This report provides the technical basis for reliability-based load and resistance factor design (LRFD) methods for piping, more specifically for Class 2/3 piping for primary loading that include pressure, deadweight, seismic and accidental loading. The outcomes of the project include design models and equations, and partial safety factors that can be used to compose LRFD quidelines and criteria. It provides a proof of concept of the LRFD for the design of piping. Such design methods should lead to consistent reliability levels. The LRFD guidelines and criteria can initially be used in parallel with currently used procedures.