News | May 9, 2000

NAPF Authors New Surface Preparation Standard for Ductile Iron Pipe, Fittings

The National Association of Pipe Fabricators has formulated the first industry standard for the surface preparation for ductile iron pipe and fittings prior to the application of special interior and exterior coatings and linings. The NAPF Standard 500-03 was unanimously adopted by the producer members at their recent annual conference in Ponte Vedra, FL.

Ductile iron is used in the manufacture of pipe and fittings and has long been recognized as the industry standard for water and wastewater systems due to its strength, durability and reliability for the transportation of raw and potable water, sewage, slurries and process chemicals.

Several publications and standards exist for surface preparation of steel pipe but, until now, no authority has addressed the surface preparation of ductile iron. Although ductile iron and carbon steel are both ferrous metals, there are inherent metallurgical, manufacturing and processing differences between them. These differences preclude certain parts of the Steel Structures Painting Council (SSPC) and the National Association of Corrosion Engineers (NACE) and other standards from being applied to ductile iron pipe and fittings.

It has been determined that attempts to apply steel surface preparation specifications to ductile iron is inappropriate and may actually result in damage to the pipe surface with subsequent reduced coating effectiveness and life expectancy.

This standard was compiled with the help of many consulting engineers, pipe and fittings producers as well as coatings manufacturers and applicators. If you would like a copy of this standard, one may be obtained by sending E-mail to or sending request to National Association of Pipe Fabricators, 13726 N. Penn #113, Oklahoma City, OK 73134.

Edited by Tracy Fabre