Unhealthy Hong Kong Homes

by John Herbert

We spend many hours indoors every day, and during the covid19 pandemic many people are forced to work from home.

If you or your family are suffering from persistent illness, symptoms might include headaches, fatigue, allergy, asthma, diarrhoea, or flu like symptoms, your home could be unhealthy causing sickness. Kids are still growing, and can be particularly susceptible to different types of illness during their development.

If you want to discuss your unhealthy building, call John Herbert 2335 9830 today!

Damp, pollution, faulty drains, faulty ventilation, and water seepage are just of some of the reasons causing an unhealthy home, persistent illness in your family indicates you could have a problem. Do you regularly see your neighbour in the local GP’s surgery or in the hospital, that could indicate both families are living in a sick, unhealthy building.

In Hong Kong, medical professionals are reporting that patients appear to be ignoring symptoms and illness, and do not seek medical attention early enough! Don’t delay already seek doctors advice immediately.

#sickbuilding #sickbuildingsyndrome #unhealthy

Lousy IAQ Analysis

Restaurants in Hong Kong must comply with the relevant provision of the FEHD licensing requirements. For Air-conditioned restaurants, typically the indoor air is largely recirculated with a small quantity of fresh air / outdoor air added into recirculating air steam.

By law, the minimum requirement is provided in clause 42 of the licensing requirements, only 17m3/hr/person (or 4.2 litres/sec/person) [1] of fresh air / outdoor is required, to put that into perspective that rate is lower than the normal 7-10 litres/sec/person rate.

Of course, the result is poor IAQ quality, because the air pollutants, including airborne covid19 [2] concentrations, are diluted extremely slowly.

“Poor ventilation may play a major role in transmission” RTHK reported the spread of covid19 investigation [3]. However, as explained above, it is no surprise, all Hong Kong restaurants have little fresh air/outdoor air, thus are poorly ventilated, and any bacteria/virus in the air is not diluted.

[1]https://www.fehd.gov.hk/english/howtoseries/forms/new/A_Guide_to_Restaurant.PDF#page=31 
[2] http://www.kelcroft.com.hk/20200404-news-covid19.htm
[3] https://news.rthk.hk/rthk/en/component/k2/1537915-20200715.htm

Building Infrared Inspection

Building infrared inspection reveals hidden defects not visible to the human eye, the temperature image can locate the source of water ingress, damp, water damage, locate missing sections of thermal insulation missing, identify overheating switchgear, and much more.

#hongkong #thermography #infrared #building #inspection #condition survey

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Vapour diffusion

Moisture is a problem in the tropics so its important to understand two issues, moisture is transported within the air, and through a process known as Diffusion.

One property of air is the water vapour pressure, for air-conditioned buildings, we are mainly concerned with the difference between the outdoor and indoor water vapour pressure. Why air-conditioned buildings? Cooling and dehumidifying indoor air lowers the indoor water vapour pressure.

In the CIBSE guide or equal, properties of air, look up the water vapour pressure for outdoor air say 35 db/28 wb and an air-conditioned space, lets say 24 degC and 50% rh. That delta P, the pressure difference is the driving force for moisture diffusion through the building envelope, including curtain walls, towards the lower pressure space inside buildings.

Typically, we expect that “Good Ventilation” inside the building will transport that moisture and condense it on the cooling coil. However, if the internal face of the external wall is blocked, with a vapour barrier on the inside or obstacles preventing air movement, moisture will accumulate internally causing mould.

Often vinyl wallpaper or a polymer type paint, essentially a layer of plastic, is used inside buildings, which stalls diffusion, causing moisture to accumulate internally, causing damp and mould as shown in the diagram above. If the room is naturally ventilated the water vapour pressure inside and outdoor are effectively equal, and adjacent air-conditioned rooms would with similar conditions means the delta P is also effectively zero.

So its important to understand the different processes, to solve IAQ problems.

Productivity & Sick Days

The Hong Kong outdoor air quality and therefore the indoor air quality will be miserable for the first week of Oct. 2019 impacting productivity as the number of sick days is likely to increase in the urban areas (the places where people work).

The AQICN.org website is an invaluable resource reporting the real-time outdoor air quality but also providing a prediction for the next few days, and its bad news, it predicts Unhealthy (over 100) air quality.

Causeway Bay – greater than 100 is unhealthy
poor Outdoor Air Quality predicted 30 Sept – 5 Oct. 2019

Study after study shows poor air quality correlates with increasing hospital visits for respiratory problems.

Can we improve the Hong Kong Indoor Air Quality? the simple answer is yes, controlling the outdoor air is important to prevent condensation, and properly cleaning the air, before pumping it around the office, is the most practical solution.

CENTRAL – greater than 100 is unhealthy
poor Outdoor Air Quality predicted 30 Sept – 5 Oct. 2019

Hong Kong’s IAQ certificate requires the outdoor air quality to meet the same criteria as the indoor air quality values, so we guarantee no measurements can be taken this week!

And that’s its weakness, those measurements are a snapshot, taken on days with “good” outdoor air quality, this gives owners a false sense of security, on other occasions the Outdoor Air Quality and therefore the Indoor Air Quality does not meet the objective.

Proper air outdoor air management, including air cleaning, will improve the indoor air quality in your building, in your lungs, and lower the number of Hong Kong sick days.