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Ventilation Design

This document contains a ventilation design worksheet for calculating ductwork parameters such as volumetric flow rate, duct velocity, velocity pressure, static pressure loss, and fan specifications. It includes pertinent equations for corrected flow rate and velocity pressure calculations. Tables provide loss factors for elbows, branches, and other fittings to determine static pressure losses throughout the duct system from the hood to the fan. The goal is to calculate the required fan specifications and static pressure to balance the system based on the design criteria and duct layout.

Uploaded by

Phyu Mar Thein Kyaw
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© © All Rights Reserved
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244 views4 pages

Ventilation Design

This document contains a ventilation design worksheet for calculating ductwork parameters such as volumetric flow rate, duct velocity, velocity pressure, static pressure loss, and fan specifications. It includes pertinent equations for corrected flow rate and velocity pressure calculations. Tables provide loss factors for elbows, branches, and other fittings to determine static pressure losses throughout the duct system from the hood to the fan. The goal is to calculate the required fan specifications and static pressure to balance the system based on the design criteria and duct layout.

Uploaded by

Phyu Mar Thein Kyaw
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as XLS, PDF, TXT or read online on Scribd
You are on page 1/ 4

VentDesign

VENTILATION DESIGN WORK SHEET


Organization:

Elevation:

Location:
Shop:

Temperature:

0 Feet
70 Degrees F

Factor:

Velocity Pressure Calculation Method


1
1a
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36

Duct Segment Identification


Type of Duct (GALV=Galvinzied) (BLK=Black Iron, Al, SS)
Volumetric Flowrate: (See Design Criteria)
cfm
Minimium Transport Velocity (See Design Criteria) fpm
Duct Diameter
(Round Duct)
inches
Duct Area
Actual Duct Velocity
Duct Velocity Pressure (Vd/4005)^2 = VP
"w
H
Slot Area
Sq. Ft.
O S Slot Velocity
fpm
O L Slot Velocity Pressure
"
D O Slot Loss Factor
(ACGIH Vent Manual Chapter 10)
T Acceleration Factor
0o
S S Plenum Loss per VP
U
Plenum SP
C Duct Entry Loss Factor (See Design Specifications)
T Acceleration Factor
(if Vd>Vs; 1)
1 or 0
I Duct Entry Loss per VP
O Duct Entry Loss
N Other Loss
"wg
Hood Static Pressure
(SPh)
"
Straight Duct Length
feet
Friction Factor (Hf)
Friction Loss per VP
No. of 90 Degree Elbows
Elbow Loss per VP
(See Table Below or ACGIH, Fig 5-13)
Number of Entries
Entry Loss per VP
(See Table Below or ACGIH, Fig 5-14)
Special Fittings Loss Factors
Duct Loss per VP
Duct Loss
Duct SP Loss
Cumulative Static Pressure
"wg
Governing Static Pressure
"wg
Corrected Volumetric Flowrate (Balanced)
cfm
Resultant Velocity Pressure
"
Corrected Velocity (Based on the Governing SP) fpm

PERTINENT EQUATIONS:
Q corr.

= Q Design (SP gov./ SP duct)^1/2

VP r

= ((Q1 + Q2)/(4005(A1 + A2)))^2


= (Q1/Q3)*VP1 + (Q2/Q3)*VP2

or

Page1

R/D
0.5
Stamped
0.71
5Piece
4Piece
3Piece
0.9
60 elbow = 2/3 loss

90 Degree Round Elb


0.75
0.33
0.46
0.5
0.54

VentDesign

Hf

= 0.0307(V^0.533)/(Q^0.612) = GALV in Line 1a

45 elbow = 1/2 loss


30 elbow = 1/3 loss

= 0.0425(V^0.465)/(Q^0.602) = BLK in Line 1a


FSP

= SP outlet - SP inlet - VP inlet

Ce
SPh

= Coefficient of Entry
= (VP / SPh)^1/2
or
1 (for perfect hood - No losses)
= HoodStaticPressure=(V/4005)^2

VP

= VelocityPressure=SPhhe

he

= EntryLoss=FhxVP

TP

= TotalPressure=SP+VP

SP;VP = StaticPressure;VelocityPressure
Vd

Branch Entry
Loss Factors
Angle
Factor
15
0.09
30
0.18
45
0.28
60
0.44
90
1

Fan Specifications
Blade Type:
Size:
RPM:
HP:

= DuctVelocity

Page2

VentDesign

HEET
Date:

29-Jul-15

Drawing No.

Designer:

Method

90 Degree Round Elbow Loss Factors


1
1.5
2
0.22
0.15
0.13
0.33
0.24
0.19
0.37
0.27
0.24
0.42
0.34
0.33

2.5
0.12
0.17
0.23
0.33

Page3

VentDesign

FSP=

Fan Static Pressure

#VALUE!

TP=

FSP+VPout=

#VALUE!

ME=

Mechanicalefficiency
(Usually.5.65)

ME=

Q=

BHP=

QxTP=
6356xME

#VALUE!

Existing

DeltainSP:

#VALUE!

DeltainSP(1):

#VALUE!

Required
Tubeaxial

###

Page4

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