MCAC-VTSM-2011-09
Installation
Duct Engineering
107
As for duct of high pressure system, it should be no more than 100mm.
4) Four angles of rectangle duct flange should be designed with screw hole.
5) When improving the strength of duct flange position by adopting reinforcement method, the applied
condition corresponding to flange specification could be extended.
2. Connection of nonmetallic duct
Specification of flange should be in accordance with standard, gap of bolt hole should be no more than
120m. Four angles of rectangle duct flange should be designed with screw hole.
3. Strengthening of metal duct
When edge length of rectangle duct is more than 630mm, edge length of insulation duct is more than
800mm and length of pipe section is more than 1250mm, or single-edge level area of low pressure duct
is more than 1.2 square meters and single-edge level area of high/middle pressure duct is more than 1.0
square meter, strengthening measures should be conducted.
4. Strengthening of nonmetallic duct
When diameter or edge length of HPVC duct is more than 500mm, the joint section of duct and flange
should be equipped with strengthening board and the gap should not be more than 450mm.
5.3. Connecting Highlights of Duct
1. Supporting, hanging and mounting bracket should be made of angle steel. Position of expansion bolt
should be correct, firm and reliable. The buried part could not be painted and oil pollution should be
eliminated. Gap should be in accordance with regulation below:
1) If duct is installed horizontally, gap should be no more than 4m when diameter or edge length is less
than or equal to 400mm, while the gap should be no more than 3m when diameter or edge length is
more than 400mm.
2) If duct is installed vertically, gap should be no more than 4m and make sure there is at least 2 fixed
points on single straight pipe.
2. Supporting, hanging and mounting bracket could not be installed at air opening, valve, checking door
and automatically controlled device, and distance to air opening or plugged tube shall not be less than
200mm.
3. Hanging bracket should not be hung above flange.
4. Thickness of flange gasket should be 3-5mm. Gasket should be flat on flange and inserting to pipe is
not allowed. Set up fixed points at proper place for hanging pipe to prevent vibration.
5. Vertical splice seam of duct should be stagger. Make sure there is no vertical seam at the bottom of
duct installed horizontally. As for the installation of flexible short duct, keep proper tightness and no
distortion.
6. All metal parts (including supporting, hanging and mounting bracket) on pipeline system engineering
should be conducted anti-corrosion treatment.
5.4. Installation of Assembly
1. The regulating device of duct should be installed in place where is easy to operate, flexible and
reliable.
2. The air port should be installed firmly and air pipe should be connected tightly. Frame should be tightly
contact with decorate of building. The appearance should be smooth and flat, and regulation is flexible.
3. If air port is installed horizontally, deviation of levelness is no more than 3/1000. If air port is installed
vertically, deviation of perpendicular should be no more than 2/1000.
4. The same air port in same room should be installed at the same height, and put in order.
