Steel Pipe And Fittings

The decision regarding where to apply the mortar lining for steel pipe — at the manufacturing plant or in the field — is based on a number of factors including manufacturer capabilities, pipe diameter, shipping and handling considerations, and field installation conditions. As with ductile iron pipe, steel pipe can be supplied

with a range of linings, only one of which is cement mortar lining.

Table A summarizes the mortar lining application methods, curing methods, and mix proportions used in the manufacturing plant and in the field for lining steel pipe and fittings. 

		Applied at manufacturing plant	Applied in the field
Pipe	Application	Centrifugal casting or pneumatic placement	Mechanical placement and troweling
	Curing	Asphaltic seal coat, steam, or water	Water
	Mix proportions	1 part portland cement, not more than 2 parts fine aggregate, and sufficient water to achieve required workability	1 part portland cement to 1–1¹⁄₂ parts fine aggregate, and sufficient water to achieve required workability
Fittings	Application	Hand-placed or pneumatic placement	Hand-placed if not by mechanical placement and troweling
	Curing	Asphaltic seal coat, steam, or water	Water
	Mix proportions	1 part portland cement, not more than 2 parts fine aggregate, and sufficient water to achieve required workability	1 part portland cement to 1–1¹⁄₂ parts fine aggregate, and sufficient water to achieve required workability

Table A: Cement Mortar Lining Application, Curing, and Mix Proportions for Steel Pipe and Fittings

Table B shows the factory-applied mortar lining thickness requirements for steel pipe and fittings. 

Pipe size range	Mortar lining thickness for old and new ductile iron
4–10 in (100–250 mm)	0.25 in (6 mm)
11–23 in (280–580 mm)	0.3125 in (8 mm)
24–36 in (600–900 mm)	0.375 in (10 mm)
>36 in (900 mm)	0.50 in (13 mm)

Table B: Factory-Applied Mortar Lining Thickness for Steel Pipe and Fittings

Table C shows the typical field-applied mortar lining thickness requirements for steel pipe and fittings.

Pipe size range	Mortar lining thickness for old steel	Mortar lining thickness for new steel
4–10 in (100–250 mm)	0.25 in (6 mm)	0.25 in (6 mm)
11–23 in (280–580 mm)	0.3125 in (8 mm)	0.25 in (6 mm)
24–36 in (600–900 mm)	0.375 in (10 mm)	0.375 in (10 mm)
>36 in (900 mm)	0.50 in (13 mm)	0.50 in (13 mm)

Table C: Field-Applied Mortar Lining Thickness for Steel Pipe and Fittings

Joint Protection

In the case of factory-applied mortar linings, it is necessary for the contractor to mortar the inside gap at the joints after installation. Field-welded joints, for instance, will have had the mortar lining held back a few inches at each end to avoid damage due to welding. 

Figure A illustrates this example showing a steel pipe lap-welded slip joint. 

Fig 1: Mortaring of interior joint recess for field-welded lap joint steel pipe

The installing contractor must hand-place the mortar to these uncoated surfaces after welding. This mortar shall be mixed using 1 part portland cement to not more than 3 parts fine aggregate by weight. Use only enough water to obtain the required workability. In the case of field-applied mortar lining, the lining is continuous across the joint, and no further work is needed at the joint.

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