Incoming Air Volume; Table 3. Grains Of Water Per Cubic Foot - Saturated Air (100% Rh) - Nortec NHPC Engineer's Manual

Table 3. Grains of Water Per Cubic Foot – Saturated Air (100% rh)
°C °F Grains °C °F
-23 -10 .29 4 40
-5 .35 41
-18 0 .48 42
8 .61 43
-12 10 .78 44
-9 15 .99 7 45
-7 20 1.24 46
-4 25 1.56 47
-1 30 1.95 48
31 2.04 49
32 2.13 10 50
33 2.21 51
34 2.29 52
2 35 2.38 53
36 2.47 54
37 2.56 13 55
38 2.66 56
39 2.76 57
(2) Formula 2
Assume our printing plant is located in Denver, Colorado. From Table 4, the worst
case is -10
From Table 3:
0.29 gr/ft
Combining this result with that of Moisture Required (A) we see that we will need
5.19 - 0.11 = 5.08 grains of moisture for every cubic foot of outside air brought in.
E. INCOMING AIR VOLUME
(1) The following outlines the steps necessary to determine the amount of outside air being
brought into the humidified space and the corresponding amount of moisture required.
There are three basic means by which outside air is introduced into the humidified
space. These are:
(a) Through natural ventilation, for example, opening and closing doors and windows,
and by infiltration through cracks and openings in the building construction.
(b) Through mechanical ventilation, for example, the introduction of make-up air, or
the exhausting of stale air by the building HVAC system.
(c) Through the economizer section of the HVAC system - if this feature is included in
the system.
(2) For maximum accuracy, all three should be estimated and the largest chosen.
Grains °C °F Grains
2.86 58 5.41
2.97 59 5.60
3.08 16 60 5.80
3.20 61 6.00
3.32 62 6.20
3.44 63 6.41
3.56 64 6.62
3.69 18 65 6.85
3.83 66 7.07
3.97 67 7.31
4.11 68 7.57
4.26 69 7.80
4.41 21 70 8.10
4.56 71 8.32
4.72 72 8.59
4.89 73 8.87
5.06 74 9.15
5.23 24 75 9.45
°
F with 37% rh
3 3
x 37% rh - 0.11 gr/ft
°C °F Grains °C °F
76 9.75 35 95
77 10.06 96
78 10.40 97
79 10.80 98
27 80 11.04 99
81 11.40 38 100
82 11.75 101
83 12.11 102
84 12.49 103
29 85 12.87 104
86 13.27 41 105
87 13.67 106
88 14.08 107
89 14.51 108
32 90 14.94 109
91 15.39 43 110
92 15.84 111
93 16.31 112
94 16.79 113
Grains °C °F Grains
17.28 114 29.34
17.80 115 30.13
18.31 49 120 34.38
18.85 125 39.13
19.39 54 130 44.41
19.95 135 50.30
20.52 60 140 56.81
21.11 145 64.04
21.71 66 150 72.00
22.32 155 80.77
22.95 71 160 90.43
23.60 165 101.00
24.26 77 170 112.60
24.93 175 125.40
25.62 82 180 139.20
26.34 185 154.30
27.07 88 190 170.70
27.81 195 188.60
28.57
10-10
Page 15
2008-10-01