Case Studies on the Causes and Cures of Corrosion in Building Equipment

Abstract

Building equipment is subdivided into three categories: electrical, plumbing and air conditioning equipment. The plumbing equipment is further divided into cold and hot water supplies and drainage system as well as gas supplies, and fire-fighting installations. Depending on its purposes, the plumbing equipment is also subdivided into cooling water supply, chilled water and hot water supplies, the return condensation and the oil supply. In this paper, plumbing and air conditioning equipment related to water use in general is discussed. Because very little research has been conducted on building equipment, the technology nedded to evaluate it is insufficient in many respects compared with industrial plant construction works. The problems of corrosion experienced with building equipment were reported a decade ago. They were: grooving corrosion on electric resistance welded pipes; pitting corrosion and red water on galvanized steel pipes; stress corrosion cracking on stainless hot water tanks; pitting corrosion, corrosion and fatigue cracking on copper pipes for hot water supply; dezincification on brass valves; corrosion on condenser tubes for the refrigeration machine; and macro-cell corrosion on underground pipes. However, problems with building equipment are on the decline because their causes and cures have been clarified and identified in recent years. In this paper, individual cases of corrosion have been examined to determine causes and cures.