Nitrogen Purging Procedure | Method Statement

1. PURPOSE
2. SCOPE
3. REFERENCES
4. RESPONSIBILITIES
5. MANPOWER
6. TOOLS AND EQUIPMENT
7. METHODOLOGY
8. QUALITY CONTROL AND INSPECTION
9. SAFETY INSTRUCTIONS AND PRECAUTIONS
10. ATTACHMENTS

1.0 PURPOSE

This Procedure / Method Statement will serve as a minimum guidelines to carry out the Nitrogen Purging works in buildings, plants and refineries.

2.0 SCOPE

This specification covers all mechanical equipment that requires preservation by nitrogen purging for buildings, plants and refineries.

3.0 REFERENCES

3.1 SAIC-D-2005 Storage, Handling and Preservation (Vessels and Tanks)
3.2 32-SAMMS-004 Manufacture of Pressure Vessels
3.3 GI-0002-100 Work Permit System
3.4 PIP REIE-686 Recommended Practice for Machinery Installation and Installation Design
3.5 Construction Safety Manual
3.6 Manufacturer’s Recommendations

4.0 RESPONSIBILITIES

Site Manager

Ensure full compliance by all personnel involved in the implementation of this Nitrogen Purging work and implementation of HSE procedure in accordance with project requirement and specflcatlons. Confirm availability of all materials, tools, equipment and required personnel who will carry out the work.

Construction Manager

In-charge in the pre-mobilization inspection and color coding of all tools and equipment to be use on site. Ensure that all safety requirements have been adequately addressed and the work is carried out in accordance with ARAMCO project safety procedures. Ensure relevant documentation and certifications are submitted for all personnel involved in the work execution.

Quality Control Inspector

Conduct inspection in accordance with this procedure. Monitor daily activities and verify compliance to ARAMCO Specifications. Prepares record and final acceptance documentation where required.

Mechanical Supervisor

Ensure full compliance of all workers in the performance of work activity. Warrants that all works are as per the schedule and project standards and confirm availability of quality and safety documents where and when required.

Safety Officer

Check the work areas and monitor from time to time in the implementation of safety procedure and assuring that all safety equipment and tools are present at site and in good working condition.

5.0 MANPOWER

5.1 Mechanical Supervisor shall be responsible to coordinate and supervise the nitrogen purging activities. Manpower under him includes but not limited to:
0 Mechanical Foreman
0 Mechanical Fitter
0 Pipe Fitter
0 Forklift or Crane Operator
0 Rigger
0 Scaffolder

Note: Only qualified and oriented crew shall do the purging activities.

6.0 TOOLS AND EQUIPMENT

6.1 Tools and equipment shall be in good condition and must be checked by Mechanical Supervisor and/or Safety Officer prior to use in the construction area. These includes but not limited to:
o Mobile Crane as required for blinding
o Lifting accessories
o Man lift
o Boom truck
o Hand tools and Fixtures as required
o Trolley
o Purging hoses
o Gas mask
o Pressure gauges
o Blinds

7.0 METHODOLOGY

7.1 Preparation

7.1.1 Prepare all necessary materials needed for purging.
7.1.2 All nozzles with piping connection shall be temporary blinded. Install spectacle blind with proper gasket to close all openings. Manway covers shall be temporary tightened with proper gasket installed.
7.1.3 Determine the volume of nitrogen to be filled/purged in every equipment.
7.1.4 Temporary platform on all inaccessible nozzles/openings shall be provided.
7.1.5 The equipment shall have a temporary gauge to determine purge pressure. Remove the temporary gauge before startup. The equipment shall be inspected as per Method Statement for Preservation Execution Procedure to ensure that purge integrity is maintained. API Recommended Practice 686/PIP REIE 686 Sec.1.5.15.
7.1.6 Threaded nozzle connections shall be protected with threaded plugs. 32-SAMSS-004 Para. 19.3.2
7.1.7 Flanges with permanent blind flanges or covers shall be secured with the gaskets and bolting specified for service. 32-SAMSS-004 Para. 19.3.5

7.2 Purging / Filling

7.2.1 Secure work permit from Safety Department before filling/purging activities.
7.2.2 Connect the nitrogen filling assembly as shown in attachment “A”. Purge connection must be at low point.
7.2.3 Initially fill the equipment with open vent at highest point to release moisture and oxygen content of equipment.
7.2.4 Pressure of nitrogen purge shall be as manufacturer’s recommendation.
7.2.5 Adjust the pressure regulator gradually to required pressure.
7.2.6 When the required pressure is attained, closed the valve after the tee as shown in attachment “A”. Remove filing assembly and install plug. Temporary pressure gauge remains on equipment for pressure monitoring purposes in the entire duration of preservation or until nitrogen releasing/depurging.
7.2.7 Check blind flanges for any leakage until the pressure stabilizes.
7.2.8 Preservation groups shall keep the record and frequently check as required in the Method Statement for Preservation Execution Procedure.
7.2.9 Provide safety warning devices at manhole such as “Vessel Pressurized with Ni’ or equivalent.
7.2.10 All equipment shall have a capability of controlled draining and purging and lockout-tag out. API Recommended Practice 686/PIP REIE 686 Section 3 – Commissioning Design Para. 3.4
7.2.11 After purging of equipment, it shall be noted on the Preservation Log.

7.3 Depurging / Releasing

7.3.1 Secure work permit from JGC/DEC Safety Department before nitrogen releasing/depurging activities.
7.3.2 Releasing shall be at the highest polnt of the equipment to prevent vacuum forming.
o Open the valve gradually on desiqnated vent until atmospheric pressure is reached.

8.0 QUALITY CONTROL and INSPECTION

A regular weekly series of inspections by related preservation team shall be carried out to audit the state of the preservation and to rectify all non-conformances discovered during surveillance. Likewise, QC Inspectors should perform daily surveillance inspection to ensure quality in field implementation of the equipment preservation and proper actions shall be done if needed and recorded on the log card. Preservation activity can also be checked randomly at site by the PMT/PID at their own discretion.

9.0 SAFETY INSTRUCTIONS AND PRECAUTIONS

9.1 Make sure that all necessary work permits are issued prior to commencement of work.
9.2 Work execution shall be carried out in accordance with the approved Method Statement.
9.3 Wear minimum PPE and full body harness when working at elevated platform and confined space.
9.4 Ensure that barricades and warning signs are visible and properly installed.

9.5 Check all nitrogen gas hoses and calibrated pressure gauges prior to each use.
9.6 Install adequate illumination when working at dark areas.
9.7 Copy of approved Job Hazard and Risk Assessment (JHRA) to be maintained at work site by Work Supervisor. Conduct daily TSTI and discuss work methodology prior to commencement of work.
9.8 Implement and monitor safety instruction on site.
9.9 Review all nitrogen purge installation with respect to confined space procedure, warning signs devices and asphyxiation hazard before putting the purge in services as per PIP REIE 686.
9.10 Warning sign such as “Nitrogen Purging-in-Progress” during filling shall be provided.
9.11 Ensure that all equipment to be use during the work activity are properly inspected and color coded.
9 .12 Housekeeping shall be maintained and working area shall be kept in a clean and orderly manner before and after work activity.

GENERAL ARRANGEMENT OF NITROGEN PURGING