This Practice provides guidance for the design of insulation systems used in a hygienic environment requiring clean or Current Good Manufacturing Practices (CGMP) design. This Practice describes the types of insulation systems that are indicated by the type code on the Piping and Instrumentation Diagrams (P&IDs), data sheets, and other design documents. This Practice provides guidance on insulation design criteria, insulation materials, extent of insulation, determination of insulation thickness, and insulation material properties. Insulation in non-hygienic facilities/non-CGMP areas should refer to PIP INEG1000.