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Chapter IV Ducting

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    CHAPTER IV

    DUCT SIZING

    The function of a duct sizing is to transmit air from the air handling apparatus to the

    space to be conditioned. To fulfill this function in physical manner, the system must be

    designed with prescribe limits available space, frictional loss, sound level, heat and leakage

    losses and gains.

    Method use: Equal Friction Method

    Operating pressure for all terminals = 0.15 in. wg (From HVAC, by McQuiston, 5th Ed, PP 437)

    Radius elbows = R/D = 1.25

    Initial Duct supply air Velocity = 1 700 fpm (From the Book of Carrier, PP 2-37, Table 7)

    Initial Duct return air Velocity = 1 500 fpm (From the Book of Carrier, PP 2-37, Table 7)

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    ZONE 1

    Duct Sizing for Supply Air in Zone 1:

    Total number of diffuser = 49

    Percent of cfm =

    Duct area entering section 1:

    Duct area = percent of area times initial duct area (fan at section 1)

    All areas are listed in Table 3.1.1

    The Duct sizes can then be determined by using Carrier handbook, PP 2-36, Table 6.

    Table 3.1.1 listed all the duct size.

    The Additional Equivalent Length can be determining from Carrier handbook, PP 2-44,

    Table 12.

    Duct

    Section

    Air

    Quantity

    CFM

    Capacity

    %

    Area

    %

    Area

    ft

    Duct

    SizeItem

    Length

    (m)

    Length

    (ft.)

    Added

    Equiv.

    length

    AHU1-A 22399.00 100.00 100 13.18 44 X 46 Duct Elbow 8.6 28.208 25

    A-B 19199.16 85.71 89.5 11.79 40 X 46 Duct 4.5 14.76

    B-C 15999.32 71.43 78 10.28 40 X 40 Duct 4.5 14.76

    C-D 14627.96 65.31 72.5 9.55 38 X 40 Duct 4.5 14.76

    D-E 13256.60 59.18 67.5 8.89 34 X 40 Duct 4.5 14.76

    E-F 11885.24 53.06 61 8.04 34 X 36 Duct 4.5 14.76

    F-36 6399.80 28.57 36.5 4.81 22 X 36 Duct Elbow 5.5 18.04 13

    A-1 3199.84 14.29 20.5 2.70 22 X 20 Elbow Duct 1 3.28 11

    1-2 2742.72 12.24 18.5 2.44 20 X20 Duct 4.5 14.76

    2-3 2285.60 10.20 16.5 2.17 18 X 20 Duct 4.5 14.76

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    3-4 1828.48 8.16 13 1.71 14 X 20 Duct 4.5 14.76

    4-5 1371.36 6.12 10.5 1.38 14 X 16 Duct 4.5 14.76

    5-6 914.24 4.08 7 0.92 10 X 16 Duct 4.5 14.76

    6-7 457.12 2.04 3.5 0.46 10 X 8 Duct 4.5 14.76

    B-8 3199.84 14.29 20.5 2.70 22 X 20 Elbow Duct 1 3.28 11

    8-9 2742.72 12.24 18.5 2.44 20 X20 Duct 4.5 14.76

    9-10 2285.60 10.20 16.5 2.17 18 X 20 Duct 4.5 14.76

    10-11 1828.48 8.16 13 1.71 14 X 20 Duct 4.5 14.76

    11-12 1371.36 6.12 10.5 1.38 14 X 16 Duct 4.5 14.76

    12-13 914.24 4.08 7 0.92 10 X 16 Duct 4.5 14.76

    13-14 457.12 2.04 3.5 0.46 10 X 8 Duct 4.5 14.76

    C-15 1371.36 6.12 10.5 1.38 14 X 16 Elbow Duct 1 3.28 9

    15-16 914.24 4.08 7 0.92 10 X 16 Duct 4.5 14.76

    16-17 457.12 2.04 3.5 0.46 10 X 8 Duct 4.5 14.76

    D-18 1371.36 6.12 10.5 1.38 14 X 16 Elbow Duct 1 3.28 9

    18-19 914.24 4.08 7 0.92 10 X 16 Duct 4.5 14.76

    19-20 457.12 2.04 3.5 0.46 10 X 8 Duct 4.5 14.76

    E-21 1371.36 6.12 10.5 1.38 14 X 16 Elbow Duct 1 3.28 9

    21-22 914.24 4.08 7 0.92 10 X 16 Duct 4.5 14.76

    22-23 457.12 2.04 3.5 0.46 10 X 8 Duct 4.5 14.76

    F-24 5484.44 24.49 32.5 4.28 20 X 36 Elbow Duct 1 3.28 22

    24-25 5028.32 22.45 29.5 3.89 18 X 36 Duct 4.5 14.76

    25-26 4571.20 20.41 27 3.56 16 X 36 Duct 4.5 14.76

    26-27 4114.08 18.37 25 3.29 14 X 34 Duct 4.5 14.76

    27-28 3656.96 16.33 23 3.03 14 X 34 Duct 4.5 14.7628-29 3199.84 14.29 20.5 2.70 22 X 20 Duct 4.5 14.76

    29-30 2742.72 12.24 18.5 2.44 20 X20 Duct 4.5 14.76

    30-31 2285.60 10.20 16.5 2.17 18 X 20 Duct 4.5 14.76

    31-32 1828.48 8.16 13 1.71 14 X 20 Duct 4.5 14.76

    32-33 1371.36 6.12 10.5 1.38 14 X 16 Duct 4.5 14.76

    33-34 914.24 4.08 7 0.92 10 X 16 Duct 4.5 14.76

    34-35 457.12 2.04 3.5 0.46 10 X 8 Duct 4.5 14.76

    36-37 5942.56 26.53 34.5 4.55 20 X 36 Duct 4.5 14.76

    37-38 5485.44 24.49 32.5 4.28 20 X 36 Duct 4.5 14.76

    38-39 5028.32 22.45 30.5 4.02 18 X 36 Duct 4.5 14.7639-40 4571.20 20.41 27 3.56 16 X 36 Duct 4.5 14.76

    40-41 4114.08 18.37 25 3.29 14 X 34 Duct 4.5 14.76

    41-42 3656.96 16.33 23 3.03 14 X 34 Duct 4.5 14.76

    42-43 3199.84 14.29 20.5 2.70 22 X 20 Duct 4.5 14.76

    43-44 2742.72 12.24 18.5 2.44 20 X20 Duct Elbow 4.5 14.76 11

    44-45 2285.60 10.20 16.5 2.17 18 X 20 Duct 4.5 14.76

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    45-46 1828.48 8.16 13 1.71 14 X 20 Duct 4.5 14.76

    46-47 1371.36 6.12 10.5 1.38 14 X 16 Duct 4.5 14.76

    47-48 914.24 4.08 7 0.92 10 X 16 Duct 4.5 14.76

    48-49 457.12 2.04 3.5 0.46 10 X 8 Duct 4.5 14.76

    TOTAL LENGTH 759.648 120

    The total friction loss in the duct work from fan to last terminal 49 is:

    Loss = total equivalent length x friction rate

    For the total equivalent length, it appears that the longer run is from AHU 1 to terminal

    49: 312.3 + 47 = 359.3 ft.

    Friction rate: using Vsupply = 1700 fpm, cfm = 22399, Fr = 0.062 (from chart 7, page 2-33

    friction loss for round duct)

    Loss = 359.3 ft. x (0.062 in wg /100 ft.)

    Loss = 0.223 in wg

    The total static pressure required at fan discharge is the sum of the terminal operating

    pressure and the loss in the duct work. Credit can be taken for the regain between the

    first and last section of the duct.

    From chart 7, p. 2-33 of Carrier Handbook with cfm of 457.12 and equivalent circular

    duct diameter = 9.8 in., velocity in the last section = 920 fpm.

    Using 75% regain coefficient;

    Regain = = 0.096 in wg

    Therefore, the total static pressure at fan discharge is;

    = duct friction + terminal pressure regain

    = 0.223 + 0.15 0.096

    = 0.277 in wg

    Duct Sizing for Return Air in Zone 1:

    Total number of diffuser = 14

    Percent of cfm =

    Duct area entering section 1:

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    Duct

    Section

    Air

    Quantity

    CFM

    Capacity

    %

    Area

    %

    Area

    ft.

    Duct

    SizeItem

    Length

    (m)

    Length

    (ft)

    Added

    Equiv.

    LengthAHU 1 - 1 21049 100.00 100 14.03 46 x 48 Duct Elbow 15.25 50.02 25

    1-2 19545.5 92.86 94.5 13.26 46 x 44 Duct 6.46 21.1888

    2-3 18042 85.71 89.5 12.56 44 x 44 Duct Elbow 10.6 34.768 24

    3-A 7517.5 35.71 44 6.17 30 x 32 Duct Elbow 4.5 14.76 16

    A-10 3007 14.29 20.5 2.88 16 x 28 Duct Elbow 4.5 14.76 10

    10-11 1503.5 7.14 11.5 1.61 16 x 16 Duct 9 29.52

    A-12 4510.5 21.43 28 3.93 22 x 28 Duct 9 29.52

    12-13 3007 14.29 20.5 2.88 16 x 28 Duct 9 29.52

    13-14 1503.5 7.14 11.5 1.61 16 x 16 Duct 9 29.52

    3-4 9021 42.86 51 7.16 32 x 34 Duct 9 29.52

    4-5 7517.5 35.71 44 6.17 32 x 30 Duct 9 29.52

    5-6 6014 28.57 36.5 5.12 28 X 28 Duct Elbow 9 29.52 15

    6-7 4510.5 21.43 28 3.93 22 x 28 Duct 9 29.52

    7-8 3007 14.29 20.5 2.88 16 x 28 Duct 9 29.52

    8-9 1503.5 7.14 11.5 1.61 16 x 16 Duct 9 29.52

    TOTAL LENGTH 430.6968 90

    The total friction loss in the duct work from fan to last terminal 14 is:

    Loss = total equivalent length x friction rate

    For the total equivalent length, it appears that the longer run is from AHU 1 to terminal

    9: 86.3 + 64 = 150.3 ft.

    Friction rate: using Vsupply = 1500 fpm, cfm = 21049, Fr = 0.047 (from chart 7, page 2-33

    friction loss for round duct)

    Loss = 150.3 ft. x (0.047 in wg /100 ft.)

    Loss = 0.0706 in wg

    The total static pressure required at fan discharge is the sum of the terminal operating

    pressure and the loss in the duct work. Credit can be taken for the regain between the

    first and last section of the duct.

    From chart 7, p. 2-33 of Carrier Handbook with cfm of 1503.5 and equivalent circular

    duct diameter = 17.5 in., velocity in the last section = 920 fpm.

    Using 75% regain coefficient;

    Regain = = 0.0658 in wg

    Therefore, the total static pressure at fan discharge is;

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    = duct friction + terminal pressure regain

    = 00706 + 0.15 0.0658

    = 0.15 in wg

    ZONE 2

    Duct Sizing for Supply Air in Zone 2:

    Total number of diffuser = 42

    Percent of cfm =

    Duct area entering section 1:

    Duct area = percent of area times initial duct area (fan at section 1)

    All areas are listed in Table 3.1.1

    The Duct sizes can then be determined by using Carrier handbook, PP 2-36, Table 6.

    Table 3.1.1 listed all the duct size.

    The Additional Equivalent Length can be determining from Carrier handbook, PP 2-44,

    Table 12.

    Duct

    Section

    Air

    Quantity

    CFM

    Capacity%

    Area

    %

    Area

    ft

    Duct

    Size Item

    Length

    (m)

    Length

    (ft)

    Added

    Equiv.length

    AHU2-A 50136.00 100.00 100 29.50 64 x 72 Duct Elbow 10.75 35.26 34.67

    A-B 50136.00 100.00 100 29.50 64 x 72 Duct Elbow 10.7 35.096 34.67

    B-C 40586.40 80.95 85.5 25.22 64 x 60

    Series of

    Elbow 7 22.96 33.67

    C-D 31036.80 61.91 69 20.36 52 x 60

    Series of

    Elbow 4.2 13.776 28.67

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    D-E 22680.90 45.24 53 15.64 52 x 46

    Series of

    Elbow 4.7 15.416 26.5

    E-F 14325.00 28.57 36.5 10.77 36 x 46 Elbow Duct 3.5 11.48 20

    F-38 5969.10 11.91 18.5 5.46 30 x 28 Duct Elbow 6.6 21.648 16

    B-1 9549.60 19.05 26 7.67 32 x 38 Elbow Duct 2.6 8.528 20

    1-2 8355.90 16.67 24 7.08 32 x 34 Duct 4.5 14.76

    2-3 7162.20 14.29 20.5 6.05 28 x 34 Duct 4.5 14.76

    3-4 5968.50 11.90 18.5 5.46 28 x 30 Duct 4.5 14.76

    4-5 4774.80 9.52 16.5 4.87 28 x 26 Duct 4.5 14.76

    5-6 3581.10 7.14 11.5 3.39 20 x 26 Duct 4.5 14.76

    6-7 2387.40 4.76 9 2.66 20 x 20 Duct 4.5 14.76

    7-8 1193.70 2.38 3.5 1.03 10 x 16 Duct 4.5 14.76

    C-9 9549.60 19.05 26 7.67 32 x 38 Elbow Duct 2.4 7.872 20

    9-10 8355.90 16.67 24 7.08 32 x 34 Duct 4.5 14.76

    10-11 7162.20 14.29 20.5 6.05 28 x 34 Duct 4.5 14.76

    11-12 5968.50 11.90 18.5 5.46 28 x 30 Duct 4.5 14.76

    12-13 4774.80 9.52 16.5 4.87 28 x 26 Duct 4.5 14.76

    13-14 3581.10 7.14 11.5 3.39 20 x 26 Duct 4.5 14.76

    14-15 2387.40 4.76 9 2.66 20 x 20 Duct 4.5 14.76

    15-16 1193.70 2.38 3.5 1.03 10 x 16 Duct 4.5 14.76

    D-17 8355.90 16.67 24 7.08 32 x 34 Elbow Duct 4.35 14.268 18

    17-18 7162.20 14.29 20.5 6.05 28 x 34 Duct 4.5 14.76

    18-19 5968.50 11.90 18.5 5.46 28 x 30 Duct 4.5 14.76

    19-20 4774.80 9.52 16.5 4.87 28 x 26 Duct 4.5 14.76

    20-21 3581.10 7.14 11.5 3.39 20 x 26 Duct 4.5 14.76

    21-22 2387.40 4.76 9 2.66 20 x 20 Duct 4.5 14.76

    22-23 1193.70 2.38 3.5 1.03 10 x 16 Duct 4.5 14.76

    E-24 8355.90 16.67 24 7.08 32 x 34 Elbow Duct 8.14 26.6992 18

    24-25 7162.20 14.29 20.5 6.05 28 x 34 Duct 4.5 14.76

    25-26 5968.50 11.90 18.5 5.46 28 x 30 Duct 4.5 14.76

    26-27 4774.80 9.52 16.5 4.87 28 x 26 Duct 4.5 14.76

    27-28 3581.10 7.14 11.5 3.39 20 x 26 Duct 4.5 14.76

    28-29 2387.40 4.76 9 2.66 20 x 20 Duct 4.5 14.76

    29-30 1193.70 2.38 3.5 1.03 10 x 16 Duct 4.5 14.76

    F-31 8355.90 16.67 24 7.08 32 x 34 Elbow Duct 3.6 11.808 18

    31-32 7162.20 14.29 20.5 6.05 28 x 34 Duct 4.5 14.76

    32-33 5968.50 11.90 18.5 5.46 28 x 30 Duct 4.5 14.76

    33-34 4774.80 9.52 16.5 4.87 28 x 26 Duct 4.5 14.76

    34-35 3581.10 7.14 11.5 3.39 20 x 26 Duct 4.5 14.76

    35-36 2387.40 4.76 9 2.66 20 x 20 Duct 4.5 14.76

    36-37 1193.70 2.38 3.5 1.03 10 x 16 Duct 4.5 14.76

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    38-39 4774.80 9.52 16.5 4.87 28 x 26 Duct 4.5 14.76

    39-40 3581.10 7.14 11.5 3.39 20 x 26 Duct 4.5 14.76

    40-41 2387.40 4.76 9 2.66 20 x 20 Duct 4.5 14.76

    41-42 1193.70 2.38 3.5 1.03 10 x 16 Duct 4.45 14.596

    TOTAL LENGTH 756.0072 288.18

    The total friction loss in the duct work from fan to last terminal 42 is:

    Loss = total equivalent length x friction rate

    For the total equivalent length, it appears that the longer run is from AHU 2 to terminal

    42: 211.04 + 174.18 = 385.22 ft.

    Friction rate: using Vsupply = 1700 fpm, cfm = 50136, Fr = 0.032 (from chart 7, page 2-33

    friction loss for round duct)

    Loss = 385.22 ft. x (0.032 in wg /100 ft.)

    Loss = 0.1387 in wgThe total static pressure required at fan discharge is the sum of the terminal operating

    pressure and the loss in the duct work. Credit can be taken for the regain between the

    first and last section of the duct.

    From chart 7, p. 2-33 of Carrier Handbook with cfm of 1193.7 and equivalent circular

    duct diameter = 13.7 in., velocity in the last section = 1220 fpm.

    Using 75% regain coefficient;

    Regain = = 0.0657 in wg

    Therefore, the total static pressure at fan discharge is;

    = duct friction + terminal pressure regain= 0.1387 + 0.15 0.0657

    = 0.223 in wg

    Duct Sizing for Return Air in Zone 2:

    Total number of diffuser = 27

    Percent of cfm =

    Duct area entering section 1:

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    DuctSection

    AirQuantity

    CFM

    Capacity

    %

    Area%

    Areaft.

    DuctSize

    Item Length(m)

    Length(ft)

    Added

    Equiv.

    Length

    AHU 2 - 1 47533.5 100.00 100 31.69 68 x 72 Elbow Duct 15.55 51.004 36.33

    1-2 45773 96.30 96.5 30.5868 x 72

    series

    Elbow 5.44 17.8432 36.33

    2-3 44012.5 92.59 94.5 29.95 64 x 72 Duct 9 29.52

    3-4 42242 88.87 91.5 29.00 64 x 72 Duct 9 29.52

    4-5 40491.5 85.19 88.5 28.05 64 x 68 Duct 9 29.52

    5-6 38731 81.48 86 27.25 64 x 68 Duct 9 29.52

    6-7 36970.5 77.78 83 26.30 60 x 68 Duct 5.25 17.22

    7-8 35210 74.07 80 25.35 60 x 60 Duct 5.25 17.228-A 26407.5 55.56 64 20.28 52 x 60 Duct Elbow 3.5 11.48 28

    A-B 19365.5 40.74 49 15.53 52 x 46 Elbow Duct 6.95 22.796 28

    B-C 12323.5 25.93 33.5 10.62 36 x 46 Duct 6.95 22.796

    C-25 5281.5 11.11 17.5 5.55 36 x 24 Duct 6.95 22.796

    8-9 7042 14.81 21.5 6.81 36 x 30 Duct 9 29.52

    9-10 5281.5 11.11 17.5 5.55 36 x 24 Duct 9 29.52

    10-11 3521 7.41 11.5 3.64 24 x 24 Duct 9 29.52

    11-12 1760.5 3.70 7 2.22 16 x 24 Duct 9 29.52

    A-13 7042 14.81 21.5 6.81 36 x 30 Elbow Duct 4.5 14.76 16

    13-14 5281.5 11.11 17.5 5.55 36 x 24 Duct 9 29.52

    14-15 3521 7.41 11.5 3.64 24 x 24 Duct 9 29.52

    15-16 1760.5 3.70 7 2.22 16 x 24 Duct 9 29.52

    B-17 7042 14.81 21.5 6.81 36 x 30 Elbow Duct 3 9.84 16

    17-18 5281.5 11.11 17.5 5.55 36 x 24 Duct 9 29.52

    18-19 3521 7.41 11.5 3.64 24 x 24 Duct 9 29.52

    19-20 1760.5 3.70 7 2.22 16 x 24 Duct 9 29.52

    C-21 7042 14.81 21.5 6.81 36 x 30 Elbow Duct 1.5 4.92 16

    21-22 5281.5 11.11 17.5 5.55 36 x 24 Duct 9 29.52

    22-23 3521 7.41 11.5 3.64 24 x 24 Duct 9 29.52

    23-24 1760.5 3.70 7 2.22 16 x 24 Duct 9 29.52

    25-26 3521 7.41 11.5 3.64 24 x 24 Duct 9 29.52

    26-27 1760.5 3.70 7 2.22 16 x 24 Duct 9 29.52

    TOTAL LENGTH 773.5552 176.66

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    The total friction loss in the duct work from fan to last terminal 27 is:

    Loss = total equivalent length x friction rate

    For the total equivalent length, it appears that the longer run is from AHU 2 to terminal

    27: 109.83 + 128.66 = 238.5 ft.

    Friction rate: using Vsupply = 1500 fpm, cfm = 47533.5, Fr = 0.028 (from chart 7, page 2-33 friction loss for round duct)

    Loss = 238.5 ft. x (0.028 in wg /100 ft.)

    Loss = 0.0668 in wg

    The total static pressure required at fan discharge is the sum of the terminal operating

    pressure and the loss in the duct work. Credit can be taken for the regain between the

    first and last section of the duct.

    From chart 7, p. 2-33 of Carrier Handbook with cfm of 1760.5 and equivalent circular

    duct diameter = 21.3 in., velocity in the last section = 720 fpm.

    Using 75% regain coefficient;

    Regain = = 0.0812 in wgTherefore, the total static pressure at fan discharge is;

    = duct friction + terminal pressure regain

    = 0.0668 + 0.15 0.0812

    = 0.1356 in wg

    ZONE 3

    Duct Sizing for Supply Air in Zone 3:

    Total number of diffuser = 79

    Percent of cfm =

    Duct area entering section 1:

    Duct area = percent of area times initial duct area (fan at section 1)

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    All areas are listed in Table 3.1.1

    The Duct sizes can then be determined by using Carrier handbook, PP 2-36, Table 6.

    Table 3.1.1 listed all the duct size.

    The Additional Equivalent Length can be determining from Carrier handbook, PP 2-44,

    Table 12.

    Duct

    Section

    Air

    Quantity

    CFM

    Capacity

    %

    Area

    %

    Area

    ft

    Duct

    Size Item

    Length

    (m) Length (ft)

    Added

    Equiv.

    length

    AHU 3 - A 60838.80 100.00 100 35.79 72 x 76 Duct Elbow 7.8 25.584 38

    A-1 53907.80 88.61 91.5 32.75 68 x 76 series elbow 8 26.24 36.33

    1-2 53137.70 87.34 90 32.21 68 x 68 series elbow 5.4 17.712 36

    2-B 52367.59 86.08 89.5 32.03 68 x 68 series elbow 1.2 3.936 36

    B-C 40815.94 67.09 73.5 26.31 68 x 56 series elbow 8.4 27.552 35

    C-D 29264.29 48.10 56 20.04 52 x 56 series elbow 3.76 12.3328 29.56

    D-E 16942.53 27.85 35.5 12.71 42 x 44 series elbow 8.6 28.208 24

    E-68 2310.44 3.80 7 2.51 18 x 20 Duct Elbow 3.9 12.792 10

    B-3 11551.65 18.99 26 9.31 36 x 38 Elbow Duct 2.4 7.872 19.83

    3-4 10781.54 17.72 25 8.95 36 x 36 Duct 4 13.12

    4-5 10011.43 16.46 23 8.23 34 x 36 Duct 4.2 13.776

    5-6 9241.32 15.19 21.5 7.69 34 x 34 Duct 4.15 13.612

    6-7 8471.21 13.92 20.5 7.34 32 x 34 Duct 4 13.12

    7-8 7701.1 12.66 19.5 6.98 32 x 32 Duct 4.2 13.776

    8-9 6930.99 11.39 18.5 6.62 30 x 32 Duct 4.15 13.612

    9-10 6160.88 10.13 16.5 5.91 30 x 30 Duct 4 13.12

    10-11 5390.77 8.86 14.5 5.19 26 x 30 Duct 4.2 13.776

    11-12 4620.66 7.59 13 4.65 26 x 26 Duct 4.15 13.612

    12-13 3850.55 6.33 10.5 3.76 26 x 24 Duct 4 13.12

    13-14 3080.44 5.06 9 3.22 20 x 24 Duct 4.2 13.776

    14-15 2310.33 3.80 7 2.51 20 x 18 Duct 4.15 13.612

    15-16 1540.22 2.53 5.5 1.97 16 x 18 Duct 4 13.12

    16-17 770.11 1.27 2 0.72 6 x 18 Duct 4.2 13.776

    C-18 11551.65 18.99 26 9.31 36 x 38 Elbow Duct 5.87 19.2536 19.83

    18-19 10781.54 17.72 25 8.95 36 x 36 Duct 4 13.12

    19-20 10011.43 16.46 23 8.23 34 x 36 Duct 4.2 13.776

    20-21 9241.32 15.19 21.5 7.69 34 x 34 Duct 4.15 13.612

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    21-22 8471.21 13.92 20.5 7.34 32 x 34 Duct 4 13.12

    22-23 7701.1 12.66 19.5 6.98 32 x 32 Duct 4.2 13.776

    23-24 6930.99 11.39 18.5 6.62 30 x 32 Duct 4.15 13.612

    24-25 6160.88 10.13 16.5 5.91 30 x 30 Duct 4 13.12

    25-26 5390.77 8.86 14.5 5.19 26 x 30 Duct 4.2 13.77626-27 4620.66 7.59 13 4.65 26 x 26 Duct 4.15 13.612

    27-28 3850.55 6.33 10.5 3.76 26 x 24 Duct 4 13.12

    28-29 3080.44 5.06 9 3.22 20 x 24 Duct 4.2 13.776

    29-30 2310.33 3.80 7 2.51 20 x 18 Duct 4.15 13.612

    30-31 1540.22 2.53 5.5 1.97 16 x 18 Duct 4 13.12

    31-32 770.11 1.27 2 0.72 6 x 18 Duct 4.2 13.776

    D-33 12321.76 20.25 27 9.66 36 x 38 Elbow Duct 4.7 15.416 19.83

    33-34 11551.65 18.99 26 9.31 36 x 38 Duct 6.4 20.992

    34-35 10781.54 17.72 25 8.95 36 x 36 Duct 4.5 14.76

    35-36 10011.43 16.46 23 8.23 34 x 36 Duct 4.5 14.76

    36-37 9241.32 15.19 21.5 7.69 34 x 34 Duct 3.4 11.152

    37-38 8471.21 13.92 20.5 7.34 32 x 34 Duct 4.5 14.76

    38-39 7701.1 12.66 19.5 6.98 32 x 32 Duct 4.5 14.76

    39-40 6930.99 11.39 18.5 6.62 30 x 32 Duct 3.4 11.152

    40-41 6160.88 10.13 16.5 5.91 30 x 30 Duct 4.5 14.76

    41-42 5390.77 8.86 14.5 5.19 26 x 30 Duct 4.5 14.76

    42-43 4620.66 7.59 13 4.65 26 x 26 Duct 3.4 11.152

    43-44 3850.55 6.33 10.5 3.76 26 x 24 Duct 4.5 14.76

    44-45 3080.44 5.06 9 3.22 20 x 24 Duct 4.5 14.76

    45-46 2310.33 3.80 7 2.51 20 x 18 Duct 3.4 11.152

    46-47 1540.22 2.53 5.5 1.97 16 x 18 Duct 4.5 14.76

    47-48 770.11 1.27 2 0.72 6 x 18 Duct 4.5 14.76

    E-49 14632.09 24.05 31.5 11.27 40 x 40 Elbow Duct 0.8 2.624 21.56

    49-50 13861.98 22.78 30.5 10.92 40 x 40 Duct 4.5 14.76

    50-51 13091.89 21.52 29.5 10.56 40 x 38 Duct 4.5 14.76

    51-52 12321.76 20.25 27 9.66 36 x 38 Duct Elbow 4.2 13.776 19.83

    52-53 11551.65 18.99 26 9.31 36 x 38 Duct 6.3 20.664

    53-54 10781.54 17.72 25 8.95 36 x 36 Duct 4.5 14.76

    54-55 10011.43 16.46 23 8.23 34 x 36 Duct 4.5 14.76

    55-56 9241.32 15.19 21.5 7.69 34 x 34 Duct 3.4 11.152

    56-57 8471.21 13.92 20.5 7.34 32 x 34 Duct 4.5 14.76

    57-58 7701.1 12.66 19.5 6.98 32 x 32 Duct 4.5 14.76

    58-59 6930.99 11.39 18.5 6.62 30 x 32 Duct 3.4 11.152

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    59-60 6160.88 10.13 16.5 5.91 30 x 30 Duct 4.5 14.76

    60-61 5390.77 8.86 14.5 5.19 26 x 30 Duct 4.5 14.76

    61-62 4620.66 7.59 13 4.65 26 x 26 Duct 3.4 11.152

    62-63 3850.55 6.33 10.5 3.76 26 x 24 Duct 4.5 14.76

    63-64 3080.44 5.06 9 3.22 20 x 24 Duct 4.5 14.7664-65 2310.33 3.80 7 2.51 20 x 18 Duct 3.4 11.152

    65-66 1540.22 2.53 5.5 1.97 16 x 18 Duct 4.5 14.76

    66-67 770.11 1.27 2 0.72 6 x 18 Duct 4.5 14.76

    68-69 1540.22 2.53 5.5 1.97 10 x 12 Duct 4.5 14.76

    69-70 770.11 1.27 2 0.72 6 x 10 Duct 4.5 14.76

    A-H 6930.99 11.39 18.5 6.62 30 x 32 Duct Elbow 4.4 14.432

    H-71 6930.99 11.39 18.5 6.62 30 x 32 series elbow 4.85 15.908

    71-72 6160.88 10.13 16.5 5.91 30 x 30 series elbow 5.6 18.368 16

    72-73 5390.77 8.86 14.5 5.19 26 x 30 series elbow 5 16.4 15.625

    73-74 4620.66 7.59 13 4.65 26 x 26 series elbow 5.8 19.024 13.875

    74-75 3850.55 6.33 10.5 3.76 26 x 24 series elbow 5.9 19.352 13.75

    75-76 3080.44 5.06 9 3.22 20 x 24 series elbow 6.25 20.5 11

    76-77 2310.33 3.80 7 2.51 20 x 18 series elbow 5.45 17.876 10

    77-78 1540.22 2.53 5.5 1.97 16 x 18 series elbow 5 16.4 10

    78-79 770.11 1.27 2 0.72 6 x 18 series elbow 4.86 15.9408 8

    TOTAL LENGTH 1250.4672 444.02

    The total friction loss in the duct work from fan to last terminal 79 is:

    Loss = total equivalent length x friction rate

    For the total equivalent length, it appears that the longer run is from AHU 3 to terminal

    67: 399.64 + 276.28 = 675.92 ft.

    Friction rate: using Vsupply = 1700 fpm, cfm = 60838.8, Fr = 0.0325 (from chart 7, page

    2-33 friction loss for round duct)

    Loss = 675.92 ft. x (0.0325 in wg /100 ft.)

    Loss = 0.22 in wg

    The total static pressure required at fan discharge is the sum of the terminal operating

    pressure and the loss in the duct work. Credit can be taken for the regain between the

    first and last section of the duct.

    From chart 7, p. 2-33 of Carrier Handbook with cfm of 770.11 and equivalent circular

    duct diameter = 11.5 in., velocity in the last section = 1110 fpm.

    Using 75% regain coefficient;

    Regain = = 0.0777 in wg

    Therefore, the total static pressure at fan discharge is;

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    = duct friction + terminal pressure regain

    = 0.22 + 0.15 0.0777

    = 02923 in wg

    Duct Sizing for Return Air in Zone 3:

    Total number of diffuser = 27

    Percent of cfm =

    Duct area entering section 1:

    Duct

    Section

    Air

    Quantity

    CFM

    Capacity

    %

    Area

    %

    Area

    ft.

    Duct

    SizeItem

    Length

    (m)

    Length

    (ft)

    Added

    Equiv.

    Length

    AHU 3 - 1 57253.8 100.00 100 38.17 68 x 88 Elbow 32 104.96 39.44

    1-2 55133.3 96.30 96.5 36.83 64 x 88 Duct 8.2 26.896

    2-3 53012.8 92.59 94.5 36.07 64 x 88 Duct 8.2 26.896

    3-4 50892.3 88.89 91.5 34.93 64 x 84 Duct 8.2 26.896

    4-5 48771.8 85.19 88.5 33.78 64 x 80 Duct 8.2 26.896

    5-6 46651.3 81.48 86 32.83 64 x 80 Duct 8.2 26.896

    6-A 44530.8 77.78 83 31.68 60 x 80 Elbow Duct 12.6 41.328 40.33

    A-15 27566.8 48.15 56 21.38 60 x 56 Duct Elbow 12.7 41.656 30.33

    A-7 16964 29.63 37.5 14.31 42 x 54 Elbow Duct 3.9 12.792 29

    7-8 14843.5 25.93 33.5 12.79 42 x 48 Duct 8.2 26.896

    8-9 12723 22.22 29.5 11.26 42 x 42 Duct 8.2 26.896

    9-10 10602.5 18.52 26 9.92 38 x 42 Duct 8.2 26.896

    10-11 8482 14.81 21.5 8.21 38 x 34 Duct 8.2 26.896

    11-12 6361.5 11.11 17.5 6.68 30 x 34 Duct 8.2 26.896

    12-13 4241 7.41 11.5 4.39 30 x 24 Duct 8.2 26.896

    13-14 2120.5 3.70 7 2.67 18 x 24 Duct 8.2 26.896

    15-16 25446 44.44 52 19.85 56 x 56 Duct 4.5 14.76

    16-17 23325.5 40.74 49 18.70 52 x 56 Duct 7.9 25.912

    17-18 21205 37.04 45 17.18 52 x 50 Duct 4.5 14.76

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    18-19 19084.5 33.33 41 15.65 48 x 50 Duct 7.9 25.912

    19-20 16964 29.63 37.5 14.31 42 x 54 Duct 4.5 14.76

    20-21 14843.5 25.93 33.5 12.79 42 x 48 Duct 7.9 25.912

    21-22 12723 22.22 29.5 11.26 42 x 42 Duct 4.5 14.76

    22-23 10602.5 18.52 26 9.92 38 x 42 Duct 7.9 25.912

    23-24 8482 14.81 21.5 8.21 38 x 34 Duct 4.5 14.76

    24-25 6361.5 11.11 17.5 6.68 30 x 34 Duct 4.5 14.76

    25-26 4241 7.41 11.5 4.39 30 x 24 Duct 4.5 14.76

    26-27 2120.5 3.70 7 2.67 18 x 24 Duct 4.5 14.76

    TOTAL LENGTH 745.216 139.1

    The total friction loss in the duct work from fan to last terminal 27 is:

    Loss = total equivalent length x friction rate

    For the total equivalent length, it appears that the longer run is from AHU 3 to terminal

    27: 166.22 + 110.06 = 276.28 ft.

    Friction rate: using Vsupply = 1500 fpm, cfm = 57253.8, Fr = 0.025 (from chart 7, page 2-

    33 friction loss for round duct)

    Loss = 276.28 ft. x (0.025 in wg /100 ft.)

    Loss = 0.069 in wg

    The total static pressure required at fan discharge is the sum of the terminal operating

    pressure and the loss in the duct work. Credit can be taken for the regain between the

    first and last section of the duct.

    From chart 7, p. 2-33 of Carrier Handbook with cfm of 2120.5 and equivalent circular

    duct diameter = 22.6 in., velocity in the last section = 780 fpm.

    Using 75% regain coefficient;

    Regain = = 0.0777 in wgTherefore, the total static pressure at fan discharge is;

    = duct friction + terminal pressure regain

    = 0.069 + 0.15 0.0777

    = 0.142 in wg

    ZONE 4

    Duct Sizing for Supply Air in Zone 4:

    Total number of diffuser = 45

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    Percent of cfm =

    Duct area entering section 1:

    Duct area = percent of area times initial duct area (fan at section 1)

    All areas are listed in Table 3.1.1

    The Duct sizes can then be determined by using Carrier handbook, PP 2-36, Table 6.

    Table 3.1.1 listed all the duct size.

    The Additional Equivalent Length can be determining from Carrier handbook, PP 2-44,

    Table 12.

    Duct

    Section

    Air

    Quantity

    CFM

    Capacity

    %

    Area

    %

    Area

    ft

    Duct

    SizeItem

    Length

    (m)Length(ft)

    Added

    Equiv.

    length

    AHU 4 - 1 26131 100.00 100 15.37 48 x 50 Duct 8.88 29.12641-2 25550.3 97.78 98 15.06 46 x 50 Duct 4.5 14.76

    2-3 24969.6 95.56 96.5 14.83 46 x 50 Duct 4.5 14.76

    3-4 24388.9 93.33 94.5 14.52 46 x 50 Duct 4.5 14.76

    4-A 23808.2 91.11 93 14.29 46 x 48 Elbow Duct 6 19.68 25

    A-B 19162.6 73.33 79 12.14 42 x 44 Duct 4.5 14.76

    B-C 14517 55.55 64 9.84 42 x 36 Duct 4.5 14.76

    C-D 9871.4 37.78 46 7.07 34 x 32 Duct Elbow 3.5 11.48 18

    D-E 9290.7 35.55 44 6.76 32 x 32 Duct 4.5 14.76

    E-F 8710 33.33 41 6.30 32 x 30 Duct 4.5 14.76

    F-G 8129.3 31.11 39 5.99 30 x 30 Duct 4.5 14.76

    G-H 6387.2 24.44 31.5 4.84 28 x 28 Duct 4.5 14.76

    H-I 4645.1 17.78 25 3.84 24 x 28 Duct 4.5 14.76

    I-J 2903 11.11 17.5 2.69 24 x 18 Duct 4.5 14.76

    A-5 4645.6 17.78 25 3.84 24 x 28 Elbow Duct 1.5 4.92 13

    5-6 4064.9 15.56 23 3.54 20 x 28 Duct 4.5 14.76

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    6-7 3484.2 13.33 19.5 3.00 20 x 24 Duct 4.5 14.76

    7-8 2903.5 11.11 17.5 2.69 18 x 24 Duct 4.5 14.76

    8-9 2322.8 8.89 14.5 2.23 18 x 20 Duct 4.5 14.76

    9-10 1742.1 6.67 11.5 1.77 14 x 20 Duct 4.5 14.76

    10-11 1161.4 4.44 7 1.08 14 x 12 Duct 4.5 14.7611-12 580.7 2.22 3.5 0.54 8 x 12 Duct 4.5 14.76

    B-13 4645.6 17.78 25 3.84 24 x 28 Elbow Duct 1.5 4.92 13

    13-14 4064.9 15.56 23 3.54 20 x 28 Duct 4.5 14.76

    14-15 3484.2 13.33 19.5 3.00 20 x 24 Duct 4.5 14.76

    15-16 2903.5 11.11 17.5 2.69 18 x 24 Duct 4.5 14.76

    16-17 2322.8 8.89 14.5 2.23 18 x 20 Duct 4.5 14.76

    17-18 1742.1 6.67 11.5 1.77 14 x 20 Duct 4.5 14.76

    18-19 1161.4 4.44 7 1.08 14 x 12 Duct 4.5 14.76

    19-20 580.7 2.22 3.5 0.54 8 x 12 Duct 4.5 14.76

    C-21 4645.6 17.78 25 3.84 24 x 28 Elbow Duct 1.5 4.92 13

    21-22 4064.9 15.56 23 3.54 20 x 28 Duct 4.5 14.76

    22-23 3484.2 13.33 19.5 3.00 20 x 24 Duct 4.5 14.76

    23-24 2903.5 11.11 17.5 2.69 18 x 24 Duct 4.5 14.76

    24-25 2322.8 8.89 14.5 2.23 18 x 20 Duct 4.5 14.76

    25-26 1742.1 6.67 11.5 1.77 14 x 20 Duct 4.5 14.76

    26-27 1161.4 4.44 7 1.08 14 x 12 Duct 4.5 14.76

    27-28 580.7 2.22 3.5 0.54 8 x 12 Duct 4.5 14.76

    D-29 580.7 2.22 3.5 0.54 8 x 12 Elbow Duct 1 3.28 5

    E-30 580.7 2.22 3.5 0.54 8 x 12 Elbow Duct 1 3.28 5

    F-31 580.7 2.22 3.5 0.54 8 x 12 Elbow Duct 1 3.28 5

    G-32 1742.1 6.67 11.5 1.77 14 x 20 Elbow Duct 1 3.28 8

    32-33 1161.4 4.44 7 1.08 14 x 12 Duct 4.5 14.76

    33-34 580.7 2.22 3.5 0.54 8 x 12 Duct 4.5 14.76

    H-35 1742.1 6.67 11.5 1.77 14 x 20 Elbow Duct 1 3.28 8

    35-36 1161.4 4.44 7 1.08 14 x 12 Duct 4.5 14.76

    36-37 580.7 2.22 3.5 0.54 8 x 12 Duct 4.5 14.76

    I-38 1742.1 6.67 11.5 1.77 14 x 20 Elbow Duct 1 3.28 8

    38-39 1161.4 4.44 7 1.08 14 x 12 Duct 4.5 14.76

    39-40 580.7 2.22 3.5 0.54 8 x 12 Duct 4.5 14.76

    J-41 1742.1 6.67 11.5 1.77 14 x 20 Elbow Duct 1 3.28 8

    41-42 1161.4 4.44 7 1.08 14 x 12 Duct 4.5 14.76

    42-43 580.7 2.22 3.5 0.54 8 x 12 Duct 4.5 14.76

    J-44 1160.9 4.44 7 1.08 14 x 12 Duct Elbow 5.5 18.04 8

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    44-45 580.7 2.22 3.5 0.54 8 x 12 Duct 4.5 14.76

    TOTAL LENGTH 721.2064 137

    The total friction loss in the duct work from fan to last terminal 45 is:

    Loss = total equivalent length x friction rateFor the total equivalent length, it appears that the longer run is from AHU 4 to terminal

    43: 260.33 + 51 = 311.33 ft.

    Friction rate: using Vsupply = 1700 fpm, cfm = 26131, Fr = 0.056 (from chart 7, page 2-33

    friction loss for round duct)

    Loss = 311.33 ft. x (0.056 in wg /100 ft.)

    Loss = 0.1743 in wg

    The total static pressure required at fan discharge is the sum of the terminal operating

    pressure and the loss in the duct work. Credit can be taken for the regain between the

    first and last section of the duct.

    From chart 7, p. 2-33 of Carrier Handbook with cfm of 580.7 and equivalent circular duct

    diameter = 10.7 in., velocity in the last section = 940 fpm.

    Using 75% regain coefficient;

    Regain = = 0.09405 in wg

    Therefore, the total static pressure at fan discharge is;

    = duct friction + terminal pressure regain

    = 0.1743 + 0.15 0.09405

    = 0.230 in wg

    Duct Sizing for Return Air in Zone 4:

    Total number of diffuser = 18

    Percent of cfm =

    Duct area entering section 1:

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    Duct

    Section

    Air

    Quantity

    CFM

    Capacity

    %

    Area

    %

    Area

    ft.

    Duct

    SizeItem

    Length

    (m)

    Length

    (ft)

    Added

    Equiv.

    Length

    AHU 4 - A 24706 100.00 100 16.47 50 x 50 Duct 0.95 3.116

    A-1 20588.33 83.33 87 14.33 44 x 50 Elbow Duct 3.88 12.7264 27

    1-B 19215.78 77.78 83 13.67 44 x 48 Duct Elbow 8.82 28.9296 24B-C 15098.11 61.11 68 11.20 42 x 42 Duct 4.5 14.76

    C-D 9607.89 38.89 47 7.74 30 x 40 Duct 4.5 14.76

    D-15 5490.22 22.22 29.5 4.86 30 x 26 Duct 4 13.12

    A-2 4117.67 16.67 24 3.95 24 x 26 Elbow Duct 5 16.4 14

    2-3 2745.11 11.11 17.5 2.88 22 x 20 Duct 9 29.52

    3-4 1372.56 5.56 10.6 1.75 14 x 20 Duct 9 29.52

    B-5 4117.67 16.67 24 3.95 24 x 26 Elbow Duct 8.82 28.9296 14

    5-6 2745.11 11.11 17.5 2.88 22 x 20 Duct 9 29.52

    6-7 1372.56 5.56 10.6 1.75 14 x 20 Duct 9 29.52

    C-8 5490.22 22.22 29.5 4.86 30 x 26 Elbow Duct 4.32 14.1696 15

    8-9 4117.67 16.67 24 3.95 24 x 26 Duct 9 29.52

    9-10 2745.11 11.11 17.5 2.88 22 x 20 Duct 9 29.52

    10-11 1372.56 5.56 10.6 1.75 14 x 20 Duct 9 29.52

    D-12 4117.67 16.67 24 3.95 24 x 26 Elbow Duct 8.82 28.9296 14

    12-13 2745.11 11.11 17.5 2.88 22 x 20 Duct 9 29.52

    13-14 1372.56 5.56 10.6 1.75 14 x 20 Duct 9 29.52

    15-16 4117.67 16.67 24 3.95 24 x 26 Duct Elbow 9.32 30.5696 14

    16-17 2745.11 11.11 17.5 2.88 22 x 20 Duct Elbow 10 32.8 8

    17-18 1372.56 5.56 10.6 1.75 14 x 20 Duct 9 29.52

    TOTAL LENGTH 534.4104 130

    The total friction loss in the duct work from fan to last terminal 18 is:

    Loss = total equivalent length x friction rate

    For the total equivalent length, it appears that the longer run is from AHU 4 to terminal

    18: 55.03 + 73 = 128.03 ft.

    Friction rate: using Vsupply = 1500 fpm, cfm = 24706, Fr = 0.0435 (from chart 7, page 2-33 friction loss for round duct)

    Loss = 128.03 ft. x (0.0435 in wg /100 ft.)

    Loss = 0.0557 in wg

    The total static pressure required at fan discharge is the sum of the terminal operating

    pressure and the loss in the duct work. Credit can be taken for the regain between the

    first and last section of the duct.

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    From chart 7, p. 2-33 of Carrier Handbook with cfm of 1372.56 and equivalent circular

    duct diameter = 18.2 in., velocity in the last section = 720 fpm.

    Using 75% regain coefficient;

    Regain = = 0.0812 in wg

    Therefore, the total static pressure at fan discharge is;= duct friction + terminal pressure regain

    = 0.0557 + 0.15 0.0812

    = 0.1245 in wg

    ZONE 5

    Duct Sizing for Supply Air in Zone 5:

    Total number of diffuser = 25

    Percent of cfm =

    Duct area entering section 1:

    Duct area = percent of area times initial duct area (fan at section 1)

    All areas are listed in Table 3.1.1

    The Duct sizes can then be determined by using Carrier handbook, PP 2-36, Table 6.

    Table 3.1.1 listed all the duct size.

    The Additional Equivalent Length can be determining from Carrier handbook, PP 2-44,

    Table 12.

    Duct

    Section

    Air

    Quantity

    CFM

    Capacity

    Area

    %

    Area

    ft

    Duct

    SizeItem

    Length

    (m)

    Length

    (ft)

    Added

    Equiv.

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    % length

    AHU 5 - A 21216.43 100.00 100 12.48 44 x 44 Elbow 1.6 5.248

    A-10 16124.47 76.00 81 10.11 36 x 44 Duct 4.5 14.76

    10-16 11032.51 52.00 60 7.49 36 x 32 Duct 4.5 14.76

    16-21 6789.21 32.00 40 4.99 24 x 32 Duct 4.5 14.7621-25 2545.91 12.00 18.5 2.31 24 x 16 Duct 4.5 14.76

    A-2 1697.32 8.00 13 1.62 16 x 16 Elbow Duct 4.5 14.76 7.67

    2-1 848.66 4.00 7 0.87 8 x 16 Duct 4.5 14.76

    A-3 3394.64 16.00 23 2.87 20 x 22 Elbow Duct 4.5 14.76 13.2

    3-4 2545.98 12.00 18.5 2.31 20 x 18 Duct 4.5 14.76

    4-5 1697.32 8.00 13 1.62 14 x 18 Duct 4.5 14.76

    5-6 848.66 4.00 7 0.87 14 x 10 Duct 4.5 14.76

    10-9 2545.98 12.00 18.5 2.31 20 x 18 Duct 4.5 14.76

    9-8 1697.32 8.00 13 1.62 14 x 18 Duct 4.5 14.76

    8-7 848.66 4.00 7 0.87 14 x 10 Duct 4.5 14.76

    10-11 1697.32 8.00 13 1.62 14 x 18 Duct 4.5 14.76

    11-12 848.66 4.00 7 0.87 14 x 10 Duct 4.5 14.76

    16-17 848.66 4.00 7 0.87 14 x 10 Duct 4.5 14.76

    16-15 2545.98 12.00 18.5 2.31 20 x 18 Duct 4.5 14.76

    15-14 1697.32 8.00 13 1.62 14 x 18 Duct 4.5 14.76

    14-13 848.66 4.00 7 0.87 14 x 10 Duct 4.5 14.76

    21-22 848.66 4.00 7 0.87 14 x 10 Duct 4.5 14.76

    21-20 2545.98 12.00 18.5 2.31 20 x 18 Duct 4.5 14.76

    20-19 1697.32 8.00 13 1.62 14 x 18 Duct 4.5 14.76

    19-18 848.66 4.00 7 0.87 14 x 10 Duct 4.5 14.76

    25-24 1697.32 8.00 13 1.62 14 x 18 Duct 4.5 14.76

    24-23 848.66 4.00 7 0.87 14 x 10 Duct 4.5 14.76

    TOTAL LENGTH 374.248 20.87

    The total friction loss in the duct work from fan to last terminal 25 is:

    Loss = total equivalent length x friction rate

    For the total equivalent length, it appears that the longer run is from AHU 5 to terminal

    25: 28.5 ft.

    Friction rate: using Vsupply = 1700 fpm, cfm = 21216.3, Fr = 0.064 (from chart 7, page 2-

    33 friction loss for round duct)

    Loss = 28.5 ft. x (0.064 in wg /100 ft.)

    Loss = 0.01824 in wg

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    The total static pressure required at fan discharge is the sum of the terminal operating

    pressure and the loss in the duct work. Credit can be taken for the regain between the

    first and last section of the duct.

    From chart 7, p. 2-33 of Carrier Handbook with cfm of 848.66 and equivalent circular

    duct diameter = 12.9 in., velocity in the last section = 1000 fpm.Using 75% regain coefficient;

    Regain = = 0.0886 in wg

    Therefore, the total static pressure at fan discharge is;

    = duct friction + terminal pressure regain

    = 0.01824 + 0.15 0.0886

    = 0.15 in wg

    Duct Sizing for Return Air in Zone 5:

    Total number of diffuser = 12

    Percent of cfm =

    Duct area entering section 1:

    Duct

    Section

    Air

    Quantity

    CFM

    Capacity

    %

    Area

    %

    Area

    ft.

    Duct

    Size

    Item

    Length

    (m)

    Length

    (ft)

    Added

    Equiv.

    LengthAHU 5 - A 20766.43 100.00 100 13.84 46 x 46 Duct Elbow 16.8 55.104 25

    A-B 19035.89 91.67 94 13.01 44 x 46 Duct 4.66 15.2848

    B-C 15574.82 75.00 80.5 11.14 44 x 40 Duct 4.66 15.2848

    C-D 12113.75 58.33 65.6 9.08 36 x 40 Duct 4.66 15.2848

    D-7 10383.22 50.00 58 8.03 34 x 38 Duct Elbow 14 45.92 20

    7-E 8652.68 41.67 50 6.92 30 x 36 Duct Elbow 12.86 42.1808 16

  • 8/8/2019 Chapter IV Ducting

    24/24

    E-F 6922.14 33.33 41 5.67 30 x 30 Duct 5.56 18.2368

    F-G 5191.61 25.00 32.5 4.50 24 x 30 Duct 5.56 18.2368

    G-11 3461.07 16.67 24 3.32 24 x 22 Duct Elbow 7.96 26.1088 12

    A-1 1730.54 8.33 13 1.80 14 x 22 Elbow Duct 7.8 25.584 10.5

    B-2 3461.07 16.67 24 3.32 24 x 22 Elbow Duct 4.5 14.76 12

    2-3 1730.54 8.33 13 1.80 14 x 22 Duct 9 29.52

    C-4 3461.07 16.67 24 3.32 24 x 22 Elbow Duct 1.2 3.936 12

    4-5 1730.54 8.33 13 1.80 14 x 22 Duct 9 29.52

    D-6 1730.54 8.33 13 1.80 14 x 22 Elbow Duct 6.9 22.632 10.5

    E-8 1730.54 8.33 13 1.80 14 x 22 Elbow Duct 6.1 20.008 10.5

    F-9 1730.54 8.33 13 1.80 14 x 22 Elbow Duct 4.87 15.9736 10.5

    G-10 1730.54 8.33 13 1.80 14 x 22 Elbow Duct 3.64 11.9392 10.5

    11-12 1730.54 8.33 13 1.80 14 x 22 Duct 9 29.52

    TOTAL LENGTH 455.0344 149.5

    The total friction loss in the duct work from fan to last terminal 12 is:

    Loss = total equivalent length x friction rate

    For the total equivalent length, it appears that the longer run is from AHU 5 to terminal

    12: 85.95 ft. + 73 = 158.95 ft.

    Friction rate: using Vsupply = 1500 fpm, cfm = 20766.43, Fr = 0.04 (from chart 7, page 2-

    33 friction loss for round duct)

    Loss = 158.95 ft. x (0.04 in wg /100 ft.)

    Loss = 0.0636 in wg

    The total static pressure required at fan discharge is the sum of the terminal operating

    pressure and the loss in the duct work. Credit can be taken for the regain between the

    first and last section of the duct.

    From chart 7, p. 2-33 of Carrier Handbook with cfm of 1730.54 and equivalent circular

    duct diameter = 19.1 in., velocity in the last section = 880 fpm.

    Using 75% regain coefficient;

    Regain = = 0.0692 in wg

    Therefore, the total static pressure at fan discharge is;

    = duct friction + terminal pressure regain

    = 0.0636 + 0.15 0.0692

    = 0.144 in wg


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