Eni S.p.A. Exploration & Production Division COMPANY STANDARD INTERNAL CORROSION MONITORING SPECIFICATION FUNCTIONAL REQUIREMENTS 20556.VAR.COR.FUN Rev. 0 – February 2008 ENGINEERING COMPANY STANDARD Documento riservato di proprietà di Eni S.p.A. Divisione Agip. Esso non sarà mostrato a Terzi né utilizzato per scopi diversi da quelli per i quali è stato inviato. This document is property of Eni S.p.A. Divisione Agip. It shall neither be shown to Third Parties not used for purposes other than those for which it has been sent. Eni S.p.A. Exploration & Production Division 20556.VAR.COR.FUN Rev. 0 February 2008 Page 2 of 14 PREMISE Rev. 0 February 2008 ISSUE The documents 20196.VAR.COR.FUN and 20197.VAR.COR.SDS have been withdraws Eni S.p.A. Exploration & Production Division 20556.VAR.COR.FUN Rev. 0 February 2008 Page 3 of 14 TABLE OF CONTENTS 1. INTRODUCTION 1.1 Scope 1.2 Reference Normative 1.3 ENI Internal Normative 1.4 Definitions 1.4.1 General Definitions 1.4.2 Specific Definitions 1.5 Symbols and abbreviations 1.6 Quality Assurance and Company Inspection 1.7 Special Requirements 2. 2.1 2.2 2.3 HEALTH, SAFETY AND ENVIRONMENTAL REQUIREMENTS Environmental Conditions Area Classification Health, Safety and Environmental Regulations 3. DESIGN CONDITIONS AND FUNCTIONAL REQUIREMENTS 3.1 Design Conditions 3.2 Test Point Location and Corrosion Monitoring Probes Selection 3.3 Intrusive Probes Assembly 3.3.1 Access Fittings 3.3.2 Access Fitting Location 3.4 Intrusive Probe Retrieval 3.5 Retriever 4. INSTRUMENTATION ASPECTS 5. TESTING REQUIREMENTS 6. DOCUMENTATION Eni S.p.A. Exploration & Production Division 20556.VAR.COR.FUN Rev. 0 February 2008 Page 4 of 14 1. INTRODUCTION 1.1 Scope This Specification provides the functional requirements for the supply of internal corrosion monitoring equipment and accessories defined in the Company Standards XXXX “Internal Corrosion Monitoring”. The requirements provided by this Specification are intended to be used for the purchase of internal corrosion monitoring equipment selected in the detail design phase of the Project. 1.2 Reference Normative ISO 9000 family International Quality Management Standards IEC 60079 Electrical Apparatus for Explosive Gas Atmospheres IEC 60529 Degree of Protection Provided by Enclosures Directive 94/9/EC Equipment Intended for Use in Potentially Explosive Atmospheres (ATEX) NACE RP0775 Preparation and Installation of Corrosion Coupons and Interpretation of Test Data in Oil Production Practice NACE MR0175/ISO 15156 Petroleum and Natural gas industries – Materials for use in H2S containing environments in oil and gas production Part 1 General principles for selection of cracking resistant materials Part 2 Cracking resistant carbon and low alloy steels Part 3 Cracking resistant CRAs NORSOK M-001 1.3 Materials Selection ENI Internal Normative XXX.XXX.XXX.XXX Internal Corrosion Monitoring MOD.COR.MON.001 Data sheet. Monitoring systems MOD.COR.MON.002 Data sheet. Testing report for monitoring systems 1.4 1.4.1 Definitions General Definitions For the purpose of applying this Specification to a contract or purchase order, the word ‘shall’ indicates a mandatory requirement; the word ‘should’ indicates a recommendation; and following definitions shall apply: COMPANY Shall mean Eni E&P or its elected representatives. CONTRACTOR Shall mean the company appointed by COMPANY to perform the EPCI works of a package, and its subcontractors, vendors, agents and authorised representatives. Eni S.p.A. Exploration & Production Division 20556.VAR.COR.FUN Rev. 0 February 2008 Page 5 of 14 MANUFACTURER Shall mean the party that manufactures equipment and services to perform the duties specified by COMPANY or CONTRACTOR. SUPPLIER Shall mean the party that supplies equipment and services to perform the duties specified by COMPANY or CONTRACTOR. 1.4.2 Specific Definitions Access fittings Fittings flanged or welded to a pipeline or a vessel for the installation of corrosion probes. Probe for corrosion monitoring in aqueous environments by microbial growth on exposed coupons. Coupons are eventually removed and microbial analysis carried out. Bioprobe Corrosion Coupon Probe Probes with metal samples exposed to the fluid inside pipes or equipment for a prefixed period; the evaluation of the corrosivity is based on the metal weight loss. Corrosion Monitoring Test Point – CMP Positions in correspondence to pipelines or equipment where internal corrosion monitoring is foreseen by means of suitable probes. It can consists of a pipe spool, flanged on the line to be monitored, on which the access fittings and the probes are mounted. Electrical Resistance Probe Device for measuring the cumulative metal loss by measuring the electrical resistance of a metallic element (wire, flat sample, tube). Hydrogen Probe Device for corrosion monitoring in environments containing H2S, based on the measure of the hydrogen entrapped in the metal. Linear Polarization Resistance Electrochemical technique for measuring instantaneous corrosion rate of a metal in a conductive fluid. Linear Polarization Resistance Probe Device for corrosion monitoring based on the principle of the linear polarization resistance. Probe General term to indicate a device for internal corrosion monitoring. Retriever Device for insertion, substitution or removal of probes from pipes or equipment without service interruption. They are of mechanical or hydraulic type. Water trap It consists of a small section of pipe, welded or flanged on the lower side of a pipeline or equipment, where separation and collection of water from multiphase systems occurs. Inside the water trap, corrosion monitoring probes are installed. 1.5 Symbols and abbreviations ATEX Explosive Atmospheres CC Corrosion Coupon CIE Corrosion Inhibitor Efficiency CMP Corrosion Monitoring Point CRA Corrosion Resistant Alloy Eni S.p.A. Exploration & Production Division ER Electrical Resistance Probe (traditional) FSM Field Signature Method HIC Hydrogen Induced Cracking HP Hydrogen Probe IP Ingress Protection classification LPR Linear Polarization Resistance Probe mpy Unit for corrosion rate: mils per year UTMAT Ultrasonic Thickness Transducer Mat 1.6 20556.VAR.COR.FUN Rev. 0 February 2008 Page 6 of 14 Quality Assurance and Company Inspection The SUPPLIER shall have in place a quality assurance organization responsible for formulating and implementing a quality system, which ensures that the requirements of this specification are achieved. Unless otherwise stated in a purchase order, the SUPPLIER’s quality system shall be based on ISO 9000 (or COMPANY approved equivalent) and shall be described in a Quality Assurance Manual. The Quality Manual and Quality Plan shall be submitted to COMPANY with the tender documents. 1.7 Special Requirements All correspondence, reports, manuals, test reports, certificates shall be in the English language or shall have authenticated translations accompanying them. If the requirements of this specification cannot be met, written notification of non-compliance, including explanations and proposed change, shall be provided at the bid stage by the SUPPLIER for COMPANY approval. Eni S.p.A. Exploration & Production Division 20556.VAR.COR.FUN Rev. 0 February 2008 Page 7 of 14 2. HEALTH, SAFETY AND ENVIRONMENTAL REQUIREMENTS 2.1 Environmental Conditions Instrument for external areas shall be suitable to operate in industrial, humid, saline and corrosive atmospheres, in the ambient minimum and maximum temperature extremes as defined in the basis of design, including maximum temperature excursions due to solar radiation. Instrumentation shall be suitable for relative humidity conditions range from 25% up to 100%. 2.2 Area Classification Electrical and electronic instrumentation for installation in hazardous areas shall in general be suitable for use in hazardous areas as defined by IEC 60079 ‘Electrical Apparatus for Explosive Gas Atmospheres’. Intrinsic safety, EEx (i)a shall be used as the prime method of protection. Deviation from this will require written permission from the COMPANY. Should permission be given, the allowable alternative methods of hazardous area protection are listed below in order or preference: − Flameproof or explosion proof type EEx(d) − Increased safety, type EEx(e) − Special protection, type EEx(s). All electrical systems shall be designed to conform to ATEX requirements. All equipment and protective system intended for use in potentially explosive atmospheres within the European Economic Area will have to display the CE marking in accordance with the ATEX Directive 94/9/EC. ATEX covers equipment and protective system that may be used in areas endangered by potentially explosive atmospheres created by the presence of flammable gases, vapours, mists or ducts. 2.3 Health, Safety and Environmental Regulations The SUPPLIER shall be responsible for ensuring that goods and services supplied meet all applicable regulations on health, safety and environmental issues. The equipment shall be designed to operate safely and satisfactorily at all expected combinations of process, utilities, climates and environmental conditions including those at start-up, shutdown, partial load operation, and emergency cases while retaining the overall system security, reliability and availability. Eni S.p.A. Exploration & Production Division 20556.VAR.COR.FUN Rev. 0 February 2008 Page 8 of 14 3. DESIGN CONDITIONS AND FUNCTIONAL REQUIREMENTS 3.1 Design Conditions Unless to be installed into an environmentally controlled area, all corrosion monitoring system equipment (instrumentation, probes etc.) shall be suitable to operate at the ambient conditions as defined in paragraph 2.1. The design life of the corrosion monitoring system shall match the design life of the structure to monitor. Weight loss corrosion coupons and intrusive corrosion sensors subjected to consumption shall guarantee the maximum lifespan obtainable without compromising the functionality and the specified requirements of the probe, as sensitivity, response time etc. As a minimum, the design life of the sensor should be equal to 2 years, and consistent with the inter-period between shutdowns if sensor retrieving under pressure is not allowed. In presence of toxic/lethal fluid, the retrieval of intrusive probes from live lines shall not be permitted. Retrieval of probes and coupons shall be undertaken only after depressurisation and possibly purging. For safety reasons, the installation of intrusive probes on piping systems designed for pressure above class #900 psi is to be carefully considered and possibly excluded to avoid leakage of toxic fluid from critical high-pressure systems. The installation of intrusive probes on piping systems designed for pressure above class #2000 psi is not recommended. The SUPPLIER shall review and confirm suitability of the corrosion monitoring devices and accessories with respect of the following environmental factors and aspects: − minimum and maximum design temperature; − minimum and maximum design pressures; − formation of condensates; − presence of corrosive species or pollutants; − formation of moulds; − electrical hazard; − mechanical stress and vibrations during operation; − electro-magnetic influence; − explosion and fire hazard. The SUPPLIER of corrosion monitoring system equipment shall also provide details of in-built safety features to avoid leakage as well as any venting requirements. The SUPPLIER of probes shall recommend element types for the indicated sensitivity and design life as specified in this document. 3.2 Test Point Location and Corrosion Monitoring Probes Selection The basic guidelines for the design of internal corrosion monitoring system are provided by Company Standards XXX “Internal Corrosion Monitoring”. This Standard provides criteria for the selection of the location of the corrosion monitoring test point “CMP”, a description of the different types of the available probes and criteria for the probes to install at each CMP and their method of installation. 3.3 Intrusive Probes Assembly The assembly of intrusive probe consists of the following components: Eni S.p.A. Exploration & Production Division − − − − − − − 20556.VAR.COR.FUN Rev. 0 February 2008 Page 9 of 14 access fitting, probe, solid plug (corrosion coupon) and hollow plug (ER probes), cap, probe holder, electronic equipment, spare parts. Functional requirements for the above components are herein specified. 3.3.1 Access Fittings Intrusive monitoring probes and coupons shall be installed by means of two-inch high-pressure access fittings at the pre-selected locations (CMPs). For piping design pressure lower than 150 psig (piping class rating #150 psi) the use of high-pressure access fittings may be waived. For highpressure piping (piping class rating above #2000 psi) the use of intrusive probes to be installed through access fittings is to be avoided. Access fittings may be flareweld or flanged and may be normal or tee-type. For systems containing toxic or lethal fluids or for high pressures system (above #900), the tee-type shall not be used. Flanged type access fittings shall be ANSI flange RJ or RF, non-tee type. Two-inch weld-o-flange shall match, as a minimum, rating and material of the parent pipe. Blind flanges shall be used where preliminary installation of access fittings is initially foreseen to allow a subsequent upgrading of the CMPs. Access fitting material (weld-o-flange assembly) shall conform to the requirements of the project piping specification as a minimum. If dissimilar materials were considered in flanged assembly, galvanic corrosion shall be avoided by using electrical insulation kits. The welding of access fittings onto any equipment shall comply with the requirements of the applicable Project documents and Codes. Welding of different materials should be avoided. 3.3.2 Access Fitting Location In selecting the exact location of the access fitting at the pre-selected CMP’s location, adequate clearance shall be guaranteed to allow comfortable and safe operations of maintenance, periodical probe replacement or manual data retrieving. At this purposes, adequate horizontal and vertical clearance shall be foreseen in the design phase (typically, clearance to accommodate the probe retriever shall be verified). The Supplier shall provide all relevant information on detailed datasheets to permit the verification that all clearances constraints are satisfied. When more than one access fitting are installed at a CMP, the inter-axial distance between two fittings shall not be lower than 500 mm. To minimise the effect of flow rate and flow regime on corrosivity, the access fittings should be located at a minimum distance of 7 pipe diameters downstream-of and a minimum of 3 pipe diameters upstream-of any changes in flow caused by bends, reducers, valves etc. To avoid debris accumulation leading to galling at the threads, a top of the line installation is preferable, unless the specific need of bottom of the line installation is dictated by preferential corrosion in this area (typically in oil systems where water stratification at the bottom is expected). In the latter case the Supplier shall provide evidence that a specific design of the probe assembly or a specific retrieval procedure can prevent this problem. Access fittings orientation shall be vertical, unless the specific purpose and location of the probe dictates a different orientation. Eni S.p.A. Exploration & Production Division 3.4 20556.VAR.COR.FUN Rev. 0 February 2008 Page 10 of 14 Intrusive Probe Retrieval Weight loss corrosion coupons require periodic retrieval at scheduled frequency (typically 6 months) for replacement and corrosion rate measurements. is designed to be carried out by means of appropriate extractor tools. Other intrusive probes may also require occasional probe retrieval in case of sensor malfunction or consumption. This operation is carried out with a proper extractor tool (or retriever) described in paragraph 3.5. The retrieval of intrusive probes from live lines may represent a safety hazard and shall be carefully evaluated as discussed in paragraph 3.1. If the retrieval operation involves risk for personnel associated to the release of lethal or toxic fluid and/or the high system pressure, retrieval under pressure shall not be permitted and the installation of block and bleed valves is required to allow local depressurization and avoid major shutdown to accomplish this operation. After depressurization local purging may also be required depending on the level of toxicity of the fluid. These operational procedures shall be clearly stated in the Operation Manual of the corrosion monitoring system. Probe assembly, access fittings, clearances etc. should be designed to allow the retrieval of intrusive probes with the same extractor tool. All intrusive probes shall be checked during each scheduled plant shutdown, and replaced where necessary 3.5 Extractor Tool (or Retriever) Commercially available extractor tools (or retrievers) allow the insertion and the extraction of coupons and other intrusive probes on “live lines” under pressure. This operation may be therefore carried out with no necessary need for shutdown. Market available tools permit to operate with temperatures up to 120°C and pressures up to 600 bar. However, as discussed in paragraphs 3.1 and 3.4, safety considerations may dictate that this operation be preceded by depressurisation and possibly decontamination (purging). Two types of retriever are accepted: − mechanical; − hydraulic. In a mechanical retriever, the counter pressure to extract the probe is effected by a threaded mechanical seal. In a hydraulic extractor, the counter pressure is provided by a hydraulic system. Hydraulic extractor has smaller dimensions and weight and is usually more reliable. From a safety perspective, hydraulic system has to be preferred because it allows remote control in the most critical phases (extraction and installing). The materials used for the extractor and valve, both internal and external, shall be suitable to resist corrosion from process fluids and to warehouse storage conditions. In the presence of H2S-containing fluids (sour service), the materials that may be exposed to the contact with sour fluid shall be compliant with the requirements of ISO 15156 / NACE MR0175 with respect to both material requirements and environmental application limits. The materials of each component shall be submitted to Company for review and approval. The threads of access nozzles, the extractor service valve and the extractor itself, must be trapezoidal, for rapid connection operations. The extractor tool should be equally capable of retrieving corrosion coupons and other intrusive probes in use in the field. Eni S.p.A. Exploration & Production Division 20556.VAR.COR.FUN Rev. 0 February 2008 Page 11 of 14 Adequate maintenance shall be periodically provided to all moving parts of the retriever. Eni S.p.A. Exploration & Production Division 20556.VAR.COR.FUN Rev. 0 February 2008 Page 12 of 14 4. INSTRUMENTATION ASPECTS The supply of corrosion monitoring system shall include all instrumentation required for manual or remote (on-line) data retrieving, data interpretation and data storage, maintenance, probe retrieval (retriever or extractor tool), spare parts etc. Transmitters and other electronic items shall be suitable for use in hazardous areas as defined by IEC 60079 ‘Electrical Apparatus for Explosive Gas Atmospheres’. The protection level of mechanical instruments and field junction boxes shall have the appropriate IP, as per IEC 60529, for the specific exposure in accordance with the appropriate Project documentation. The electrical certification shall be EEx (e). Junction Box enclosure material shall be stainless steel or GRP. Electronic instrument method of protection shall be selected in accordance with the appropriate Project documentation. All instruments shall be accessible for operation and maintenance and where necessary platforms and stairs shall be supplied with package skid. Instruments shall be located as near to the point of measurement as practicable and mounted on instrument stands or brackets. Instrumentation and cables, primary connection, pneumatic connection, electrical connection, bulk instrument types and materials for impulse line and for air network shall be in according to the applicable Project documentation. Instrumentation shall be suitably protected from the environment. Heated enclosures, heat tracing and insulation shall be applied as appropriate. Heaters and heat tracing shall be of the self-regulating type with sufficient rating to be able to heat impulse lines and instrument bodies to the minimum operating temperature from the minimum ambient temperature. Adequate electronic instruments are required to measure the signal and to determine the corrosion rate. Portable instruments shall be able to operate: − at the minimum and maximum design ambient temperature − at a relative humidity of 100% − at the applicable IP and explosion proof classification. Eni S.p.A. Exploration & Production Division 20556.VAR.COR.FUN Rev. 0 February 2008 Page 13 of 14 5. TESTING REQUIREMENTS Probes Each apparatus containing electrical or electronic components shall be subjected to testing as follows: − electrical test: it will be switched on for 24 hours consecutively and shall not overheat in any part; − functional test: on properly prepared samples, the equipment must operate properly in all possible conditions (in minimum and maximum conditions as regards the signal or the measured value) both immediately it is switched on and after 24 hours continuous operation Apparatus that does not pass the specified tests shall be rejected. Each probe shall be subjected to testing as follows: − electrical test: all electrical contacts will be verified. On hydraulically tested probes, the electric isolations of sensors will also be checked (electrodes for linear polarisation probes; calibrated wire for electrical probes) at the beginning and after 24 hours exposure. − functional test: the probes subjected to hydraulic test must be subjected to functional tests at the beginning and end of the electrical testing. The probes that do not pass the specified tests shall be rejected. Probe Housing and access fitting Each component of the monitoring system shall be tested by the Supplier according to the following procedures. Mechanical parts (certification and traceability) Mechanical parts forming the access fitting and all the related accessories shall be subjected to the following check: − identification of serial numbers: for each mechanical component (access nozzle, extractor and the relevant service valve, probes) it shall be verified that each part has a permanent label with the corresponding catalogue number; − certification: each part identified with a code number shall be supplied with a certificate of chemical analysis and mechanical properties, carried out by the supplier of the materials or a recognised laboratory; − positive material identification: components manufactured from special materials shall be subjected to positive material identification as per Project procedures. Hydraulic Test Probes shall be subjected to hydraulic test for at least two consecutive hours at a test pressure of 150% the maximum design pressure. The test must be carried out with an aqueous solution coloured with appropriate red or fluorescent colouring. The test result will be considered positive if no leak of solution is observed and the pressure remains constant (accepted variation: 1%). The testing frequency on the probes shall be, as a minimum, each type of probe (solid or hollow) and then a minimum of 10% of the total for each type supplied. Eni S.p.A. Exploration & Production Division 20556.VAR.COR.FUN Rev. 0 February 2008 Page 14 of 14 6. DOCUMENTATION The Supplier shall submit a complete set of technical documentation, which shall include also catalogues and technical bulletins, with the indication of codes for each part of the system. Each part identified with a code number must be supplied with a certificate of chemical analysis and mechanical properties, carried out by the Supplier of materials or a recognised laboratory. For electrical resistance probes, technical documentation indicating reference hydrodynamic conditions shall be provided for the adjustment of the probe. Quality Assurance manual and Quality Certificate are required. The Supplier shall provide all information and technical bulletin relevant to: − acquisition data system, − elaboration data system, − personnel training, − installation, extraction and cleaning operation of probes, − analysis and interpretations of results, − probe length for specified fitting stand-off.
