As Hong Kong prepared for the peak of the Covid 19 pandemic, a group of eminent local engineers developed a potential solution for rapidly increasing isolation ward capacity. Two WSP engineers were part of that team – Thomas Chan, Executive Director, Building MEP, and Kwok-Fai Tsui Technical Director, Building MEP who worked in their free time on a design to transform a 20-foot container into an isolation unit. 

The negative pressure isolation room they designed, also known as an airborne infection isolation room, would be built using the Modular Integrated Construction method (MiC).

The challenge was to transform a 20ft x 8ft (6m x 2.4m) standard container into a high standard hospital isolation room with interlocking door entrances and en-suite bathrooms. Each isolation ward would operate at negative pressure 10 Pa and would be sealed by a built-in ante room to create an air lock. The room would also be equipped with a specialised air conditioning system and exhaust ventilation system, as well as a high efficiency particulate air filter for air filtration before discharge. In the ante room, the pressure would be set at negative 5 Pa to allow medical staff to safely put on and remove personal protective clothing. The same principles were implemented in Hong Kong hospitals during the 2003 SARS outbreak, and proved to be safe and highly effective in preventing contaminated air from leaking out of the room.

Assembled using MiC, a 20ft x 3ft (6m x 1m) electrical & mechanical (E&M) module would be attached alongside the container to house all the E&M systems and equipment serving this isolation room. This design would allow the connection of the E&M equipment to the isolation room using ready-to-plug-in methods.

By adopting MiC, the construction team could quickly and safely complete fabrication of these containers off-site, allowing full inspection and fine tuning before transferring them to the actual hospital construction site. Not only would the containers be stackable, but their use could also be converted into a variety of configurations for offices, laboratories and other purposes – all connectable and easily transported by sea or land.

According to Thomas, using this technology a fully functional isolation hospital could be built in Hong Kong in approximately one and a half months. 

Contact Thomas Chan

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