NTP - Normal Temperature and Pressure - is defined as air at 20oC (293.15 K, 68oF) and 1 atm ( 101.325 kN/m2, 101.325 kPa, 14.7 psia, 0 psig, 30 in Hg, 760 torr)






http://www.engineeringtoolbox.com/specific-gravities-gases-d_334.html







density of air defined http://hypertextbook.com/facts/2000/RachelChu.shtml using 1.25 kg/m3



















Saturated Water Vapor Pressure in mb es

Saturated vapor density vs Temp C








1.25 kg/m3
density of dry air 0C & 760mm es=6.112*EXP(17.87*B62/(B62+243.5))

VD=6.335 + .6718TC – 2.0887 x10-2TC2 + 7.3095 x 10-4TC3











Bolton (1980) (0.3% within -35C to 35C)




density of dry air.





sat. vapor density(1)
3.5/(B7+253)

sat. vapor density
change in density from 0C


Temp F. Temp. Celsius gm/m3




gr/m3

gm/m3 kg/m3

Temp. Celsius Temp F.





pws = e(77.3450 + 0.0057 T - 7,235 / T) / T8.2 (1)(77.3450 + 0.0057 T - 7,235 / T) /T 8.2










-31 -35

0.314764 18.090698
-74.104056 0.015982


1.433708 183.707747
-35 -31
-29.2 -34

0.347347 19.952821
-69.380831 0.015909


1.427713 177.712733
-34 -29.2
-27.4 -33

0.382945 21.986533

0.015837


1.421768 171.767645
-33 -27.4
-25.6 -32

0.421801 24.205712

0.015766


1.415872 165.871864
-32 -25.6
-23.8 -31

0.464178 26.62519

0.015695


1.410025 160.024778
-31 -23.8
-22 -30

0.510354 29.260811

0.015625


1.404226 154.225787
-30 -22
-20.2 -29

0.560628 32.129481

0.015556


1.398474 148.474299
-29 -20.2
-18.4 -28

0.615318 35.24923

0.015487


1.39277 142.769733
-28 -18.4
-16.6 -27

0.674762 38.639269

0.015419


1.387112 137.111517
-27 -16.6
-14.8 -26

0.739322 42.320052

0.015351


1.381499 131.49909
-26 -14.8
-13 -25

0.809381 46.313344

0.015284


1.375932 125.931896
-25 -13
-11.2 -24

0.885349 50.642283

0.015217


1.370409 120.409392
-24 -11.2
-9.4 -23

0.967659 55.331451

0.015152


1.364931 114.931041
-23 -9.4
-7.6 -22

1.056773 60.406947

0.015086


1.359496 109.496317
-22 -7.6
-5.8 -21

1.15318 65.896459

0.015021


1.354105 104.1047
-21 -5.8
-4 -20

1.2574 71.829342
-18.258259 0.014957


1.348756 98.755678
-20 -4
-2.2 -19

1.369982 78.236694

0.014894


1.343449 93.448751
-19 -2.2
-0.4 -18

1.491509 85.151441

0.014831


1.338183 88.183422
-18 -0.4
1.4 -17

1.622599 92.608419

0.014768


1.332959 82.959204
-17 1.4
3.2 -16

1.763903 100.644462

0.014706


1.327776 77.775617
-16 3.2
5 -15

1.916111 109.298488

0.014644


1.322632 72.632191
-15 5
6.8 -14

2.079954 118.611595

0.014583


1.317528 67.528458
-14 6.8
8.6 -13

2.256199 128.627153

0.014523


1.312464 62.463963
-13 8.6
10.4 -12

2.445659 139.390899

0.014463


1.307438 57.438254
-12 10.4
12.2 -11

2.64919 150.951042

0.014403


1.302451 52.450887
-11 12.2
14 -10 2.36
2.867696 163.35836
-2.822007 0.014344

2.36 1.297501 47.501425
-10 14
15.8 -9

3.102126 176.666309

0.014286


1.292589 42.589438
-9 15.8
17.6 -8

3.353482 190.931125

0.014228


1.287715 37.714501
-8 17.6
19.4 -7

3.622817 206.211943

0.01417


1.282876 32.876198
-7 19.4
21.2 -6

3.911238 222.5709

0.014113


1.278074 28.074116
-6 21.2
23 -5

4.21991 240.073258

0.014056


1.273308 23.30785
-5 23
24.8 -4

4.550055 258.787518

0.014


1.268577 18.577002
-4 24.8
26.6 -3

4.902956 278.785542

0.013944


1.263881 13.881177
-3 26.6
28.4 -2

5.279961 300.142678

0.013889


1.25922 9.219989
-2 28.4
30.2 -1

5.682482 322.937883

0.013834


1.254593 4.593055
-1 30.2
32 0 4.85
6.112 347.253851
6.335 0.01378

4.85 1.25 0
0 32
33.8 1

6.570067 373.177149

0.013725


1.24544 -4.559548
1 33.8
35.6 2

7.058307 400.798345

0.013672


1.240914 -9.085953
2 35.6
37.4 3

7.57842 430.212146

0.013619


1.23642 -13.579576
3 37.4
39.2 4

8.132186 461.517539

0.013566


1.231959 -18.040772
4 39.2
41 5 6.8
8.721465 494.817928

0.013514

6.8 1.22753 -22.46989
5 41
42.8 6

9.348201 530.221277

0.013462


1.223133 -26.867276
6 42.8
44.6 7

10.014425 567.84026

0.01341


1.218767 -31.233268
7 44.6
46.4 8

10.722257 607.792404

0.013359


1.214432 -35.568202
8 46.4
48.2 9

11.473911 650.200242

0.013308


1.210128 -39.872408
9 48.2
50 10 9.4
12.271696 695.191465

0.013258

9.4 1.205854 -44.146212
10 50
51.8 11 10.01
13.11802 742.899075

0.013208

10.01 1.20161 -48.389935
11 51.8
53.6 12 10.66
14.015393 793.461543

0.013158

10.66 1.197396 -52.603893
12 53.6
55.4 13 11.35
14.966429 847.022965

0.013109

11.35 1.193212 -56.788398
13 55.4
57.2 14 12.07
15.973851 903.733226

0.01306

12.07 1.189056 -60.943758
14 57.2
59 15 12.83
17.040495 963.748161

0.013011

12.83 1.18493 -65.070276
15 59
60.8 16

18.169308 1027.229719

0.012963


1.180832 -69.168252
16 60.8
62.6 17

19.363361 1094.346127

0.012915


1.176762 -73.23798
17 62.6
64.4 18

20.62584 1165.272064

0.012868


1.17272 -77.279753
18 64.4
66.2 19

21.960063 1240.188821

0.012821


1.168706 -81.293856
19 66.2
68 20 17.3
23.369471 1319.284481

0.012774

17.3 1.164719 -85.280573
20 68
69.8 21

24.857641 1402.754088
24.857641 0.012727


1.16076 -89.240184
21 69.8
71.6 22

26.428285 1490.799818

0.012681


1.156827 -93.172963
22 71.6
73.4 23

28.085254 1583.631158

0.012635


1.152921 -97.079183
23 73.4
75.2 24

29.832543 1681.465082

0.01259


1.149041 -100.959112
24 75.2
77 25 23
31.674294 1784.526227

0.012545

23 1.145187 -104.813014
25 77
78.8 26

33.614801 1893.047074

0.0125


1.141359 -108.64115
26 78.8
80.6 27

35.658512 2007.268125

0.012456


1.137556 -112.443778
27 80.6
82.4 28

37.810033 2127.438087

0.012411


1.133779 -116.221152
28 82.4
84.2 29

40.074135 2253.814049

0.012367


1.130026 -119.973523
29 84.2
86 30 30.4
42.455754 2386.66167
43.397434 0.012324

30.4 1.126299 -123.701138
30 86
87.8 31

44.959999 2526.255358

0.012281


1.122596 -127.404241
31 87.8
89.6 32

47.592151 2672.878453

0.012238


1.118917 -131.083074
32 89.6
91.4 33

50.357672 2826.823413

0.012195


1.115262 -134.737874
33 91.4
93.2 34

53.262207 2988.391999

0.012153


1.111631 -138.368875
34 93.2
95 35

56.31159 3157.895458

0.012111


1.108024 -141.97631
35 95
96.8 36


3335.654706








36 96.8
98.6 37 44

3522.000518




44


37 98.6
100.4 38


3717.273708








38 100.4
102.2 39


3921.825315








39 102.2

40 51.1

4136.016789




51.1


40 104
Temp F. Temp. Celsius (1) values above from: http://hyperphysics.phy-astr.gsu.edu/hbase/Kinetic/watvap.html#c1

















equation above from http://hurri.kean.edu/~yoh/calculations/moisture/Equations/moist.html
















pws = e(77.3450 + 0.0057 T - 7,235 / T) / T8.2 (1)(77.3450 + 0.0057 T - 7,235 / T) /T 8.2















equation above from http://www.engineeringtoolbox.com/water-vapor-saturation-pressure-air-d_689.html