The pipe covered by this specification is intended for water transmission, distribution, and feeder pipelines under pressure and for sewer force mains. Total steel areas required per foot are computed on the basis of an allowable fiber stress in the steel reinforcement assembly of 16,500 pounds per square inch. Local conditions may necessitate further design, installation, and operating considerations; such as intermediate working pressures (see 6.3), pipe bedding, depth of backfill, terrain, and prevailing soil conditions.