# Tensioning Procedure

WARNING

High-Pressure Fluids Hazard

Never grab, touch, or in any way come in contact with a hydraulic pressure leak. When the hydraulic circuit is pressurized, the hydraulic fluid can escape at high speed. Escaping fluid under pressure can penetrate the skin causing serious injury. If an accident occurs, contact the nearest health service immediately! Any fluid injected into the skin must be surgically removed within a few hours or gangrene may result.

- Always relieve pressure before disconnecting hydraulic or other lines. Tighten all connections before applying pressure.

- Always wear safety approved eye wear when checking for leaks. Do not use your hands to check for leaks in the hydraulic circuit.

- Always keep away from leaking elements during the tightening process.

- Always wear impact-resistant eye and face protection when involved with or near the operation, repair or maintenance of the unit.

- Be sure all others in the area are wearing impact-resistant eye and face protection.

- Even small projectiles can injure eyes and cause blindness.

WARNING

Risk of Severe Injury

Always use personal protective equipment when operating the unit. Below are possible hazardous situations:

- Impact blows to the head

- Foot injuries

- Exposure to high noise levels

- Heat, splashes from liquids, impacts, cuts, air contaminated with harmful dusts, fumes, mists, sprays, and vapors.

If not avoided, the above hazardous situations could result in severe bodily injury or death.

- Always use the adequate personal protective equipment on your job site.

WARNING

Risk of Severe Injury

Always protect the face when working with high-pressure equipment. High-pressure equipment could cause severe bodily injury.

- Always wear goggles and/or face shield.

- Monitor the pressurized equipment and pay attention to the pressure gauge, because the pressure can increase quite rapidly in case of low volume circuits.

WARNING

Projectile Hazard

Never pressurize an unconnected male coupler. Male couplers are not designed to withstand high pressure, in the unconnected mode. Pressurizing an unconnected male coupler can lead to serious bodily injury or death.

- If you are left with an unconnected male connection, check the hydraulic hose assembly and correct the error.

WARNING

Projectile Hazard

Unexpected bolt failure can result in serious personal injury or death. Premature bolt failure can lead to parts of the tensioner or bolt becoming high velocity projectiles.

- Never stand in-line with the bolt axis during the tensioning or de-tensioning procedure.

- Alert all personnel to the consequences of premature bolt failure and clear the area of non essential personnel before the procedure starts.

## Procedure

1. Make sure that the two halves of the bolted joint are fully and correctly aligned.

2. Fit the hydraulic nuts to all of the stud bolts.

   See section Hydraulic Nut System Configuration for configuration illustrations of hydraulic nut set up.

   See section Hydraulic Nut Installation for installation instructions.

3. Make sure the pump is turned off and the pressure release valve is in the open position.

4. By using suitable link hoses, connect the hydraulic nuts together and to a suitable pump unit.

   If simultaneous tensioning of more than one bolt is to be carried out, fit one male and one female quick connect coupling to each hydraulic nut, and by using link hoses, link each nut together. The end nut on the application should have either an unconnected female coupling (to a link hose) or a blanking plug.

   Make sure the tensioning team is aware of the target working pressure.

5. Operate the pump unit and pressurize the system to 1000 psi (70 bar) and check that the pressure is holding steady. If the pressure drops, investigate the problem by looking for leaks.

   For pump operation, see the pump instruction document.

   All investigation, maintenance or leak repair work should only be carried out when the tensioning system is at zero pressure.

6. When the pressure is holding steady, continue to pressurize the system up to the target calculated working pressure.

   Never exceed the maximum working pressure.

   Never leave high pressure hydraulic tools unattended while pressurized.

   Never exceed the maximum piston stroke capability of the tensioning tool.

   If the maximum stroke indicator appears on any of the tools before the target operating pressure is reached, immediately stop the pressurization sequence. Slowly open the pump pressure release valve and make sure that the pressure drops to zero. Return the body and restart the tensioning procedure.

7. When the target working pressure is reached, stop the pump to hold pressure. Monitor the pump pressure gauge to make sure the pressure is holding steady.

8. Approach the hydraulic nuts and by using a tommy bar inserted into the load retaining collar, rotate the collar upwards until it is seated tightly up against the underside of the hydraulic nut body. Repeat until all of the load retaining collars are firmly seated.

9. Slowly open the pressure release valve, the pressure will drop to zero.

10. Repeat steps 5 to 9.

11. Open the pump pressure release valve and make sure the pressure falls to zero.

12. Remove all link hoses from the hydraulic nuts.

13. Remove the hydraulic coupler(s) and replace the blanking plugs that were removed during the hydraulic nut installation.

    Hydraulic couplers of either type should be tightened into the tool from the adaptor piece only. Required tightening torque is 25 Nm.

The tensioning procedure is now complete.

Relevant Information

- Hydraulic Nut Installation
- Hydraulic Nut System Configuration