Saep 27 [PDF]

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Engineering Procedure SAEP-27

19 July 2009

Pipelines/Piping Hydraulic Surge Analysis Document Responsibility: Process and Control Systems Dept.

Saudi Aramco DeskTop Standards Table of Contents 1 2 3 4 5 6

Scope............................................................. 2 Conflicts and Deviations…………………….... 2 Applicable Documents................................... 2 Definitions...................................................... 4 Instructions.................................................... 5 Responsibilities............................................ 11

Exhibits............................................................... 12

Previous Issue: New Next Planned Update: 19 July 2014 Page 1 of 14 Primary contact: Rasheed, Mahmood Ayish on 966-3-8730674 Copyright©Saudi Aramco 2009. All rights reserved.

Document Responsibility: Process and Control Systems Dept. Issue Date: 19 July 2014 Next Planned Update: 19 July 2014

1

SAEP-27 Pipelines/Piping Hydraulic Surge Analysis

Scope This Saudi Aramco Engineering Procedure (SAEP) provides technical guidance to define full scope of hydraulic surge analysis during DBSP, Project Proposal, Detailed Design and throughout the different stages of a project cycle and throughout the operational life of a pipeline to ensure consistent approach. It provides Saudi Aramco engineers and engineering design contractors with guidelines describing the requirements to conduct and review pipelines hydraulic surge analysis studies for existing and new facilities.

2

3

Conflicts and Deviations 2.1

Any conflicts between this standard and other applicable Saudi Aramco Engineering Standards (SAESs) or industry standards, codes, and forms shall be resolved in writing through the Manager, Process & Control Systems Department of Saudi Aramco, Dhahran.

2.2

Direct all requests to deviate from this standard in writing to the Company, who shall follow internal company procedure SAEP-302 and forward such requests to the Manager, Process & Control Systems Department of Saudi Aramco, Dhahran.

Applicable Documents To ensure compliance with the appropriate Saudi Aramco and International Standards and Codes for over pressure protection of pipelines, the following Engineering Standards shall be reviewed in conjunction with hydraulic surge analysis studies. These Standards encompass hydraulic analysis, surge analysis, over pressure protection of pipelines, design pressure, materials, operating conditions, Maximum Allowable Operating Pressures and Maximum Allowable Surge Pressures. 3.1

Saudi Aramco References Saudi Aramco Engineering Procedures SAEP-12

Project Execution Plan

SAEP-14

Project Proposal

SAEP-302

Instructions for Obtaining a Waiver of a Mandatory Saudi Aramco Engineering Requirement

SAEP-303

Engineering Reviews of Project Proposal and Detail Design Documentation

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Document Responsibility: Process and Control Systems Dept. Issue Date: 19 July 2014 Next Planned Update: 19 July 2014

SAEP-27 Pipelines/Piping Hydraulic Surge Analysis

SAEP-354

High Integrity Protective Systems Design Requirements

SAEP-363

Pipeline Simulation Model Development and Support

Saudi Aramco Engineering Standards SAES-B-017

Fire Water System Design

SAES-B-058

Emergency Shutdown, Isolation, and Depressuring

SAES-B-060

Fire Protection for Piers, Wharves and Sea Islands

SAES-B-064

Onshore and Nearshore Pipeline Safety

SAES-B-070

Fire and Safety Requirements for Bulk Plants

SAES-J-600

Pressure Relief Devices

SAES-J-601

Emergency Shutdown and Isolation Systems

SAES-J-605

Surge Relief Protection Systems

SAES-J-700

Control Valves

SAES-L-100

Applicable Codes and Standards for Pressure Piping Systems

SAES-L-132

Material Selection of Piping Systems

SAES-L-310

Design of Plant Piping

SAES-L-410

Design of Pipelines

Saudi Aramco Engineering Reports

3.2

SAER-5437

Guidelines for Conducting HAZOP Studies

SAER-6043

High Integrity Protection System (HIPS) Evaluation Team Report

International Standards and Codes ANSI/ASME Code “Process Piping” Chemical plant and petroleum refinery pipeline for in-plant piping ANSI/ASME B16.5

Pipe Flanges and Flanged Fittings

ANSI/ASME B31.1

Power Piping

ANSI/ASME B31.3

Chemical Plant and Petroleum Refinery Pipeline or In-Plant Piping

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Document Responsibility: Process and Control Systems Dept. Issue Date: 19 July 2014 Next Planned Update: 19 July 2014

SAEP-27 Pipelines/Piping Hydraulic Surge Analysis

ANSI/ASME B31.4

Liquid Petroleum Transportation Piping Systems for Cross-Country Liquid Pipelines

ANSI/ASME B31.8

Gas Transmission and Distribution Piping Systems

American Petroleum Institute API STD 521

Pressure-Relieving and Depressuring Systems

American Water Works Association AWWA M45

American Water Works Association, Fiberglass Pipe Design

National Fire Protection Association

4

NFPA 24

Installation of Private Fire Services Mains and their Appurtenances

NFPA 25

Inspection, Testing and Maintenance of Water based Fire Protection Systems

Definitions Hydraulic Surge: Also referred to as “water hammer.” This is a phenomenon in pipeline operations characterized by a sudden increase in internal pressure. Hydraulic surge is often caused by the transformation of kinetic energy to potential energy as a stream of fluid is suddenly stopped. Surge Analysis: An engineering study that is undertaken to perform a hydraulic transient analysis of a specific system through the use of specialized simulation software which models the system, fluid and operating conditions. The transient analysis will predict the time history of pressures and flows throughout a system as a result of potentially applicable transient events. From the results, an experienced engineer/specialist can determine whether additional surge protection is required, what form of surge protection is most suitable, its capacity and where it should be located. The surge/transient analysis referred to in this Standard is specific to pipelines/piping systems. HAZOP (Hazard and Operability): A systematic, detailed analysis technique applied to identify hazards and operability issues which have the potential to place the process plant, environment or personnel at risk. The HAZOP study identifies abnormal process deviations that may require additional protective functions. The HAZOP analysis shall follow the guidelines of SAER-5437, Saudi Aramco HAZOP Engineering Report. PHA (Preliminary Hazards Analysis): An initial screening exercise that can be used to identify, describe, and rank major hazards. This technique can also be used to

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Document Responsibility: Process and Control Systems Dept. Issue Date: 19 July 2014 Next Planned Update: 19 July 2014

SAEP-27 Pipelines/Piping Hydraulic Surge Analysis

identify possible consequences and likelihood of occurrence and provide recommendations for hazard mitigation. 5

Instructions 5.1

5.2

General Requirements 5.1.1

PMT shall provide a copy of this Engineering Procedure to the Engineering design contractor involved in conducting the hydraulic and surge analysis study and a full comply to this procedure shall be notified to the contractor.

5.1.2

Risk assessment studies such as PHA or HAZOP, if available, shall be used as a basis for the surge analysis. The whole risk assessment (PHA and HAZOP) shall be an exercise in which all concerned parties (stakeholder organizations) are involved in sharing awareness and responsibility for the decisions and assumptions made to commence the surge analysis study. The risk assessment shall be conducted as defined in SAEP-12, SAEP-14 and SAEP-303.

5.1.3

The engineering design contractor shall use the approved pipeline simulation software that is defined in the Saudi Aramco Recommended Simulation Software Vendor List. The approved list can be obtained from P&CSD/Pipelines & Simulation Unit.

5.1.4

At the completion of the hydraulic surge studies, the engineering design contractor shall submit an electronic copy of complete simulation models and supporting documents to P&CSD/Pipelines & Simulation Unit, the Proponent and FPD for review and approval.

Surge Analysis Preparation Procedures The hydraulic surge analysis study shall be undertaken if over pressure or transient risks to piping or pipelines are identified in the following phases of a project or where changes to operating conditions are made including: 1)

Conceptual and Feasibility studies have been completed, detailed engineering design such as DBSP, Project Proposal and Detailed Design is in progress.

2)

Prior to any change in existing pipeline operation or modification to the pipeline system. If the maximum flow rates or maximum operating pressures increased from the previous operation, a new surge analysis at the new conditions to ensure that the pipeline system is protected.

3)

Any change or equipment data update in the detailed design, final pipeline design, at the last minute, or during construction works. Page 5 of 14

Document Responsibility: Process and Control Systems Dept. Issue Date: 19 July 2014 Next Planned Update: 19 July 2014

4)

SAEP-27 Pipelines/Piping Hydraulic Surge Analysis

During commissioning and start up activities, especially for testing sections of the pipeline system or if the tested system is different from the standard design configuration.

The study shall not be limited to the mentioned transient risk situations and P&CSD shall endorse the hydraulic surge analysis study timing. Before the surge analysis commences, a technical specification for the surge analysis study shall be prepared and approved by Proponent or SAPMT’s engineering contractor to acknowledge the problem for further assessment, scope development, and possible surge protection solution. The following list shall be completed to define full scope of the surge analysis for pipelines to ensure a consistent approach for all projects. 5.2.1

Analysis Objective The objective of the analysis will determine the extent of the pipeline system to be modeled and the accuracy of data required during pipeline model development and evaluation. A clear surge analysis objective shall be prepared and agreed with the pipeline hydraulic and surge analysis specialist of P&CSD prior to conducting the analysis.

5.2.2

Pipeline System Scope Hydraulic surge analysis shall not be limited by project scope of work. The whole pipeline system needs to be analyzed and the model built for hydraulic surge analysis shall include all the possible causes from within or beyond project scope boundaries and interfaces with other related facilities.

5.2.3

Possible Scenarios of Surge Analysis The transient/surge flow conditions that are expected to occur shall be defined. The analysis shall look at various possible causes, identify the critical cases, specify and design the necessary surge protection system as identified during the PHA, HAZOP and surge analysis studies. Exhibit II shall be used as a checklist to identify potential causes of transient pressure. As a minimum the following potential causes of liquid piping overpressure shall be investigated: a)

Inadvertent closure of a pipeline Class-1 or Class-2 valve.

b)

Closure of a downstream plant ESD valve.

c)

Trip of intermediate pump.

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Document Responsibility: Process and Control Systems Dept. Issue Date: 19 July 2014 Next Planned Update: 19 July 2014

5.2.4

SAEP-27 Pipelines/Piping Hydraulic Surge Analysis

d)

Closure of one looped pipeline.

e)

Closure of more than one looped pipeline.

f)

Closure of isolation valves, inside interfacing, upstream and downstream.

g)

Closure or control failure of a pipeline or downstream control valve.

h)

Inadvertent start of a standby pump, in addition to existing pump(s) operation

i)

Impact of new pipeline interfacing with existing pipeline

Data Requirements The following list identifies data that shall be gathered before a surge analysis study is conducted: a)

Pipeline system data: General description of the pipeline system, function and a summary of the likely hazard scenarios as identified in the PHA and HAZOP studies. Pipeline data including length, elevation profile, diameter, wall thickness, roughness or friction factor, elastic (Young’s) modulus, pressure rating, maximum permissible pressure (pipes, components, joints, support), minimum acceptable pressure (pipes, components, joints, supports).

b)

Operating conditions: pipeline inlet pressure and temperature, arrival pressure, maximum and minimum flow rates.

c)

Fluid data: The key data required are the physical properties at the relevant operating pressure and temperature for the evaluated pipeline system. Physical properties include: density, viscosity, true vapor pressure, bulk modulus, working temperature. Alternatively, for compositional analysis, the fluid composition shall be defined.

d)

Ambient conditions (summer/winter temperatures), thermal conductivities for pipelines and soil and/or the overall heat transfer coefficient between the pipeline and soil.

e)

Pumps: Type, number, location, performance characteristics, with operating curves and the following rated conditions: (head, flow, speed, power and efficiency), Inertia of rotating elements (impeller, motor and coupling)

f)

Valves: Type, number, location, dynamic performance characteristic (Cv curve), open/close time, pressure rating and maximum permissible pressure. Additional data for pressure relief valves: set

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Document Responsibility: Process and Control Systems Dept. Issue Date: 19 July 2014 Next Planned Update: 19 July 2014

SAEP-27 Pipelines/Piping Hydraulic Surge Analysis

pressures for opening and closing, time needed to open and close, discharge pressure.

5.2.5

g)

Tanks: Location, general layout, dimensions, maximum, minimum and normal levels of the liquid surface, elevation relative to the main pipeline, length and diameter of the connecting piping.

h)

Bypass piping: Location, length, diameter, head loss.

i)

Surge and transient event data: Time scale of valve and pumps operation (Control Logic) and sequence of events to be investigated.

j)

Units of measurements must be consistent.

Surge Analysis Methodology 1)

The analysis shall be performed first without assuming the intervention of any overpressure protection devices or equipments. Refer to Exhibit II for a list of potential causes of a transient pressure in a pipeline/piping system.

2)

Additional analysis shall be performed where the introduction of modifications to the system design are made to mitigate identified overpressure conditions, e.g., trimming pump impellers, increasing pipe wall thickness, removing or modifying the device causing the excessive transient pressures, adding overpressure protection equipment such as relief systems as specified in SAES-J-600 and SAES-J-605 or HIPS as per Saudi Aramco Engineering Procedure & Report SAEP-354 & SAER-6043.

Surge analysis shall ensure compliance with the appropriate Saudi Aramco and International Standards and Codes ANSI/ASME B31.1, ANSI/ASME B31.3, ANSI/ASME B31.4, ANSI/ASME B31.8, or ANSI/ASME B16.5 for over pressure protection of pipelines and process piping. For fire water and safety related systems, surge analysis shall ensure compliance with the appropriate International Standards Codes API STD 521, AWWA M45, NFPA 24 and NFPA 25. Surge analysis studies shall be conducted assuming that process initiated shutdown signals triggering pump trips, due to low suction and high discharge pressure, successfully stop pumps. This is provided that such signals originate from an ESD system and the signal loops and ESD system meet the required Safety Integrity Level (SIL) assessment and design requirements of SAES-J-601.

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Document Responsibility: Process and Control Systems Dept. Issue Date: 19 July 2014 Next Planned Update: 19 July 2014

5.2.6

SAEP-27 Pipelines/Piping Hydraulic Surge Analysis

Pipeline Model Validation When plant and pipeline operating data is available, the model shall be validated against a set of operating data within the known constraints of, 1) accuracy of plant measurements, 2) tolerance and convergence limitations within the simulator, and 3) the errors associated with simplifying assumptions made during model development. Models shall be validated also during project proposal and/or detailed design by SAPMT’s engineering contractor. Before the data can be applied to the model, it shall be necessary to evaluate the quality of the measurements caused by faulty instruments. If available, a software package shall be used to evaluate all elements of the data. The software package shall reconcile the data to identify faulty instruments and to eliminate or reduce measurements errors. Following model validation, if it is determined that the model results are not within acceptable limits, tuning of specific parameters may be required to improve accuracy. Model parameters may only be changed, following discussion and agreement with P&CSD. Typically, the difference between pipeline model results and operating data can be less than 2%. If the discrepancies are greater than 2%, the design contractor shall submit explanations for the discrepancies to P&CSD and seek approval to use the model for studies. This is covered by SAEP-363.

5.3

Documentation Requirements A surge analysis specific sheet shall be developed per Exhibit I and submitted for approval prior to performing surge analysis. At the completion of the transient analysis studies, documentation shall be developed containing, as a minimum requirement, the following sections: a)

An executive summary that shall include a brief description of the problem under investigation, background, objective, proposed solution, tool used and concluding remarks.

b)

A system description of the pipeline and study objectives.

c)

A description of the model including a detailed description of the simulation software components being used.

d)

A description of each scenario adopted for the study.

e)

Operation Control Philosophy/Logic implemented in the simulation.

f)

The methodology used to extract, reconcile, and filter the operating data.

g)

Model drawings. Page 9 of 14

Document Responsibility: Process and Control Systems Dept. Issue Date: 19 July 2014 Next Planned Update: 19 July 2014

SAEP-27 Pipelines/Piping Hydraulic Surge Analysis

h)

Tabulated results for each scenario.

i)

Graphical results representing time plots and/or profile plots of critical variables to support conclusions established for each scenario.

The following sections provide a detailed description of requirements for the documentation. 5.3.1

Study Objective Describe the purpose of the study and the role that simulation plays in addressing that purpose. The objective of the simulation must be clearly stated. The model shall be represented as a tool to help solve specific problems or answer specific questions rather than as an end product. The simulation package and version used to build the model shall be defined.

5.3.2

Work Scope Describe the system under investigation. The level of detail, model boundaries, sources of feed…etc. This can be accomplished by referencing available documents. Major relevant system characteristics should be summarized in the report that describes the simulation.

5.3.3

Study Assumptions In order to understand the model and its limitations, all assumptions shall be identified. Discuss the limitations of the model’s representation of the actual system and the impact those limitations have on the results and conclusions presented.

5.3.4

Property Package Describe the thermodynamics packages that were utilized to define the fluid properties. Flow, heat transfer and pressure drop correlations must also be described.

5.3.5

System Drawings (PFD’s, P&ID’s and Model Sketches) Provide the modeled system Process Flow Diagrams and Process Instrumentation Diagrams. Also, provide the simulation schematic used to build the model and compare the simulation model with the overview and actual pipelines/process to highlight differences.

5.3.6

Model Results Analysis Present the calibration criteria, procedure, and results. Describe the source of the observed data to which model results are compared. Page 10 of 14

Document Responsibility: Process and Control Systems Dept. Issue Date: 19 July 2014 Next Planned Update: 19 July 2014

SAEP-27 Pipelines/Piping Hydraulic Surge Analysis

Explain the appropriateness of using these data for model comparisons and the basis for any adjustments made to actual observations when making the comparisons. It is important to report and use as many types of data as possible for successful calibration of the model. 5.3.7

Results Analysis Profile and Trends Provide results analysis in profiles (specific variables vs. length of pipeline) and trends (specific variables vs. time) for all the evaluated cases.

All the prepared document shall be submitted to P&CSD for review and approval. 6

Responsibilities P&CSD provides technical guidance for all hydraulic and surge analysis, or pipeline control system studies during DBSP, Project Proposal, and Detailed Design phases of a project. P&CSD proactively works with Proponent and SAPMT on pipeline design; reviews all related pipelines studies and models; and provide guidance during each design stage. It is P&CSD responsibility to approve and endorse the pipeline studies and models. SAPMT or proponent shall be responsible for obtaining approval for the surge analysis technical specification (Exhibit I) from the appropriate organizations prior to performing the analysis. If any changes are made to the system or its operating conditions or procedures, the technical specification shall be revised. It is the responsibility of Proponent and SAPMT to consider the implications of pipeline transient risk assessment, if the project scope is changed or it is part of a phased development. Suppliers for pipeline and related components such as surge relief, rotating equipments shall provide Saudi Aramco and the design contractor the required equation data for conducting detailed surge analysis studies.

19 July 2014

Revision Summary New Saudi Aramco Engineering Procedure.

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Document Responsibility: Process and Control Systems Dept. Issue Date: 19 July 2014 Next Planned Update: 19 July 2014

SAEP-27 Pipelines/Piping Hydraulic Surge Analysis

EXHIBITS

TABLE OF CONTENTS

EXHIBIT I

Surge Analysis Technical Specification – Summary Sheet

EXHIBIT II

List of Potential Causes of Transient Pressure in a Pipeline/Piping System – Checklist

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Document Responsibility: Process and Control Systems Dept. Issue Date: 19 July 2014 Next Planned Update: 19 July 2014

SAEP-27 Pipelines/Piping Hydraulic Surge Analysis

EXHIBIT I – Surge Analysis Technical Specification – Summary Sheet The following sheet summarizes minimum surge analysis requirements for the pipeline system specified. The analysis report that follows from this is only valid for the pipeline system as defined. If any changes are made to the system or its operating conditions or procedures, the report shall be reviewed. ____________________________________________________________________________ Project Name: Scope: Data Requirements:

Data requirements as listed in Section 4.2 of the Procedure

Design and Operating Criteria:

Pipelines & Piping Design as per Saudi Aramco Engineering Standards (SAES-L-100, SAES-L-132, SAES-L-310 and SAES-L-410) Fire and Safety related system design as per Saudi Aramco Engineering Standards (SAES-B-017, SAES-B-060, SAES-B-064 and SAES-B-070)

Design Constrains: Maximum operating Pressure Minimum operating Pressure Maximum Flow Rate Minimum Flow Rate Other Parameters Pipeline Transient Criteria: Maximum Transient Pressure Minimum permitted pressure Other Parameters Transient Pressure Causes and scenarios

List of the causes to be investigated

Study Basic Assumptions Recommended Surge Protection Systems

This should be modified as required.

Operational Requirements

Constrains that should be included in the operation instruction manual Date:

Specification completed by:

______________________

*Approved by: Proponent Representative

______________________

P&CSD Representative

______________________

* P&CSD shall decide on the approval level

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Document Responsibility: Process and Control Systems Dept. Issue Date: 19 July 2014 Next Planned Update: 19 July 2014

SAEP-27 Pipelines/Piping Hydraulic Surge Analysis

EXHIBIT II – List of Potential Causes of Transient Pressure in a Pipeline/Piping System – Checklist ____________________________________________________________________________ Item No. Possible Causes ____________________________________________________________________________ 1.

Inadvertent closure of a pipeline Class-1 or Class-2 valve as per SAES-B-058.

2.

Closure of a downstream plant ESD valve.

3.

Trip of intermediate pump.

4.

Closure of one looped pipeline.

5.

Closure of more than one looped pipeline.

6.

Closure of isolation valves, inside interfacing, upstream and downstream.

7.

Closure or control failure of a pipeline or downstream control valve as per SAES-J-700.

8.

Impact of new pipeline interfacing with existing pipeline.

9.

Inadvertent start of a standby pump, in addition to existing pump(s) operation

10.

The pipeline system start up and shutdown

11.

The lineup of the pipeline is changed

12.

The flow rate or capacity of the pipeline system increases/decreases

13.

Changes are made to the original design of the system

14.

Component (e.g., flow/pressure control valve, surge relief valve, etc.) malfunctions

15.

Basic design data (flow rates, fluid properties, materials spec., etc,) are inaccurate

16.

The surge protection system and control fail

17.

Any other potential causes that a risk assessment (PHA & HAZOP) identifies

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