Welcome to HSI HSI is a fully integrated single source manufacturer of refractory lined vessels and equipment for the oil refining, chemical process, power generation and incineration industries. Our unique turnkey approach to manufacturing gives us complete control over every aspect of a project. This eliminates inherent scheduling, quality control and manufacturing problems associated with using several different subcontractors. One source, one project manager . . . HSI can help you simplify the complex and sometimes frustrating vessel and equipment acquisition process while providing unparalleled quality, the latest technology and schedule reliability throughout manufacturing.