Ключевые слова: black, circle, communication, connection, construction, damaged, diameter, drain, drainage, engineering, equipment, facilities, group, hardware, hdpe, heap, heavy, industrial, industry, installation, large, line, long, material, occupation, operation, pattern, pile, pipe, pipeline, piping, plastic, plastic pipes, plumber, plumbing, polymer, power, pvc, repair, repairman, replace, replacement, rubber, sewer, stacked, supply, system, tube, underground, water,