Just came back from Dungun, Trengganu where I was asked to install BH sound system for the owner.
The two stories building 20X60X2 stories high was ready about one months back and the owner called asking my help to install my recommended sound system.
"Pak Harry please install your sound system plus any other things that deem fit for the BH. I am using solar power." the owner told me on the phone.
I took the job because I was free and I wanted to mobilize those solar powered sound system that was compact and unusual.
The first unit was installed at Karak, Pahang and now another chance to install in Dungun.
It seems that this newly completed BH in Dungun, Trengganu was having some temperature and air flow problems.
Within less than 5 minutes if you enter the BH you will sweat to the bone. I mean you sweat all over the body.
My workers complained about it over and over again.
I wonder what can be wrong with the BH.
I talked to the owner and he seems to confirmed that the BH was double walled and it should be okay.
I told myself that there must be something wrong with the air flow and at the same time I was very sure that the heat was coming from those walls.
What happened next was interesting.
1) This BH was constructed with the main walls facing the east and the west. The sun will he hitting the wall facing the east as soon as the sun is high enough. By noon the wall facing the west will be the next victim.
2) The heat will start to form on the outer surface of the wall and slowly creep into the inner surface.
3) If the wall is single layer the heat will reach the inner surface within less than 2 hours. If there is another wall with a gap or insulated with styrofoam, the heat will be halt for some time or stop totally from heating the surface of the second wall.
4) For this particular BH I was very curious about the claim that it was with double walls. What I did was to open the ventilation hole PVC pipes and check the thickness.
5) The moment I removed the pipe I told myself that this BH is one wall and not two walls. The thickness of the wall was too thin and was about 6-7 inches. Usually a two walls building will have at least 11-12 inches wall thickness.
6) My worst nightmare was to see how the ventilation holes were all covered with cement. Out of the original 4 inches diameter PVC opening only about 30-40% were opened. The rest were plug with cement and the grill to prevent those wild birds from building their nest in them.
What I recommended the owner to do were the followings:
1) He need to quickly erect a new wall, not necessarily be cement walls, to prevent direct sunlight on both the main walls. Most important will be the one facing the west.
2) My suggestion was to erect some steel frame with railings about about 2-3 feet apart. Once these railings are welded or mounted he can install those orchid mat using those cable tie to lock them tough.
3) If he can he can opt for the installation of those zinc or asbestos ceiling sheet.
4) A suitable air gap need to be provided between the barrier and the cement wall. The best is about 8 inches. This will allow the hot air to flow upward in a laminar flow. Larger gap sizes will cause the air to flow in a turbulent manner this in turn will create heat sink thus defeating the purpose.
5) All the ventilation holes grills needs to be inspected and cleaned.
There are more than just building a BH.
If the nesting room temperature hits 30*C and above you will have a very tough time to get those swiftlet to stay.
This specific BH was already recording 30.8*C on a normal day with some drizzle in the afternoon.
Can you imagine what kind of record high if it is during those hot and dry season?