From parking lots to arenas, hospitals rapidly build pandemic response units

It started with a hand-drawn design on paper. Within two weeks, the schematic came to life at Joseph Brant Hospital in Burlington, Ont., with the opening of Canada’s first modular Pandemic Response Unit to help manage the surge of COVID-19 patients.

The 8,250 sq. ft., 93-bed temporary unit, which opened in early April, provides the extra space needed for patients with mild to moderate virus symptoms, freeing up acute care space for patients with more severe needs.

Construction firm BLT designed and built the temporary ward using a reusable tension fabric building from Sprung Structures, creating a contained environment that can support screening, testing and isolation activities. The project relied on a network of suppliers, regulatory agencies, regional healthcare providers, and sub-contractors who pulled out all the stops to meet a seemingly impossible timeline, including The HIDI Group and Modern Niagara who handled the mechanical design and installation.

“While we were experienced in infection control in a built environment, this was definitely not the same,” says Bryce Jones, construction manager at Modern Niagara. “Normally we have a partially finished building to work with. In this case we were putting equipment on sloped asphalt, sidewalks and grass.”

Building in the hospital parking lot created a few challenges the team had never had to face before, Jones says.

“We had to work around shrubs, bushes, trees, and an active roadway to a parking garage. Because we were at ground level, we also had to deal with an abnormally high intake rate of dirt, dust, pollen, and leaves blowing in.”

Of course, the biggest wrench was co-ordinating everything on such a small timeline.

“There was no precedent for COVID in terms of codes for guidance, and we had only two weeks to pull all of it together, from design kickoff to commissioning,” says Paul Waddell, vice-president, Design + Build for BLT. “There was no time to develop 3D renderings while working from home. Despite the challenges, I’ve never seen a group mesh more quickly to get this done.”

Formulating the design
Hospitals need HVAC, but since the facility was not intended to operate in winter months, it was possible to use a minimum design temperature of 0°C to size the heating system. In order to maintain the necessary negative pressure differential of 7.5 Pa relative to the adjacent corridor, continuously operating exhaust fans were installed.

“It was essential to maintain a negative pressure within the enclosure to ensure no virus could escape without going through a HEPA filter,” explains John Ferguson, design principal with The HIDI Group.

The ventilation air handling unit supplies 100 per cent outdoor air to the main room and is run by a supply fan equipped with a variable speed drive. This allows for fan speeds to be adjusted to deliver 7,500 cfm, or 3 ACH, as per CSA Z317.2.

Outdoor air is filtered and cooled to 12.8°C before mixing with filtered conditioned air from the recirculating air handling unit and being supplied to the main room.

Two main exhaust fans are each equipped with a HEPA final filter and variable speed drive to automatically maintain the appropriate pressure differential. A separate washroom trailer is equipped with its own HVAC system, water supply and holding tank.

Another dedicated air handling unit heats, cools and ventilates the corridor that connects the main room to the hospital.

Two 52-ton air cooled chillers circulate chilled water to the cooling coils. The entire HVAC system is run by a local DDC control system that controls fan speeds and valve positions.

Overhead, more than 38,280 lb. of prefabricated ductwork was used, with grilles supplying air downwards towards the floor along two main access aisles that run the length of the structure. The air is returned by grilles located in the headwall above each patient’s bed.

“We went with two large spiral runs for the supply ductwork,” Ferguson explains. “We had two main supply runs and ducted returns from each bed (headwall) with the main return down the middle arching over the nurses’ stations. Additional supply air grilles on top of the supply ducts helped wash the tent walls and roof with air to avoid condensation.”

The main room’s handwash sinks are supplied by water from a fire hydrant. Each has a small electric water heater where hot and cold water is supplied by an automatic handsfree faucet. Drain water is pumped from each sink to an existing sewage ejector pit.

Tackling the supply challenge
Getting all this equipment was no small feat, Waddell notes. “Normally it takes six weeks. Suppliers were able to cut down that time because they knew they were supporting the greater good and were very willing to jump in to help.”

Given the tight timing, they also had to adjust the design based on the availability of equipment, Jones notes.

“Normally we have all that information ahead of time. As we progressed, we found out some equipment might be slightly different than we assumed, so we had to make adjustments on-site.”

From empty arena to COVID-19 field hospital
Field hospitals are springing up all across the country to handle the COVID-19 crisis, with some communities modifying existing buildings on a temporary basis.

When Grey Bruce Health Services (GBHS) in Owen Sound, Ont., was given two weeks to build a field hospital to support COVID-19 patients in recovery, it turned to the arena at Harry Lumley Bayshore Community Centre for a solution.

With no events currently being held, the arena had plenty of room to build an open-pod hospital to service up to 75 patients, explains Neil Havens, director, facilities management.

Working with JaLand Construction and Benedict Electrical Contracting, gas piping and electricity were delivered to each bed location, with medical gas work for oxygen and vacuum piping being completed over a span of about three days. “A lot of copper piping went into that,” says Havens.

Getting electricity to each bed was a little easier.

“All drops feed off services that were already pre-installed for the annual Home Show,” he explains. “We just had to add 200-amp service panels on each side and provide the feeder wiring to support the additional electrical services.”

Did you know?
The 24/7 construction work had to be done under COVID safety conditions, with workers being screened daily, and work spaced out, so the number of trades professionals on site at one time was limited compared to a more traditional build site.

Written by Denise Deveau

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