The Water Technology Subcommittee of the ASME Research and Technology Committee on Water and Steam in Thermal Systems, has established a Consensus on Best Tube Sampling Practices for Boilers & Nonnuclear Steam Generators. This publication is an important companion to previously published documents prepared to inform and educate the reader and to develop good chemistry control and operating practices for steam and water usage in thermal systems. The earlier publications are Consensus on Operating Practices for the Control of Feedwater and Boiler Water Chemistry in Modern Industrial Boilers; A Practical Guide to Avoiding Steam Purity Problems in the Industrial Plant; Consensus for the Lay-up of Boilers, Turbines, Turbine Condensers, and Auxiliary Equipment, Consensus on Operating Practices for the Sampling and Monitoring of Feedwater and Boiler Water Chemistry in Modern Industrial Boilers, and Consensus on Operating Practices for Control of Water and Steam Chemistry in Combined Cycle and Cogeneration Power Plants.