Hot Surface Ignition Temperatures: Their Impact on Electrical Area Classification Plans

For many years, hazardous-area classification (HAC) drawings have been used primarily by the electrical discipline (hereafter referred to as electrical) to determine what type of electrical equipment and materials could be installed in different areas of a facility. There has been a growing trend toward global refineries and petrochemical plants that rely on HAC drawings to determine hazardous equipment ratings and locations, not only for electrical equipment but also for nonelectrical equipment with hot surfaces. This article will examine how hot surface temperatures in classified areas are addressed both in the United States and international communities. A possible approach for implementing a new procedure in the United States is also discussed.