On Site Services Ltd.
On Site Services Ltd.
On Site Services Ltd.

Bolt Torquing and Tensioning

On Site Services Ltd. conforms to the ASME-PCC-1 2016 - Guidelines for Pressure Boundary Flanged Bolted Joint Assemblies. To date we have a Leak Free record! We have the tools, the people and the application.

OSSL has trained, experienced and certified technicians that are capable of assessing the specific requirements for most bolted assemblies. We will complete joints safely, timely and efficiently.

Bolt Torquing and Tensioning Bolt Torquing and Tensioning Bolt Torquing and Tensioning


  • Hydraulic Bolt Torquing and Tensioning for Shutdowns and Turnarounds
  • Owns low-clearance tools for tight locations
  • Owns a wide assortment of tensioning and torquing tools
  • New lightweight bolting pumps with four tool connection for parallel joint closure
  • On-board with new Mechanical Tensioning to replace Hydraulic
  • Equipment minimizes pinch points

Recent Projects

  • Yara 2012 EEIP TAR 6 months - old piping, thousands of joints – NO LEAKS
  • ALNG Carillion Massy TAR 3 months – NO LEAKS
  • ALNG/Massy TROC Project – Torquing and Tensioning – ZERO LEAKS
  • PCS UREA outage April 2016, installation of Hytorc Nuts and Washers – mechanical tensioning
  • NMAP TAR February 2016 – 2 months - ZERO LEAKS
  • BGTT BTIC Tie in and Compression (2010-2013). All shutdown and commissioning works
  • BGTT Poinsettia, Dolphin and Hibiscus Shutdowns (2010-2013)
  • bpTT Galeota Terminal Fire Water Pump-house Re-location Project
  • Petrotrin Shutdowns (4VDU 2011, 2HTU 2011, A-Topping 2011)
  • ALNG Train 1 & 2 Shutdown 2011
  • PDVSA Curacao Refinery Shutdown 2012
  • M5000 Turnaround 2013
  • M1000 Turnaround 2013

Yara - revolutionary service in tensioning – Hytorc mechanical tensioning – not using the very high associated pressures (upwards of 60,000 psi) and attendant risk.

Hytorc/OSSL will guarantee NO LEAKS on startup with this system (once parallel joint closure and Hytorc equipment is used).

OSSL (January 2015) executed dormant platform topside piping re-start hydro-testing on bpTT Mahogany with OSSL pneumatic, small footprint, design specific lower-cost equipment as compared to the competition engine-driven, heavy, large-footprint, more expensive equipment – job cost was cut in half.