Urban Mining

If you live in an urban environment, the storage bank for constructing tomorrow’s buildings is all around you. Yes, those buildings will be deconstructed, becoming the raw material for tomorrow’s buildings. And if you are lucky you might find a building constructed from steel, which can be infinitely recycled.

Therefore, designers must consider how the building will be demolished and reused before its open.

Don’t Do Stupid Things

The above drawing is from a new air conditioning building (designed 2020), an interior vapour barrier is stupid!

Why? The external vapour pressure is significantly higher (approx. 1kpa higher) than the interior vapour pressure in the air conditioning space, causing moisture flows toward and into the room.

However, the internal vapour barrier stops the flow, and traps moisture saturating the thermal insulation with water and destroying its thermal properties, and increasing the building energy consumption.

HKGBC recent asked for ideas to promote nett zero and lower energy consumption, the first step I suggest must be stopping architects doing stupid things!

*****END

How to avoid mould in air conditioned buildings

moisture mould problems air conditioned buildings

In air conditioned buildings, the exterior vapour pressure will be higher than the vapour pressure in the air conditioned room, therefore the vapour and moisture flow is high to low (blue line in the diagram above)

Now normally this is not an issue, because a decent ventilation system will transport moisture back to the air conditioning cooling coil, it’s condensed, and safely drained away.

However, problems occur when a vapour retarder is installed (red line in above diagram) interrupting the flow. Moisture becomes trapped, and even the best ventilation system cannot transport it to the cooling coil. Instead what happens, damp, moisture, and then mould growth occurs (left of red line in diagram above).

wall-mould-800w-2

And we already know the problems associated with mould, it causes poor indoor air quality, and therefore health issues for the occupants. If the air conditioning room also happens to be under negative (relatively) pressure, as often occurs in hotel rooms, the situation is compounded because the vapour quantity is increased, accelerating the process. It should be taught in school “don’t ever use vinyl wallpaper in air conditioned buildings” because it causes mould.’

This phenomenon is not limited to Hong Kong, it occurs in hot tropical climates, whether you are in Singapore, Indonesia, Shanghai, or Hong Kong.

Furthermore, it’s the type of problem that’s not immediately apparent, mould doesn’t just appear overnight, and it is unlikely to surface within the defects liability period (DLP).

thermal-scan-101

So it is obvious, lining the external wall of an air conditioned space with any vapour retarder must be avoided at all costs. But sadly it still happens today, increasing maintenance and costs for building owners and operators.

About Kelcroft

Kelcroft based in Hong Kong provides specialist advice, including energy, built environment, and green building consulting services, advising owners and design teams, to lower the cost of building operations.

tags

#mould #mold #hongkong #buildings #hotels #maintenance

BEEO compliance for new construction by John A. Herbert

by John A. Herbert

emsd cocr stage 1

How to comply with BEEO ordinance for new construction?

To build in Hong Kong you follow the traditional BD submission format, but you must also fulfil the mandatory requirements detailed in the Building Energy Efficiency Code (BEEO). How does that impact the construction process?

The building owner must engage an EMSD Registered Energy Assessor (REA) to complete and issue EMSD Form EE1, also known as Stage 1 Certificate of Compliance Registration (COCR), and an EMSD Form EE2, known as Stage 2 COCR.

When does the COCR need to be issued?

Stage 1 COCR must be submitted within two months after obtaining BD consent. For Stage 2 COCR, that must be submitted within four months after obtaining BD Occupation permit.

further details are provided on the EMSD website.

hongkong-emsd-energy-code-2015-rev-a