This is the way you mix shipping container transport tech with spaces that work for human beings.
Shipping containers changed the world; because of their standard sizes and those little corner castings, they can move stuff around the world quickly and cheaply. But as we noted in an earlier post on a hospital made of shipping containers, they are not a very good size for people, and certainly not for an Intensive Care Unit (ICU).
That's why this new "Restackable COVID Hospital" developed and built by Broad Sustainable Building is so interesting. It is transported as if it was a shipping container and then folds out to make larger spaces. They are not shipping a lot of air; the 3D stuff like the beds, bathrooms are in the core, while the circulation spaces are enclosed by the 2D panels.
I can't overstress the significance of this, and not because I have been saying that this is how it should be done literally for decades, from back when I was in architecture school. Because to reiterate, it adapts the transportability of shipping containers to real human needs, in this case, a working hospital. Here's their iconic timelapse video of the assembly of the hospital in Mungyeong, South Korea.
Seoul National University has signed the contract with BROAD Group on 8th, March. The turnkey project is delivered less than 30 days after contract-signing while construction is finished in only 2 days. Once equipped with medical devices and sickbeds, the hospital can put into operation immediately on April 1st.
Broad Sustainable Buildings is known to TreeHugger for its prefabricated building systems that famously built 30 story hotels in two weeks and the world's tallest 57 storey prefab in a few months. I was their guest in Changsha for a few weeks and became a big fan of their building system.
I was not so convinced a few years ago when I first saw their BCore CTS panel, a structural sandwich made out of two stainless steel panels separated by stainless steel tubes. Broad claimed that they would "trigger a global and unprecedented lightweight structural material revolution," significantly reduce embodied and operating energy, and being made from stainless steel, " the theoretical service life can reach 10,000 years." It would be fun plugging that into Life Cycle Analysis programs.
But now, these BCore panels look very interesting indeed. As Daniel Zhang of Broad explained to TreeHugger, "The strength comes from the higher weight to strength ratio, the little tubes does all the shear wall, compression work."
First of all, they made the construction of the units really fast, signing a contract on March 8 and delivering on March 27. According to Li Shuai of Broad, "We have to complete all the project from design, production, transportation, construction, installation and commissioning in 20 days."
Another feature of the design is that these units are restackable, "which means stories of the hospital can be added later according to their requirements. Designs of the foundation have been taken into consideration at the beginning. Owing to this, the hospital could be more multifunctional in the future."
The key to solving the shipping container dimension problem is to build the box specifically for the purpose, which is why this one has such a high ceiling, and to unfold the walls so that you can get up to 4.5 m (14.75 feet) inside. That's a dimension you can work with.
It's all about the air
Most of our coverage of Broad has been related to their structural systems, but Chairman Zhang Yue actually built the company as a supplier of giant absorption chillers and air conditioning systems, and it produces a lot of air handling and filtration equipment. So they have figured out how to do a ventilation system that maintains negative air pressure in all of the patient rooms more efficiently than conventional systems.
NPI stands for Negative Pressure Isolation. It is an isolation technique used in hospitals and medical centers to prevent cross-contamination from room to room. It includes a ventilation that generates negative pressure to allow air to flow into the isolation room but not escape from the room, as air will naturally flow from areas with higher pressure to areas with lower pressure, thereby preventing contaminated air from escaping the room. This technique is used to isolate patients with airborne contagious diseases such as tuberculosis, influenza, COVID-19 and so on.
Traditionally this is done almost entirely with fresh air, which takes a lot of energy. If any air is recirculated, then it has to be filtered with HEPA filters which have to be replaced, which can be dangerous for the workers. Broad takes a different approach:
After studying national standards and American disinfection measures for NPI, we developed BROAD negative pressure fresh air system, which can directly kill the bacteria of the indoor air. Polluted air is vented outside after heat exchanging and ozone virus killing. We not only meet the standard of 40m³/h fresh air per person, but also reduce air supply. This can reduce energy consumption and operation costs.
Again, I do not mean to criticize the hospital in a shipping container that we showed previously, but Broad's looks a bit more resolved. Note how there is a corridor down the middle for staff, buffer rooms between the ward rooms and the corridor, all with different air pressures. There is also a totally separate patient corridor and elevator bank around the exterior; patients could actually have visitors in a setup like this.
Wen Yuesheng of Broad summarizes the project:
BCore slab is adopted as the structural material, which can achieve 100% factory prefabrication. The main structure, mechanical and electrical, internal assembly and other prefabrication production can be completed in the factory. Rapid construction can be realized through hoisting on site, which greatly shortens the construction period. At the same time, the interior equipped with the BROAD negative pressure fresh air system can prevent indoor cross-infection and outdoor environmental pollution.
Meanwhile, the hospital adopts BCore slabs stuffed with rock wool as the outer wall, which can greatly reduce energy consumption and play a role of carbon-reduction and environment-protection by cooperating with our original negative pressure fresh air system. It is because of BCore slabs, BROAD NPI hospital will not be a one-time temporary hospital and can be used for a long time.
Whenever I have written about Broad Sustainable Buildings, there has been pushback from people who say that it's nothing special, just a lot of people working around the clock, or the quality won't be that great because it is done in such a hurry. In fact, they are probably uniquely suited to do this kind of project, not just because we all need this in a hurry, but also because "due to the experience and lessons drawn from SARS and the COVID-19, Chinese standards are stricter than European and American standards in many aspects." Their combination of structural and mechanical skills seem perfect for these times.
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