Cast iron pipe

From Wikipedia, the free encyclopedia
Jump to: navigation, search

Cast iron pipe is a pipe which has had historic use as a pressure pipe for transmission of water, gas and sewage, and as a water drainage pipe during the 19th and 20th centuries. It comprises predominantly a gray cast iron tube and was frequently used uncoated, although later coatings and linings reduced corrosion and improve hydraulics. Cast iron pipe was superseded by ductile iron pipe, which is a direct development, with most existing manufacturing plants transitioning to the new material during the 1970s and 1980s. Little cast iron pipe is currently manufactured.

History[edit]

Early Use[edit]

The oldest extant water pipes date from the 17th century and were installed to distribute water throughout the gardens of the Chateau de Versailles. These amount to some 35 km of pipe, typically 1m lengths with flanged joints. The extreme age of these pipes make them of considerable historical value. Following extensive refurbishment in 2008 by Saint-Gobain PAM, 80% remain original.

The flanged joints of cast-iron drainpipe were sealed with oakum and molten-lead joints.

Manufacture[edit]

Horizontally Cast[edit]

The first cast iron pipe was produced in horizontal moulds, the core of the mould would be supported on small iron rods which would become part of the pipe. Horizontal casting resulted in an uneven distribution of metal around the pipe circumference. Typically slag would collect at the crown of the pipe creating a much weaker section.

Vertically Cast[edit]

In 1845, the first pipe was cast vertically in a pit and by the turn of the century, all pipe was manufactured by this method. Using this method the slag would all collect at the top of the casting and could be removed by simply cutting off the end of the pipe. Pipes cast using this method often suffered from off centre bores resulting in one side of the pipe being thicker than the opposite side, this was caused by the core of the mould being placed off centre.

Centrifugally Cast[edit]

Subsequent to its invention by Dimitri Sensaud deLavaud, a French-Brazilian, in 1918, much cast iron pipe manufacture shifted to the dramatically different technique of centrifugal casting. Modern ductile iron pipe production continues to use this method of casting.

Standardization[edit]

The first standardization of cast iron water pipes in Britain occurred in 1917 with the publishing of BS 78. This standard specified a dimensionless nominal size, which approximately corresponded with the internal diameter in inches of the pipe, and four pressure classes, Class A, Class B, Class C and Class D, each with a specified wall thickness and outer diameter. It is noted that the outer diameter is identical between classes with the exception of sizes 12 to 27, where Classes A and B share one diameter and Classes C and D have another, larger diameter.

Nominal Size Class
A & B A B C & D C D
Outer Diameter
[in (mm)]
Wall Thickness
[in (mm)]
Internal Diameter
[in (mm)]
Wall Thickness
[in (mm)]
Internal Diameter
[in (mm)]
Outer Diameter
[in (mm)]
Wall Thickness
[in (mm)]
Internal Diameter
[in (mm)]
Wall Thickness
[in (mm)]
Internal Diameter
[in (mm)]
3 3.76 (95.504) 0.38 (9.652) 3.00 (76.200) 0.38 (9.652) 3.00 (76.200) 3.76 (95.504) 0.38 (9.652) 3.00 (76.200) 0.40 (10.160) 2.96 (75.184)
4 4.80 (121.920) 0.39 (9.906) 4.02 (102.108) 0.39 (9.906) 4.02 (102.108) 4.80 (121.920) 0.40 (10.160) 4.00 (101.600) 0.46 (11.684) 3.88 (98.552)
5 5.90 (149.860) 0.41 (10.414) 5.08 (129.032) 0.41 (10.414) 5.08 (129.032) 5.90 (149.860) 0.45 (11.430) 5.00 (127.000) 0.52 (13.208) 4.86 (123.444)
6 6.98 (177.292) 0.43 (10.922) 6.12 (155.448) 0.43 (10.922) 6.12 (155.448) 6.98 (177.292) 0.49 (12.446) 6.00 (152.400) 0.57 (14.478) 5.84 (148.336)
7 8.06 (204.724) 0.45 (11.430) 7.16 (181.864) 0.45 (11.430) 7.16 (181.864) 8.06 (204.724) 0.53 (13.462) 7.00 (177.800) 0.61 (15.494) 6.84 (173.736)
8 9.14 (232.156) 0.47 (11.938) 8.20 (208.280) 0.47 (11.938) 8.20 (208.280) 9.14 (232.156) 0.57 (14.478) 8.00 (203.200) 0.65 (16.510) 7.84 (199.136)
9 10.20 (259.080) 0.48 (12.192) 9.22 (234.188) 0.49 (12.446) 9.22 (234.188) 10.20 (259.080) 0.60 (15.240) 9.00 (228.600) 0.69 (17.526) 8.82 (224.028)
10 11.26 (286.004) 0.52 (13.208) 10.22 (259.588) 0.52 (13.208) 10.22 (259.588) 11.26 (286.004) 0.63 (16.002) 10.00 (254.000) 0.73 (18.542) 9.80 (248.920)
12 13.14 (333.756) 0.55 (13.970) 12.04 (305.816) 0.57 (14.478) 12.00 (304.800) 13.60 (345.440) 0.69 (17.526) 12.22 (310.388) 0.80 (20.320) 12.00 (304.800)
14 15.22 (386.588) 0.57 (14.478) 14.08 (357.632) 0.61 (15.494) 14.00 (355.600) 15.72 (399.288) 0.75 (19.050) 14.22 (361.188) 0.86 (21.844) 14.00 (355.600)
15 16.26 (413.004) 0.59 (14.986) 15.08 (383.032) 0.63 (16.002) 15.00 (381.000) 16.78 (426.212) 0.77 (19.558) 15.24 (387.096) 0.89 (22.606) 15.00 (381.000)
16 17.30 (439.420) 0.60 (15.240) 16.10 (408.940) 0.65 (16.510) 16.00 (406.400) 17.84 (453.136) 0.80 (20.320) 16.24 (412.496) 0.92 (23.368) 16.00 (406.400)
18 19.38 (492.252) 0.63 (16.002) 18.12 (460.248) 0.69 (17.526) 18.00 (457.200) 19.96 (506.984) 0.85 (21.590) 18.26 (463.804) 0.98 (24.892) 18.00 (457.200)
20 21.46 (545.084) 0.65 (16.510) 20.16 (512.064) 0.73 (18.542) 20.00 (508.000) 22.06 (560.324) 0.89 (22.606) 20.28 (515.112) 1.03 (26.162) 20.00 (508.000)
21 22.50 (571.500) 0.67 (17.018) 21.16 (537.464) 0.75 (19.050) 21.00 (533.400) 23.12 (587.248) 0.92 (23.368) 21.28 (540.512) 1.03 (26.162) 21.00 (533.400)
24 25.60 (650.240) 0.71 (18.034) 24.18 (614.172) 0.80 (20.320) 24.00 (609.600) 26.26 (667.004) 0.98 (24.892) 24.30 (617.220) 1.13 (28.702) 24.00 (609.600)
27 28.70 (728.980) 0.75 (19.050) 27.20 (690.880) 0.85 (21.590) 27.00 (685.800) 29.40 (746.760) 1.04 (26.416) 27.32 (693.928) 1.20 (30.480) 27.00 (685.800)
30 32.52 (826.008) 0.79 (20.066) 30.94 (785.876) 0.89 (22.606) 30.74 (780.796) 32.52 (826.008) 1.09 (27.686) 30.34 (770.636) 1.26 (32.004) 30.00 (762.000)
33 35.66 (905.764) 0.83 (21.082) 34.00 (863.600) 0.94 (23.876) 33.78 (858.012) 35.66 (905.764) 1.15 (29.210) 33.36 (847.344) 1.33 (33.782) 33.00 (838.200)
36 38.76 (984.504) 0.87 (22.098) 37.02 (940.308) 0.98 (24.892) 36.80 (934.720) 38.76 (984.504) 1.20 (30.480) 36.36 (923.544) 1.38 (35.052) 36.00 (914.400)
40 42.92 (1,090.168) 0.92 (23.368) 41.08 (1,043.432) 1.03 (26.162) 40.86 (1,037.844) 42.92 (1,090.168) 1.26 (32.004) 40.40 (1,026.160) 1.46 (37.084) 40.00 (1,016.000)
42 45.00 (1,143.000) 0.95 (24.130) 43.10 (1,094.740) 1.06 (26.924) 42.88 (1,089.152) 45.00 (1,143.000) 1.30 (33.020) 42.40 (1,076.960) 1.50 (38.100) 42.00 (1,066.800)
45 48.10 (1,221.740) 0.99 (25.146) 46.12 (1,171.448) 1.09 (27.686) 45.92 (1,166.368) 48.10 (1,221.740) 1.35 (34.290) 45.40 (1,153.160) 1.55 (39.370) 45.00 (1,143.000)
48 51.20 (1,300.480) 1.03 (26.162) 49.14 (1,248.156) 1.13 (28.702) 48.94 (1,243.076) 51.20 (1,300.480) 1.38 (35.052) 48.44 (1,230.376) 1.68 (42.672) 47.84 (1,215.136)

BS 78 was finally superseded when the U.K. harmonised with incompatible European standards, however, the specified outer dimensions continue to remain in effect (albeit in metric form) as the standard pipe outer diameter for ductile iron pipe in Australia and New Zealand through the descendant specification, AS/NZS 2280.

External links[edit]