This research report, sponsored by the ASME Center for Research and Technology Development, has been issued in an effort to comply with the advances in equipment design and lay-up technology. Topics covered include: Factors to be Considered; Identification of Materials in Equipment; Use and Disposal of Lay-up Chemicals; Boiler Lay-up: Fireside; Lay-up of Turbine Oil System; Lay-up of Auxiliary Components and Pre-boiler Systems; Conclusions, Glossary of Terms, Tables, Figures and References; Reasons for Lay-up; Inspection and Cleaning of Equipment; Boiler Lay-up: Waterside; Steam Turbine, Turbine Condenser and Reheater Lay- up; Lay-up of Feedwater Heaters and Deaerators; Lay-up Monitoring and Maintenance; Start-up After Lay-up.