Gilbreths presented their proposal or system of process charting in 1921 (Annual meeting ASME 5 to 9 December 1921 at New York). They did not use the term flow process chart.
ASME used the terms flow process chart and operation process charts.
A.S.M.E. standard operation and flow process charts, developed by the A.S.M.E. Special committee on standardization of therbligs, process charts, and their symbols, 1947.
Corporate Author: American Society of Mechanical Engineers.
Published: New York, N.Y., The American society of mechanical engineers 
Physical Description: 21 p. incl. forms, diagrs. 26 1/2cm.
In text books, Barnes did not mention the term operation process chart in his Motion and Time Study Book.
ILO Work Study, used the term outline process chart.
They describe its utility:
In an outline process chart, only the principal operations carried out and the inspection made to ensure their effectiveness are recorded, irrespective of who does them and where they are performed.
The outline process chart is intended to provide a first "bird's-eye" view of the activities involved, for the purpose of eliminating unnecessary ones or combining those that could be done together.
Book - Fundamentals of Work Measurement: What Every Engineer Should Know
Anil Mital, Anoop Desai, Aashi Mital
Poor choice of manufacturing process can add to the work content.
p.3 of Fundamentals of Work Measurement: What Every Engineer Should Know
Anil Mital, Anoop Desai, Aashi Mital
CRC Press, 03-Oct-2016 - Technology & Engineering - 210 pages
I agree with Mital et al. and propose that operation process chart analysis has to evaluate each manufacturing process.
WORLD CLASS WAREHOUSING AND MATERIAL HANDLING  Timeless Insights for Planning and Managing 21st-Century Warehouse Operations
Number of Pages 242
Author Frazelle, Edward H., Ph.d.
Publication Date January, 1970
Written by one of today's recognized logistics thought leaders, this comprehensive resource provides authoritative answers on such topics as: The seven principles of world-class warehousing Warehouse activity profiling Warehouse performance measures Warehouse automation and computerization Receiving and put away Storage and retrieval operations Picking and packing Humanizing warehouse operations
"World-Class Warehousing and Material Handling describes the processes and systems required for meeting the changing demands of warehousing. Filled with practices from proven to innovative, it will help all logistics professionals improve the productivity, quality, and cycle time of their existing warehouse operations.
"World-Class Warehousing and Material Handling breaks through the confusing array of warehouse technology, buzzwords, and third-partyproviders to describe the principles of warehousing required for the implementation of world-class warehousing operations. Holding up efficiency and accuracy as the keys to success in warehousing, it is the first widely published methodology for warehouse problem solving across "all areas of the supply chain, providing an organized set of principles that can be used to streamline all types of warehousing operations.
Case studies from Avon, Ford, Xerox, True Value Hardware, and others detail how today's most innovative logistics and supply chain managers are arriving at proven solutions to a wide variety of warehousing challenges. Topics discussed include: Warehouse activity profiling--for identifying causes of information and material flow problems and pinpointing opportunities for improvement Warehouse performance measures--for monitoring, reporting, and benchmarking warehouse performance Storage and retrieval system selection--for improving storage density, handling productivity, and trade-offs in required capital investment Order picking strategies--for improving the productivity and accuracy of order fulfillment Computerizing warehousing operations--for profiling activity, monitoring performance, and simplifying operations
"World-Class Warehousing and Material Handling integrates global and e-commerce issues as it addresses customization, information technology, performance analysis, expansion and contraction planning, and the overall role of the warehouse in logistics management and the supply chain. Filled with proven operational solutions, it will guide managers as they develop a warehouse master plan, one designed to minimize the effects of supply chain inefficiencies as it improves logistics accuracy and inventory management--and reduces overall warehousing expense.
Updated 5 Feb 2019
Published 1 July 2017