Practical Selection of Material for Large Water Pipe

Practical considerations are compared in selecting materials for water pipe 30 in. and larger in size. Materials are steel, ductile-iron and reinforced concrete as covered by American Water Works Association Standards. Steel and ductile-iron are flexible pipes and reinforced concrete is rigid pipe. Steel pipe considerations are external load, internal pressure, deflection, shell thickness, shell stress from internal pressure, corrosion protective coatings, lengths, field joints, fabricating, shipping and laying conditions and procedures. Ductile-iron pipe considerations are similar to those for steel with less emphasis on corrosion protective coatings and deflection. Reinforced concrete pipe considerations are similar to those for steel and ductile-iron except deflection related considerations do not apply. The best and practical way to determine the lowest cost for a pipeline is to take bids on pipe in place under alternative material specifications.