NuAire LabGard D NU-543-400, Manual

Page: 48 / 70

OM0283 Page 48 of 70
Rev 2 July/2021
Alternate Procedure:
The alternative procedure to determine inflow velocity uses a thermo anemometer in a constricted window access
opening of 3 inches (76mm) with the armrest removed. Inflow air velocity is measured in the center of the constricted
opening 1-1/2 inches (38mm) above the work access opening on the following specified grid. Use the correction factor
table to calculate the inflow velocity.
c. Test Data - Inches (mm):
1. DIM Measurement
Inflow Volume
ft.
3
/min.(m
3
/s)
Access Opening
ft.
2
(m
2
)
Inflow Velocity
ft./min(m/s)
2. Constricted 3 inch (76mm) high access opening measurement - Inches (mm):
300
4
(102)
8.3966
(213)
12.792
(325)
17.188
(437)
21.584
(548)
25.980
(660)
30.375
(771)
400
4
(102)
8.264
(210)
12.528
(318)
16.792
(426)
21.056
(535)
25.320
(643)
29.584
(751)
33.848
(860)
38.112
(968)
42.375
(1076)
500
4
(102)
8.198
(208)
12.396
(315)
16.594
(421)
20.792
(528)
24.990
(635)
29.188
(741)
33.386
(848)
37.584
(955)
41.782
(1061)
45.980
(1168)
50.178
(1274)
54.375
(1381)
600
4
(102)
8.158
(207)
12.316
(313)
16.474
(481)
20.632
(524)
24.790
(630)
28.948
(735)
33.106
(841)
37.264
(946)
41.422
(1052)
45.580
(1158)
49.738
(1263)
53.896
(1369)
58.054
(1475)
62.212
(1580)
66.375
(1686)
Number of Readings:
Average Velocity of Constricted Area
ft./min.(ms)
1. Average Velocity of Constricted Area fpm (m/s)
2. X Constricted Access Area ft
2
(m
2
)
3. = Constricted Area Volume CFM(m
3
/s)
4. Constricted Area Volume CFM(m
3
/s)
5.

10”(254) or 8” (203) or 12" (305mm) Access Window Area ft
2
(m
2
)
6. = Average Velocity of 10”(254) or 8” (203) or 12" (305mm) Access Window Area fpm (m/s)
7. Average Velocity of 10”(254) or 8” (203) or 12" (305mm) Access Window Area fpm (m/s)
8. X Correction Factor for Window Height
9. = Average Inflow Velocity fpm (m/s)
d. Acceptance Criteria: Access Opening Inflow Velocity = 100 to 110 fpm (.51 to .56 m/s)
Areas/Correction Factors for Calculations
Cabinet
Size
Window Access Opening Correction Factor For
3" (76mm)
Constricted
10" (254mm) 8" (203mm) 12" (305mm) 10 ” (254mm)
Window
8"(203mm)
Window
12"(305mm)
Window
300
.72
(.067)
2.39
(.222)
1.91
(.177)
2.86
(.267)
1.01 1.0 1.0
400
.97
(.090)
3.22
(.299)
2.58
(.240)
3.86
(.358)
1.0 1.0 1.03
500
1.22
(.113)
4.05
(.376)
3.24
(.301)
4.86
(.451)
1.0 1.03 1.03
600
1.47
(.137)
4.89
(.454)
3.91
(.363)
5.86
(.544)
1.02 1.02 1.0