More air time

A watchtower – or diaolou – submerged in a reservoir in the Guangdong Province

Stopping the spread of COVID-19 is not just going to happen with vaccinations. Our knowledge of heating and ventilation – and learning from the SARS outbreak – shows air spread is a real problem.

We were invited to join a Taskforce Working Group on the work fighting against the virus.

The group includes the Hong Kong Institution of Engineers – Building Services Division, HKIE BSD and the Chartered Institution of Building Services Engineers – Hong Kong Region.

We’re getting the attention of the public and the industry to raise awareness on the importance of drainage systems – from design and installation- operation and maintenance. And, work together to avoid any kind of leakage at drains in buildings.

Circulating fresh air is also important so we were pleased to be part of a technical seminar on ‘Ventilation and Building Air Disinfection Strategies Against Aerosol and Airborne Transmissible Diseases’ through a Zoom webinar in December.

The seminar heard that like typical airborne particles, viral aerosols follow the same physical mechanisms in their transportation and removal. There are challenges of risk mitigation and prevention of disease transmission in aerosol and airborne routes.

A simple pollutant mass (quantity) balancing model can be used to evaluate the effectiveness and feasibility of different ventilation and building air disinfection strategies against aerosol and airborne transmissible diseases. Options include: increase ventilation rate; increase return air flow rate; improve filter efficiency in ventilation system; use of UV light; emission of disinfectant; and air purifier with effective filter.

The seminar emphasised the importance of using antiviral air filter. Studies show that COVID-19 virus (SARS-CoV-2) can survive on objects for up to 28 days. Virus can accumulate on air filters in tremendous quantity if the air filter is not replaced professionally with medical grade equipment.

This means that the accumulated virus could re-enter the air, putting workers and occupants at risk. An effective antiviral air filter could eliminate virus captured and greatly mitigate the risk during filter replacement.

We also heard important research findings on using masks to greatly reduce the quantity of aerosols generated by coughing and sneezing. Wearing masks not only demonstrates an effective source control measure as a filter, but also serves as the last defence against infectious aerosols.

Getting together again

We held a conference on ways to improve water use. Water Conference 2021 – Future Intelligent / Smart Water Resources Management took place on Tuesday, 27 April 2021 at Multi-Purpose Hall, Zero Carbon Park, Kowloon Bay. Guest of honour was Mr Kelvin K W Lo, JP, Director of Water Supplies and Dr Benjamin P L Ho, Senior Lecturer, Department of Mechanical Engineering, The University of Hong Kong.

They were joined by waterworks professionals, building designers, building construction and maintenance professionals.

Water usage is a big issue for us: our three main sources of water are from Guangdong Province, rainwater stored in reservoirs and seawater for flushing toilets. Our water quality has been ranked among the best in the world, but we have to be efficient.

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