General catalog of Micro Ducts
Features of Micro Duct
Features of Micro Duct ● Excellent sound absorption, thermal insulation and airtightness. ● Duct work, sound-absorbing work, and thermal insulation work are completed in one process, and the construction
period can be shortened. ● It can also be processed on-site, making it ideal for renovation work. ● This is a standard product for JIS A 4009 (components of ducts for air conditioning and ventilating facilities). ● Non-combustible material [Certification No. NM-8569]. ● It is described in SHASE-S (The society of heating, air-conditioning and sanitary engineers of Japan) Standards
for Facility Construction. ● The Micro Duct product is F****.
General Characteristics Duct thickness
25mm
MICRO DUCT
Weight (per deployed area)
1.8kg/m2
Density of glass wool used
64kg/m3
Micro Ducts create a quiet environment. It is lightweight and contributes to labor saving and safety, making it ideal as exposed duct.
Allowable stress for long-
Modulus of elasticity
450kg/cm2 0.96kg/cm2 *
term loads Thermal conductivity
0.035W/m・K
(at20℃) ◆ This value is the allowable stress of the supply duct without reinforcement.
Usable range Square duct (1) Wind velocity in duct (maximum)
INDEX
(2) Total pressure in the duct (3) Temperature in the duct
Features of Micro Duct ................................................................ 1
Rounded duct
13 m/s or less
15 m/s or less
490 Pa or less (50mmAq)
590 Pa or less (60mmAq) 75°C max.
Micro Duct board......................................................................... 2 Micro round duct ......................................................................... 2 Aluminum tape exclusively for Micro Ducts.............................. 3 Dedicated tool for Micro Ducts ................................................... 3 Construction example .................................................................. 4 Micro Duct Board Usage Example ............................................. 5
(1) (2) (3) (4) (5)
Design calculations for Micro Ducts
Performance and Design Guidance Micro Duct performance 1. Acoustic Performance 2. Ventilation performance 3. Air-tightness performance 4. Insulation Performance 5. Durability 6. Reinforcing Material Performance
1. Acoustic Design Calculations
6 7 7 8 8 8
2. Resistance Calculation 3. Airtightness calculations 4. Adiabatic calculations 5. Strength Design Calculation Processing and assembly of Micro Ducts
9 15 17 18 19
There is no abnormality even if a gas of 120 to 130°C passes through the duct temporarily (0.5 to 1 hour), but do not use it for industrial purposes such as continuously flowing gas exceeding 75°C. Use in a temperature range that exceeds the allowable range will shorten the life of the duct. In principle, avoid using the product in a machine room. Contact us in advance for use before VAV or CAV. Water is strictly prohibited! Do not use the product if it gets wet.
F**** represents the lowest grade for emission levels of causative hazardous substances, such as formaldehyde, that cause building sick syndrome. Formaldehyde emission rate: below 5μg/m2.h
20 1
Application Feature MDB (after fabrication)
For air conditioning and ventilation low pressure ducts ● Excellent
Feature
sound absorption, thermal insulation and
airtightness. one process, duct work, thermal insulation work, and sound absorption work have been completed, The construction period can be shortened.
● In
● It
Tape seals are of paramount importance for glass wool ducts.
● In
addition to being heat-resistant, cold-resistant, and durable,
Micro Duct tapes. This is a specially designed aluminum tape with a proven workability.
can also be processed on-site, making it ideal for
● Aluminum
renovation work. ● JIS A 4009 (components of air-conditioning and ventilating ducts) Standards.
tapes for Micro Ducts, which boast a track record of
30 years, It is stamped with "MICRO DUCT” (Micro Duct). Therefore, it is easy to check design and construction management, including those for government offices. Performance
Dimensions (mm)
Density
Product code
Area
Weight
JIS
Packing
(㎡/sheet) (kg/sheet) (board/bo
(kg/㎥)
x) Thickn
Width
Length
1,225
2,400
Non-combustible materials approved by the Ministry of Land, Infrastructur e and Transport
standar d A9504
A6301
● Aluminum foil thickness ● Tape
A9521 Always use special aluminum tape for the construction of the Micro Duct. "MICRO DUCT" is stamped for quality assurance.
ess *
MDB24
64
25
3.0
MDB30
64
25
1,225
3,000
3.7
MDB9612
96
12
1,225
2,000
2.5
8
●
6.6
6
●
3.4
13
●
5.3
※ "*" indicates the nominal thickness according to JIS standard.
width
75mm50mm
● Viscosity
Force
5.49N/cm or more
● Holding
Force
1.5mm/24hrs or less
NM-8569 Aluminum foil/glass thread/kraft paper/glass paper backing/glass wool heat insulating board
Product code
Thickness (μm)
Width (mm)
Length (m/roll)
● JIS A9504 artificial mineral fiber heat insulating material (F****)
MDSTP 50I (for round ducts)
50 50
75 50
50 50
Product code
Applications for low pressure ducts for air conditioning and ventilation
MWD:Thickness25mm
Dimensions (mm) Inside Outer
Length
diamet diame er
ter
MWD150 MWD175 MWD200 MWD225
100 125 150 175 200 225
150 175 200 225 250 275
MWD250 MWD275 MWD300 MWD350
250 275 300 350
300 325 350
MWD100 MWD125
2
400
2,000 2,000 2,000 2,000 2,000 2,000 2,000 2,000 2,000 2,000
Weig ht (kg/pc.)(
1.5 1.8 2.1 2.4 2.7 3.0 3.3 3.6 3.9 4.5
Packaging (rolls/boxes)
MDSTP 75I (for square ducts)
Product code
0.05mm
Packin g duct/bo xes
16 16 9 9 6 6 4 4 4 4
For
How to Use
For V-shaped grooving
Features
MDSTOOL S (silver tool)
For female slip joint
● Excellent sound absorption, thermal insulation and airtightness.
MDSTOOL P (Purple tool)
For male slip joint
●
MDSTOOL C (round tool)
In one process, duct work, thermal insulation work, and sound absorption work have been completed, The construction period can be shortened. ● It can also be processed on-site, making it ideal for renovation work. ● Lightweight and ideal for exposed ducts. ● JIS A 4009 (components of air-conditioning and ventilating ducts) Standards.
Prescribed in Ordinances of the
Product code
Ministry of Transport ) Non-combustible material
Custom order products
NM-8569 Aluminum foil, glass thread, etc. Craft paperlining/Glass paper lining/Glass wool board
MDSTOOL G (gold-colored tool)
12 18
MWD400 MWD450 MWD500 MWD550 MWD600 MWD650 MWD700 MWD800 MWD900 MWD1000
Dimensions (mm) Inside
Outer
diameter
diame
Length
Weig ht
Pack ing duct/ boxes
(kg/pc.)(
650 700 800 900 1,000
450 500 550 600 650
Gold tools (V-shaped tools)
Purple tool (male tool)
For round duct ship wrap For cutting round ducts (800mm
Silver tool (female tool)
Round tool
Non-combustible material
ter
400 450 500 550 600
Prescribed in Ordinances of the Ministry of Transport
MWD CUT (MWD-cutter)
2,000 2,000 2,000 2,000 2,000
4.9 5.5 6.5 7.1 7.7
2 2 2 1 1
700 2,000 750 2,000 850 2,000 950 2,000 1,050 2,000
8.3 10.1 11.5 12.9 14.3
1 1 1 1 1
NM-8569 Aluminum foil, glass thread, etc. Craft paperlining/Glass paper lining/Glass wool board
MWD cutter
3
Examples of use
Micro Duct Board Usage Example
Construction example
<Duct box made of glass wool> Supervision of the Ministry of Land, Infrastructure, Transport and Tourism, Secretariat Building Department
[Features] Kansai International Airport Passenger Terminal Building: Color Aluminum (0. 6t) Exterior Finish[Features] University: Paint finish
Standard Drawing for Public Building Equipment Work
4
[Features] Station Building: Exterior Color Iron Plate Racking
[Features] Plant garden: Exterior color iron plate racking
[Features] Gymnasium: Exterior Color Iron Plate Racking
[Features] Racing boat yard: Paint finish
5
Micro Duct performances
Performance and Design Guidance
2. Ventilation performance 2-1 Coefficient of frictional resistance of straight pipe
Micro Duct performance
1. Acoustic performance 1-1 Sound attenuation of a straight duct
(dB/m) Center frequency (Hz
Duct Example
63
125
250
500
1,000
2,000
4,000
8,000
Section size (mm)
Micro Duct
Metal duct + glass wool (glass wool is 25mm thick)
Metal duct
2
Square duct
90° elbow
1.26
1.50
3
2
(Aspect ratio = 1.0)
Elbow
(3 Piece) 0.53
(r/a = 0.75)*1 0.41
6
3
2
Round duct
90° elbow
1.20
1.20
21
10
5
3 Piece elbow
0.45
(r/d = 0.75)*2 0.54
11
5
2
16
19
17
ー
15
15
3
ー
5
12
2
ー
ー
2
3
8
4
2
2
ー
ー
ー
ー
ー
ー
15
19
28
9
5
300 × 300
3
5
8
8
12
10
4
600 × 600
3
4
4
5
12
3
300 × 1,000
6
5
6
7
12
200 φ
1
2
3
9
20
300 φ
1
1
2
8
16
150 × 150
ー
5
4
11
300 × 300
ー
2
2
7
600 × 600
ー
1
1
600 × 1,200
ー
1
150 × 150
1
1
Center frequency (Hz
ー
ー
ー
ー
ー
ー (dB/m)
63
125
250
500
1,000
2,000
4,000
8,000
200 × 200
ー
ー
4
2
8
6
23
23
〃
300 × 300
2
6
1
13
12
6
14
20
〃
600 × 600
4
1
2
15
ー
6
15
17
〃
200 φ
ー
ー
ー
4
5
7
15
22
〃
300 φ
ー
ー
ー
3
7
14
23
29
3 Piece elbow
2-2 Shape resistance coefficient of curved pipe Iron plate duct
9
1-2 Silencing characteristics of curved Micro Duct Section size (mm)
0.020 ～ 0.023
Micro Duct
10
1
0.020 ～ 0.025
Another bend
3
1
Metal duct
Another of the duct
200 × 200
600 × 600
Coefficient of skin friction
Micro Duct
* 1. r is the radius of curvature, a is the long side of the duct *2. r is the radius of curvature, and d is the diameter of the duct
2-3 Shape resistance coefficient of the branch Micro Duct Square duct Area Specific
*1
A2 /A1 = A3/A1≒ 1.0
Square duct *1 Surface product ratio A2/A1 = A3/A1≒ 0.5
1-3 Muffling characteristics of the branch Micro Duct
(dB)
Flow rate ratio Q2/Q1 = 0.8 *2 Flow rate ratio Q2 /Q1 = 0.6 *2 Flow rate ratio Q2 /Q1 = 0.8 *2 Flow rate ratio Q2 /Q1 = 0.6 *2
Iron plate duct
Straight pipe
0.05
− 0.04
Branch pipe
1.02
0.55
Straight pipe
0.08
− 0.01
Branch pipe
1.00
0.37
Straight pipe
0.21
0.48
Branch pipe
0.98
0.38
Straight pipe
0.03
0.13
Branch pipe
1.04
0.41
*3
*1. Cross-section area of main, direct, and branch pipes for A1, A2, A3 *2. Q1, Q2 is the amount of ventilation of main and direct pipes. *3. The iron plate duct was made to be a shallow interrupted shunt. NOTE) For detailed data on Micro Duct, please refer to the "Technical Documentation" of Micro Duct (by the Institute of Architectural Engineering, Faculty of Production Engineering, University of Japan). Data on steel sheet ducts were quoted from the Architectural Handbook I Project (Maruzen) compiled by the Architectural Institute of Japan and the Duct Design and Construction Handbook (Maruzen) compiled by the Inoue Uichi.
Center frequency (Hz Section size (mm)
63
125
250
500
1,000
2,000
4,000
8,000
300 × 300
Straight pipe
5
7
3
5
5
ー
1
1
→ 300 × 300
Branch pipe
ー
6
3
16
14
24
39
50
600 × 600
Straight pipe
4
1
1
5
4
1
1
1
→ 600 × 600
Branch pipe
ー
3
7
7
6
36
41
41
600 × 600
Straight pipe
5
3
3
8
10
4
5
4
→ 450 × 450
Branch pipe
10
4
7
9
16
33
36
43
3. Airtightness performance 3-1. Amount of leaked air Micro Duct Amount of leaked air
0.005% or less
3-2. Airtightness of Micro Ducts Note 1) For more information on the acoustic properties of Micro Duct, refer to the "Technical Documentation" of Micro Duct (from the Architectural Engineering Department, Faculty of Production Engineering, University of Japan). Data on steel plate ducts were quoted from the Architectural Handbook I and the Duct Design and Construction Handbook (previously published). Note 2) (-) in the table means that attenuation cannot be expected.
6
Total pressure (Pa)
98
196
294
392
490
588
Leakage air volume (m3/min•㎡)
4.2×10−5
5.9×10−5
7.2×10−5
8.3×10−5
9.4×10−5
10.2×10−5
7
Design calculations for Micro Ducts
4. Insulation performance
(Unit: W/m•K)
Design calculations for Micro Ducts
4-1. Thermal Average of both surface temperatures (°C)
conductivity
0
10
20
30
40
50
Micro Duct 64K-25mm
0.031
0.033
0.035
0.036
0.037
0.040
Glass wool 24 K-25 mm
0.034
0.036
0.038
0.041
0.042
0.044
Product-specific
1. Acoustic design calculation For acoustic design calculations in the case of adopting a Micro Duct, The following formula is used for the general duct system as shown in the figure below.
4-2. Thermal transmittance Thermal transmittance(W/㎡・ K ) Micro Duct 64K-25mm
1.10
Heat insulation of glass wool 24K-25mm in metal duct
1.19
The temperature inside and outside the duct was set at 12°C and 32°C, and the wind velocity inside the duct was set at 10m/s. We considered the glass wool for heat insulation of steel plate ducts to be an aluminum kraft paper laminate. The heat transfer coefficient of the outer surface of the Micro Duct and the surface of the aluminum kraft paper side of the iron plate duct heat insulating material was treated as 7W/m · K considering the change of the emissivity of the aluminum foil with time.
5. Durability The table below shows the corrosion resistance of the Micro Duct to various materials. Micro Duct Inner surface of the duct
Outer surface of
Iron plate duct
When using a Micro Duct, Note the presence of alkali and halogen groups.
the duct
(Glass wool surface)
(Aluminum foil surface)
Water vapor
A
A
B
Water
B
A
C
B
C
D
CO2 gas
A
A
A
Carbon monoxide
A
A
A
Sulfurous acid gas
B
B
D
Halogen group (chlorine, etc.)
B
D
C
Sea
Water
NOTE) A is good B is roughly good C is somewhat inferior D is inferior
PWL=10×ℓog10Q+20×ℓog10P+C+Bri-12.6 .............................................................. (1)
1.
Noise generated by
P: Static pressure (mmAq) of the blower C : Constant determined by the type and frequency of the blower Bri: Increase due to the sound passing through the blade
6. Performance of the reinforcement Item
Stiffener
Cross-sectional shape
50×25×5×3×0.5tmm or more
Heavy Amount
0.41kg/m
Second moment of section
0.40cm4
Modulus of section
Z1=0.30㎝3 Z2=0.52㎝3
Q : Air flow rate (m3/min)
ΔL=10×ℓog10(A/Se).................................................................................................................... (2)
2.
Sound attenuation
Se: Outlet area of the chamber (㎡) A: Total sound absorbing power of the chamber (α × Sw) α : Sound absorption coefficient of inner paste Sw: Interior pasted area (㎡)
NOTE) When a material other than the above is used as a reinforcement material, carefully check its cross-sectional performance.
8
9
Design calculations for Micro Ducts
It varies with the synergistic product of the long side and frequency.
3.
Obtain from the diagram.
8.
Aperture edge reflection
f: Frequency (Hz) ℓe : Diameter d (m) for circular cross-section In the rectangular cross section,
Aperture Reflection
ΔL : Sound attenuation of the silencing elbow (dB) f : Frequency (Hz) ℓ : Silence elbow long side length (or diameter) (m)
4.
Noise generated by a silencing elbow
l x × l y (m)
PWL=C+20×ℓogb+C´×ℓogV
Fl(e Hz・m)
PWL : Noise generated by the silencing elbow (dB) b : Cross-sectional area of the duct to be connected (㎡) v : Wind velocity in duct at the relevant part (m/s) C,C´: Constants per frequency
5.
........................................................................... (3)
9.
If the effect of sound generated in a straight micro-duct is neglected, there are three possible phenomena: sound attenuation inside the duct, transmission to the outside of the duct through the sidewall of the duct, and incidence from the outside of the duct to the inside of the duct through the sidewall. Here, when the micro duct is installed in a space with a small sound absorption coefficient that can be regarded as a diffuse sound field, the power level at any position in the duct in consideration of the above three phenomena can be obtained by the formula (6).
SDi : Cross-sectional area of tributary I considered (㎡) N
ℓ' 1m
ΣSDi : Total cross-sectional area of the downstream section branched into n lines (㎡) i=1
PWLm=[PWL0-R・ℓ]+ [SPL However, when R≧13.0dB PWL=Lθ+10×ℓog10A+55×ℓog10V+C ..........................................................................(4) Lθ: Damper constant due to blade angle θ (0° when fully opened) A: Duct cross-sectional area (㎡) V: Average wind speed in duct (m/s) C: Frequency Correction Value
PWL=10×ℓogA+a×ℓogV+b+c ..................................................................................... (5)
7.
A: Cross-sectional area or neck area of air outlet and suction port (㎡) V: Wind speed or neck wind speed at air outlet and inlet surface (m/s) a, b: constant determined by the type of air outlet and suction port c: Frequency correction value according to the type of air outlet and suction port
10
1+b
-D 2+10ℓog10{L・(1 -e-k.ℓ)/ (1-e-k)}] ......... (6)
SPL1+b=[PWL0-D1+10ℓog10{4(1-α)・(S・α)}]+[SPLb] ....................................................... (7) When R ≦ 12.5dB SPL1+b=[PWL0-D1+10ℓog10{4(1-α)・(1-e-k.ℓ')/S・α(1-e-k)}]+[SPLb]...... (8) Where PWLm: power-level at one end of a duct of any length. dB (10-12 Watt reference) PWLo: Power-level in the duct at the inlet of the duct installation space. dB (10-12 Watt reference) SPL1 + b = [APL1]+[SPLb]: The sum of the sound pressure level of the sound transmitted from inside the duct to the outside of the duct and the sound pressure level around the duct when PWL0=0. dB (0.0002 μb standard) SPL1: Sound pressure level of sound transmitted from inside the duct to outside the duct. dB (0.0002 μb standard) SPLb: Sound pressure level around the duct when PWL0=0. dB (0.0002 μb standard) R: Acoustic attenuation in the duct per unit length. dB/m k=0.23R: Acoustic attenuation coefficient in the duct per unit length. D1: Power level difference when permeating from inside the duct to outside the duct per unit length (1 m). dB D2: Power level difference when incident on the inside of the duct from outside the duct per unit length (1 m). dB S: Surface area of duct installation space. M2 α: Average sound absorption coefficient of the duct installation space. L: Perimeter of duct. m ℓ: Duct length from the entrance of the duct installation space. m ℓ': The length of the duct installation space from the entrance to the exit. m [ ] + [ ]: Indicates energy addition.
11
Design calculations for Micro Ducts
If there is no data for the relevant cross-sectional dimensions, use the data for the approximate cross-sectional dimensions.
Table 1 R, D1, D2 according to Micro Duct dimensions (see page 11)
(dB)
R, D1, D2 by frequency
Duct dimensions (mm)
Frequency (Hz)
R
63
125
250
500
1,000
2,000
4,000
8,000
200×200
−
−
4
2
8
6
23
23
2
6
1
13
12
6
14
20
Cross-sectional dimensions (mm)
(Hz) 63
125
250
500
1,000
2,000
4,000
8,000
300×300
3
10
9
15
19
28
9
5
600×600
4
1
2
15
−
6
15
17
200φ
−
−
−
4
5
7
15
22
300φ
−
−
−
3
7
14
23
29
200×200 D1
15
10
11
13
12
18
25
33
D2
14
12
16
22
28
30
36
43
R
6
7
9
10
11
16
6
4
D1
17
11
13
13
13
21
25
29
D2
11
12
15
21
24
28
36
45
R
3
5
8
8
12
10
4
2
D1
15
11
11
13
14
17
26
32
D2
11
10
17
22
24
28
35
41
R
5
6
7
7
20
18
4
3
D1
14
10
12
10
16
19
26
30
D2
8
12
18
19
21
26
33
39
R
6
5
6
7
12
6
3
2
D1
11
11
6
9
15
22
26
31
D2
5
10
17
17
20
25
32
39
R
3
4
4
5
12
3
3
2
D1
11
11
10
10
11
17
23
30
D2
7
12
17
17
19
25
30
37
Table-2 Acoustic Attenuation of Three-piece Elbow
200×400 ....................................................................................................................................................(9)
C: correction coefficient by frequency
300×300
when f > 250Hz, C=1.0 when f ≦ 250 Hz, C-0.0035*f F: frequency (Hz)
a: Cross-sectional area of the box (㎡) b: Cross-sectional area of inlet (㎡)
300×600
b: ′ Cross-sectional area of outlet (㎡) R: Sound attenuation of Micro Ducts with the same cross-section as the boxes (dB/m) (P12 Table-1) L: Box length (m)
.................................................................................................................................................. (10)
300×1,000
Q: Directivity factor of the sound source (figure below) r: Distance between sound source and sound receiving point (m) R: Room constant R=Sα/ (1-α) S: Room surface area (㎡) α: Average indoor sound absorption coefficient n: Number of sound sources
600×600
10
D
8 6
R
4
3
4
6
9
3
3
3
C
Q4 10¹
B
3
2
7.5 1.5 2.5
600×1,000
2
D1
11
11
1
6
13
17
27
31
1.5 1
A 5
10¹ 2 7.5
D2
7
13
18
15
18
23
31
38
R
3
3
2
2
3
4
3
5
D1
12
10
4
−
11
16
22
30
D2
10
16
17
17
18
24
29
37
R
1
2
3
9
20
21
10
5
1,000×1,000
5 1.5
2.5 3.75
10² 7.5
2 1.5 2.5 3.75
f×L(Hz・m )
5
f : Frequency (Hz) L : A(m) A: Outlet cross section (m2)
................................................................................................................................................. (11)
200φ
N : Number of sounds SPLi: Individual notes to be synthesized (dB)
D1
41
37
37
32
26
23
26
32
D2
35
35
41
39
36
30
32
41
R
1
1
2
8
16
11
5
2
D1
37
33
30
24
15
15
28
29
D2
27
30
33
33
24
26
32
38
300φ
12
13
Design calculations for Micro Ducts
Calculation example
2. Resistance calculation The pressure loss in the straight pipe section of the Micro Duct is calculated by Darcy-Weisbach's equation as shown below.
....................................................................................
(1)
ΔP : Pressure-loss (mmAq) λ : Friction resistance coefficient Frequency (Hz) Point B (noise entering the duct entrance)
ℓ : Duct length (m)
63
125
250
500
1,000
2,000
4,000
8,000
82
78
73
68
63
60
58
55
d : Duct diameter (m)
Point C (Calculation by equation (6) to (8))
64
60
48
38
30
14
41
43
γ : Specific weight of air (kg/㎡)
Damping due to branching at point C (straight pipe)
–5
–7
–3
–5
–5
−
–1
–1
v : Wind speed in duct (m/s)
Point C (noise at the point immediately after
59
53
45
33
25
14
40
42
g : Acceleration of gravity 9. 8m/s2
Point D (Calculation by equation (6) to (8))
55
56
39
29
21
5
16
30
Damping by elbow
–2
–6
–1
–13
–12
–6
–14
–20
Point D (noise immediately after elbow)
53
50
38
16
9
−
2
10
E point (Calculation by equation (6) to (8))
54
56
39
29
21
5
−
4
branching)
Damping due to branching at point C (branch pipe)
−
–6
–3
–16
–14
–24
–39
–50
Noise entering the branch side of point C
64
54
45
22
16
−
−
−
Point F (Calculation by equation (6) to (8))
57
56
39
29
21
5
−
−
For square ducts, calculate the equivalent diameter de using equation (2) as d=de. [a•b is the length of the long and short sides (m)]
........................................................................... (2)
In addition, the pressure loss at the local area such as bent pipes and branches is calculated by equation (3).
Frequency (Hz)
63
125
250
500
1,000
2,000
4,000
8,000
Noise level at point B
82
78
73
68
63
60
58
55
Ambient sound pressure level
42
35
25
20
15
10
10
−
0.05
0.05
0.06
0.07
0.08
0.10
0.15
0.20
7
9
10
11
16
6
4
Sound absorption coefficient of the room R
6
Remark .............................................................................................................................................................
(3)
ζ: shape resistance coefficient 200×400
400×250
D1
17
11
13
13
13
21
25
29
D2
11
12
15
21
24
28
36
45
R
3
5
8
8
12
10
4
2
D1
15
11
11
13
14
17
26
32
D2
11
10
17
22
24
28
35
41
Straight pipe
5
7
3
5
5
−
1
1
Data
Refer to the draft performance section for the frictional resistance coefficient and shape resistance coefficient of the Micro Duct.
300×300
250×250 400×250 ↓ 250×250
Data 300×300 Branch data
Damped branch pipe of the branch
−
6
3
16
14
24
39
50
Attenuation of the 250×250-90° elbow
2
6
1
13
12
6
14
20
300×300 Three-piece data
14
15
Design calculations for Micro Ducts
Calculation example
3. Airtightness calculation The total amount of leaked air when ventilating the Micro Duct is calculated by the following equation. q=Σ2(ai+bi)×ℓ・ i ci+Σei
(0.4
q : Total air leakage in the duct system Ai,bi : Length of long side and short side of duct i (m) ℓi : Length of duct i (m) Ci : Leakage air quantity per unit area of duct wall in duct i (m3/min•㎡) ei : Leakage air quantity of equipment such as damper in duct system (m3/min) For the amount of leaked air per unit area of the duct wall of the Micro Duct, refer to the section on airtightness performance.
0.52mmAq
For round ducts (diameter di), the total leaked air volume in the Micro Duct system is calculated to be 0.005% or less of the ventilation volume. NOTE) Air leakage in an iron plate duct system, which generally reaches 10% of the air flow rate, is the sum of air leaks from main ducts, branch pipes, dampers, and other appliances, each of which is 2 to 4%. Therefore, replacing branch pipes with Micro Ducts improves the overall air leakage of the system to less than 0.005%.
8m/s
0.13
0.17
0.5
1.2
2.1
0.1
0.2
Algorithm for the resistance of a Micro Duct system
0.4
1.0
2.2
3.9
Swing Deformation Reduction Sharp reduction Magnification Rapid expansion
0.3
0.6
1.1
0.2
0.4
0.8
0.02
0.04
0.08
0.4
0.9
1.6
0.2
0.5
0.9
0.7
1.5
2.7
0.2
0.4
0.8
0.5
1.2
1.9 5.0
VD
V 15°D
FD Blade angle 15
Blade angle 15° Blade angle 30° Blade angle
30° Air outlet (suction port) Dynamic pressure
16
1.0
Internal pressure Wall area (㎡)
8m
6m/s
0.1
3m
4m/s
Straight pipe (per length 1m) Elbow Straight pipe Bifurcation Bifurcation Branch pipe
250×250
Wind
Element speed
250×250
Calculation example
Air leakage (m3/min•㎡)
(mmAq) AB
7.26
2.6
4.2×10-3 ※1
2.1
BC
7.00
3.9
4.2×10-5 ※2
4.3
7.6
CD
6.56
6.0
4.2×10-5 ※2
11.0
20.0
DE
5.31
3.0
4.2×10-5 ※2
CF
5.31
3.0
4.2×10-5 ※2
2.2
3.9
17
Design calculations for Micro Ducts
4. Thermal insulation calculation
5. Strength design calculation
The heat loss (heat acquisition) of the Micro Duct is calculated by the following equation.
The strength calculation without reinforcement of the square duct is performed by the following formula (positive pressure).
Qd=0.24γQΔt 1-e-
p=83400×-a2
(
0.24γQ)
p : Total pressure in duct (mmAq)
Qd : Heat loss (heat acquisition) of the duct (W/h) γ : Specific weight of air (kg/m3)
σ : Allowable stress (kg/c㎡)
Q : Ventilation volume of duct (m3/h)
a : Length of long side of duct (cm)
Δt : Temperature difference betw een the inside and outside of the duct at the start point of the duct (°C) K : Thermal Transmission Rate of Duct (W/㎡•K)
The allowable stress of 400×250mm in the P17 duct system is σ=0.96kg/c m2 (P17), so
S : Circumference of duct (m) ℓ : Duct length (m)
The heat transfer coefficient of the Micro Duct is 0.95W/㎡•K.
As a result, the total resistor calculated on the duct system on page 17 is 7.26mmAq, so it is considered safe enough. In addition, the 250×250mm
For the values for steel plate ducts, refer to the section on insulation performance.
duct is similarly obtained as 120mmAq. When using at a total pressure exceeding the value calculated by this formula, reinforce the outer material with a reinforcing material. Refer to the figure below for the relationship between the side length of the supply duct (square duct) that is reinforced with a reinforcing material ( 50 × 25 × 5 × 3 × 0. 5t or more) on the outside and the allowable pressure.
Calculation example Air volume (㎥/h) Q
Temperature difference inside / outside (℃)
Duct circumference (m) S
Duct length (m) ℓ
Thermal transmittance (W/㎡・ K ) K
Δt
AB (steel plate)
2,000
20 ※1
1.3
2
1.19 ※2
BC
2,000
20
1.3
3
1.10 ※3
CDE
1,000
20
1.0
9
1.10 ※3
CF
1,000
20
1.0
3
1.10 ※3
Reinforcement of 300 mm pitch and one rod for each trisection point
50
With a pitch of 300 mm 2 Each 1 pc.( otal of
40
od
30
Total Total pressure pressure (mmAq) (mmAq)
400mm pitch reinforcement
400mm pitch
600mm pitch reinforcement
No reinforcement
20
No reinforcement
wo)
2 Reinforcement of 400 mm pitch and one rod in the center ofInthe side With
reinforcement
the cent er of H
Rod
10
0 0
500
1,000
1,500
2,000
Long side of duct (mm)
(
)
(
)
Relationship between supply duct side length and allowable pressure
Duct long side (mm)
(
)
For negative pressure (return duct), calculate σ (allowable stress) in the equation as 0.96 × 0.7 = 0.67kg/c㎡. Note that 0.7 is a coefficient for load types when using with negative pressure. When using the above figure for a return duct (inner roll reinforcement with reinforcing material), replace the value with a value obtained by multiplying the total pressure by static pressure and the length of the side by 0.8.
18
19
sing and assembly of Ducts
Processing and assembly of Micro Ducts This section explains the manufacturing procedure of "one-board" which is often used as the most common method of manufacturing rectangular straight ducts by photography.
1.
4.
After drawing a line on the glass fiber surface of the duct board, place a ruler so that this line is at the center of the tool, and cut three grooves with the gold color tool.
Cut the other end into a male shape with the purple tool.
2.
5.
Cut the duct board to the length obtained by adding 210mm to the total value of the four sides of the dimension in the duct to make a 40mm flap, and then cut this part into a female form with the silver tool.
Lap aluminum foil flaps and hit the staple.
Precautions for Use 1. Do not use at wind speeds exceeding the allowable range (13m/s for square ducts and 15m/s or more for round ducts) and at full pressure (more than 490Pa for square ducts and 590Pa for round ducts). 2. Do not operate the air conditioner with the damper fully closed when using the product on the upstream side before FD or VD.
Cut one end of the duct perpendicular to the flap into a female form with the silver tool.
6.
Use a special tape to friction-crimp the joint completely using a spatula.
3.
Contact CKD when using the product on the primary side from VAV, etc.
4.
Do not use at temperatures exceeding the allowable range.
5.
Do not use outdoors without reinforcement and waterproof covering.
6.
Avoid direct contact with concrete.
7. After hanging the duct, do not hang ladder or climb on it. (Attach a caution label after installation.) 8. 9.
20
3.
After installation, provide about 30 minutes of spare ventilation before use. Water wetting is strictly prohibited! Do not use if wet.