Download PR-1073 - Gas Freeing, Purging and Leak Testing of Process Equipment (Excluding Tanks)-2 PDF

TitlePR-1073 - Gas Freeing, Purging and Leak Testing of Process Equipment (Excluding Tanks)-2
File Size987.8 KB
Total Pages35
Table of Contents
                            i Document Authorisation
ii Revision History
iii Related Business Processes
iv Related Corporate Management Frame Work (CMF) Documents
1 Introduction
	1.1 Background
	1.2 Purpose
	1.3 Scope
	1.4 Distribution / Target Audience
	1.5 Changes to the Document
	1.6 Step-out Approval
	1.7 ALARP
2 Roles and Responsibilities
3 Gas-Freeing, Purging Process Equipment
	3.1 General
	3.2 Draining of Vessels and Pipework to Open Pits
		3.2.1 Considerations When Draining Vessels and Pipework
		3.2.2 Criteria for Using an Open Pit
		3.2.3 Control Required for using Open Pits
	3.3 Gas-Freeing and Purging
		3.3.1 Preparation and Precautions
		3.3.2 Gas Freeing
		3.3.3 Atmospheric Pressure Method
		3.3.4 Cyclic Pressure Purge Method
		3.3.5 Water Displacement Method
		3.3.6 Series Purging
		3.3.7 Displacing To Air
	3.4 Purging Following Inspection or Maintenance
	3.5 Sampling
4 Leak Testing
	4.1 Objective
	4.2 Definitions for Leak Testing
	4.3 Reinstatement Policy
		4.3.1 Method Options in Order of Consideration
	4.4 Planning Reinstatement Leak Test
	4.5 Nitrogen Leak Testing of Systems
		4.5.1 Bubble Forming Solution
		4.5.2 Acceptance Criteria for N2 Leak Testing (Bubble Test)
	4.6 Performing the In-Service Reinstatement Test
	4.7 Vacuum Testing
	4.8 Reinstatement Testing of Relief Valves Connected to the Flare or Relief Headers
5 Hazards
	5.1 Draining and Flushing to Open Pits
	5.2 Gas-Freeing and Purging
	5.3 Leak Testing
Document Text Contents
Page 18

Page 35

Petroleum Development Oman LLC Revision 4.1 Effective: Mar-11

Interim Amendment March 2011 (Revision 4.1)

Page 7 Section 1.1 – Added “IMPORTANT: This procedure will be used for gas freeing, purging
and leak testing process system and equipment that has been commissioned and is being
operated as a production unit.

Page 14 Section 3.3.2 – Changed sub-heading to “Gas Freeing”. This is to avoid confusion
with purging operations after the work is completed.

Page 18 Section 4.3 – Changed 3rd & 4th paras to read “In-service Leak Testing may be utilised
only if achieving the Standard is ‘Not Practicable’ and has been Risk Assessed as acceptable.

Minimum In-service Reinstatement pressure is Maximum Operating Pressure as defined in 4.2
above and shall be used for ‘Low Risk’ scenarios where 5 or less flanges have been disturbed”.

Page 18 Section 4.3.1 – Added para “The PDO Standard is Sensitive Leak Testing for Sour
Service and Nitrogen for Sweet Service. Option 3 below shall only be considered if Options 1
& 2 are ‘Not Practicable’, the affected flanges are 5 or less and a Risk Assessment has been
conducted. Refer to Section 4.4 for more detail”. Removed “NOTE: In-Service Leak Testing on
its own should only considered when all other options are not Technically feasible.”

Page 19 Section 4.4 – Section amended to reflect changes made in Sections 4.3 and 4.3.1.

Page 24 Section 4.8 –“Reinstatement Testing of Multistage Compressors” removed.

Page 24 Section 4.8 – “Reinstatement Testing of Relief Valves Connected to the Flare or Relief
Headers” added

Purpose for changes / additions – Strengthening the requirement for achieving the
Reinstatement Test Standards and assisting Operations where meeting the Standards are not
achievable i.e. Flare and Relief Systems.

Page 35 PR-1073 - Gas-Freeing, Purging and Leak Testing Process
Equipment and Pipework

Printed 07/03/11

The controlled version of this CMF Document resides online in Livelink®. Printed copies are UNCONTROLLED.

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