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

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.