Ключевые слова: abstract, background, blue, build, circle, civil, colours, connection, construction, development, distribution, drain, drainage, duct, engineering, equipment, fitting, improve, industrial, industry, infrastructure, maintenance, manufacturing, material, new, pipe, pipeline, piping, plastic, plumber, plumbing, public, pvc, repair, replace, residential, round, service, sewage, sewer, site, stack, supply, tube, tubing, urban, utility, water, work,