Bolt Torque Procedure

Bolt-Tension Procedure For Flanges

Doc: PRCD.Bolt.001 Rev.: 01 Date:12-Jul-09

Page 1 of 5

Name Position Signature Date

Done By Eng. Saad Abou-Zeid Mech. Superintendent

Checked By Mr. Jose Antonio Sipan QA/QC Manager

Approved By Mr. Danilo Ceci Construction Manager

12/07/2004

12/07/2004

12/07/2004

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Bolt-Tension Procedure For Flanges

Doc: PRCD.Bolt.001 Rev.: 01 Date:12-Jul-09

Page 2 of 5

Index 1.0

Preliminary Instructions

2.0

Bolt Tensioning Pre-Activities

3.0

Tension Sequence.

4.0

Tension Calculation.

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Bolt-Tension Procedure For Flanges

Doc: PRCD.Bolt.001 Rev.: 01 Date:12-Jul-09

Page 3 of 5

1.0

Preliminary Instructions ¾ This procedure shall be used for bolt sizes 2” and larger in all services with pressure ratings upto and including class 900 as per SP-2020. ¾ Check the good condition of threads, and surfaces of bolts, nuts and flanges. ¾ Studs and nuts shall be cleaned using wire brush to remove any dirt on the threads. ¾ Visual examine studs and nuts after cleaning to ensure that they are free from Burrs. ¾ Ensure that all bolts are installed with an extra length of threaded stud, above the nut, of at least 1 X Bolt Diameter protrusion through the nuts at both sides.

2.0

Bolt Tensioning Pre Activities. ¾ “ Hand “ tighten bolts with a short wrench following the “Criss-Cross” pattern,. Do not tighten the bolts using impact force. ¾ Torque tensioners shall be calibrated and used within the dates of validity for calibration. ¾ In the event that set-up or seizure of the nut being tensioned is encountered, back the nut off until seizure is eliminated and torque again. ¾ Apply lubricant if necessary and replace the nut and/ or bolt in case of seizure again occurs.

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Bolt-Tension Procedure For Flanges

Doc: PRCD.Bolt.001 Rev.: 01 Date:12-Jul-09

Page 4 of 5

3.0

Tensioning Sequence. All bolts in the joint should be tensioned simultaneously, 25% simultaneous tensioning will be carried out, which requires the operator to make four or five tensioning operations by moving

around

the

bolts

in

diametrically

opposed fashion (see Figure 9). Refer to section 4 for the tension value and pump settings for the 4 or 5 passes required. Hydraulic stud bolt tensioners are designed to directly stretch the bolt by applying a known load to the fastener (see section 4 for values) using a hydraulic cylinder and threaded puller. The securing nut is then rotated using a short Tommy bar, whilst the thread is being stretched, until it is firmly tightened against the joint face. Immediately the hydraulic pressure (load) is released the bolt tension (residual load) is retained, within the clamp length of the stud bolt, because it is prevented from returning to its original length by the tightened nut. To operate hydraulic stud bolt tensioners, on bolted connections safely and efficently, an extra length of threaded stud, above the nut, of at least one x bolt diameter, is required to facilitate easy fitment of the equipment (see figure 1). If this cannot be achieved by attaching all bolt tensioners to one side of the flange due to lack of space, then alternate the tensioners on opposite side. Assembly of the tensioners to the stud bolt is quick and easy, provided of course that the stud bolts and nuts are clean, lubricated and in good condition Refer to section 2 (see figures 2 -5).

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Bolt-Tension Procedure For Flanges

Doc: PRCD.Bolt.001 Rev.: 01 Date:12-Jul-09

Page 5 of 5

4.0

Tension Calculations

4.1

Doc. No.

: 20”-900

4.2

Doc. No.

: 24”-900

4.3

Doc. No.

: 28”-900

4.4

Doc. No.

: 30”-900

4.5

Doc. No.

: 32”-900

4.6

Doc. No.

: 36”-900

4.7

Doc. No.

: 42”-900

4.8

Doc. No.

: 48”-900 -5-