118
TECHNICAL RESOURCES
Conversion Tables
The fluid transfer community uses both the International System of Units (Metric
System) and the U.S. Customary System, often simultaneously — which frequently
creates confusion.
CONVERSION FACTORS
For dimensions, this catalog generally uses the U.S. Customary System in fractional
form (1/16”) or decimal form (.062”). Pressures are listed in pounds per square
inch (psi). However, pore sizes and volumes are most often expressed in the
Metric System as microns (µm) or microliters (µL), respectively.
Conversion Desired
Inches to millimeters
Inches to centimeters
Inches to microns
Diameter in inches to linear volume (µL/inch)
The tables on these two pages provide easy cross-referencing of commonly used
Diameter in inches to linear volume (µL/cm)
Celsius to Fahrenheit
Fahrenheit to Celsius
psi to bar
psi to MPa
psi to torr
psi to ATM
TUBING INTERNAL DIAMETERS AND VOLUMES
Inches Wire Gauge*
0.001
—
0.002
—
0.0025
—
0.003
—
0.004
36
0.005
35
0.006
—
0.007
34
0.008
33
0.009
32
0.010
31
0.011
—
0.012
30
0.013
29
0.014
28
0.015
—
0.016
27
0.017
—
0.018
26
0.019
—
0.020
25
0.028
22
0.030
—
0.032
21
0.040
—
0.042
19
0.055
—
0.062
—
Millimeters
0.025
0.051
0.064
0.076
0.102
0.127
0.152
0.178
0.203
0.229
0.254
0.279
0.305
0.330
0.356
0.381
0.406
0.432
0.457
0.483
0.508
0.711
0.762
0.813
1.016
1.067
1.397
1.575
Microns
25
51
64
76
102
127
152
178
203
229
254
279
305
330
356
381
406
432
457
483
508
711
762
813
1016
1067
1397
1575
Volume µL/in
0.013
0.051
0.081
0.116
0.206
0.322
0.463
0.631
0.824
1.042
1.287
1.557
1.853
2.175
2.523
2.896
3.295
3.720
4.170
4.646
5.148
10.090
11.583
13.179
20.593
22.703
38.933
49.474
Volume µL/cm
0.005
0.020
0.032
0.046
0.081
0.127
0.182
0.248
0.324
0.410
0.507
0.613
0.730
0.856
0.993
1.140
1.297
1.464
1.642
1.829
2.027
3.973
4.560
5.189
8.107
8.938
15.328
19.478
* Wire Gauge numbers are referencing Birmingham or Stub’s Iron Wire Gauge values, which are
commonly used by most stainless steel syringe manufacturers.
Formula
Inches x 25.4 mm/in.
Inches x 2.54 cm/in.
Inches x 25.4 mm/in. x 1000 µm/mm
(Inches/2) x 2.54cm/in.)2 x 3.14
x 2.54cm/in. x 1000 µL/cm3
(Inches/2) x 2.54cm/in.)2 x 3.14
x 1 cm/cm x 1000 µL/cm3
(Celsius x 9/5) + 32
(Fahrenheit - 32) x 5/9
psi x 0.06894757
psi x 0.00689476
psi x 51.7150733
psi x 0.06804596
TEMPERATURE
Celsius (oC)
0
1
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
105
110
115
120
125
130
135
140
145
150
155
160
165
170
175
180
185
190
195
200
205
210
215
Fahrenheit(oF)
32
34
41
50
59
68
77
86
95
104
113
122
131
140
149
158
167
176
185
194
203
212
221
230
239
248
257
266
275
284
293
302
311
320
329
338
347
356
365
374
383
392
401
410
419
119
TECHNICAL RESOURCES
Conversion Tables
DIMENSIONS: INCHES TO METRIC
Decimal Inches
0.031”
0.062”
0.125”
0.188”
0.250”
0.313”
0.375”
0.438”
0.500”
0.563”
0.625”
0.688”
0.750”
0.813”
0.875”
0.938”
1”
2”
3”
4”
5”
6”
7”
10”
Fractional Inches
1/32”
1/16”
1/8”
3/16”
1/4”
5/16”
3/8”
7/16”
1/2”
9/16”
5/8”
11/16”
3/4”
13/16”
7/8”
15/16”
1”
2”
3”
4”
5”
6”
7”
10”
PRESSURE CONVERSION
Metric
0.79mm
1.57mm
3.18mm
4.78mm
6.35mm
7.95mm
9.53mm
11.13mm
12.70mm
14.30mm
15.88mm
17.48mm
19.05mm
20.65mm
22.23mm
23.83mm
2.54cm
5.08cm
7.62cm
10.16cm
12.70cm
15.24cm
17.78cm
25.40cm
psi
100
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
4,500
5,000
5,500
6,000
6,500
7,000
7,500
8,000
8,500
9,000
10,000
bar
6.9
34.5
68.9
103.4
137.9
172.4
206.8
241.3
275.8
310.3
344.7
379.2
413.7
448.2
482.6
517.1
551.6
586.1
620.5
689.5
MPa
0.7
3.4
6.9
10.3
13.8
17.2
20.7
24.1
27.6
31.0
34.5
37.9
41.4
44.8
48.3
51.7
55.2
58.6
62.1
68.9
ATM
6.8
34.0
68.0
102.1
136.1
170.1
204.1
238.2
272.2
306.2
340.2
374.3
408.3
442.3
476.3
510.3
544.4
578.4
612.4
680.5
To calculate the theoretical pressure drop along a length of tubing,
use the following formula:
P = (( F x 8 x L x V )/( π x r 4 )) x 2.42 x 10 -9
Where:
DIMENSIONS: METRIC TO INCHES
Metric
1.0mm
1.8mm
2.0mm
3.0mm
3.2mm
4.0mm
4.3mm
4.6mm
5.0mm
6.0mm
7.0mm
8.0mm
9.0mm
1.0cm
2.0cm
3.0cm
4.0cm
5.0cm
6.0cm
7.0cm
8.0cm
9.0cm
10.0cm
Decimal Inches
0.039”
0.071”
0.079”
0.118”
0.126”
0.157”
0.169”
0.181”
0.197”
0.236”
0.276”
0.315”
0.354”
0.394”
0.787”
1.181”
1.575”
1.969”
2.362”
2.756”
3.150”
3.543”
3.937”
F = flow rate in mL/min.
L = tubing length in cm
V = viscoscity in centipoise (cp)
r = tubing inside radius in cm
WHAT THREADS DO I HAVE?
Hold your fitting over the thread silhouettes below to identify the threads.
U.S. CUSTOMARY THREADS
6•32
10•32
1/4•28
5/16•24
1/2•20
METRIC THREADS
M6
M8X1
Please see page 3 for assistance in finding fittings in this catalog. Refer to page 122 for an explanation of
thread nomenclature.