PRESSURE DROP CALCULATION FOR STERILIZATION EXHAUST FANS FRSH-MED-0
PROJECT WORKER HOSPITAL , DOHA, QATAR
SYSTEM FRESH AIR DUCT (FRSH-MED-01 FANS)
DESIGN FLOW 170 L/s
VERIFIED FLOW 170 L/s
DESIGN ESP 150 Pa
VERIFIED ESP 200Pa
PROPOSED ESP 150 pa
AIR AIR FRICTION
DUCT
DUCT WIDTH HEIGHT AIR FLOW FLOW FLOW NO.OF LOSS FOR
DUCT ELEMENT LENGTH FITTINGS
SECTION (mm) (mm) RATE (cfm) RATE RATE ST. DUCT
(m)
(l/s) (m3/s) (pa/m)
MAKE UP AIR DUCT (SUPPLY)
1 Fresh air louver 350 300 360 170 0.2 1.0
2 Bell mouth 350 300
250 200 360 170 0.2
3,5,9,12,20 Straight duct 250 200 360 170 0.2 43.0 0.751
4, Elbow 90° (smooth radius) 250 200 360 170 0.2 1.0
6,8,11,18 Elbow 45° (smooth radius) 250 200 360 170 0.2 4.0
10,19 Wye - Rectangular 250 200
250 200 360 170 0.2 2.0
13,16 Fan connection (Transition) 250 200
350 300 360 170 0.2 2.0 0.685
14,15 Flexible connector 350 300 360 170 0.2 2.0
17 Back draft damper 250 200 360 170 0.2
21 Rectangular to Round 250 200
Dia -250 360 170 0.2
Volume damper
22 (Fully open) Dia -250 360 170 0.2
23 Flexible duct Ø 250 360 170 0.2
PRESSURE DROP CALCULATION FOR STERILIZATION EXHAUST FANS FRSH-MED-0
PROJECT WORKER HOSPITAL , DOHA, QATAR
SYSTEM FRESH AIR DUCT (FRSH-MED-01 FANS)
DESIGN FLOW 170 L/s
VERIFIED FLOW 170 L/s
DESIGN ESP 150 Pa
VERIFIED ESP 200Pa
PROPOSED ESP 150 pa
AIR AIR FRICTION
DUCT
DUCT WIDTH HEIGHT AIR FLOW FLOW FLOW NO.OF LOSS FOR
DUCT ELEMENT LENGTH FITTINGS
SECTION (mm) (mm) RATE (cfm) RATE RATE ST. DUCT
(m)
(l/s) (m3/s) (pa/m)
24 Grills/Diffusers 400 200 360 170 0.2
TOTAL MAKE UP AIR DUCT (SUPPLY) PRESSURE DROP
Add margin of safety (15%)
Total Pressure loss
NOTE:
1 ρ - air temp at 20deg -density 1.20kg/m³ at relative humidity of 50% - cibse table 4.A1.2
2 ESP Calculations based on ASHRAE & SMACNA Engineering data, Duct design and tables [Chapter 16]
3 VCDs considered as 100% open / opposed blade construction
4 Elbows are considered smooth radius for the calculations
5 Highest pressure drops are considered for each fitting
6 Duct Correction factor considered for Medium Rough Surface
7 Calculations are done as per design flow
IZATION EXHAUST FANS FRSH-MED-01 (TYPICAL 4 NOS)
FLOW VELOCITY VELOCITY LOSS LOSS PER
PRESSURE COEFFICIENT ITEM REMARKS
(pa)
(pa) FOR FITTING
(m/s) FPM
1.62 318.63 1.58 0.31 35.00 Assumed
3.40 669.12 6.96 0.46 3.20 From SMACNA
From Mcquay
3.40 669.12 6.96 32.29 Ductulator
3.40 669.12 6.96 0.22 1.53 From ASHRAE
3.40 669.12 6.96 0.13 3.62 From ASHRAE
3.40 669.12 6.96 2.3 32.03 From SMACNA
0.00 0.00 0.00
1.62 318.63 1.58 0.28 0.88 From SMACNA
1.62 318.63 1.58 5.00 Assumed
3.40 669.12 6.96 31.00 KMC
2.68 682.00 7.23 0.03 0.22 From ASHRAE
2.68 682.00 7.23 0.52 3.76 From ASHRAE
2.68 682.00 7.23 5.00 Assumed
IZATION EXHAUST FANS FRSH-MED-01 (TYPICAL 4 NOS)
FLOW VELOCITY VELOCITY LOSS LOSS PER
PRESSURE COEFFICIENT ITEM REMARKS
(pa)
(pa) FOR FITTING
(m/s) FPM
2.33 456.00 3.13 20.00 Assumed
173.54
26.03
199.58
ign and tables [Chapter 16]
LOSS COEFFICIENT TABULATION FOR DUCT FITTINGS
MED ROOM FANS ( SUPPLY - FAN) - FRSH-MED-01
Elbows, smooth radius (ASHRAE Figure CR3-3)
W H θ° R r = R+W/2 r/W H/W Cp K Factor C=KCp
Element No.
4 250 200 90 150 275 1.10 0.80 0.22 1.00 0.22
6,8,11,18 250 200 90 150 275 1.10 0.80 0.22 0.60 0.13
Transition Rectangular, Exhaust Air System (SMACNA )
Size Area
A1/A θ° C
Element No. W H A A1
250 200
13,16 0.05 0.105 2.10 45 0.28
350 300
Transition Rectangular to Round
Size Area
Ao/A1 θ° C
Element No. W H Ao A1
250 200
21 0.05 0.049 1.02 30 0.03
dia - 250
Wye - Rectangular (SMACNA)
Main Duct Size Area Branch Duct Size Area Branch Duct Size Area Air Flow
Duct
Element
W H Ac W H Ab W H Ac Qc Qb ᶿ
10,19 250 200 0.05 250 200 0.05 250 200 0.05 170 170 45
Qb/Qc Cs
1.00 2.30
BELL MOUTH
Duct Main Duct Size Area St. Duct Size Area
Ao/A1 L Dh L/Dh Co
Element W1 H1 A1 Wo Ho Ao ᶿ
2 350 300 0.11 250 200 0.05 0.4762 150 222.2222 0.68 26 0.46
Dh= (2HoWo / (Ho+Wo))
A B
10 1.1 1.2
C D D
18 2.14 2.4 0.26 64.532
E F F 595.68
20 2.4 2.7
0.5 0.75
1 1.5 2 2.5 1 2
A 0.7 0.04 0.02 0 -0.1 A 0.7 0.052
B 0.73 0.052 0.026 0 -0.097 B 0.75 0.039
C 0.8 0.08 0.04 0 -0.09 C 0.8 0.026
A 0.5 0.33 2 0.23 0.5 0.04 11.42
B 0.996 0.0026 1.12 0.0276 0.55 0.07
C 1 0 1 0 0.6 0.1
50 75 0.628
0.028 0.063
6499
0.078 10693.35
0.000669
4 400
603360000
10693.35
0.4 500
1 6500
0.45 1000
0.607761
0.36
1.1808
1979.021
1676
2805625
0.185074 4489000
-1675.82
-3351.64
