PIPES, FITTINGS, AND VALVES
Excerpt from “Handbook for Chemical Technicians” by Howard Strauss and Milton Kaufman, McGraw Hill and from the ‘Valve Handbook’ by Philip Skousen, McGraw Hill.
Piping systems are constructed from straight-run piping, fittings to change direction and size, and valves to control flow rate. A large variety of standard pipes and fittings are available. When selecting piping or fittings, one must consider factors such as corrosion, resistance, pressure and temperature that will have to be endured.
Connecting Pipes and Fittings:
Pipes and fittings are connected by welded, threaded, flared, compressed, sweated (soldered) and glued (solvent welded) joints.
In general, welded joints and flangedjoints (shown later) are used for large diameter pipe (> 2 in), while threaded joints are used for smaller diameter pipe. Flared, compressed, soldered joints are used for small-diameter copper and brass tubing. See Figure 1.
Piping
Iron and steel piping comes in a number of ‘schedules’, or wall thicknesses, to accommodate various maximum pressures. See Tables 1 to 6.
Schedule / Wrought iron / SteelMax
allowable
pressure
(lb/in2) / Normal
design
max
(lb/in2) / Max
allowable
pressure
(lb/in2) / Normal
design
max
(lb/in2)
10 / 50 / 25 / 75 / 50
20 / 100 / 50 / 150 / 75
30 / 150 / 75 / 200 / 100
40 / 25Q / 125 / 300 / 150
60 / 350 / 200 / 450 / 250
80 / 450 / 250 / 600 / 300
100 / 600 / 300 / 700 / 350
120 / 700 / 350 / 900 / 450
140 / 800 / 400 / 1,000 / 500
160 / 900 / 450 / 1,200 / 600
TABLE II Dimensions of Wrought-Iron or Steel Pipe
Diameters / Thick- ness(in) / Circumference / Transverse areas / Length of pipe/ft / Length of pipe holding
1 ft3 (ft) / Wt./ft
plain ends
(lb) / Wt. of water/ft (lb)
Size (in) / External (in) / Internal (in) / External (in) / Internal, (in) / External
(in2) / Internal
(in2) / Metal
(in2) / External
Surface
(ft) / Internal
Surface
(ft)
SCHEDULE 40 (ST –STANDARD WALL)
1/8 / 0.405 / 0.269 / 0.068 / 1.272 / 0.845 / 0.129 / 0.057 / 0.072 / 9.431 / 14.199 / 2533.775 / 0.244 / 0.0251/4 / 0.540 / 0.364 / 0.088 / 1.696 / 1.144 / 0.229 / 0.104 / 0.125 / 7.073 / 10.493 / 1383.789 / 0.424 / 0.045
3/8 / 0.675 / 0.493 / 0.091 / 2.121 / 1.549 / 0.358 / 0.191 / 0.167 / 5.658 / 7.747 / 754.360 / 0.567 / 0.083
1/2 / 0.840 / 0.622 / 0.109 / 2.639 / 1.954 / 0.554 / 0.304 / 0.250 / 4.547 / 6.141 / 473.906 / 0.850 / 0.132
3/4 / 1.050 / 0.824 / 0.113 / 3.299 / 2.589 / 0.866 / 0.533 / 0.333 / 3.637 / 4.635 / 270.034 / 1.130 / 0.231
1 / 1.315 / 1.049 / 0.133 / 4.131 / 3.296 / 1.358 / 0.864 / 0.494 / 2.904 / 3.641 / 166.618 / 1.678 / 0.375
1 ¼ / 1.660 / 1.380 / 0.140 / 5.215 / 4.335 / 2.164 / 1.495 / 0.669 / 2.301 / 2.767 / 96.275 / 2.272 / 0.65
1 ½ / 1.900 / 1.610 / 0.145 / 5.969 / 5.058 / 2.835 / 2.036 / 0.799 / 2.010 / 2.372 / 70.733 / 2.717 / 0.88
2 / 2.375 / 2.067 / 0.154 / 7.461 / 6.494 / 4.430 / 3.355 / 1.075 / 1.608 / 1.847 / 42.913 / 3.652 / 1.45
2 ½ / 2.875 / 2.469 / 0.203 / 9.032 / 7.757 / 6.492 / 4.788 / 1.704 / 1.328 / 1.547 / 30.077 / 5.793 / 2.07
3 / 3.500 / 3.068 / 0.216 / 10.996 / 9.638 / 9.621 / 7.393 / 2.228 / 1.091 / 1.245 / 19.479 / 7.575 / 3.20
3 ½ / 4.000 / 3.548 / 0.226 / 12.566 / 11.146 / 12.566 / 9.886 / 2.680 / 0.954 / 1.076 / 14.565 / 9.109 / 4.29
4 / 4.500 / 4.026 / 0.237 / 14.137 / 12.648 / 15.904 / 12.730 / 3.174 / 0.848 / 0.948 / 11.312 / 10.790 / 5.50
4 ½ / 5.000 / 4.506 / 0.247 / 15.708 / 14.156 / 19.635 / 15.947 / 3.688 / 0.763 / 0.847 / 9.030 / 12.5.38 / 6.91
5 / 5.563 / 5.047 / 0.258 / 17.477 / 15.856 / 24.306 / 20.006 / 4.300 / 0.686 / 0.756 / 7.198 / 14.617 / 8.67
6 / 6.625 / 6.065 / 0.280 / 20.813 / 19.054 / 34.4 72 / 28.891 / 5.581 / 0.576 / 0.629 / 4.984 / 18.974 / 12.51
7 / 7.625 / 7.023 / 0.301 / 23.955 / 22.063 / 45.664 / 38.738 / 6.926 / 0.500 / 0.543 / 3.717 / 23.544 / 16.80
8 / 8.625 / 8.071 / 0.277 / 27.096 / 25.356 / 58.426 / 51.161 / 7.265 / 0.442 / 0.473 / 2.815 / 24.696 / 22.18
8 / 8.625 / 7.981 / 0.322 / 27.096 / 25.073 / 58.426 / 50.027 / 8.399 / 0.442 / 0.478 / 2.878 / 28.554 / 21.70
9 / 9.625 / 8.941 / 0.342 / 30.238 / 28.089 / 72.760 / 62.786 / 9.974 / 0.396 / 0.427 / 2.294 / 33.907 / 27.20
10 / 10.750 / 10.192 / 0.279 / 33.772 / 32.019 / 90.763 / 81.585 / 9.178 / 0.355 / 0.374 / 1.765 / 31.201 / 35.37
10 / 10.750 / 10.136 / 0.307 / 33.772 / 31.843 / 90.763 / 80.091 / 10.072 / 0.355 / 0.376 / 1.785 / 34.240 / 34.95
10 / 10.750 / 10.020 / 0.365 / 33.772 / 31.479 / 90.76:3 / 78.855 / 11.908 / 0.355 / 0.381 / 1.826 / 40.483 / 34.20
11 / 11.750 / 11.000 / 0.375 / 36.914 / 34.558 / 108.434 / 95.033 / 13.401 / 0.325 / 0.347 / 1.515 / 45.557 / 41.20
12 / 12.750 / 12.090 / 0.330 / 40.055 / 37.982 / 127.676 / 114.800 / 12.876 / 0.299 / 0.315 / 1.254 / 43.773 / 49.70
12 / 12.750 / 12.000 / 0.375 / 40.055 / 37.699 / 127.676 / 113.097 / 14.579 / 0.299 / 0.318 / 1.273 / 49.562 / 49.00
TABLE II (Cont’d) Dimensions of Wrought-Iron or Steel Pipe
Diameters / Thick- ness(in) / Circumference / Transverse areas / Length of pipe/ft / Length of pipe holding
1 ft3 (ft) / Wt./ft
plain ends
(lb) / Wt. of water/ft (lb)
Size (in) / External (in) / Internal (in) / External (in) / Internal, (in) / External
(in2) / Internal
(in2) / Metal
(in2) / External
Surface
(ft) / Internal
Surface
(ft)
SCHEDULE 80 (XS–EXTRA STRONG WALL)
1/8 / 0.405 / 0.215 / 0.095 / 1.272 / 0.676 / 0.129 / 0.036 / 0.093 / 9.431 / 17.766 / 3966.392 / 0.314 / 0.0161/4 / 0.540 / 0.302 / 0.1l9 / 1.696 / 0.949 / 0.229 / 0.072 / 0.157 / 7.073 / 12.648 / 2010.290 / 0.535 / 0.031
3/8 / 0.675 / 0.423 / 0.126 / 2.121 / 1.329 / 0.358 / 0.141 / 0.217 / 5.658 / 9.030 / 1024.689 / 0.738 / 0.061
1/2 / 0.840 / 0.546 / 0.147 / 2.639 / 1.715 / 0.554 / 0.234 / 0.320 / 4.547 / 6.995 / 615.017 / 1.087 / 0.102
3/4 / 1.050 / 0.742 / 0.154 / 3.299 / 2.331 / 0.866 / 0.433 / 0.433 / 3.637 / 5.147 / 333.0l6 / 1.473 / 0.188
1 / 1.315 / 0.957 / 0.179 / 4.131 / 3.007 / 1.358 / 0.719 / 0.639 / 2.904 / 3.991 / 200.193 / 2.171 / 0.312
1 ¼ / 1.660 / 1.278 / 0.191 / 5.215 / 4.015 / 2.164 / 1.283 / 0.881 / 2.301 / 2.988 / 112.256 / 2.996 / 0.56
1 ½ / 1.900 / 1.500 / 0.200 / 5.969 / 4.712 / 2.835 / 1.767 / 1.068 / 2.010 / 2.546 / 81.487 / 3.631 / 0.77
2 / 2.375 / 1.939 / 0.218 / 7.461 / 6.092 / 4.430 / 2.953 / 1.477 / 1.608 / 1.969 / 48.766 / 5.022 / 1.28
2 ½ / 2.875 / 2.323 / 0.276 / 9.032 / 7.298 / 6.492 / 4.238 / 2.254 / 1.328 / 1.644 / 33.976 / 7.661 / 1.87
3 / 3.500 / 2.900 / 0.300 / 10.996 / 9.111 / 9.621 / 6.605 / 3.016 / 1.091 / 1.317 / 21.801 / 10.252 / 2 .86
3 ½ / 4.000 / 3.364 / 0.318 / 12.566 / 10.568 / 12.566 / 8.888 / 3.678 / 0.954 / 1.135 / 16.202 / 12.505 / 3.84
4 / 4.500 / 3.820 / 0.337 / 14.137 / 12.020 / 15.904 / 11.497 / 4.407 / 0.848 / 0.998 / 12.525 / 14.983 / 4.98
4 ½ / 5.000 / 4.290 / 0.355 / 15.708 / 13.477 / 19.635 / 14.455 / 5.180 / 0.763 / 0.890 / 9.962 / 17.611 / 6.27
5 / 5.503 / 4.813 / 0.375 / 17.477 / 15.120 / 24.306 / 18.194 / 6.112 / 0.686 / 0.793 / 7.915 / 20.778 / 7.88
6 / 6.625 / 5.761 / 0.432 / 20.813 / 18.099 / 34.472 / 26.067 / 8.405 / 0.576 / 0.663 / 5.524 / 28.573 / 1l.29
7 / 7.625 / 6.625 / 0.500 / 23.955 / 20.813 / 45.664 / 34.4 72 / 11.192 / 0.500 / 0.576 / 4.177 / 38.048 / 14.95
8 / 8.625 / 7.625 / 0.500 / 27.096 / 23.955 / 58.426 / 45.663 / 12.763 / 0.442 / 0.500 / 3.154 / 43.388 / 19.78
9 / 9.625 / 8.625 / 0.500 / 30.238 / 27.096 / 72.760 / 58.426 / 14.334 / 0.396 / 0.442 / 2.464 / 48.728 / 25.30
10 / 10.750 / 9.750 / 0.500 / 33.772 / 30.631 / 90.763 / 74.662 / 16.101 / 0.355 / 0.391 / 1.929 / 54.735 / 32.35
11 / l1.750 / 10.750 / 0.500 / 36.914 / 33.772 / 108.434 / 90.763 / 17.671 / 0.325 / 0.355 / 1.587 / 60.076 / 39.40
12 / l2.750 / 11.750 / 0.500 / 40.055 / 36.914 / 127.676 / 108.434 / 19.242 / 0.209 / 0.325 / 1.328 / 65.415 / 46.92
TABLE II (Cont’d) Dimensions of Wrought-Iron or Steel Pipe
Diameters / Thick- ness(in) / Circumference / Transverse areas / Length of pipe/ft / Length of pipe holding
1 ft3 (ft) / Wt./ft
plain ends
(lb) / Wt. of water/ft (lb)
Size (in) / External (in) / Internal (in) / External (in) / Internal, (in) / External
(in2) / Internal
(in2) / Metal
(in2) / External
Surface
(ft) / Internal
Surface
(ft)
SCHEDULE 160 (XX –DOUBLE EXTRA STRONG WALL)
1/2 / 0.840 / 0.252 / 0.294 / 2.639 / 0.792 / 0.554 / 0.050 / 0.504 / 4.547 / 15.157 / 2887.164 / 1.714 / 0.0223/4 / 1.050 / 0.434 / 0.308 / 3.299 / 1.363 / 0.866 / 0.148 / 0.718 / 3.637 / 8.801 / 973.404 / 2.440 / 0.064
1 / 1.315 / 0.599 / 0.358 / 4.131 / 1.882 / 1.358 / 0.282 / 1.076 / 2.904 / 6.376 / 510.998 / 3.659 / 0.122
1 ¼ / 1.600 / 0.890 / 0.382 / 5.215 / 2.815 / 2.164 / 0.630 / 1.534 / 2.301 / 4.263 / 228.379 / 5.214 / 0.273
1 ½ / 1.900 / 1.100 / 0.400 / 5.969 / 3.456 / 2.835 / 0.950 / 1.885 / 2.010 / 3.472 / 151.526 / 6.408 / 0.42
2 / 2.375 / 1.503 / 0.436 / 7.461 / 4.722 / 4.430 / 1.774 / 2.656 / 1.608 / 2.541 / 81.162 / 9.029 / 0.77
2 ½ / 2.875 / 1.771 / 0.552 / 9.032 / 5.564 / 6.492 / 2.464 / 4.028 / 1.328 / 2.156 / 58.457 / 13.695 / 1.07
3 / 3.500 / 2.300 / 0.600 / 10.996 / 7.226 / 9.621 / 4.155 / 5.466 / 1.091 / 1. 660 / 34.659 / 18.583 / 1.80
3 ½ / 4.000 / 2.728 / 0.636 / 12.566 / 8.570 / 12.566 / 5.845 / 6.721 / 0.954 / 1.400 / 24.637 / 22.850 / 2.53
4 / 4.500 / 3.152 / 0.674 / 14.137 / 9.902 / 15.904 / 7.803 / 8.101 / 0.848 / 1.211 / 18.454 / 27.541 / 3.38
4 ½ / 5.000 / 3.580 / 0.710 / 15.708 / 11.247 / 19.635 / 10.066 / 9.569 / 0.763 / 1.066 / 14.306 / 32.530 / 4.36
5 / 5.563 / 4.06:3 / 0.750 / 17.477 / 12.764 / 24.306 / 12.966 / 11.340 / 0.686 / 0.940 / 11.107 / 38.552 / 5.61
6 / 6.625 / 4.897 / 0.864 / 20.813 / 15.384 / 34.472 / 18.835 / 15.637 / 0.576 / 0.780 / 7.640 / 53.160 / 8.16
7 / 7.625 / 5.875 / 0.875 / 23.955 / 18.457 / 45.664 / 27.109 / 18.555 / 0.500 / 0.650 / 5.312 / 63.079 / 11.75
8 / 8.625 / 6.875 / 0.875 / 27.096 / 21.598 / 58.426 / 37.122 / 21.304 / 0.442 / 0.555 / 3.879 / 72.424 / 16.10
Note that the dimensions of only the 3 most common wall strengths (schedule 40, 80 and 120) are given.
“Nominal Pipe Size” (NPS) is the older system and refers to valve and pipe sizes. It is controlled by the American National Standards Institute (ANSI). For pipes up to 12 inches, NPS refers approximately to internal diameter (ID). For pipes larger than 12 inches, NPS values refers approximately to outside diameter (OD). ANSI pressure specifications are given in psi.
In many countries outside US and Canada, the pipe size is based on the International System of Units (metric system) established by the International Standards Organization (ISO). In the ISU system, pipe diameters are referred to as ‘Nominal Diameters’ (DN) in units of mm or cm, and pressure ratings are referred to as Nominal Pressure (PN) in units of kPa or bars.
For example, an ANSI 1 inchdiameter, 150 psi NPS pipe is equivalent to an ISO 25 mm DN, 16 bar PN.
PIPES AND FITTINGS (STRAUSS & KAUFMAN)PAGE 1 OF 12
TABLE III Flow Capacities of Iron/Steel Pipe
Capacity at velocity of 1 ft/sNominal
size
(in) / ST (Sch 40) / XS (Sch 80) / XX (Sch 160)
gal/min / lb H2O/h / gal/min / lb H2O/h / gal/min / lb H2O/h
1/8 / 0.179 / 89.5 / 0.113 / 56.6
1/4 / 0.323 / 162 / 0.224 / 112
3/8 / 0.596 / 298 / 0.440 / 220
1/2 / 0.945 / 472 / 0.730 / 365 / 0.158 / 79.2
3/4 / 1. 665 / 833 / 1.345 / 673 / 0.460 / 230
1 / 2.69 / 1,345 / 2.240 / 1,120 / 0.878 / 439
1 ¼ / 4.57 / 2,285 / 3.99 / 1,995 / 1.97 / 983
1 ½ / 6.34 / 3,170 / 5.49 / 2,745 / 3.02 / 1,512
2 / 10.45 / 5,225 / 9.20 / 4,600 / 5.54 / 2,772
2 ½ / 14.92 / 7,460 / 13.20 / 6,600 / 7.70 / 3,852
3 / 23.00 / 11,500 / 20.55 / 10,275 / 12.96 / 6,480
3 ½ / 30.80 / 15,400 / 27.70 / 13,850 / 18.22 / 9,108
4 / 39.6 / 19,800 / 35.80 / 17,900 / 24.34 / 12,168
4 ½ / 31.39 / 15,696
5 / 62.3 / 31,150 / 57.7 / 28,850 / 40.39 / 20,196
6 / 90.0 / 45,000 / 81.1 / 40,550 / 58.75 / 29,376
7 / 84.60 / 42,300
8 / 155.7 / 79,800 / 142 / 71,200 / 116 / 57,960
8 / 152.4 / 78,100
9 / 191.0 / 97,900 / 182 / 91,100
10 / 248.4 / 127,300 / 233 / 116,500
10 / 245.5 / 125,800
10 / 240.2 / 123,100
11 / 289.4 / 148,300 / 284 / 141,800
12 / 290.6 / 178,900 / 338 / 168,900
12 / 286.5 / 176,400
Nomi-
nal
size / Actual
outside
diam., in. / Mean outside diam.
tolerances, in. / Wall thickness, in. / Theoretical weight, lb/ft.
Type K / Type L / Type M
Soft annealed / Hard drawn / Nominal / Tolerance / Nominal / Tolerance / Nominal / Tolerance / Type K / Type L / Type M
1/8 / 0.375 / 0.002 / 0.001 / 0.035 / 0.004 / 0.030 / 0:0035 / ….. / ….. / 0.145 / 0.126 / …..
1/4 / .500 / .0025 / .001 / .049 / .004 / .035 / .0035 / 0.025 / 0:0025 / .269 / .198 / 0.145
3/8 / .625 / .0025 / .001 / .049 / .004 / .040 / .0035 / .028 / .0025 / .344 / .285 / .204
1/2 / .750 / .0025 / .001 / .049 / .004 / .042 / .0035 / ….. / ….. / .418 / .362 / …..
3/4 / .875 / .003 / .001 / .065 / .0045 / .045 / .004 / .032 / .003 / .641 / .455 / .328
1 / 1.125 / .0035 / .0015 / .065 / .0045 / .050 / .004 / .035 / .0035 / .839 / .655 / .465
1 ¼ / 1.375 / .004 / .0015 / .065 / .005 / .055 / .0045 / .1142 / .0035 / 1.04 / .884 / .682
1 ½ / 1.625 / .0045 / .002 / .072 / .005 / .060 / .0045 / .049 / .004 / 1.36 / 1.14 / .940
2 / 2.125 / .005 / .002 / .083 / .007 / .070 / .006 / .058 / .006 / 2.06 / 1.75 / 1.46
2 ½ / 2.625 / .005 / .002 / .095 / .007 / .080 / .006 / .065 / .006 / 2.93 / 2.48 / 2.03
3 / 3.125 / .005 / .002 / .109 / .007 / .090 / .007 / .072 / .006 / 4.00 / 3.33 / 2.68
3 ½ / 3.625 / .005 / .002 / .120 / .008 / .100 / .007 / .083 / .007 / 5.12 / 4.29 / 3.58
4 / 4.125 / .005 / .002 / .134 / .010 / .110 / .009 / .095 / .009 / 6.51 / 5.38 / 4.66
5 / 5.125 / .005 / .002 / .160 / .010 / .125 / .010 / .109 / .009 / 9.67 / 7.61 / 6.66
6 / 6.125 / .005 / .002 / .192 / .012 / .140 / .011 / .122 / .010 / 13.9 / 10.2 / 8.92
+ / -
8 / 8.125 / .006 / .002 .004 / .271 / .016 / .200 / .014 / .170 / .014 / 25.9 / 19.3 / 16.5
10 / 10.125 / .008 / .002 .006 / .338 / .018 / .250 / .016 / .212 / .015 / 40.3 / 30.1 / 25.6
12 / 12.125 / .008 / .002 .006 / .405 / .020 / .280 / .018 / .254 / .016 / 57.8 / 40.4 / 36.7
TABLEIV Dimensions of Copper Water Tubing
Adapted from Robert H. Perry and Cecil H. Chilton (eds.), "Chemical Engineers' Handbook," 5th ed., McGraw-Hill Book Company, New York, 1973.
Nominalsize / Actual
outside
diam.
(in) / Mean
outside
diam.
tolerances (in) / Wall
thickness
(in) / Wall-
thickness
tolerances
(in) / Nominal
wt.
(lb/ft)
1/8 / 0.125 / 0.002 / 0.030 / 0.003 / 0.0347
3/16 / 0.188 / 0.002 / 0.030 / 0.0025 / 0.575
1/4 / 0.250 / 0.002 / 0.030 / 0.0025 / 0.0804
5/16 / 0.312 / 0.002 / 0.032 / 0.0025 / 0.109
3/8 / . 0.375 / 0.002 / 0.032 / 0.0025 / 0.134
1/2 / 0.500 / 0.002 / 0.032 / 0.0025 / 0.182
5/8 / 0.625 / 0.002 / 0.035 / 0.003 / 0.251
3/4 / 0.750 / 0.0025 / 0.035 / 0.003 / 0.305
Inside diam. (in) / Outside diam. (in) / Wall thickness (in) / Weight per ft (lb)
1 / 1.31 / 0.156 / 0.55
1.5 / 1.84 / 0.171 / 0.87
2 / 2.34 / 0.171 / 1.13
3 / 3.41 / 0.202 / 1.97
4 / 4.50 / 0.264 / 3.41
6 / 6.66 / 0.328 / 6.30
Common Industrial Valves
Valves are mechanical devices designed to start, stop, direct, or regulate flow of a process fluid. Valves come in a variety of sizes.
The smallest industrial valves can weigh as little as 1 lb (454 g) and fit comfortably in the human hand, while the largest can weigh up to 10 tons (9070 kg) and extend in height over 24 ft (6.1 m).
Industrial valves can be used with pipeline sizes less than 0.5 in to beyond 48 in..
Valves can be used in pressures from full vacuum (-1 atmgage) to over 13,000 psi (885 atm)
Valves are manufactured from a number of materials, the most common materials being steel, iron, plastic, brass (alloy of Cu and Zn), bronze (alloy of Cu and Sn), and special alloys.
Some common types of industrial valves are shown in Figure 2. The dotted lines show the position of an open valve. Vertical and circular arrows show the motion of the valve stems.
Figure 2. Common Industrial Valves
Valve Classification According to Function
Valves are categorized into three functions:
- on-off valves, which block or allow flow (fully closed or fully open) but are not used for throttling (regulating) flow
- non-return valves, which allow flow in only one direction
- throttling valves, which regulate flow at any point between fully open and fully closed.
On-Off Valves
Gate valves and pressure relief valvesare exclusively used for on-off control. Plug valves and ball valves are most often used as on-off valves but can be used for throttling service.
On-off valves are used where the flow must be diverted around an area in which maintenance is being performed. Safety regulations also require on-off valves to immediately shut off a system when an emergency situation occurs.
Pressure relief valves are self-actuated valves that open only when a preset pressure is exceeded. Pressure relief valves are discussed in more detail in the document ‘PIPES, FITTINGS AND VALVES by Schmidt.
Non-Return Valves
Non-return valves allow fluid flow in only the desired direction. Preventing back flow is particularly important with corrosive or dirty fluids that could otherwise damage equipment or spoil product quality.
All check valves are non-return valves. The swing check valve, lift check valve and the ball check valve are discussed in more detail in the document ‘PIPES, FITTINGS AND VALVES by Schmidt.
Check valves are easy to recognize since they have no external handle. They are self-actuating.
Throttling Valves
Throttling valves allow adjustable flow metering from fully open to fully closed. They are often used to regulate flow, temperature or pressure of a process. Globe valves, butterfly valves, and diaphragm valves are common examples. The angle valve (Fig. 2) is a modified globe valve.
Handling Slurries
When slurries are being handled, there is a potential for deposition of solids that hinder or prevent valve operation. This is particularly problematic in valves that have high pressure drops (due to abrupt changes in direction of fluid flow). The globe valve is an example of a valve that will become be plugged by slurries. Valves with straight-through flow (low pressure drop) are best for handling slurries. These include ball valves, plug valves, butterfly valves and diaphragm valves. Look at the flow path (indicated by the arrows) in the valves in Fig. 2.
WORKBOOK FOR PIPES, FITTINGS AND VALVES by Strauss
STEP 2:
Read the excerpt from “Handbook for Chemical Technicians” by Howard J. Strauss and answer the following questions in the spaces provided.
- A pipeline is to carry water at a pressure of 200 psi. Would schedule 40 steel pipe be suitable for this service? Give reasons for your answer. Refer to Table I
- A pipeline is to be loaded to a maximum pressure of 500 psi. What schedule of steel pipe should be used for this service? Justify your answer with reasons.
- When referring to pipe we say 2 in., 2 ½ in., 3 in. etc. and this is called the nominal size. Does nominal size refer to the inside diameter (I.D.) or outside diameter (O.D.) of the pipe?
up to 12 “ diameter ………………………………………………..
above 12” diameter ………………………………………………… - Considering a nominal size of 3 in. pipe, complete the following table for wrought-iron or steel pipe. Refer to Table II.
What do you note about the dimensions of a 3 in. pipe?
- Pipe tables provide much useful information. Complete the following using Table II.
a)What is the external diameter of a 1 in. sch. 40 steel pipe? ………………………
b)What is the I.D. of a 2 in. sch. 40 steel pipe? ………………………………………
c)What is the thickness of a 5 in. sch. 40 steel pipe? ……………………………….
d)What is the external circumference of a 1 in. sch. 80 steel pipe? ……………………..
e)What is the internal circumference of a 2 in. sch. 80 steel pipe? ………………….
f)A fluid is flowing in a 3 in. sch. 40 steel pipe. What is the cross-sectional area of flow in this system? ……………………………………………………………..
g)The pipe in f) is changed to sch. 80; what is the new cross-sectional area of flow?
…………………………………………………………………
h)What is the weight of a 20 ft. section of 5 in. sch. 40 pipe?
i)A 3 in. sch. 80 steel pipe is carrying water at 200 psi. What is the weight of water in a 100 ft. section of this pipe?
j)A 1 in. sch. 40 steel pipe is being used in a heating unit. It is required to have 16 sq. ft. of external surface on this pipe. What length of pipe should be used?
k)A 5 in. sch. 80 steel pipe is carrying a fluid through a plant. If the line is 250 ft. long, what volume of fluid is contained in the pipe?
- Refer to Table III to answer the following questions.
a)Note that the flow capacities are given in gal/min. and lb H2O/h. A 1 in. standard wall (sch. 40) iron pipe with a velocity of 1 ft/s can carry 2.690 gal/min or 1345 lb H2O/h. Are the gallons referred to as Imperial gallons or U.S. gallons? Justify your answer with calculations.
b)If the velocity is 2 ft/s, what is the flow capacity of a 1 in. standard iron pipe in lb H2O/h?
c)Is there a practical limit to the increase in the velocity and hence the flow capacity of a system? State reasons for your answer.
- Refer to Table IV.
a)How many types of copper water tubing are there?
b)What is one difference between these types?
- Compare Tables IV and V.
a)In what respects do general service copper tubing and copper water tubing differ?
b)With general-service water tubing, what is the relationship between nominal size and the external diameter?
Answers to questions on Strauss.
1.Schedule 40 steel pipe is designed for 150 psi and handles 300 psi max. Schedule 40 should be suitable by not recommended. Best to use Schedule 60 pipe
2.Schedule 80 pipe handles 600 psi max. Schedule 140 is designed for 500 psi. Use pipe that is designed to handle the working pressures. Avoid problems.
3.Up to 12”, nominal size = ID (for low pressure pipe)
For sizes larger than 12:, nominal size = OD.
4.
a)Fill out the table
b)3” is nominal not actual ID. ID decreases as schedule (thickness) increases. OD is constant. As thickness increases, internal volume decreases.
5.
a)1.315 in.
b)2.067 in
c)0.258 in
d)4.131 in
e)6.092 in
f)7.393 in2
g)6.605 in2
h)292 lb
i)286 lb H2O
j)46.5 ft
k)31.6 ft3
6.
a)Volumes are US gal.
b)2690 lb/h
c)Yes. Frictional resistance increases with fluid velocity and pressure drop increases with flow velocity. Increasing pressure drop will limit velocity.
7.
a)Three: Type K, Type L, and Type M.
b)They have different wall thickness and weight.
8.
a)Copper water tubing: actual OD > nominal size, ID nominal size.
General service Copper: actual OD = nominal size, ID < nominal size.
b)nominal size = OD
PIPES, FITTINGS, VALVES AND PUMPS (STRAUSS & KAUFMAN)PAGE 1 OF 53