property’s environmental footprint, and reaffirms the TD Centre’s position as one of the most sustainable office communities in North America.

In order to achieve LEED EB: O&M platinum certification, strict, measurable and actual performance metrics had to be met, in areas such as energy and water reduction, waste diversion, transportation, electricity, sustainable construction and infrastructure, and occupant engagement.

HH Angus & Associates has been working with Cadillac Fairview for several years on infrastructure upgrades to support this certification. By way of background, we were the original base building engineers for the TD Centre (Canada’s first skyscraper, designed by Ludwig Mies van der Rohe), and have been working at the complex ever since on renovations, upgrades and fitouts.

Our work enabling the certification includes Mechanical & Electrical (M&E) improvements to support LEED® EB standards, M&E infrastructure upgrades in conjunction with building envelope renewal, infrastructure upgrades to increase tenant space and reworking of the plaza area to improve drainage.

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Today's Building Automation Systems provide a host of detailed data that is for identifying problems, but they also require that operators receive appropriate training.

 

As building owners require more data on the operational and energy efficiency of their facilities, building automation systems (BAS) are evolving to keep pace with this need for smarter buildings.

In HH Angus` role as consulting engineers for the design, engineering and commissioning of building systems, we are seeing numerous developments in the BAS products offered by manufacturers, and increasing use of the data available through the BAS.

One recent development in the BAS field is in graphical representation. According to Mike Loughry, P.Eng., senior mechanical engineer at HH Angus, “Most BAS companies have made significant improvements in how they represent mechanical systems. We’re finding much more operator-friendly displays that convey detailed information in a more accessible interface. They include better use of colour, more animation and increased isometric or 3D drawings.”

The clearest advantage of the new graphics,” Loughry says, “is that they more realistically reflect the arrangement and layout of the equipment, which makes the operator’s job easier. The graphic display is more intuitively understandable compared to the older-style abstract diagrams. Owners and operators can more readily understand the information presented on the screen and can react faster and more appropriately to new data.” 

Continuous commissioning advantages
Loughry also cites as an important development the availability of continuous commissioning systems. “These software packages monitor the operation and performance of building systems 24/7, looking for unusual events and calculating, for example, energy consumption. This helps to identify operational anomalies: if there is equipment failure, a spike in energy consumption or unusual system activation, the system will advise the operator. For example, if the BAS sees that a fan scheduled to operate from 7 a.m. to 7 p.m. is operating round the clock, the system will flag this.” Also it is becoming easier to take measurements at the specific system or equipment level. The building engineer can then identify systems that are the high energy users and focus improvements where they are most effective.

When it comes to upgrading existing buildings, Mark Benedet, P.Eng., a senior mechanical engineer and group manager in HH Angus’ technology division, cites the example of a building where systems dating back to the 1960s had been upgraded to pneumatic systems. That upgrade worked for a while, but the current occupants and facility managers are now demanding better results. In these cases, “We perform an evaluation to match available options with the client’s goals,” explains Benedet. “The clients can’t always upgrade the entire system at once, but there are a lot of levels of ‘doing better’ in energy efficiency. We can design new systems that will allow the electronics to talk to the control system or, if necessary we can update older systems with ‘interpreters’ so that those systems interface with new controllers. We also advise clients on energy grants that may assist them financially with equipment changeovers.”

Operations staff may need more training
With the new, highly functional BAS features, owners should be cognizant that their operations staff may need more training since their experience with these systems varies greatly. Engineers are learning to be much more detailed as to the type of training they specify when designing a sophisticated BAS system that includes complicated operating strategies. These strategies provide great benefits in energy consumption and flexibility. But in order to ensure the owner’s staff can operate the BAS equipment and efficiently deal with the range of data it provides, the training sessions have to be tailored to the knowledge level of the participants.

As Loughry points out, “Building owners rely on us for our expertise and for our knowledge of the various BAS technologies on the market. An operator may look at the BAS as a simple tool for starting/stopping equipment and adjusting temperatures. But we look at it from the point of view of providing many features, including ease of operation, equipment monitoring, innovative design, long-term energy consumption, and safety and code compliance. Clients count on us to understand and evaluate the options, make recommendations and inform them of the consequences of selecting particular systems. So it’s important that the required training is specified in the design documents to ensure the realization of the value of the systems being provided.”

How much is enough? … That depends
Determining the degree of sophistication required of a BAS depends on the purpose of the building in question. Data centres require high-quality equipment and an extraordinary degree of system redundancy across the board to meet uptime guarantees. Healthcare facilities must comply with stringent codes and the equipment must offer ease of service. They also have specialized requirements such as air pressure controls for infection control procedures. Commercial developers owning office buildings require BAS systems that can deliver reasonable temperature control measures, but perhaps without the expensive bells and whistles. Since they may not intend to operate the property long term, investing in comprehensive and expensive systems is not a priority for them. On the other hand, owner-occupied buildings such as hospitals are looking to maximize the life of their operating systems and minimize their maintenance costs, so a BAS that can address their controls automation needs now and for the next 50 years is a realistic and desirable investment.

“Consulting engineers have a responsibility to be very knowledgeable and to bring these technologies to the table during the design development stage. That’s part of the value we bring and where we can show leadership.”

- Senior Project Manger at HH Angus 

Dovas estimates it will be a few years still before BAS equipment is standard in base building specifications, but that day is coming: “It’s important that the technology selected be web accessible and, if necessary, we need to educate our clients to make them aware of the power of the data they can measure. The days of controlling and measuring only the low-hanging fruit, for example lighting, are over. We know where the energy savings are, and the BAS trend data backs that up.”  

Author:

Kirsten Nielson - Communication specilist, HH Angus

From Canadian Consulting Engineer  -  August-September 2015 print and digital issue, page 37-39.

Thanks to all who entered the HH Angus draw that was part of our celebrations for National Engineering Month 2015. Ten names were drawn at random, and these lucky people each received a Slimline Power Bank, adding hours of power to their exhausted devices!

We also sent out close to 1000 notepads featuring entertaining facts, fortunes, conversions, lingo and rules drawn from the engineering industry! (And you knew there would be rules, didn’t you!)

National Engineering Month is a month-long celebration of all things engineering, and aims to familiarize young people with the impact engineering has on modern life and the career options open to them in the sector.

Our internal staff celebrations recognized all those employees who achieved new professional credentials over the past year and we congratulate them on their hard work and success.

On November 19, 2014, HH Angus’ - Paul Isaac will be a panelist for an energy generation discussion on “CHP – poised for a resurgence in Ontario?”

From APPrO  – the Association of Power Producers of Ontario: “The prospects for CHP (Combined Heat and Power technology) have rarely been better in Ontario: Improving economics, and the widening recognition that CHP can help to meet objectives for urban resiliency, grid reliability and environmental sustainability, have created the potential for a groundswell of new development. Experts identify the key obstacles to building capacity and how they are being addressed.”

Paul Isaac will be addressing “How new technology can be used to help mitigate short circuit fault capacity issues.”  Paul Isaac, ing., P. Eng., is a senior electrical engineer and a principal at HH Angus and Associates.

Panel:  “CHP – poised for a resurgence in Ontario?” 1:00 pm, Metro Convention Centre, South Building, Toronto, ON – Nov. 19, 2014

The 26th Anniversary of Canadian Power Conference and Networking Centre takes place on November 18 & 19, 2014.  For more information on this event, please click here to visit the APPrO website