Pitot Tube Calculator
Variable Input Values Notes
Δ P
(Differential Pressure) 		Enter in. H2O  
P
(Static Line Pressure) 		Enter (-) for Vacuum / (+) for Pressure <--- Use this cell if field reading was recorded in in. H2O [leave cell blank, or enter "0" if reading is in. Hg, and fill in below cell]
<--- Use this cell if field reading was recorded in in. Hg [or converts above cell to in. Hg = 13.596 in. H2O]
T
(Temperature) 		Enter Temp in oF  
D
(Inside Pipe Diameter) 		Enter inches  
K Value
(Flow Coefficient) 		Enter from Table  
Ss
(Specific Gravity of Air) 		   
Q
(Flow) 		  Resulting Flow in SCFM
in. H2O = 13.596 in. Hg  
in. H2O = 0.03613 psi  
1 ATM = 14.696 psi  
psia = psig + 14.696 psi  
 
TEMPERATURE CONVERSIONS
Temp. Convert Equation oC = 5/9 x (oF-32)
oF = 9/5 x (oC) + 32
Enter oC = oF
Enter oF = oC
Typical weight and dimensions of PVC and CPVC pipes according ASTM D1785 "Standard Specification for Poly(Vinyl Chloride) (PVC) Plastic Pipe, Schedules 40, 80, and 120" can be found in the table below:
 
PVC and CPVC Pipes - Schedule 40  
Nominal Pipe Size Outside Diameter Minimum Wall Thickness Nominal Inside Diameter Weight  
(inches) (inches) (inches) (inches) (lb/ft)  
        PVC CPVC  
1/2 0.84 0.109 0.622 0.16 0.17  
3/4 1.05 0.113 0.824 0.21 0.23  
1 1.315 0.133 1.049 0.32 0.34  
1.25 1.66 0.14 1.38 0.43 0.46  
1.5 1.9 0.145 1.61 0.51 0.55  
2 2.375 0.154 2.067 0.68 0.74  
2.5 2.875 0.203 2.469 1.07 1.18  
3 3.5 0.216 3.068 1.41 1.54  
4 4.5 0.237 4.026 2.01 2.2  
5 5.563 0.258 5.047 2.73    
6 6.625 0.28 6.065 3.53 3.86  
8 8.625 0.322 7.981 5.39 5.81  
10 10.75 0.365 10.02 7.55 8.24  
12 12.75 0.406 11.938 10.01 10.89  
14 14 0.438 13.124 11.8    
16 16 0.5 15 15.43    
PVC and CPVC Pipes - Schedule 80  
Nominal Pipe Size Outside Diameter Minimum Wall Thickness Nominal Inside Diameter Weight  
(inches) (inches) (inches) (inches) (lb/ft)  
        PVC CPVC  
1/2 0.84 0.147 0.546 0.2 0.22  
3/4 1.05 0.154 0.742 0.27 0.3  
1 1.315 0.179 0.957 0.41 0.44  
1.25 1.66 0.191 1.278 0.52 0.61  
1.5 1.9 0.2 1.5 0.67 0.74  
2 2.375 0.218 1.939 0.95 1.02  
2.5 2.875 0.276 2.323 1.45 1.56  
3 3.5 0.3 2.9 1.94 2.09  
4 4.5 0.337 3.826 2.75 3.05  
5 5.563 0.375 4.813 3.87    
6 6.625 0.432 5.761 5.42 5.82  
8 8.625 0.5 7.625 8.05 8.83  
10 10.75 0.593 9.564 12 13.09  
12 12.75 0.687 11376 16.5 18  
14 14 0.75 12.5 19.3    
16 16 0.843 14.314 25.44    
1 lb = 0.4536 kg  
1 ft (foot) = 0.3048 m
1 in (inch) = 25.4 mm
Specific gravity of air at 60F = 1.0
 
Density of air 1) (lb/ft3)
Air temperature (oF) Gauge Pressure (psi)
0 5 10 20 30 40 50 60 70 80 90 100
30 0.081 0.109 0.136 0.192 0.247 0.302 0.357 0.412 0.467 0.522 0.578 0.633
40 0.08 0.107 0.134 0.188 0.242 0.295 0.35 0.404 0.458 0.512 0.566 0.62
50 0.078 0.105 0.131 0.185 0.238 0.291 0.344 0.397 0.451 0.504 0.557 0.61
60 0.076 0.102 0.128 0.18 0.232 0.284 0.336 0.388 0.44 0.492 0.544 0.596
70 0.075 0.101 0.126 0.177 0.228 0.279 0.33 0.381 0.432 0.483 0.534 0.585
80 0.074 0.099 0.124 0.174 0.224 0.274 0.324 0.374 0.424 0.474 0.524 0.574
90 0.072 0.097 0.121 0.171 0.22 0.269 0.318 0.367 0.416 0.465 0.515 0.564
100 0.071 0.095 0.119 0.168 0.216 0.264 0.312 0.361 0.409 0.457 0.505 0.554
120 0.069 0.092 0.115 0.162 0.208 0.255 0.302 0.348 0.395 0.441 0.488 0.535
140 0.066 0.089 0.111 0.156 0.201 0.246 0.291 0.337 0.382 0.427 0.472 0.517
150 0.065 0.087 0.109 0.154 0.198 0.242 0.287 0.331 0.375 0.42 0.464 0.508
200 0.06 0.081 0.101 0.142 0.183 0.244 0.265 0.306 0.347 0.388 0.429 0.47
250 0.056 0.075 0.094 0.132 0.17 0.208 0.246 0.284 0.322 0.361 0.399 0.437
300 0.052 0.07 0.088 0.123 0.159 0.195 0.23 0.266 0.301 0.337 0.372 0.408
400 0.046 0.062 0.078 0.109 0.141 0.172 0.203 0.235 0.266 0.298 0.329 0.36
500 0.041 0.056 0.07 0.098 0.126 0.154 0.182 0.21 0.238 0.267 0.295 0.323
600 0.038 0.05 0.063 0.089 0.114 0.14 0.165 0.19 0.216 0.241 0.267 0.292
Density of air 1) (lb/ft3)
Air temperature (oF) Gauge Pressure (psi)
120 140 150 200 250 300 400 500 700 800 900 1000
30 0.743 0.853 0.909 1.185 1.46 1.736 2.29 1.84 3.94 4.49 5.05 5.6
40 0.728 0.836 0.89 1.161 1.431 1.702 2.24 2.78 3.86 4.4 4.95 5.49
50 0.717 0.823 0.876 1.142 1.408 1.674 2.21 2.74 3.8 4.33 4.87 5.4
60 0.7 0.804 0.856 1.116 1.376 1.636 2.16 2.68 3.72 4.24 4.76 5.28
70 0.687 0.789 0.84 1.095 1.35 1.605 2.12 2.63 3.65 4.16 4.67 5.18
80 0.674 0.774 0.824 1.075 1.325 1.575 2.08 2.58 3.58 4.08 4.58 5.08
90 0.662 0.76 0.809 1.055 1.301 1.547 2.04 2.53 3.51 4 4.5 4.99
100 0.65 0.747 0.795 1.036 1.278 1.519 2 2.48 3.45 3.93 4.42 4.9
120 0.628 0.721 0.768 1.001 1.234 1.467 1.933 2.4 3.33 3.8 4.26 4.73
140 0.607 0.697 0.742 0.967 1.193 1.418 1.868 2.32 3.22 3.67 4.12 4.57
150 0.597 0.686 0.73 0.951 1.173 1.395 1.838 2.28 3.17 3.61 4.05 4.5
200 0.552 0.634 0.675 0.879 1.084 1.289 1.698 2.11 2.93 3.34 3.75 4.16
250 0.513 0.589 0.627 0.817 1.088 1.198 1.579 1.959 2.72 3.1 3.48 3.86
300 0.479 0.55 0.586 0.764 0.941 1.119 1.475 1.83 2.54 2.9 3.25 3.61
400 0.423 0.486 0.518 0.675 0.832 0.989 1.303 1.618 2.25 2.56 2.87 3.19
500 0.379 0.436 0.464 0.604 0.745 0.886 1.167 1.449 2.01 2.29 2.58 2.86
600 0.343 0.394 0.42 0.547 0.675 0.802 1.057 1.312 1.822 2.08 2.33 2.59
   
1) Density is based on atmospheric pressure 14.696 psia and molecular weight of air 28.97
density - 1 lb/ft3 = 16.018 kg/m3
pressure - 1 psi (lb/in2) = 6,894.8 Pa (N/m2)
temperature - T(oC) = 5/9[T(oF) - 32]
Unit Converter
Density of air can also be expressed as
ρ = 1.325 pin Hg / TR         (1)  
where
ρ = density (lb/ft3)
pin Hg = pressure (inches Hg)  
TR = absolute temperature (Rankine)