주식회사 태연이엔지


	(1) The duct facility needs to adequately distribute incoming air (from heating system and the air conditioner) to each room. Additionally, its material should not cause pollution or absorb moisture. (2) The duct should be leak free, have minimum deformation from inner air pressure, and a low air resistance. Additionally, its structure needs to cause as little noise as possible.


	(1) Duct Material 1) Zinc Alloy Coated Steel · Galvalume Aluminum Zinc Alloy Coated Steel Sheet (KS D 3770) is used. · Hot Rolled stainless steel sheets (KS D 3705) and strips. or Cold Rolled stainless steel sheets and strips (KS D 3698) are used. 2) Vinyl Chloride steel sheet Use Class C, Group 1 of KS M 3343 (Poly Vinyl Chloride or Vinyl Chloride Resin Composite Laminates) 3) Hard Chlorinate Vinyl Plate Use Class 1, Group 1 of KS M 3501(Hard Chlorinate Vinyl Plate) (2) Joint and Support Material 1) Steel Class 1 of KS D 3503 (Rolled steel for general structure use) or more products are used. The shape, size, weight and allowable error follow the description on KS D 3501 and KS D 3052 (these standards refer to the shape, size, weight and allowable error of rolled steel plates) 2) Rivet Zinc-coated plate ducts need to follow the standards regarding zinc coated steel rivet in KS B 1101 (Cold headed rivets). If the duct material is stainless or vinyl chloride steel plate, the applied standard is the stainless rivet or copper rivet standard. 3) Bolts and Nuts The higher standard between KS B 1002 (Hexagonal bolts) and KS B 1012 (Hexagonal bolts) needs to be applied. Zinc coated steel bolts and nuts are used. (3) Duct Accessories 1) Outdoor Air Intake Grilles KS D 3770 (Galvanized zinc coated steel plates and rods) products with the thickness of 0.6mm or more, KS D 3512 (Cold rolled plates and rods) or KS D 6701 (Aluminum and Aluminum alloy plates and strips) are used. Additionally, it should have enough reinforcement. 2) Exhaust Grilles The structure is the same with that of the outdoor air intake grilles. 3) Air Outlet and Inlet They should cause as little noise as possible and effectively function as an inlet and outlet. The rear damper thickness and the inlet and outlet shutter should be 0.5mm or more. Material used is KS D 3512 (Cold rolled plates and rods), KS D 6701 (Aluminum and aluminum alloy steel plates and strips) with a thickness of 1.0 mm or more, or KS D 6759 (Aluminum and aluminum alloy extrusion products). The structure of inlet and outlet must be strong enough and should make it easy to control air volume. Various shape specifications are as follows. 4) Volume Damper Damper wings should be made of KS D 3506 (Galvanized zinc coated plates and rods) products with a thickness of 1.2 mm or more. They should have guaranteed functionality and cause as little noise and vibration as possible. In addition, when opened, they need to have as little resistance to air flow as possible. The casing should have the same thickness as the linking duct, or should be made from thicker steel plates or zinc coated steel plates with adequate support. As for the rectangular duct damper, one wing or more should be placed per duct at a height of 250 mm. Wings should be overlapped more than 15mm. The circular duct damper has only one wing. If the damper is to be manually controlled, an opening and closing indicator is required. 5) Fire Damper For the wing and frame, steel plates or KS D 3501 (Hot rolled mild steel plate and rods) products with the thickness of 1.6mm or more should be used. The deformation caused by heat should not interrupt the damper function. The gap between the wing peripheral and the casing inside should be constant. The damper and bearing should be made up of material as indicated in number 4). 6) Fire and Volume Damper Fire and volume dampers having structures fitting the description on number 4) and 5) can be used. 7) Piston Damper It consists of casing, movable wing and piston releaser, and has structure that is closed with the piston releaser. When opened, it needs to have guarantied fire protection functionity and as little resistance to air flow as possible. Casing, movable wing plate thickness, damper side material and bearing material all need to follow the standard described in number 5). The piston releaser should have a structure that is effectively run by fire extinguisher gas, and needs to be constructed with brass or stainless. Return control can be manually done, if necessary. 8) Flexible Damper Proven fire stopping material needs to be used. The damper should have adequate flexibility and high puncture strength. If it is used for heating, the damper is required to have low thermal conductivity. 9) Flexible Joint The material used for flexible joint, in principle, should be glass cloth and have aluminum coating on one or both sides. The material needs to have substantial heat and fire resistance. The standard flange distance between the two ends, according to KS D 3556, is around 150- 200mm. Therefore, as the outdoor flexible joint needs to be water-resistant, the company- proposed specification should be followed. 10) Access and cleaning holes The holes should be easily opened and closed. When closed, air leaks should be as few as possible. For the opening and closing lid, KS D 3506 (Galvanized zinc coated steel plates and rods) or KS D 3512 (Cold rolled steel plates and rods) having the same thickness as the duct needs to be used. As for the holes where conditioned air passes, insulation material is required. 11) Silencer It needs to maintain designated silencing capacity, while having no negative influence on airflow. It also has to have a structure that prevents sound and noise that penetrated the silencers main body from interrupting operation. The sound absorption material to be used is required to be fire-retardant or resistant, and needs to absorb as little water as possible. In addition, it should be resistant to fungus and corrosion. Also the dust from this material should not become airborne or be separated into the airflow. Casing or steel sub frame is built with KS D 3506 (Galvanized zinc coated steel plates and rods) with the thickness of 0.5mm or more, and their structure should be strong.

(1) Duct Manufacturing and Installation

1) Zinc Steel Sheet and Vinyl Chloride Steel Sheet Ducts
    According to the degree of internal positive pressure, duct can be classified as follows: Low
    pressure duct; High pressure duct I, and High pressure duct II. The air temperature in and out
    of the vinyl chloride steel duct should be 40℃ or less.

     ① Duct Type and Pressure Range
       Different pressure duct types (and pressure ranges) are described in the following table.

Duct Name for different pressure	Pressure Range		Airflow speed range [m/s]
Duct Name for different pressure	Gauge Pressure [Pa]{mmAq}	Recommended Pressure [Pa]{mmAq}	Airflow speed range [m/s]
Low Pressure Duct	+490{+50}or more -490{-50}or more	+980{+100}or less -735{-75}or less	15or less
High Pressure Duct I	-490{+50}~+980{-100}or less -490{-50}~+980{-100}or less	+1470{+150}or less -2450{-150}or less	20or less
High Pressure Duct II	-980{+100} ~+2450{-250}or less -980{-100} ~+1960{-200}or less	+2940{+300}or less -2450{-250}or less	20or less

     ② Duct Plate Thickness
      · Rectangular Duct
        Rectangular ducts should be installed through the angle flange method and corner bolt
        method.
        The duct thickness is described in the following table. As for special tubes, the maximum
        size should be used.

Duct Pressure	Low Pressure Duct [mm]	High Pressure Duct I [mm]	High Pressure Duct II [mm]	Plate Thickness [mm]
Duct long side	450or less Longer than 450 to a maximum of 750 Longer than 750 to a maximum of 1500 Longer than 1500 to a maximum of 2200 Longer than 2200	450 or less Longer than 450 to a maximum of 1200 Longer than 1200		0.5 0.6 0.8 1.0 1.2

Spiral Duct: KS D 3506 (Galvanized zinc coated steel plates and rods) are used to make this spiral shape pipe. The size described here is inner diameter. The thickness is as follows.

Duct Pressure	Low Pressure Duct [mm]	High Pressure Duct I [mm]	High Pressure Duct II [mm]	Plate Thickness [mm]
Duct long side	450 or less Longer than 450 to a maximum of 750 Longer than 750 to a maximum of 1000	200 or less Longer than 200 to a maximum of 600 Longer than 600 to a maximum of 800 Longer than 800 to a maximum of 1000		0.5 0.6 0.8 1.0

     ③ Duct Joint
      · Rectangular Duct: Where the duct is bended, more than one joint should be installed.
        Methods that can be used are pitsburgh seam, button punch snap lock or double corner
        seam.
      · Spiral Duct: Folding width should be 4.8mm or more. Its pitch is as follows.

Duct Size [mm]	Pitch [mm]
Longer than 100 to a maximum of 1000	100 or less150 or less

④ Duct Bonding
Angle flange duct bonding method: The method is as follows.

Duct Type	Duct Long Side [mm]	Flange for Bonding						Flange Spacing
		Bar Size [mm]	Rivets for Flange Installation		Bolts for Bonding
			Nominal Rivet Size [mm}	Rivet Spacing [mm]	Nominal Bolt Size [mm]	Bolt Spacing [mm]		Standard Spacing [mm]	Maximum Spacing [mm]
						Corner	Center
Low Pressure Duct High Pressure Duct I High Pressure Duct II	750 or less Longer than 750 to a maximum of 1500 Longer than 1500 to a maximum of 2200 Longer than 2200	25X25X3 30X30X3 40X40X3 40X40X5	4.5 4.5 4.5 4.5	65 65 65 65	M8 M8 M8 M8	공칭 125 이하 (50-100)	200 (100) 200 (100) 200 (100) 200(100)	1820 1820 1820 1820	3640 2730 1820 1820

Steel Plate Duct Bonding: The bonding material are the corner piece, corner bolts, flange clips and bolts and steel plate flange which are made by bonding and processing steel plate. The bonding specification is as follows.

Duct long side [mm]	Bonding Flange						Flange Spacing
	Steel Plate Flange Size			Corner Piece		Clips
	A [mm]	B [mm]	T (Duct Thickness) [mm]	Plate Thickness [mm]	Bonding Bolt Size [mm]	Plate Thickness	Standard Spacing [mm]	Maximum Spacing [mm]
450 or less Longer than 450 to a maximum of 750 Longer than 750 to a maximum of 1200 Longer than 1200 to a maximum of 1500 Longer than 1500 to a maximum of 2200	30 30 30 30 30	10 10 10 10 10	0.5(1.8) 0.6(1.0) 0.8(1.2) 0.8(1.2) 1.0(1.2)	1.2(1.6) 1.2(1.6) 1.2(1.6) 1.6(1.6) 1.6(1.6)	M8 M8 M8 M8 M8	1.0(1.2) 1.0(1.2) 1.0(1.2) 1.0(1.2) 1.0(1.2)	1740 1740 1740 1740 1740	3480(2610) 3480(1740) 2610(1740) 2610(1740) 1740(1740)

3) Rectangular Duct Sealing
The degree of duct sealing depends on internal positive pressure and duct use. The duct
sealing degree and areas to be sealed are as follows.

Degree	Areas required to be sealed
N Sealing A Sealing B Sealing C Sealing	① Duct four corners bending around the duct flange joints ② Corner fixtures and flange parts ① Longitudinal direction connected parts ① Duct Joints ① All duct Joints ② Duct penetration points (including all the parts such as bolts and rivets)

4) Duct Reinforcement
Low Pressure Duct Reinforcement
Transverse reinforcement is as follows

Duct long side [mm]	Reinforcement type and spacing
	Angle size [mm]	Maximum Spacing [mm]
		Angle Method	Corner bolt method
50 or less Longer than 750 to a maximum of 1500 Longer than 1500 to a maximum of 2200 Longer than 2200	25X25X3 30X30X3 40X40X3 40X40X5	1840 925 925 925	1840 925 925+Tie Rod -

Note: Flange joints built by the angle method, or corner bolt method, are considered to be transversely reinforced.

High pressure duct I and II reinforcement
Transverse reinforcement is as follows.

Duct long side [mm]	Reinforcement Type and Spacing
	Angle Size [mm]	Maximum Spacing [mm]
		Angle Method	Corner bolt method
450 or less Longer than 450 to a maximum of 750 Longer than 750 to a maximum of 1200 Longer than 1200 to a maximum of 2200 Longer than 2200	25X25X3 25X25X3 30X30X3 40X40X3 40X40X5	925 925 925 925 925	925 925 925 925+Tie Ro -

Note: Flange joints built by the angle method, or corner bolt method, are considered to be transversely reinforced.

Longitudinal reinforcement is as follows.

Duct long side [mm]	Angle Size [mm]	Reinforcement location	Remark
Longer than 1500 to a maximum of 2200 Longer than 2200	40X40X3 40X40X5	One or more reinforcements at the center Two or more reinforcements at the center	Attach to outer or inner side.

Note: 1) For the applicable duct sizes, transverse as well as longitudinal reinforcement should be
           done.
         2) Angle attachment should be done with 4.5mm rivet or spot welding. The pitch should be
           100mm.
         3) If the duct's long side is longer than 450mm, or the duct is not insulated, a reinforcement
           rib is required using a diamond brake, or pitch with 300 or less.

Tie Rod Reinforcement
ⓐ If the duct side length is longer than 1500 mm for the low pressure duct, and longer than 1200
    mm for high pressure ducts I & II, an angle as well as tie rod should be used for reinforcement.
ⓑ To determine the number of tie rods, abstract 1100 mm from the length of the low pressure
    duct, and in the case of high pressure ducts I and II, abstrac t 900 mm. Round off the number,
    then evenly divide the length to place tie rods.
ⓒ If both angles and tie rods are used, the angle size in the longitudinal direction can be
    40X40X5 or 40X40X3, following the case where there is no tie rod.
ⓓ The tie rod diameter should be 9mm when the number for each side is less than one. When
    one or both sides has 2 or more, a 13mm size tie rod should be used.
ⓔ As for the corner bolt method, the tie rod should be within 25mm from the joints, and installed
    to be adequate for center longitudinal direction angle reinforcement.

5) Rectangular duct hanger and support are as follows.

Duct long side [mm]	Hanger		지지체	최대간격[mm]
Duct long side [mm]	Angle Size [mm]	Bar Diameter [mm]	Angle Size [mm]	Angle method, Slide method	Steel Plate Method
750 or less Longer than 750 to a maximum of 1500 Longer than 1500 to a maximum of 2200 Longer than 2200	25X25X3 30X30X3 40X40X3 40X40X5	9 9 9 9	25X25X3 30X30X3 40X40X3 40X40X5	3680 3680 3680 3680	3000 3000 3000 -

Note: 1) In the case where the steel bar has a 9mm diameter, the axis diameter is 8.1mm or
           more. Therefore, bolts with the thickness of 7.7mm should be used.
         2) For the main duct in a transverse direction, angle vibration resistant supports should be
           placed with less than 12mm spacing. In addition, as for places where vibration is already
           prevented, you can consider the vibration prevention job done.
         3) As for the ducts installed (with angle, slide or steel plate method) in main machinery
           rooms, if their long side is longer than 450mm, the duct hanger spacing should be
           2,000mm or less.

Spiral duct hangers and supports are as follows.

Size [mm]	Hanger		Supports	Maximum Spacing [mm]
Size [mm]	Steel Flat Bar Size [mm]	Bar (Diameter) [mm]	Steel Flat Bar Size [mm]
1000이하	25X3	9	25X25X3	3000

a) Duct Joint
   Rectangular Ducts: At duct corners, there should be more than one joint. The joints can be
   connected with Pittsburgh seam, button punch snap lock, double corner seam, or can be
   welded. The welding method should be arc (TIG, MIG) or spot welding.
   After welding, fully remove spatter or scale with wire brush or grinder. Flowing direction joints,
   if it can be connected by standard plate, it can be joined by double corner seam or welded.
   As for spiral duct, follow descriptions on number 1)c)②.

b) Duct Bonding
   Rectangular duct bonding: Duct bonding is as follows.

Duct long side [mm]	Bonding Flange						Maximum Frange Spacings [mm]
	Angle Size [mm]	Rivet for Flange Bonding			Bolts for Bonding
		Nominal Size [mm]		Pitch [mm]	Nominal Size [mm]	Pitch [mm]
		Stainless	Steel
750 or less Longer than 750 to a maximum of 1500 Longer than 1500 to a maximum of 2200 Longer than 2200	25X25X3 30X30X3 40X40X3 40X40X3	4.0 4.0 4.0 4.0	4.5 4.5 4.5 4.5	65 65 65 65	M8 M8 M8 M8	100 100 100 100	4000 4000 2000 2000

Note: 1) The flange joint welding areas are its four corners. The welded areas should be treated
           evenly before cutting the required holes.
         2) In order for flange bonding, gasket for flanges that have the same width as the flange
           should be used. Bolts are used to fasten the areas to be air tight.
         3) If some spots have a leak risk, their joints should be sealed.

Duct Reinforcement
Transverse reinforcements between rectangular duct joints are as follows.

Duct long side [mm]	Angle Reinforcement Duct
	Angle Size [mm]	Maximum Spacing [mm]	Rivets for Angles
			Stainless Steel Nominal Size [mm]	Pitch [mm]
750 or less Longer than 750 to a maximum of 1500 Longer than 1500 to a maximum of 2200 Longer than 2000	25X25X3 30X30X3 40X40X3 40X40X3	2000 1000 1000 1000	4.0 4.0 4.0 4.0	100 100 100 100

Duct Width [mm]	Angle Size [mm]	Attachment Spots	Rivets for Angles
			Stainless Steel Nominal Size [mm]	Pitch [mm]
Larger than 1200 to a maximum of 2200 Larger than 2200	40X40X3 40X40X5	One spot at center Two spots at center	4.0 4.0	100 100

Note: For angles, steel products (including both bolts and nuts) should be used. But, if they are used in places with high humidity, stainless products (including both bolts and nuts) should be used.

If the duct's long side is longer than 450mm, or the duct is not insulated, a reinforcement rib is required using a diamond brake, or pitch with 300 or less.

Duct Plate Thickness
Rectangular Duct
Duct plate thickness is as follows. But, as for special tubes, maximum size can be used.

Duct long side [mm]	Positive Pressure [Pa]{mmAq}
Duct long side [mm]	1470{150}or less	1470{150}or more 1960{200}or less	1960{200}or more 2940{300}or less
500 or less Longer than 500 to a maximum of 1000 Longer than 1000 to a maximum of 1500 Longer than 1500 to a maximum of 2000 Longer than 2000 to a maximum of 3000	3 4 5 5 6	3 5 5 5 6	4 5 5 5 6

Circular duct: Nominal straight pipe size is based on internal diameter. Duct thickness (mm) is as follows.

Duct long side [mm]	Positive Pressure [Pa]{mmAq}
Duct long side [mm]	1470{150}or less	1470{150}or more 1960{200}or less	1960{200}or more 2940{300}or less
300or less Longer than 300 to a maximum of 500	3 3	3 4	3 4

Duct Joint
As for straight pipes, in principle, four side bending is suitable. Plate bonding or butt welding using the hot gas welding method should be done, but not one the bent areas. The welded plate end side should be processed with an angle of 60 to 90 degrees by using a rasp or grinder.

Duct Connection
1) Rectangular duct connection is as follows.

Duct long side [mm]	Flage for Bonding
	Soft Vinyl Chloride Angle [mm]	Maximum Spacing [mm]	Bolts for Bonding
			Nominal Size [mm]	Pitch [mm]
500or less Longer than 500 to a maximum of 1000 Longer than 1000 to a maximum of 1500 Longer than 1500 to a maximum of 2000 Longer than 2000 to a maximum of 3000	50X50X6 60X60X7 60X60X7 60X60X7 60X60X7	4000 4000 3000 3000 2000	M8(M10) M8(M12) M8(M12) M8 M8	100(75) 100(75) 100(75) 100 100

Circular Duct Connection: In principle, cold working following KS M 3402 (Hard Vinyl chloride linking pipe for water works) or plate bonding using the hot gas welding method can be done. And, if necessary, flange connection method can be as follows.

Nominal Size [mm]	Flange for Bonding	Bolts for Bonding
Nominal Size [mm]	Soft Vinyl Chloride Angle [mm]	Nominal Size [mm]	Pitch [mm]
400 or less Larger than 400 to a maximum of 500	40X40X5 50X50X6	M8(M10) M8(M10)	100(75) 100(75)

Duct Hanger and Supports
Rectangular duct hanger and supports are as follows

Nominal Size [mm]	Hanger			Support
Nominal Size [mm]	Angle Size [mm]	Bar (Diameter) [mm]	Maximum Spacing [mm]	Angle Size [mm]	Maximum Spacing [mm]
500 or less Longer than 500 to a maximum of 1000 Longer than 1000 to a maximum of 1500 Longer than 1500 to a maximum of 2000 Longer than 2000 to a maximum of 3000	30X30X3 40X40X3 40X40X3 40X40X5 40X40X5	9 9 9 9 9	4000 4000 3000 3000 2000	30X30X3 40X40X3 40X40X3 40X40X5 40X40X5	4000 4000 4000 3000 3000

Note: 1) Use steel bars with a 9mm diameter to follow the process described in 1)g)①.
2) Bar vibration prevention support installed within a main duct in the transverse direction
can be constructed as indicated in 1)g)①.

Circular duct hanger and supports are as follows.

Nominal Size [mm]	Hanger			Support
Nominal Size [mm]	Angle Size [mm]	Bar (Diameter) [mm]	Maximum Spacing [mm]	Angle Size [mm]	Maximum Spacing [mm]
300 or less Longer than 300 to a maximum of 500	30X3 40X3	9(1개매담) 9(2개매담)	4000 4000	30X30X3 40X40X3	4000 4000

a) Duct Joints
   Corner bonding parts should be a rectangle shape by placing an aluminum sheet with a
   spacing of 35mm or more. On the adjacent board surface, install temporary fixation by using
   staples with a spacing of 75mm or less. Use such pressing devices that can generate friction to
   bond the aluminum tape. The width and length of staple are 12mm and 13~15mm respectively.

b) Duct Bonding
   Whether the method is overlapping or butt welding, spray adhesives described in KS M 3700
   (Vinyl acetate resin emulsion as wood adhesives) and seal the bonded part with aluminum
   tape. Then use pressing tool to press the part with friction.

c) Duct Reinforcement
   Rectangular duct reinforcement method uses either light weight channel or tie rods.
   Reinforcement spacing is described on the following table. The circular duct, in principle, does
   not need reinforcement. In case the aluminum tape reinforced by glass wool described on
   4)b)② is used, the temporary fixation staple is not required. However, you need to use a tape
   adhesion iron in order to heat and seal the tape.

① Light-weight Channel Reinforcement
   Light weight channel should be shaped as described in KS D 3506 (Galvanized zinc coated
   steel plate and rods).
    ⓐ Reinforcement for transverse duct which is subjected to positive pressure is as follows.

Positive Pressure [Pa] {mmAq}	One side length of square duct [mm]	Duct Outer Pillar Spacing [mm]	Reinforcement Material
0~123 {0~12.5}	0~800 801~2000 2001~2400	- 600Pitch 400Pitch	Light weight channels with the section strength of 50X25X5X0.5t or 75X25X0.8t or more.
123~245 {12.5~25.0}	0~600 601~1700 1701~2400	- 600Pitch 400Pitch	Light weight channels with the section strength of 50X25X5X0.5t or 75X25X0.8t or more.
245~490 {25.0~50.0}	0~400 401~1700 1701~2400	- 400Pitch 400Pitch+로드1개	Light weight channels with the section strength of 50X25X5X0.5t or 75X25X0.8t or more. Screw (with the nominal size of 6mm or more) processed and zinc coated rods described on KS d 3503 (Pressed Steel Material for General Structure).

Standing duct reinforcement subjected to positive pressure is described on the following table.

Positive Pressure [Pa] {mmAq}	One side length of square duct [mm]	Duct Outer Pillar Spacing [mm]	Duct Washer Number	Reinforcement Material
0~123 {0~12.5}	0~800 801~2000 2001~2400	- 600Pitch 400Pitch	- 3 3	Light weight channels with the section strength of 50X25X5X0.5t or 75X25X0.8t or more.
123~245 {12.5~25.0}	0~600 601~1700 1701~2400	- 600Pitch 400Pitch	- 2 3	Light weight channels with the section strength of 50X25X5X0.5t or 75X25X0.8t or more.
245~490 {25.0~50.0}	0~400 401~1700 1701~2400	- 400Pitch 400Pitch+로드1개	- 2 3	Light weight channels with the section strength of 50X25X5X0.5t or 75X25X0.8t or more. Screw (with the nominal size of 6mm or more) processed and zinc coated rods described on KS d 3503 (Pressed Steel Material for General Structure).

Duct reinforcement subjected to negative pressure is described on the following table.

Positive Pressure [Pa] {mmAq}	One side length of square duct [mm]	Duct Outer Pillar Spacing [mm]	Duct Washer Number	Reinforcement Material
0~123 {0~12.5}	0~800 801~1300 1301~2000	- 600Pitch 400Pitch	- 3 3	Light weight channels with the section strength of 50X25X5X0.5t or 75X25X0.8t or more.
123~245 {12.5~25.0}	0~600 601~1400 1401~2400	- 600Pitch 400Pitch	- 2 3	Light weight channels with the section strength of 50X25X5X0.5t or 75X25X0.8t or more.
245~490 {25.0~50.0}	0~400 401~900 901~1400 1401~2400	- 600 Pitch 400 Pitch+로드1개 300 Pitch+로드2개	- 2 2 3	Light weight channels with the section strength of 50X25X5X0.5t or 75X25X0.8t or more. Screw (with the nominal size of 6mm or more) processed and zinc coated rods described on KS d 3503 (Pressed Steel Material for General Structure).

Tie Rod Reinforcements (Both for positive and negative pressure)
In the case of tie rod method, use rods that screw (with the nominal size of 6mm or more) processed and zinc coated ones described on KS D 3503 (Pressed Steel Material for General Structure). Reinforcement method is as follows.

Positive Pressure [Pa] {mmAq}	One side length of square duct [mm]	Duct Outer Pillar Spacing [mm]	Required Number per Reinforcement
0~123 {0~ 12.5}	0~800(700) (701)801~1200 1201~1600 1601~2000 2001~2400	- 600Pitch 600Pitch 600Pitch 600Pitch	- 2 3 4 5
123~ 245 {12.5~ 25.0}	0~600 601~800 801~1200 1201~1600 1601~2000 2001~2400	- 600Pitch 600Pitch 600Pitch 600Pitch 600Pitch	- 1 2 3 4 5
245~ 490 {25.0~ 50.0}	0~400 401~600 601~800 801~1200 1201~1600 1601~2000 2001~2400	- 600Pitch 400Pitch 400Pitch 400Pitch 400Pitch 400Pitch	- 1 1 2 3 4 5

2) Washer should be made of zinc steel plate, or poly amide resin, with the strength of 75X75X0.5t
    or 75 x0.5t or more.

Duct Hanger and Supports

The rectangular duct support should have channels stronger than 50X25X0.5t or 50X25X5X0.5t.
Circular duct or decagon duct support should be steel bars with the strength of 25X0.4t or more. Hanger bars should be complete screws with the nominal size of 6m or more. Main ducts in transverse direction require vibration prevention devices with the spacing of 12m or less. When vibration is prevented by the penetration parts on the walls, it can be considered to have angle vibration prevention tools.

(2) Casing Manufacturing and Attachment

1) This process depends on zinc steel plate, steel plate, steel material, rivets, bolts to be used
    and 2.2 A, B.

2) Casing should be made from zinc steel plate or steel plate. Flange joints, or casing, or
    equipment joints should be assembled to be air tight using casket. The casing end (which has
    adequate strength) should be bent in a box shape, or be reinforced with steel bars or light
    weight soft steel. The attachment of reinforcement angles, or bonding flanges, is done with
    pressurized rivet or spot welding to be air tight. The reinforcement angle size or spacing
    should follow the standard described on the table below. If material other than light weight
    angle is used for this purpose, the material needs to have the same strength with the angle.

Casing long side [mm]	Angle		Plate Thickness [mm]
	Minimum Size [mm]	Maximum Size [mm]
2000 or less 2000 or more	40X40X3 40X40X5	900 900	1.0 1.2

3) Casing needs access holes where people can go in and out. The width of this hole should be
    400mm or more, and its height should be 500mm or more. This hole should be easy to open
    and close, and not allow air to leak. The access holes lids on casing where conditioned air
    passes require insulation material.

(3) Duct Accessory Attachment

1) Outdoor Air Intake Grill Attachment
    Grill should be firmly attached to the building. And the gap between the grill and its attached
    point should be closed sealed, not allowing air leaks.

2) Outlet Grill Attachment
    Follow indications described in number 1).

3) Outlet and Intake Attachment
    Use outlet and intake attachment gaskets to attach them without air leaks. Hard vinyl chloride
    outlet and intake holes should be welded by hot gas or fastened with bolts.

4) Air Volume Control Damper Attachment
    The damper should be attached to a location where air-tightness is maintained and the
   damper is easily controlled. When the damper is attached on the ceiling, or within a shaft,
   install access holes to allow inspection.

5) Fire Prevention Damper Attachment
    Follow KS F 2815 (Smoke Control Facility Inspection Standard).

6) Fire Prevention and Air Volume Control Damper Attachment
    Follow description 5).

7) Piston Damper Attachment
    Follow description 4)

8) Constant and Variable Air Volume Control Devices Attachment
    Follow description 4).

9) Flexible Duct Attachment
    The attachment should be air tight and have no influence on the active area.

10) Access and cleaning hole attachment
    The opening and closing of these holes should be easy. When closed, there should be no air
    leaks. Duct joints should be firmly attached using gasket.

(5) On-site Allowable Errors

Class	Management Item	Construction Standard
1. Duct Enlargement or Reduction	General Enlargement and Reduction Filter Enlargement and Reduction Dividing Plate Installation	- When duct is modified, the duct should have gentle slope in order to minimize pressure loss. As for the enlarged part, the slope angle should be 15 degree or less. And as for the reduced part, it should be 30 degree or less. - If filter or coil is installed within duct, the upper stream should have a slope angle of 30 degree or less, the lower stream, 45 degree or less. - If the above standards can not be followed due to some field conditions, you can install radiation shape dividing plate.
2. Duct Bending	General Bending Small Vending Perpendicular Bending Rectangular Duct Branch Method to install outlets on the lower stream part rather than the bent part	- As for duct bending locations, R/W = 1.25-1.5 in rectangular ductR/D = 1.25-2.0 (curvature) in circular duct - When smaller curvature is unavoidable, a guide vane is required. - For a perpendicular bending with the curvature of "0", install airfall vane. - The rectangular duct branch and bound method is to divide the duct width by the air volume ratio. ① When there is a outlet at the lower stream of one bending location, A≥8W for bending without vane A=4-8W for bending with vane A=≥4W for perpendicular bending with vane ② When there are two bending locations, ③ When there is two adjacent 45 degree bending locations, Note, A: From bending location to outlet W : Duct Width B : From the two 45 degree elbows to the direction perpendicular to air flow
3. Slenderness Ratio	.	Slenderness ration A= length of long side/ that of short side should be four or less.


	(1) On-site Tests 1) Ducts and accessories for air conditioning or ventilation can be tested and inspected as follows. ① Outlet / Intake Size and Location ② Grill Size and its location, water-proof and insect screen structures ③ Duct material and its attachment condition. ④ Damper structure, attachment location and operation status (2) Manufacturer' on-site work


	When the fan first starts its operation, massive dust from within the duct will go out into the room. Therefore, duct cleaning should thoroughly be done.


	(1) Dcut 1) Duct Insulation Damage Identification and Repair 2) Coating Inspection and Repair 3) Duct Vibration 4) Damper Operation Status Check 5) Volume Damper Control 6) FIRE DAMPER FUSE 7) Motorized Damper Control 8) Flexible Duct Connection Check (2) DIFFUSER 1) Outlet / Intake Cleaning 2) Air Leaks at Joints 3) Outlet and Intake Air Volume Check 4) Outlet Direction, Temperature, Velocity Check 5) VAV BOX (3) Air Conditioned Area 1) Temperature Check 2) Humidity Check 3) Room Ventilation Condition Check 4) Noise Check 5) Vibration Check