86 / 204
NPT
Standard Weight
Extra Heavy Weight
Schedule 160
Double Extra Heavy
Pipe
Size
O.D.
Inch
O.D.
mm
I.D.
Inch
Wall
Inch
I.D.
mm
Wall
mm
I.D.
Inch
Wall
Inch
I.D.
mm
Wall
mm
I.D.
Inch
Wall
Inch
I.D.
mm
Wall
mm
I.D.
Inch
Wall
Inch
I.D.
mm
Wall
mm
1/8”
.41
10.4
.27
.068
6.9
1.7
.22
.095
5.6
2.4
-
-
-
-
-
-
-
-
1/4”
.54
13.7
.36
.088
9.1
2.2
.30
.119
7.6
3.0
-
-
-
-
-
-
-
-
3/8”
.68
17.2
.49
.091 12.4
2.3
.42
.126 10.7
3.2
-
-
-
-
-
-
-
1/2”
.84
21.3
.62
.109 15.7
2.8
.56
.147 14.0
3.7
.466 .187 11.8
4.7
.25
.29
6.4
7.4
3/4”
1.05
26.7
.82
.113 20.8
2.9
.74
.154 18.8
3.9
.614 .218 15.6
5.5
.43
.31 10.9
7.9
1”
1.32
33.5 1.05 .133 26.7
3.4
.96
.179 24.4
4.5
.815 .250 20.7
6.4
.60
.36 15.2
9.1
1 1/4”
1.66
42.2 1.38 .140 35.1
3.6 1.28 .191 32.5
4.9
1.16 .250 29.5
6.4
.90
.38 22.8
9.7
1 1/2”
1.90
48.3 1.61 .145 40.9
3.7 1.50 .200 38.1
5.1
1.34 .281 34.0
7.1
1.10 .40 27.98 10.2
2”
2.38
60.3 2.07 .154 52.6
3.9 1.94 .218 49.3
5.5
1.69 .343 42.9
8.7
1.50 .44 38.1 11.2
2 12”
2.88
73.0 2.47 .203 62.7
5.2 2.32 .276 59.0
7.0
2.13 .375 54.1
9.5
1.77 .55 45.0 14.0
3”
3.50
88.9 3.07 .216 77.9
5.5 2.90 .300 73.7
7.6
2.62 .438 66.5 11.1 2.30 .60 58.4 15.2
3 1/2”
4.00 101.6 3.55 .226 90.1
5.7 3.36 .318 85.4
8.1
-
-
-
-
2.73 .64 69.3 16.3
4”
4.50 114.3 4.03 .237 102.3 6.0 3.83 .337 97.2
8.6
3.44 .531 87.4 13.5 3.15 .67 80.1 17.0
5”
5.56 141.3 5.04 .258 128.0 6.6 4.81 .375 122.1 9.5
4.31 .625 109.4 15.9 4.06 .75 103.1 19.0
6”
6.63 168.3 6.07 .280 154.2 7.1 5.77 .432 146.6 10.7 5.19 .719 131.8 18.3 4.91 .86 124.7 21.8
8”
8.63 219.1 7.99 .322 202.9 8.2 7.63 .500 193.8 12.7 6.82 .906 173.2 23.0 6.87 .88 174.5 22.4
10”
10.75 273.1 10.02 .365 254.5 9.3 9.56 .594 242.8 15.1 8.50 1.125 215.9 28.6 8.75 1.00 222.3 25.4
12”
12.75 323.9 11.94 .406 303.3 10.3 11.37 .688 288.8 17.5 10.13 1.312 257.3 33.3 9.94 1.00 252.4 25.4
Metal Protection Tubes -
Some General Suggestions for Effective Metal Protection Tube Use:
√
Carefully select the proper protection tube alloy for your process to maximize the service life.
√
Use a thick walled tube, such as schedule 80, double extra heavy, or Richards heavy duty
SP
size for longer service life.
√
Use a thin walled tube such as schedule 40, or smaller O.D. tube if you require a quicker response time.
√
If the protection tube will be subject to severe mechanical shock or abrasion, use the Richards heavy duty
SP
size.
√
Protection tubes should be inserted into fluids a minimum of
six
times the O.D. of the tube.
√
Protection tubes should be inserted into gases a minimum of
eight
times to the O.D. of the tube.
√
Insertion lengths for furnaces and salt baths are typically a minimum of 6 inches (152.4 mm).
√
Protection tubes, which pass through a hot zone (muffle furnace), should be inserted at least 12 inches (304.8 mm).
√
In molten salt baths, angle assembilies tube lengths should be a minimum of 18” to protect the elbow from level changes.
√
If the elbow on angle assemblies will be subjected to high temperatures, an all alloy bent type tube should be used.
√
Replace all metal protection tubes on a regular basis, since they will become porous over time.
√
Never shorten the life of new thermocouple elements by placing them into old, worn-out, porous, protection tubes.
√
Protection tube overall lengths should be long enough to insure that the head temperature will not exceed
400°F
or
204°C
.
√
Use large O.D. or thick walled protection tubes where sagging is a problem at elevated temperatures.
√
Note that metal tubes are somewhat porious above
1500°F
or
815°C
, so in some cases a ceramic inner is also used.
Metal Tubes - Technical Information, Applications, and Suggestions
Page 86
Phone: 617.527.4385 Fax: 617.964.3746 Email:
sales@asrichards.comPipe Size Dimension Chart