Congratulations to our HH Angus colleagues on winning the ACEC 2018 Schreyer Award for technical merit and innovation. The winning project is the Centre hospitalier de l’Université de Montréal (CHUM), North America’s largest healthcare P3 project and a milestone in Canadian healthcare.

We’re thrilled to be honoured with this prestigious ACEC award, and so proud that the expertise and creativity of our engineering and design colleagues has resulted in our industry’s highest honour.

On behalf of our CHUM team and everyone at HH Angus, our thanks to the Association of Consulting Engineering Companies | Canada and to Canadian Consulting Engineer magazine (CCE). The CHUM project was also honoured with this year’s Award of Excellence for Buildings.

Congratulations to all our fellow award winners at ACEC’s 50th National Awards Gala. Your outstanding achievements elevate the engineering industry and bring honour to our profession.

Read more – Press Release

Communiqué de presse

Join us in Montreal on Oct 16 as HH Angus presents “Making a Super Hospital Work” at the Canadian Centre for Healthcare Facilities conference.

As the mechanical, electrical and security design engineers for CHUM, the HH Angus team has unique insight into what it took to successfully deliver the largest healthcare project in North America – the Centre hospitalier de l’Université de Montréal. Nick Stark, Marianne Lee and Phil Schuyler, principals of HH Angus and team leaders, will detail some of the key challenges and solutions for this mega hospital project. Conference attendees will also be able to tour public, clinical, mechanical and electrical facilities at CHUM.

Meeting  stringent standards while reducing energy use.

Hospitals face unique design challenges in meeting air handling requirements, none more so than the special requirements of operating rooms. As lighting systems and building  envelopes have become more energy efficient, it is air handling systems that increasingly  represent a hospital’s greatest energy consumer. But there are options to mitigate the energy demands of these systems.

Air handling systems are an important part of any building for maintaining occupant comfort. When it comes to hospitals, there are a series of special requirements that make ventilation systems critical to the delivery of healthcare.

Firstly, air handling systems are relied on to help protect occupants and adjacent  surroundings from infectious diseases and hazards created by equipment and processes. Many contaminants are generated which must be exhausted. In many areas of a hospital, the systems are designed so that air flows from clean to less clean areas to help protect staff and other occupants. A good example of this is Airborne Isolation Rooms where differential pressures must be monitored and alarmed.

Air handling systems are also a key component of the life safety strategy for managing smoke in a fire situation. A measure of the reliance on air handling is the requirement that ventilation systems must limit smoke concentration to allow operations to be safely concluded or for critical care patients to be safely transferred.

And now the rising level of patient acuity and the pressure of high utilization, with occupancy rates well above 100%, are putting even more pressure on HVAC systems. In Canada, CSA Standard Z317.2, Special  requirements for heating, ventilation, and air-conditioning (HVAC) systems in health care facilities, is referenced in most if not all Canadian Building Codes as good practice for the design, construction and operation of air handling systems. The latest edition was published in December 2015, and work  recently started on the next version due in 2020.

Operating rooms

Operating rooms and similar spaces where invasive procedures are performed have a number of particular air supply requirements:

  • Common practice for operating rooms is to supply a high volume of air at low velocity through laminar flow ceiling diffusers in the central area of the room with the intent of achieving a piston effect. The intent is for air to generally flow first past the patient and clean surgical staff before flowing to the outer portions of the room to the exhaust grilles. Studies have shown that 20 air changes per hour is effective; note, this is a far cry from the hundreds of air changes of a true laminar flow clean room.
  • The cleanliness of operating rooms is critical. Standards call for the supply air to be filtered to at least MERV 14, but many engineers and facility managers look to increase this to a higher level. HEPA filters, which are rated to 99.97% efficiency on 0.3 micron particles, have been adopted as the standard in many cases.
  • Staff generally prefer operating rooms be kept relatively cool as they are often gowned in multiple layers to minimize the possibility of infection. The premise that a wide range of temperatures is necessary to control the temperature of the patient, particularly during cardiac surgery, is not well founded. Blankets or pads that heat or cool are used to control the patient’s temperature.
  • There has been great debate over humidity in operating rooms. Many years ago the anaesthetics in use were flammable, and operating room  humidity was maintained between 50% and 60% to minimize the possibility of static electricity discharge. As anaesthetics became safer, the low end of the humidity range was reduced to 40%. The initial concern was that less humidity would cause drying at the surgical site; however, this condition was not observed. In the 2015 version of CSA Z317.2, the lower humidity limit was lowered to 30%, similar to most other spaces in a typical hospital.
  • Design engineers must carefully analyze the psychrometrics of air supplied to operating rooms over the possible range of temperature and humidity conditions. This is particularly true in the summer when cooling coils are relied on to dehumidify moist outdoor air. If this air is not dry enough, the relative humidity limit in operating rooms kept at a cool temperature will not be maintained. Enhanced cooling coils, lower chilled water temperatures, and desiccant moisture removal are some of the solutions.
An operating room inside the Centre hospitalier de l’Université de Montréal.

Energy efficiency

These high levels of ventilation and air cleanliness, coupled with stringent temperature and humidity control and around-the-clock operation, all contribute to high energy use in hospitals; however, there are a number of strategies that can help reduce energy use:

  • Moving air at lower velocities takes less energy, so air handling equipment and ductwork with a larger cross sectional area needs less fan power to move the air.
  • Variable volume air supply and exhaust is more complex in a hospital due to the requirement to maintain directional airflow between most rooms and departments. This generally requires that each individual room or group of rooms control both supply and exhaust air in tandem so pressure relationships can be maintained.
  • A number of methods of heat recovery, when correctly applied, have proved effective while maintaining the cleanliness of the air. Projects such as the Centre hospitalier de l’Université de Montréal (CHUM) and Royal Jubilee Hospital in Victoria used enthalpy heat recovery wheels on all air handling systems to transfer heating, humidity and cooling from the exhaust air to the supply air.
  • There is a misconception that air handling systems all need to operate 24 hours a day. This is true for a number of space types but, even in more critical spaces, there are opportunities to reduce the total air volume or volume of outdoor air when the spaces are not in use, as long as certain conditions are met. Less critical areas offer more flexibility to reduce airflows or setback temperature setpoints.
Interior of the Royal Jubilee Hospital in Victoria, where enthalpy heat recovery wheels are used on all air handling systems to transfer heating, humidity and cooling from the exhaust air to the supply air.

Published in the Canadian Consulting Engineer
January/February 2018 


Nick Stark, P.Eng., CED, LEED® AP, ICD.D

Lighting in healthcare centres requires balance between aesthetics and functionality. The right illumination is essential for medical staff to perform their duties and, as growing consensus suggests, aid in patients’ recovery. Bradford Keen speaks to architects and lighting specialists working across three continents about light’s healing properties.

From ancient Egyptians worshiping the sun god Ra to a parent parting the bedroom curtains of a moping teenager, light intuitively feels right. It is able to create perspective and alter moods. When intuition is verified by science, we feel vindicated by our innate wisdom.

Light has long been manipulated in effective design, but it is now permeating healthcare centres too. Gone are the days of bright, blue lights bearing down from above with the promise of sterility. Instead, the shifting ethos, backed by medical studies, has evolved to focus on how natural and artificial light can give patients a healthy glow.

“About five to ten years ago, healthcare design had a lot more of a clinical and institutional feel,” says Philip Schuyler. “People used really high colour temperatures – over 4,000k.” The electrical engineer at HH Angus explains that the industry now seeks to create a soothing environment mimicking someone’s home or a communal space, while balancing aesthetics, cost efficiency and functionality.

HH Angus and CanonDesign have undertaken a mammoth project. Spanning two blocks in downtown Montreal, the 21-storey Centre Hospitalier de l’Université de Montréal (CHUM) subsumes three existing facilities – Hôtel Dieu, Hôpital St Luc and Hôpital Notre-Dame – in what will be one of North America’s largest academic medical centres, spanning three million square feet. Phase one of the project, which includes the hospital and ambulatory building, was completed recently, while phase two’s office building is set for 2021. The healthcare district is set to teem  with social activity, boasting an amphitheatre,
natural green spaces and one of the country’s largest displays of artwork.

The direct health benefits of lighting – improved mood, reduced hospital stay, lower mortality rates, among others – are proven, as is light’s ability to help create a sense of shared calm for patients and their loved ones.

“Lighting makes people feel a lot more receptive to treatment,” Jocelyn Stroupe, director of healthcare interiors at CanonDesign, says. “Often, healthcare encounters are filled with anxiety. We want to be sure anyone who enters the building feels a sense of comfort.”

This mindset of making hospitals communal and homely spaces is relatively new but  gaining credence among architects.

“People usually go into healthcare facilities with humility,” says architect Joaquin Perez-Goicoechea. “They are searching for something; they need support and, if the building can help them achieve this, it brings satisfaction to all of us.”

This was the weighted starting point for the cofounder of AGi architects when designing the Hisham Al Alsager Cardiac Center in Kuwait. “People with chronic diseases require constant contact with doctors,” says Perez- Goicoechea. Their loved ones often spend many hours at their side or in the facility, which motivated the architect to design the centre as a place for social cohesion. “Light is extremely important for this. It must be a sanctuary,” he adds.

With red aluminium panels, the cardiac centre is designed and coloured – at the behest of the medical staff – to resemble a heart. Its large windows, on the north facade, open up to the dazzling blue of Kuwait Bay.

The multiple vertical skylights maximise natural light. Pollution and dust dictated their positioning. Placed flat and horizontally, they would have gathered too much grime, rendering them useless even with a stringent maintenance plan.

Lighting is a powerful “abstract and immaterial architectural tool,” says Perez-Goicoechea. “The issue is how you see the space as a structure on a sequence, which is identified by different lighting experiences depending on the use or character you want to give to that space.

“If you are going to be sitting in a waiting area for half a day, because this is the reality, you don’t want to be sitting under white, fluorescent lights. You want to be under warm ambient lighting that makes it cosier; it frames the space.”

The diffused ambiance of CHUM


This is where striking a balance is essential. “It needs to be a safe environment,” Stroupe says, “and lighting has to be designed so staff can perform their job without issue.” With many hard surfaces in healthcare facilities, eliminating glare is just one necessary consideration as it will help reduce fatigue on the eyes.

It’s not only the staff, of course, but patients too. “They are often in their rooms or being transported through corridors lying on their backs,” Stroupe says. “We’d like to avoid having something in the ceiling shining in their eyes and causing discomfort.”

Nowhere is this balance between comfort and function more important than at the Dommartinlès-Toul, a short and long-term residential facility in France for people with epilepsy. While there aren’t any operational procedures being carried out, staff need to perform regular functions such as administering medication. The importance of this cannot be overstated, as was seen in a study from the early 1990s, where pharmacists’ prescription-dispensing error rate was heavily dependent on their workspaces being sufficiently lit.

A more pressing factor for epileptics is that stress – often noise and light – can be a major trigger for seizures.

“We concentrated on soft materials,” says Atelier Martel’s co-founder, Marc Chassin. The architect implemented sound absorption materials and low, non-aggressive beam lighting. The firm worked with two artists on the project to add gentle touches such as shallow, sphered indents on the external facade to pay homage to the tablet from around 600BC, considered the first written record of epileptic symptoms. Internally, a tapestry of wool acts as a centrepiece to create warmth and comfort.

“This attention to detail is very important for the people who live there,” he says. “In the bedrooms, we have really big windows that open widely, making the space feel larger, almost like a terraced area.”

A UK study from 2013 showed that patients’ length of stay in hospital was reduced by 7.3 hours per 100lux increase of daylight and, in 1998, a study of patients in a cardiac facility’s intensive-care unit found mortality rates were higher in dimly lit rooms.

An earlier study, published in Science in 1984, found patients in rooms with windows facing trees recovered 8.5% faster and required less pain medication than those with views of a brick wall.

At CHUM, there are multiple outside areas. Beyond the obvious benefit of being a place to breathe in revitalising air, they were also designed for those inside the building. “We wanted to provide people a green and healing view,” Stroupe says. “It is a very tight urban site with amazing views of the city, but this is a little more intimate.”

Lit naturally during the day and benefitting from artificial light spilling out from the inside of the building in the evening, Schuyler says they took a minimalist approach for the terraces. “There is very little specialist lighting in those terrace spaces,” he says, “but they were supposed to be more natural and comfortable.”

When natural and artificial light shine in perfect choreography, architects manage to create a “diffused ambiance”, says Perez-Goicoechea, where different sources of light react to alter the perception of space.

Studies have shown that daylight is not necessarily superior to artificial lighting but, rather, capitalising on a combination of the two yields the best results. At the epileptic care facility in France, Chassin says different sources of light are used but often with their origin concealed, rendering illumination a general impression rather than a location-specific function. “The idea of softness is in the architecture,” Chassin says, “but also in the technical aspects of light.”

Another essential function of light is how it empowers patients. “We gave people control  over their own lighting,” Chassin says. “It is important specifically for those with epilepsy because certain sorts of lighting and frequency can cause seizures.”

Even in situations where lighting does not directly impact a patient’s medical condition, it can afford them a greater sense of empowerment.

“Patients are in a stressful environment,” Schuyler says. “A big part of promoting wellness is being able to control their environment.”

A visitor bathes in natural light at the Dommartin-lès-Toul care home.


In any healthcare facility, not least one the size of CHUM, clear navigation is essential. Staff need to find their way between departments, patients have to go for tests and therapy, and visitors wish to locate their loved ones with ease.

“Every encounter has to be understandable and clear,” Stroupe says. “The wayfinding aspect is immensely important and lighting plays a big role in how we can emphasise the passage of travel for people in this facility. Lighting needs to work to support the architectural design.”

The navigational aspect plays a huge role in epileptic patients’ comfort and orientation. In the aftermath of a seizure, patients will be muddled and confused. Using light, and external contextual cues such as the courtyards and trees outside, helps them reorient themselves, offering much needed succour.

Focusing on the human condition, architects can ensure lighting is used in healthcare centres to make the work of medical staff easier and more efficient, but also help improve the physical and psychological welfare of its patients. There may no longer be a need to invoke the power of Ra, but the benefits of light remain integral to human well-being.

Leaf Review Magazine
January 2017

Montreal mega-hospital project, CHUM (Centre Hospitalier de l’Université de Montréal) is featured as the cover story in this month’s issue of Canadian Consulting Engineer magazine. The story profiles the mechanical and electrical engineering for the project, as described by HH Angus Vice President and CHUM project lead, Nick Stark, P.Eng., LEED® AP, ICD.D. Also featured is the structural engineering by Pasquin St-Jean et associés.

Nick Stark’s article describes the complexity of engineering this enormous project (2.5 city blocks, 334,000m2), which is being delivered, financed and maintained by Collectif Santé Montréal.  The project replaces three hospitals in Montreal and includes a 20 storey acute care block, 772 beds, 39 operating rooms, and a full cancer centre.  CHUM is one of the largest P3 projects in North America. Phase 1 is scheduled to open by the end of 2016.

Click here for the abridged pdf.

Click here to read the full magazine.