SCHAAF solution for a Tower Flange Stud Tensioning System Documentation – Efficiency – Quality

The design of the tools is aiming for simplicity to have reduced cost and intuitionality for the operator. There are for instance no additional engines used to operate the tools. Instead the use of a standard cordless screw-driver system is foreseen. This can be adopted using a universal fixation system matching with a large variety of tools. Visual signals show if the tensioner is handled within its limits (especially correct bolt protrusion and maximum piston stroke) to increase worker safety. Also the handwagon is not using any motors. For tangential movement on the flange handforce is sufficient. The integrated tool lifting mechanism supports the operator with a system of 2 or more gas-springs to reduce the required handforce for lifting during operation.
FSTS Flange Stud Tensioning System


  • Long life-time: All parts are designed for min. 100.000 LC. Service interval is 10.000 LC/12 months.
  • Suitable for marine and offshore environment:
    • robust against outer influences
    • up to IP67
  • Optimized Tool design: preventing collision with obstacles (tower wall, cable tray, ladder, weld seams)
  • Increased lifetime of the bolt connection
    • TTG increases the possible residual force of a bolt connection
  • Full documentation including bolt elongation, residual force and flange gap evaluation for every bolt connection to achieve maximum security
  • OBLM for real time load monitoring
  • Simple handling for the operator
FSTSThe illustration describes the optimized system for flange stud tensioning tools, including reading input data and output tracking data. Modifications to fulfill other requirements are possible.


All conceivable special designs are possible. Please let us know your requirements.

fsts montage

Areas of Application

SCHAAF FSTS is the optimal solution, where constant monitoring can prevent damages or injuries. Additional estimated bolt loads during design stage can be proved if correct. Especially for connections with permanent vibrations, weather related and temperature changes or load changes, for example wind turbines, bridge construction, cranes, electric generators and motors.


Quality Assurance

All FSTS are checked for 100 % process security. During order handling, they are accompanied by ongoing quality assurance measures and supplied with extensive documentation.




SCHAAF FSTS are user-friendly, reliable, and manufactured in accordance with the highest level of technical know-how. Our highly-motivated staff would be pleased to train your personnel, in situ or at our works, in the general handling and operation of the mobile and stationary control unit. In this way, all the process parameters can be entered optimally in order to achieve maximum process monitoring and safety. Of course, the FSTS are supplied ready for operation.

Related Accessories


TTG is a special, patented process for manufacturing threads in nuts or on bolts.

OBLM – Accurate long-term bolt load monitoring and safety failure warnings.


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Industry-specific special solutions:

All SCHAAF products offer an individual solution for every industry.

FSTS proves particularly effective for:

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