ASME B31.8: GAS TRANSMISSION AND DISTRIBUTION PIPING SYSTEMS

The printer in the office is going to broke again, the head of the printer is can not detect the cartridge, even I already install the new one, so for the moment I can not print any document, because I've only get one printer here. While waiting fix the printer, so I decided to post this ASME B31.8: GAS TRANSMISSION AND DISTRIBUTION PIPING SYSTEMS to Piping & Fabrication blog and hope the printer will be okay soon.

Scope
A pipeline or transmission line is defined as that pipe which transmits gas from a source or sources of supply to one or more large-volume customers or to a pipe used to interconnect sources of supply. ASME B31.8 prescribes requirements for the design, fabrication, installation, testing, and safety aspects of operation and maintenance of gas transmission and distribution piping systems, including gas pipelines, gas compressor stations, gas metering and regulation stations, gas mains, and service lines up to the outlet of the customer’s meter set assembly.

Also included within the scope of ASME B31.8 are gas storage equipment of the closed-pipe type, fabricated or forged from pipe or fabricated from pipe and fittings, and gas storage lines.

The requirements of ASME B31.8 also apply to the use of elements of piping systems, including but not limited to pipe, valves, fittings, flanges, bolting, gaskets, regulators, pressure vessels, pulsation dampeners, and relief valves.

The requirements of ASME B31.8 are applicable to operating and maintenance procedures of existing installations and to the update of existing installations. ASME B31.8 does not apply to the following:
•    Design and manufacture of pressure vessels covered by the ASME Boiler and Pressure Vessel Code
•    Piping with metal temperatures above 450°F (232°C) or below -20°F (-29°C)
•    Piping beyond the outlet of the customer’s meter set assembly (refer to ANSI Z223.1 and NFPA 54)
•    Piping in oil refineries or natural gasoline extraction plants, gas-treating plant piping other than the main gas stream piping in dehydration, and all other processing plants installed as part of a gas transmission system, gas manufacturing plants, industrial plants, or mines (see other applicable sections of the ASME Code for Pressure Piping, B31)
•    Vent piping to operate at substantially atmospheric pressures for waste gases of any kind
•    Wellhead assemblies, including control valves, flow lines between wellhead and trap or separator, or casing and tubing in gas or oil wells
•    The design and manufacture of proprietary items of equipment, apparatus, or instruments
•    The design and manufacture of heat exchangers
•    Liquid petroleum transportation piping systems (refer to ANSI/ASME B31.4)
•    Liquid slurry transportation piping systems (refer to ASME B31.11)
•    Carbon dioxide transportation piping systems
•    Liquefied natural gas piping systems (refer to NFPA 59 and ASME B31.3)

Effective Code Edition, Addenda, and Code Cases
To determine the effective edition, addenda, and code cases to be invoked for an application or piping systems within the jurisdiction of ASME B31.8, follow the criteria delineated for piping systems within the scope of ASME B3 1.1:
No edition and addenda shall be applied retroactively to existing installations insofar as design, fabrication, installation, and testing at the time of construction are concerned. Further, no edition and addenda shall be applied retroactively to established operating pressures of existing installations, except as provided for in Chapter V of ASME B31.8.

ASME B31.5: REFRIGERATION PIPING

I don't know if arrange the factory vacation is really take a lot of times and that make me really busy today, and I have to do this post about ASME B31.5: REFRIGERATION PIPING on Piping & Fabrication is a little bit late. But it doesn't matter now, at least almost 75% the arrangement of the vacation is already done.

Scope
This section of ASME B31, Pressure Piping Code, contains requirements for the materials, design, fabrication, assembly, erection, testing, and inspection of refrigerant and secondary coolant piping for temperatures as low as _320_F (_195.5_C), except when other sections of the code cover requirements for refrigeration piping.

ASME B31.5 does not apply to the following:
•    Self-contained or unit systems subject to the requirements of Underwriters’ Laboratories (UL) or other nationally recognized testing laboratories
•    Water piping
•    Piping designed for external or internal gauge pressure not exceeding 15 psig (100 kPa)

Effective Edition, Addenda, and Code Cases
To determine the effective edition, addenda, and code cases for piping systems within the jurisdiction of ASME B31.5, follow the guidelines delineated for nonnuclear piping systems within the jurisdiction of ASME B31.1.

ASME B31.4: LIQUID TRANSPORTATION SYSTEMS FOR HYDROCARBONS, LIQUID PETROLEUM GAS, ANHYDROUS AMMONIA, AND ALCOHOLS

Like I said before, if we talk about ASME, there is must be take a long time to talk about it, and that's only the general definition of them, and how about if we talk it more details and more accurately, that's may be will take a very long times, but don't worry because Piping & Fabrication will be patient enough to post this, and now we will talk about ASME B31.4: LIQUID TRANSPORTATION SYSTEMS FOR HYDROCARBONS, LIQUID PETROLEUM GAS, ANHYDROUS AMMONIA, AND ALCOHOLS

Scope
Section B31.4 of the ASME Pressure Piping Code prescribes requirements for the design, materials, construction, assembly, inspection, and testing of piping transporting liquids such as crude oil, condensate, natural gasoline, natural gas liquids, liquefied petroleum gas, liquid alcohol, liquid anhydrous ammonia, and liquid petroleum products between producers’ lease facilities, tank farms, natural-gas processing plants, refineries, stations, ammonia plants, terminals, and other delivery and receiving points.

The scope of ASME B31.4 also includes the following:
•    Primary and associated auxiliary liquid petroleum and liquid anhydrous ammonia piping at pipeline terminals (marine, rail, and truck), tank farms, pump stations, pressure-reducing stations, and metering stations, including scraper traps, strainers, and prover loops
•    Storage and working tanks, including pipe-type storage fabricated from pipe and fittings, and piping interconnecting these facilities
•    Liquid pertroleum and liquid anhydrous ammonia piping located on property which has been set aside for such piping within petroleum refinery, natural gasoline, gas processing, ammonia, and bulk plants
•    Those aspects of operation and maintenance of liquid pipeline systems relating to the safety and protection of the general public, operating company personnel, environment, property, and the piping systems

ASME B31.4 does not apply to
•    Auxiliary piping such as water, air, steam, lubricating oil, gas, and fuel
•    Pressure vessels, heat exchangers, pumps, meters, and other such equipment, including internal piping and connections for piping except as limited by Paragraph 423.2.4 (b) of ASME B31.4
•    Piping designed for internal pressures:
a.    At or below 15 psi (100 kPa) gauge pressure regardless of temperature
b.    Above 15 psi (100 kPa) gauge pressure if design temperature is below -20°F (-29°C) or above 250°F (120°C)
•    Casing, tubing, or pipe used in oil wells, wellhead assemblies, oil and gas separators, crude oil production tanks, other producing facilities, and pipelines interconnecting these facilities
•    Petroleum refinery, natural gasoline, gas processing, ammonia, and bulk plant piping, except as covered within the scope of the code
•    Gas transmission and distribution piping
•    The design and fabrication of proprietary items of equipment, apparatus, or instruments, except as limited by this code
•    Ammonia refrigeration piping systems provided for inASMEB31.5, Refrigeration Piping Code
•    Carbon dioxide gathering and field distribution systems

The rules of this code provide for protection of the general public and operating company personnel, for reasonable protection of the piping system against vandalism and accidental damage by others, and for reasonable protection of the environment.

Effective Edition, Addenda, and Code Cases
To determine the effective edition, addenda, and code cases for an application within the jurisdiction of ASME B31.4, follow the requirements delineated for ASME B31.1 for piping systems other than nuclear safety-related piping systems.

ASME B31.3: PROCESS PIPING

After planning for the vacation to the Ancol, and make preparation for everything, I think that would be enough for today, because I have to continue my job and input few data which is about welding consumable, etc. While I use the computer, so I stole few minutes to update this Piping & Fabrication blog and now we comes to ASME B31.3: PROCESS PIPING.

Scope
This code prescribes requirements for the materials, design, fabrication, assembly, erection, examination, inspection, and testing of piping within the property limits of facilities engaged in the processing or handling of chemical petroleum or related products. Figure A4.4 provides an illustration of the scope of ASME B31.3. The requirements of ASME B31.3 apply to piping for all fluids, including raw, intermediate, and finished chemicals; petroleum products, gas, steam, air, and water; fluidized solids; and refrigerants.

In case of packaged equipment, the interconnecting piping with the exception of refrigeration piping shall be in compliance with the requirements of ASME B31.3. The refrigeration piping may conform to either ASMEB31.3 orASMEB31.5.

The requirements of ASME B31.3 do not apply to piping systems designed for internal gauge pressures at or above 0 but less than 15 (100 kPa gauge) psig provided the fluid handled is nonflammable, nontoxic, and not damaging to human tissue and its design temperature is from -29°C (-20°F) through 180°C (366°F).

The following piping and equipment are not required to comply with the requirements of ASME B31.3:
•    Power boiler and the boiler external piping
•    Piping covered by ASME B31.4, B31.8, or B31.11, although located on the company property
•    Piping covered by applicable governmental regulations
•    Piping for fire-protection systems
•    Plumbing, sanitary sewers, and storm sewers
•    Tubes, tube headers, crossovers, and manifolds of fired heaters which are internal to the heater enclosures
•    Pressure vessels, heat exchangers, pumps, compressors, and other fluid-handling or processing equipment, including internal piping and connections for external piping

Effective Edition, Addenda, and Code Cases
The effective edition, addenda, and code cases shall be determined similarly to the approach delineated for ASME B31.1 for piping systems other than the nuclear safety-related piping systems.

FIGURE A4.4 B31.3 Jurisdictional Limits and Options.

USAS B31.2: FUEL GAS PIPING

Soon that my factory will make a family vacation, on July 3rd exactly and the destination is Taman Impian Jaya Ancol and that would be something for employee family, especially our kids. While I'm waiting for that time will comes, I will continue this Piping and Fabrication with USAS B31.2: FUEL GAS PIPING, and here we are.

In 1955 a decision was made to publish separate code sections of B31, Code for Pressure Piping. Consequently, Section 2 of B31.1-1955 was updated and revised to publish as USAS B31.2-1968, Fuel Gas Piping. No edition of this code section was published after 1968. This code was withdrawn in 1988.

Scope
USAS B31.2 covers the design, fabrication, installation, and testing of piping systems for fuel gases such as natural gas, manufactured gas, and liquefied petroleum gas (LPG); air mixtures above the upper combustible limit; LPG in the gaseous phase; or mixtures of these gases.
This code applies to fuel gas piping systems both within and between the buildings, from the outlet of the consumer meter assembly, and to and including the first pressure-containing valve upstream of the gas utilization device. This code does not apply to:

• Vacuum piping systems
• Fuel gas piping systems with metal temperatures above 450_F or below _20_F
• Fuel gas piping systems within petroleum refineries, loading terminals, natural gas processing plants, bulk plants, compounding plants, or refinery tank farms, and so forth within the scope of USAS B31.3
• Fuel gas piping systems in power and atomic energy plants within the scope of USAS B31.1
• Fuel gas piping systems within the scope of USAS B31.8
• Fuel gas piping systems within the scope of USAS Z21.30
• Piping systems within the scope of USAS Z106.1
• Proprietary items of equipment, apparatus, or instruments, such as compressors, gas-generating sets, and calorimeters
• Design and fabrication of pressure vessels covered by the ASME Boiler and Pressure Vessel Code
• Support structures and equipment such as stanchions, towers, building frames, pressure vessels, mechanical equipment, and foundations
• Piping systems for conveying premixed fuel gas-air mixtures which are in the combustible or inflammable limits or range

Effective Edition, Addenda, and Code Cases
USAS B31.2 is no longer used. It can be used for installations which were constructed in compliance with 1968 edition of this code, if permitted by the authorities having the jurisdiction.

ASME B31: CODE FOR PRESSURE PIPING & ASME B31.1: POWER PIPING CODE

ASME B31: CODE FOR PRESSURE PIPING
Another busy day and that would be a little bit late for me to post this blog and even there is so little time that Piping & Fabrication have, but that would be enough to post this ASME B31: CODE FOR PRESSURE PIPING & ASME B31.1: POWER PIPING CODE.

Starting with Project B31 in March 1926, the first edition of American tentative Standard Code for Pressure Piping was published in 1935. In view of continuous industry developments and increases in diversified needs over the years, decisions were made to publish several sections of the Code for Pressure Piping. Since December 1978, the American National Standards Committee B31 was reorganized as theASME Code for Pressure Piping B31 Committee under procedures developed by the ASME and accredited by ANSI.

Presently, the following sections ofASMEB31, Code for Pressure Piping are published:*
ASME B31.1      Power Piping
USAS B31.2       Fuel Gas Piping
ASME B31.3      Process Piping
ASME B31.4  Liquid Transportation Systems for Hydrocarbons, Liquid Petroleum Gas, Anhydrous Ammonia, and Alcohol
ASME B31.5     Refrigeration Piping
ASME B31.8     Gas Transmission and Distribution Piping Systems
ASME B31.9     Building Services Piping
ASME B31.11   Slurry Transportation Piping Systems

FIGURE A4.3 Jurisdiction of ASME B31.1, B31.4, and B31.8 Over Fuel Gas and Fuel Oil Piping

ASME B31.1: POWER PIPING CODE
Scope
ASME B31.1, Power Piping Code, prescribes requirements for the design, material, fabrication, erection, test, and inspection of power and auxiliary service piping systems for electric generation stations, industrial and institutional plants, central and district heating plants, and district heating systems. It does not apply to piping systems covered by other sections of the Code for Pressure Piping, and other piping which is specifically excluded from the scope of this code.

As explained earlier, the BEP is required to meet administrative jurisdictional requirements of ASME Section I; however, pipe connections meeting all other requirements of ASME B31.1 but not exceeding nominal pipe size (NPS) 1/2 may be welded to boiler external pipe or boiler headers without inspection and stamping required by ASME Section I.

Nonboiler external piping is defined as all the piping covered by ASME B31.1 with the exception of BEP. The nonboiler external piping must be constructed in accordance with the requirements of this code. In addition to the piping systems covered by other sections of ASME B31, Pressure Piping Code, ASME B31.1 does not cover the following:

• Economizers, heaters, pressure vessels, and components covered by the ASME Boiler and Pressure Vessel Code (except the connecting piping not covered by the ASME Boiler and Pressure Vessel Code shall meet the requirements of ASME B31.1)
• Building heating and distribution steam piping designed for 15 psig (100 kPa gauge) or less, or hot-water heating systems piping designed for 30 psig (200 kPa gauge) or less
• Piping for roof and floor drains, plumbing, sewers, and sprinkler and other fire protection systems
• Piping for hydraulic or pneumatic tools and their components downstream of the first stop valve off the system distribution header
• Piping for marine or other installations under federal control
• Piping covered by other sections of ASME B31 and ASME Section III
• Fuel gas piping within the scope of ANSI Z 223.1, National Fuel Gas Code
• Pulverized fuel piping within the scope of NFPA

The requirements of this code apply to central and district heating systems for distribution of steam and hot water away from the plants whether underground or elsewhere, and geothermal steam and hot water piping both to and from wellheads. The construction of fuel gas or fuel oil piping brought to plant site from a distribution system inside the plant property line is governed by the requirements of ASME B31.1 when the meter assembly is located outside the plant property line. In cases where the meter assembly is located within the plant property line, the requirements of this code shall apply to the fuel gas and fuel oil piping downstream from the outlet of the meter assembly (see Fig. A4.3).

This code also applies to gas and oil systems piping other than that shown in Fig. A4.3. It covers air systems, hydraulic fluid systems piping, and the steam-jet cooling systems piping which are part of the power plant cycle. In addition, building services within the scope of ASME B31.9 but outside the limits of Paragraph 900.1.2 of B31.9 are required to be designed in accordance with ASME B31.1.

Effective Edition, Addenda, and Code Cases
Prior to the publication and implementation of ASME Section III for construction of nuclear power plant components, in some nuclear power plants the safety-related piping systems now classified as ASME Classes 1, 2, and 3 were constructed to earlier versions of AMSE B31.1. Therefore, the repairs and replacements of those safety-related piping systems may be made in accordance with the edition and
addenda of ANSI B31.1 used for the original construction or the later edition and addenda of ANSI B31.1. Refer to Article IWA-4000 and Article IWA7000 of ASME Section XI for requirements related to repairs and replacements, respectively.

For power piping systems other than the nuclear safety-related piping systems constructed and new piping systems to be constructed to ASME B31.1, the following guidelines shall be used to determine the effective edition and addenda of ASME B31.1:

Editions are effective and may be used on or after the date of publication printed on the title page. Addenda are effective and may be used on or after the date of publication printed on the title page.

The latest edition and addenda, issued six months prior to the original contract date for the first phase of the activity covering a piping system(s) shall be the governing document for design, materials, fabrication, erection, examination, and testing activities for the piping system(s) until the completion of the work and initial operation.7 Unless agreement is specifically reached between the contracting parties, no code edition and/or addenda shall be retroactive.
Code cases may be used after they have been approved by the ASME Council. The provisions of a code case may be used even after its expiration or withdrawal, provided the code case was effective on the original contract date and it was used for original construction or was adopted prior to completion of work and the contracting parties agreed to its use.

Do not use revisions and code cases that are less restrictive than former requirements without having assurance that they have been accepted by the proper authorities in the jurisdictions where the piping is to be installed.

ASME SECTION XI: RULES FOR IN-SERVICE INSPECTION OF NUCLEAR POWER PLANT COMPONENTS

Talking about ASME is something that we have to careful, because there is so many of them and the function and Section is also different each other. But Piping & Fabrication will try to make it easy to all of us, today we will know about ASME SECTION XI: RULES FOR IN-SERVICE INSPECTION OF NUCLEAR POWER PLANT COMPONENTS

Scope
ASME Section XI comprises three divisions, each covering rules for inspection and testing of components of different types of nuclear power plants. These three divisions are as follows:

• ASME Section XI, Division 1: Rules for Inspection and Testing of Components of Light-Water-Cooled Plants
• ASME Section XI, Division 2: Rules for Inspection and Testing of Components of Gas-Cooled Plants
• ASME Section XI, Division 3: Rules for Inspection and Testing of Components of Liquid-Metal-Cooled Plants.

Since the publication of the first edition of ASME Section XI in 1971, significant changes and additions have been incorporated, and as such, the organization of the later versions of ASME Section XI, Division 1, is considerably different from that of the first edition.

ASME Section XI, Division 1, provides the rules and requirements for in-service inspection and testing of light-water-cooled nuclear power plants. The rules and requirements identify, as a minimum, the areas subject to inspection, responsibilities, provisions for accessibility and inspectability, examination methods and procedures, personnel qualifications, frequency of inspection, record-keeping and report requirements, procedures for evaluating inspection results, subsequent disposition of results of evaluations, and repair requirements.

Division 1 also provides for the design, fabrication, installation, and inspection of replacements. The jurisdiction of Division 1 of ASME Section XI covers individual components and complete power plants that have met all the requirements of the construction code, commencing at that time when the construction code requirements have been met, irrespective of physical location.

When portions of systems or plants are completed at different times, the jurisdiction of Division 1 shall cover only those portions on which all of the construction code requirements have been met. Rules of ASME Section XI apply to ASME Classes 1, 2, 3, and MC components and their supports, core support structures, pumps, and valves.

Rules of ASME Section XI, Division 1, apply to modifications made to ASME III components and their supports after all of the original construction code requirements have been met. Rules of ASME Section XI, Division 1, apply to systems, portions of systems, components, and their supports not originally constructed to ASME Section III requirements but based on their importance to safety if they were classified as ASME Classes 1, 2, 3, and MC.

Effective Edition, Addenda, and Code Cases
Section 10 CFR 50.55a, Codes and Standards, of the Code of Federal Regulations requires compliance with ASME Section XI for operating nuclear power plants. In addition, 10 CFR 50.55a, Paragraph (b)(2) delineates the editions and addenda of ASME Section XI that are approved for use. Only the approved editions and addenda of ASME Section XI are to be used. The latest published edition and addenda may not be approved by the U.S. NRC; therefore, they can only be used after seeking special permission from the U.S. NRC.

It is recommended that one refer to 10CFR 50.55a from time to time to determine which edition and addenda of ASME Section XI have been approved by the U.S. NRC and which edition and addenda may be applicable to a nuclear power plant at a particular time.

The requirements of 10 CFR 50.55a are based on the construction permit (CP) docket date and the operating license (OL) date of the nuclear plant. Code editions and addenda later than those established for a particular application in conformance with the requirements of 10 CFR 50.55a may be used provided they are approved and all related requirements of respective editions or addenda are met.

While establishing a particular edition and addenda of ASME Section XI, consider the limitations and modifications to the specific editions and addenda delineated in Paragraph (b)(2) of 10 CFR 50.55a, and ensure compliance to those limitations and modifications, as applicable.

For repairs and replacements, the applicable edition and addenda shall be the one in effect for that in-service inspection (ISI) interval during which the repairs and replacements are to be made. Refer to articles IWA-4000 and IWA-7000 of ASME Section XI.

Applicable Code Cases
Like the code edition and addenda, code cases are regularly reviewed by the U.S. NRC. The U.S. NRC–approved code cases with or without limitations or additional requirements are published in the Regulatory Guide 1.147, In-Service Inspection Code Case Acceptability of ASME Section XI, Division 1.4 Acceptance or endorsement by the U.S. NRC staff applies only to those code cases or code case revisions with the date of ASME Council approval, as shown in the Regulatory Guide 1.147.

ASME SECTION IX: WELDING AND BRAZING QUALIFICATIONS

I think this fast enough, because we already entering the ASME Section IX, which is about Welding and Brazing Qualification. With Piping and Fabrication I think we will continue this post step by step, and here we go.

Scope
ASME Section IX consists of two parts-Part QW and Part QB-which deal with welding and brazing, respectively. In addition, ASME Section IX contains mandatory and non mandatory appendixes. ASME Section IX requirements relate to the qualification of welders, welding operators, brazers, and brazing operators and the procedures used in welding and brazing. They establish the basic criteria for welding and brazing observed in the preparation of welding and brazing requirements that affect procedure and performance.

ASME Section IX is a supplemental code. The requirements of ASME Section IX apply when referenced by the governing code or standard or when specified in purchaser’s specification. It is usually referenced in other sections of the ASME Boiler and Pressure Vessel Code and the ASME B31, Pressure Piping Code.

Effective Edition, Addenda, and Code Cases
The applicable edition and addenda of ASME Section IX shall correspond to the edition and addenda of the referencing code. However, the later or the latest edition or addenda of ASME Section IX may be used, provided it is acceptable to the enforcement authorities having jurisdiction.

For safety-related items of an operating nuclear power plant, application of ASME Section IX will be in accordance with the requirements of ASME Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components.

For nonsafety-related items, the following guidelines apply:
•   Editions are effective and may be used on or after the date of publication on the title page.
•   Addenda are effective and may be used on or after the date of issue.
•  Addenda and revisions become mandatory as minimum requirements six months after the date of issue, except for pressure vessels or boilers contracted for prior to the end of the six-month period.
•   Code cases may be used beginning with the date of their approval by the ASME.
•   Use of revisions and addenda and code cases that are less restrictive than former requirements must not be made without assurance they have been accepted by the proper authorities in the jurisdiction where the item is to be installed.

ASME SECTION VIII: PRESSURE VESSELS

Let us continue with ASME SECTION and now we enter with the introducing of ASME Section VIII: Pressure Vessel and still with Piping & Fabrication who will lead you to the deepest knowledge of Piping System.

Scope
The rules of ASME Section VIII constitute construction requirements for pressure vessels. Division 2 of ASME Section VIII delineates alternative rules of construction to Division 1 requirements. However, there are some differences between the scopes of the two divisions. Recently added Division 3 provides Alternative Rules for Construction of High-Pressure Vessels.

The rules of ASME Section VIII apply to flanges, bolts, closures, and pressure relieving devices of a piping system when and where required by the code governing the construction of the piping. For example, ASME B31.1 requires that the safety and relief valves on nonboiler external piping, except for reheat safety valves, shall be in accordance with the requirements of ASME Section VIII, Division 1, UG-126 through UG-133.

Effective Edition, Addenda, and Code Cases
Editions are effective on—and may be used on or after—the date of publication printed on the title page. Addenda are effective on—and may be used on or after—the date of issue. Addenda and revisions become mandatory as minimum requirements six months after date of issuance, except for pressure vessels contracted for prior to the end of the six-month period.

Code cases may be used beginning with the date of their approval by the ASME. Use of revisions and addenda and code cases that are less restrictive than former requirements must not be made without assurance that they have been accepted by the proper authorities in the jurisdiction where the pressure vessel is to be installed.

ASME SECTION V: NONDESTRUCTIVE EXAMINATION

What can I said, Monday is a busy day and before all the job is coming to me soon, I'd better be post this one first which is about ASME SECTION V: NONDESTRUCTIVE EXAMINATION and I hope Piping & Fabrication will always give the best knowledge about Piping System.

Scope

ASME Section V comprises Subsection A, Subsection B, and mandatory and nonmandatory appendixes. Subsection A delineates the methods of nondestructive examination, and Subsection B contains various ASTM standards covering nondestructive examination methods that have been adopted as standards. The standards contained in Subsection B are for information only and are nonmandatory unless specifically referenced in whole or in part in Subsection A or referenced in other code sections and other codes, such as ASME B31, Pressure Piping Code.

The nondestructive examination requirements and methods included in ASME SectionVare mandatory to the extent they are invoked by other codes and standards or by the purchaser’s specifications. For example, ASME Section III requires radiographic examination of some welds to be performed in accordance with Article 2 of ASME Section V.5

ASME Section V does not contain acceptance standards for the nondestructive examination methods covered in Subsection A. The acceptance criteria or standards shall be those contained in the referencing code or standard.

Effective Edition, Addenda, and Code Cases

The applicable edition and addenda of ASME Section V shall correspond to the edition and addenda of the referencing code.

ASME SECTION III: NUCLEAR POWER PLANT COMPONENTS

Wow, this is make me so exhaust so I have to get some rest for even only a day and I choose Saturday to have some rest, pick up my daughter and then goes home. But now I'm ready again with Piping & Fabrication to continue about ASME Section and now we entering the ASME SECTION III: NUCLEAR POWER PLANT COMPONENTS.

Scope
Division 1 of ASME Section III contains requirements for piping classified as ASME Class 1, Class 2, and Class 3. ASME Section III does not delineate the criteria for classifying piping into Class 1, Class 2, or Class 3; it specifies the requirements for design, materials, fabrication, installation, examination, testing, inspection, certification, and stamping of piping systems after they have been classified Class 1, Class 2, or Class 3 based upon the applicable design criteria and Regulatory Guide 1.26, Quality Group Classifications and Standards for Water-Steam, and Radio-Waste- Containing Components of Nuclear Power Plants. Subsections NB, NC, and ND of ASME III specify the construction requirements for Class 1, Class 2, and Class 3 components, including piping, respectively. Subsection NF contains construction requirements for component supports, and a newly added Subsection NH contains requirements for 1 Class 1 Components in Elevated-Temperature Service. Subsection NCA, which is common to Divisions 1 and 2, specifies general requirements for all components within the scope of ASME Section III.

Division 3 of ASME Section III is a new addition to the code and contains requirements for containment systems and transport packaging for spent nuclear fuel and high–level radioactive waste. The construction requirements for ASME Class 1, Class 2, and Class 3 piping are based on their degree of importance to safety, with Class 1 piping being subjected to the most stringent requirements and Class 3 to the least stringent requirements. It is noted that a nuclear power plant does have piping systems other than ASME Class 1, Class 2, and Class 3, which are constructed to codes other than ASME Section III. For example, the fire protection piping systems are constructed to National Fire Protection Association (NFPA) standards, and most of the nonnuclear piping systems are constructed to ASME B31.1, Power Piping Code.

When joining piping systems or components of different classifications, the more restrictive requirements shall govern, except that connections between piping and other components such as vessels, tanks, heat exchangers, and valves shall be considered part of the piping. For example, a weld between an ASME Class 1 valve and ASME Class 2 piping shall be made in compliance with the requirements of Subsection NC, which contains rules for ASME Class 2 components, including piping (refer to Fig. A4.2). other components such as vessels, tanks, heat exchangers, and valves shall be considered part of the piping. For example, a weld between an ASME Class 1 valve and ASME Class 2 piping shall be made in compliance with the requirements of Subsection NC, which contains rules for ASME Class 2 components, including piping (refer to Fig. A4.2).

FIGURE A4.2 Code jurisdiction at interface welds between ASME III piping and components, and ASME/ANSI B31.1 piping. (a) Welds W1, W2, and W3 are between ASME III Class 1 piping and ASME III Class 1 valves/components. These welds shall comply with the requirements for ASME III Class 1 components. Weld W4 is between ASME III Class 1 valve and ASME III Class 2 piping. This weld shall comply with the requirements for ASME III Class 2 components; (b)Welds W1,W2, and W3 are between ASME III Class 2 piping and ASME III Class 2 valves/components. These welds shall comply with the requirements for ASME III Class 2 components. Weld W4 is between ASME Class 2 valve/component and ASME III Class 3 piping. This weld shall comply with the requirements for ASME III Class 3 components; (c) Welds W1, W2, and W3 are between ASME III Class 3 piping and ASME III Class 3 valves/components. These welds shall comply with the requirements for ASME III Class 3 components. Weld W4 is between ASME III Class 3 valve/component and ASME B31.1 piping. This weld shall comply with the requirements of ASME B31.1; (d) The connecting weld between two different ASME III classes of piping shall comply with more stringent requirements of the connecting classes of piping. In this case, the weld shall meet the requirements for ASME III Class 2 components; (e) The connecting weld between ASME III Class 3 and ASME B31.1 piping shall comply with more stringent requirements of ASME III Class 3 piping.

Effective Edition, Addenda, and Code Cases
Selection of effective editions and addenda of ASME Section III shall be based upon the following guidelines: Only the approved edition(s) and addenda of ASME Section III, incorporated by reference in 10 CFR 50.55a, Paragraph (b) (1) are to be used for construction of items within the scope of ASME Section III.

The latest published edition and addenda of ASME Section III may not be approved by the U.S. NRC; therefore, their use can only be made after seeking special permission from the U.S. NRC. Refer to 10 CFR50.55a, Codes and Standards from time to time to find which edition and addenda of ASME Section III have been approved by the U.S. NRC.

As per Sub subarticle NCA-1140, in no case shall the code edition and addenda dates established in the design specifications be earlier than three years prior to the date the nuclear power plant construction permit application is docketed. In addition, the guidelines of preceding paragraphs shall apply:
Code editions and addenda later than those established in the design specification and documents per the above-delineated approach may be used provided they are approved for use. Also, specific provisions within an edition or addenda later than those established in the design specifications and documents may be used provided all related requirements are met.

All code items, including piping systems, may be constructed to a single code edition and addenda, or each item may be constructed to individually specified code editions and addenda.

The use of code case(s) is optional. Only the U.S. NRC–approved code cases with or without limitations or additional requirements published in the following regulatory guides may be used without a specific request to the U.S. NRC for approval:

Regulatory Guide 1.84: Design and Fabrication Code Case Acceptability ASME Section III, Division 1.
Regulatory Guide 1.85: Materials Code Case Acceptability ASME Section III, Division 1.

The code cases not listed as approved in Regulatory Guides 1.84 and 1.85 may be used only after seeking permission from the U.S. NRC for the specific application.

ASME SECTION II: MATERIALS

Now, should we continue with ASME SECTION II: MATERIALS and of course Piping & Fabrication will told you details about it.

Scope
ASME Section II consists of four parts, three of which contain material specifications and the fourth the properties of materials which are invoked for construction of items within the scope of the various sections of the ASME Boiler and Pressure Vessel Code and ASME B31, Code for Pressure Piping. Therefore, ASME Section II is considered a supplementary section of the code.

Part A: Ferrous Material Specifications. Part A contains material specifications for steel pipe, flanges, plates, bolting materials, and castings and wrought, cast, and malleable iron. These specifications are identified by the prefix SA followed by a number such as SA-53 or SA-106.

Part B: Nonferrous Material Specifications. Part B contains materials specifications for aluminum, copper, nickel, titanium, zirconium, and their alloys. These specifications are identified by the prefix SB followed by a number such as SB-61 or SB-88.

Part C: Specifications for Welding Rods, Electrodes, and Filler Metals. Part C contains material specifications for welding rods, electrodes and filler materials, brazing materials, and so on. These specifications are identified by the prefix SFA followed by a number such as SFA-5.1 or SFA-5.27.

Part D: Properties. Part D covers material properties of all those materials that are permitted per Sections I, III, and VIII of the ASME Boiler and Pressure Vessel Code.
Subpart 1 contains allowable stress and design stress intensity tables for ferrous and nonferrous materials for pipe, fittings, plates, bolts, and so forth. In addition, it provides tensile strength and yield strength values for ferrous and nonferrous materials, and lists factors for limiting permanent strain in nickel, high-nickel alloys, and high-alloy steels.

Subpart 2 of Part D has tables and charts providing physical properties, such as coefficient of thermal expansion, moduli of elasticity, and other technical data needed for design and construction of pressure-containing components and their supports made from ferrous and nonferrous materials.

Effective Edition, Addenda, and Code Cases
The application of ASME Section II is mandatory only when referenced by other sections of the ASME Boiler and Pressure Vessel Code, ASME B31, Code for Pressure Piping, and various other industry codes and standards The applicable edition and addenda of ASME Section II shall correspond to the edition and addenda of the referencing code or standard.

Use of a later or the latest edition and addenda of ASME Section II is permissible provided it is acceptable to the enforcement authorities having jurisdiction over the site where the component is to be installed. For items within the scope of ASME Section XI, the effective edition and addenda of ASME Section II shall be in accordance with the requirements of ASME Section XI.

In case of nonnuclear items or applications, the effective edition addenda and code case shall be determined as described for ASME Section I. Use of code cases related to materials for ASME Section III applications may be made in accordance with the recommendations of Regulatory Guide 1.85, Materials
Code Case Acceptability, ASME Section III, Division 1. The code cases, as approved with or without limitations and listed in Regulatory Guide 1.85, may be used. The code case(s) not listed as approved in Regulatory Guide 1.85 by the U.S. Nuclear Regulatory Commission (NRC) may only be used after seeking approval from the NRC.

ASME SECTION I: POWER BOILERS

ASME Section I : Power Boilers will discuss here and we will talk it deeply and carefully because we will learn something precious and important, with Piping & Fabrication we will know more and more.

Scope
ASME Section I has total administrative jurisdiction and technical responsibility for boiler proper; refer to Fig. A4.1. The piping defined as boiler external piping (BEP) is required to comply with the mandatory certification by code symbol stamping, ASME data forms, and authorized inspection requirements, called Administrative Jurisdiction, of ASME Section I; however, it must satisfy the technical requirements (design, materials, fabrication, installation, nondestructive examination, etc.) of ASME B31.1, Power Piping Code.

FIGURE A4.1 ASME Section I jurisdictional limits and clarifications for jurisdiction over boiler external piping (BEP) and nonboiler external piping (NBEP)

Effective Edition, Addenda, and Code Cases
Code editions are effective on—and may be used on or after—the date of publication printed on the title page. Code addenda are effective on—and may be used on or after—the date of issue. Revisions become mandatory as minimum requirements six months after such date of issuance, except for boilers (or pressure vessels) contracted for before the end of the six-month period.

Use of revisions and code cases that are less restrictive than former requirements of the applicable edition and addenda shall not be made without assurance that they have been accepted by the proper authorities in the jurisdiction in which the power boiler (component) is to be installed. Use of code cases is permissible beginning with the ASME council approval date published on the code case.

AMERICAN SOCIETY OF MECHANICAL ENGINEERS (ASME)

It's about time that Piping & Fabrication talk about The American Society of Mechanical Engineers (ASME) is one of the leading organizations in the world which develops and publishes codes and standards. The ASME established a committee in 1911 to formulate rules for the construction of steam boilers and other pressure vessels. This committee is now known as the ASME Boiler and Pressure Vessel Committee, and it is responsible for the ASME Boiler and Pressure Vessel Code. In addition, the ASME has established other committees which develop many other codes and standards, such as the ASME B31, Code for Pressure Piping. These committees follow the procedures accredited by the American National Standards Institute (ANSI).

ASME BOILER AND PRESSURE VESSEL CODE
The ASME Boiler and Pressure Vessel Code contains 11 sections:
Section I Power Boilers
Section II Material Specifications
Section III Rules for Construction of Nuclear Power Plant Components
•    Division 1 Nuclear Power Plant Components
•    Division 2 Concrete Reactor Vessel and Containments
•    Division 3 Containment Systems and Transport Packaging for Spent Nuclear
Fuel and High-Level Radioactive Waste
Section IV Heating Boilers
Section V Nondestructive Examination
Section VI Recommended Rules for Care and Operation of Heating Boilers
Section VII Recommended Rules for Care of Power Boilers
Section VIII Pressure Vessels
•    Division 1 Pressure Vessels
•    Division 2 Pressure Vessels (Alternative Rules)
•    Division 3 Alternative Rules for Construction of High-Pressure Vessels
Section IX Welding and Brazing Qualifications
Section X Fiber-Reinforced Plastic Pressure Vessels
Section XI Rules for In-Service Inspection of Nuclear Power Plant Components
Code Cases: Boilers and Pressure Vessels
Code Cases: Nuclear Components

Primarily, Sections, I, II, III, IV, V, VIII, IX, and XI specify rules and requirements
for piping. Section II, V, and IX are supplementary sections of the code because
they have no jurisdiction of their own unless invoked by reference in the code of
record for construction, such as Section I or III.

Editions and Addenda
Code editions are published every three years and incorporate the additions and revisions made to the code during the preceding three years. Colored-sheet addenda, which include additions and revisions to individual sections of the code, are published annually. Before the 1986 edition of the code, addenda were published semiannually as summer and winter addenda.
   
Interpretations
ASME issues written replies to inquiries concerning interpretation of technical aspects of the code. The interpretations for each individual section are published separately as part of the update service to that section. They are issued semiannually up to the publication of the next edition of the code. Interpretations are not part of the code edition or the addenda.

Code Cases
The Boiler and Pressure Vessel Committee meets regularly to consider proposed additions and revisions to the code; to formulate cases to clarify the intent of the existing requirements; and/or to provide, when the need is urgent, rules for materials or construction not covered by existing code rules. The code cases are published in the appropriate code casebook: (1) Boiler and Pressure Vessel and (2) Nuclear Components. Supplements are published and issued to the code holders or buyers up to the publication of the next edition of the code.

Code case(s) can be reaffirmed or annulled by the ASME Council. Reaffirmed code case(s) can be used after approval by the council. However, the use of code case(s) is subject to acceptance by the regulatory and enforcement authorities having jurisdiction. A code case once used for construction may continue to be used even if it expires later or becomes annulled. An annulled code case may become a part of the addenda or edition of the code or just disappear after its annulment because there may not be any need for it

PIPING CODES AND STANDARDS

Now we entering the new chapter of Piping Systems which is PIPING CODES AND STANDARDS. Piping & Fabrication will explain it clearly and carefully so we all do understand what is Piping Codes and Standards.

Codes usually set forth requirements for design, materials, fabrication, erection, test, and inspection of piping systems, whereas standards contain design and construction rules and requirements for individual piping components such as elbows, tees, returns, flanges, valves, and other in-line items. Compliance to code is generally mandated by regulations imposed by regulatory and enforcement agencies. At times, the insurance carrier for the facility leaves hardly any choice for the owner but to comply with the requirements of a code or codes to ensure safety of the workers and the general public. Compliance to standards is normally required by the rules of the applicable code or the purchaser’s specification.

Each code has limits on its jurisdiction, which are precisely defined in the code. Similarly, the scope of application for each standard is defined in the standard. Therefore, users must become familiar with limits of application of a code or standard before invoking their requirements in design and construction documents of a piping system.

The codes and standards which relate to piping systems and piping components are published by various organizations. These organizations have committees made up of representatives from industry associations, manufacturers, professional groups, users, government agencies, insurance companies, and other interest groups.

The committees are responsible for maintaining, updating, and revising the codes and standards in view of technological developments, research, experience feedback, problems, and changes in referenced codes, standards, specifications, and regulations. The revisions to various codes and standards are published periodically. Therefore, it is important that engineers, designers, and other professional and technical personnel stay informed with the latest editions, addenda, or revisions of the codes and standards affecting their work.

While designing a piping system in accordance with a code or a standard, the designer must comply with the most restrictive requirements which apply to any of the piping elements. In regard to applicability of a particular edition, issue, addendum, or revision of a code or standard, one must be aware of the national, state, provincial, and local laws and regulations governing its applicability in addition to the commitments made by the owner and the limitations delineated in the code or standard. This chapter covers major codes and standards related to piping. Some of these codes and standards are discussed briefly, whereas others are listed for convenience of reference.

Tomorrow we will continue this chapter and with ASME, JIS, etc, we will know what is Piping Codes and Standards on Piping and Fabrication.

Nickel and Nickel Alloys

As I promised in the last post that I want to post about Nickel and Nickel Alloys in this Piping & Fabrication blog and here it is. Nickel is a tough, malleable metal that offers good resistance to oxidation and corrosion. When nickel is combined with copper as the secondary element, the well-known series of Monel alloys are created. Nickel,Monel, and various modifications of these materials are used in piping systems, turbine blading, valves, and miscellaneous power plant accessories handling steam.

TABLE A3.9 Nickel and Nickel-Based Pipe and Tubing Alloy Specifications

The presence of even a small amount of sulfur in a reducing environment will result in embrittlement as temperatures of 700–1200°F (370–650°C).

By addition of Cr, Co, Mo, Ti, Al, or Nb, the high temperature strength and creep resistance of the nickel-base materials can be substantially increased. However, these alloys possess low ductility values and require special care in forming of these materials, even at elevated temperatures. Table A3.9 lists a number of ASME specifications for nickel-based alloy piping and tubing.

Copper and Copper Alloys

TABLE A3.8 Copper and Copper-Based Pipe and Tubing Alloy Specifications

The use of copper and copper alloys is limited to temperatures below the lower recrystallization temperature for the particular alloy. This is the temperature at which cold-worked specimens begin to soften. This recrystallization is usually accompanied by a marked reduction in tensile strength. Typical classes of wrought copper based materials are given in Table A3.7.

Brasses containing 70 percent or more of copper may be used successfully at temperatures up to 400_F (200_C), while those containing only 60 percent of copper should not be used at temperatures above 300_F (150_C). The ASME Boiler and Pressure Vessel Code limits the use of brass and copper pipe and tubing (except for heater tubes) to temperatures not to exceed 406_F (208_C). The ASME B31 Code for Pressure Piping also limits brass and copper pipe and tubing to this temperature for steam, gas, and air piping. Table A3.8 lists a number of ASME specifications for copper and copper alloy piping and tubing. Tomorrow we will continue with Nickel and Nickel Alloy and still with Piping & Fabrication.

MATERIAL SPECIFICATIONS

It's been a busy day in the factory and I'm not too health either, but I have to post for Piping & Fabrication first and today it's about Material Specifications. The American Iron and Steel Institute (AISI) and the Society of Automotive Engineers (SAE) have devised a standardized numbering system for the various classes of carbon and alloy steels that has gained widespread acceptance in North America.

This system employs a four-digit number for carbon and low-alloy steels, and a three-digit number for stainless steels. Regarding the former, the first two digits represents the major alloying elements of the grade. The final two digits represent the nominal carbon content of each alloy, in hundreds of weight percent. For example, 10XX represents simple carbon steels, and 41XX stands for steels with chromium-molybdenum as the major alloying elements. In both classes, a specific grade possessing a nominal carbon content of 0.20 percent would be, respectively, 1020 and 4120. In this fashion the many possible alloy steels can be systematically identified.

Table A3.4 lists the carbon and alloy steel grades categories recognized by AISI and SAE.

TABLE A3.4 Carbon and Alloy Steel Grade Categories: AISI, SAE, UNS

TABLE A3.5 Selected Piping System Materials—ASME Specifications

TABLE A3.6 Cross-Reference for ASME to UNS Selected Pipe and Tubing Specifications

TABLE A3.7 Nominal Compositions of Wrought Copper Material

The stainless steels are assigned a three-digit code by AISI. Those austenitic stainless steels composed of chromium, nickel, and manganese are the 2XX series. Chromium-nickel austenitic stainless steels are 3XX; ferritic and martensitic stainless steels are 4XX. In the case of stainless steels, the last two digits represent a unique overall composition rather than the level of carbon.

Due to increasing international technical community involvement and cooperation, and with each country possessing its own alloy numbering system, a worldwide universal system of material identification was needed. The Unified Numbering System (UNS) was the result. In this system a letter is followed by a five-digit number which, taken together, uniquely defines each particular composition. Many of the conventions adopted in the AISI/SAE system were incorporated into the UNS numbers, as shown on Table A3.4.

The AISI and SAE specifications for alloys controls only material composition. Addition control over minimum properties, heat treatment, and other inspections was necessary to assure reproducibility and reliability of the materials for their intended purpose. The American Society for Testing and Materials (ASTM), the American Society of Mechanical Engineers (ASME), and the American Petroleum Institute (API) have generated a series of comprehensive material specifications that extend this control. Table A3.5 lists the more common ASME specification and grade numbers for the common piping system materials of construction. Table A3.6 gives equivalencies between selected piping material grades in ASME with the Unified Numbering System (UNS).

Oxide Thickness and Estimation of Remaining Creep Life

Something that I have to keep pushing myself more and more, so I didn't give up with the situation, so I keep trying to post this Piping & Fabrication and now we try to talk about Oxide Thickness and Estimation of Remaining Creep Life. 

Another method for estimating remaining creep life of certain high-temperature tubing and piping components considers the amount of metal oxide scale that has formed on the metals surface. Understandably, this method only applies when the tubular items contain relatively benign substances under oxidizing conditions. It has found its use in steam-carrying piping and components. This method is based on the knowledge that a given thickness of oxide scale on the tube or pipe surface represents growth for a certain time at some temperature. Since oxide growth kinetics of many alloys are well characterized, the effective temperature at which the tube was operating for a known time (service life) can be estimated. The combination of effective temperature and time can then be compared to the typical creep life of the alloy at an applied stress or stresses that are known to have acted on the component during its service life.

FIGURE A3.21 Variation of Larson-Miller rupture parameter with stress for wrought 1¹⁄₄ Cr ¹⁄₂ Mo-Si steel.

FIGURE A3.22 Variation of Larson-Miller parameter with stress for rupture of annealed 2¹⁄₄ Cr-1 Mo steel

As noted, the two principal tools needed by the metallurgist to estimate life using the oxide measurement technique are (1) steam oxidation data for the alloy in question, and (2) uniaxial creep-rupture data for that alloy across the temperature range of interest. This latter information can be found for many of the most widely used ferrous alloy piping materials in ASTM references. The specific steps followed in this approach are as follows:
1. Oxide thickness is measured either metallographically on a sample or using specialized ultrasonic techniques. Operating time is known.
2. The effective operating temperature is determined from the oxidation data. The effective temperature is defined as the constant temperature that the particular tube metal would have had to have operated at for the known service time to have resulted in the measured oxide thickness. (This is an approximation, since the tube or pipe would have operated at various temperatures, perhaps even in
upset conditions well above the design temperature limit.)
3. The hoop stress is calculated using an appropriate formula, knowing the tube or pipe size and operating pressure.
4. The Larsen-Miller Parameter (LMP) is calculated for the service time and effective temperature of the subject tube. The LMP is defined as:

Where T is temperature in degrees Rankine and t is time in hours. This is a simple factor representing the actual condition of the operating component.
5. Uniaxial creep-rupture data is obtained for the alloy in question. Examples of data for 11⁄₄Cr-1⁄₂Mo-Si and 21⁄₄Cr-1Mo, taken from creep data sources ASTM DS50 and DS652 are shown as Fig. A3.21 and Fig. A3.22. This rupture data is normally represented by curves of minimum and average behavior, and lists
applied stress versus LMP.
6. The ASTM rupture curve is entered on the stress axis at the level of appropriate calculated operating stress (from step 3). In this manner, the LMP representing the expected minimum and average total creep life at that stress is determined.
7. The operating LMP calculated in step 4 is compared to the LMPs derived in step 6. The differential in time represented by these parameters can be easily calculated from the Larsen-Miller formula, and the percentage of expended life versus minimum and average expected life can be determined by taking a ratio of these values.

This method for estimating remaining creep life has found its greatest use in the fossil power boiler industry, particularly for ferritic alloy steam piping and superheater tubing. Since a great majority of the operating power boilers in the United States are approaching their originally intended lifetime, the method is critical for establishing when major repair or replacement is necessary to restore the unit to safer and more reliable operation.

Creep Damage and Estimation of Remaining Creep Life

Creep Damage and Estimation of Remaining Creep Life is one of the important elements on Piping Materials and Piping & Fabrication will explain this one completely.

The type of damage observed in components operating at high temperatures, and high stress, typically progresses in stages occurring over a considerable period of time. Elongation or swelling of the component may be observed. Material damage manifests itself in the microstructure in characteristic form at grain boundaries. Voids will form first, which then subsequently link up to form cracks. These cracks increase in size or severity as the end-of-life condition is approached. Severe damage indications invariably signal the need for near-term corrective action. Such corrective action may entail repair or replacement of the component in question, depending upon the extent of the damage and the feasibility of repair. It is important to note that, except in the most severe cases, damage is not readily detectable by the naked eye, or even by conventional nondestructive techniques such as ultrasonic, magnetic particle, or liquid penetrant examination methods.

The degree of micro structural damage can be assessed by conventional metallographic procedures that may either take a destructive sampling approach or use nondestructive in-place (in-situ) methods. Since the determination of the structural damage allows for a ready estimation of expended creep-rupture life, these inspection methods have recently been adopted to piping and other structural components.
The power piping industry, in particular, has seen a wholesale application of metallographic examination to components that have experienced extensive time in elevated temperature service. Several serious steam line ruptures have caused deaths, serious injury, and significant lost operating time at fossil energy power plants. The steam lines that have come under the greatest scrutiny are reheat superheater piping which, based on their relatively large diameters and thin walls, had been made from rolled and welded plate. The failures have been associated with the longitudinal weld regions, which are inherently more susceptible to problems due to danger of latent defects (lack of fusion, slag entrapment, solidification cracks), and the variability in mechanical properties across the welds heat-affected zone.

Destructive sampling of material surfaces of suspected creep-damaged components, to allow for metallographic examination, has evolved to the point where there can be minimal disturbance to surrounding material. Test samples are either trepanned through thickness or smaller silver (boat-shaped) samples are removed by sawing, electro discharge machining, or other methods. However, arc gouging or any other form of heat-producing mechanism must be avoided. It not only can significantly metallurgically alter surrounding material but also can damage the destructive sample, sometimes rendering it unusable for microscopic analysis. The small samples, once properly removed, are metallographically prepared in the standard fashion. These are then examined at high magnification in metallurgical microscopes for evidence of creep damage. The area from which this sample was removed must be weld repaired, employing the required preheat, postweld heat treatment, and weld inspections.

Alternately, an evaluation of microstructure can be performed in place on the component surface, in the area of interest using a procedure called replication, which provides, in a manner of speaking, a fingerprint image of the surface. The area to be examined is first carefully polished to a mirrorlike finish using everincreasing fineness of sandpapers or grinding disks, and then polishing compounds. The surface is then etched with an appropriate acid. A thin, softened plastic film is then applied to the surface. Upon drying, the film hardens, retaining the microstructure in relief. When properly done by skilled technicians, the resolution of the metal structure at magnifications up to 500X or higher is almost equal to that achieved on an actual metal sample. The disadvantage of the replication method is that only the surface of the material can be examined, leaving any subsurface damage undetected. However, this method has proven useful when applied to weld regions, or other high-stressed areas where damage is suspected.

Remaining creep-life determination done in this fashion is not exact; the correlation between the type and degree of damage, and expended creep life is only approximate. In most cases, follow-up inspection several years hence is necessary to determine the rate of damage progression. Usually, when a network of microcracks has been generated, it is time to consider repair or replacement.

The science of estimating the expected growth rate of these cracks by creep evolved very rapidly in the 1980s. Armed with sufficient baseline creep data of a given alloy, formulas have been developed that can predict creep crack growth rates reasonably accurately. Analysis can also be made whether a pipeline would ‘‘leak before break’’; that is, weep fluid for a time prior to catastrophic rupture. All of these tools are available to the piping designer and to operating management, but will not be discussed in any greater detail in this chapter.

Intergranular Attack and Sigmatization on Piping Materials

Wow, today is very heat, the sun is like burning this place, me who working inside the container at the factory is really felt so hot because of the sun shining too bright. Lets forget about this heat and Piping & Fabrication will continue the post with Intergranular Attack and Sigmatization, and still on Piping Materials.

Intergranular Attack
When an unstabilized austenitic stainless steel is held at a temperature within the range of 850 to 1500°F (454 to 816°C), chromium carbides will quickly and preferentially form at the austenitic grain boundaries. The formation of these carbides deletes the surrounding grain matrix of chromium atoms, rendering the thin zone adjacent to grain boundary susceptible to corrosive attack in aqueous environments. This condition is called sensitization, and the resulting corrosion is termed intergranular attack (IGA).When also in the presence of local high-tension stresses, the result can be intergranular stress corrosion cracking (IGSCC). Avoidance of these failure mechanisms is best achieved by minimizing sensitization (fast cool from anneal; stabilized or L-grade steels), and eliminating local stresses.

The area of piping components most often attacked is weld regions. Sensitization can readily occur in a narrow band of base material in the heat-affected zone, caused by the heat of the weld pool. Corrosion of this area has been called knife line attack due to the characteristic appearance of a thin crack along a weld edge.

Sigmatization
A hard, brittle, nonmagnetic phase will form in some Fe-Cr and Fe-Ni-Cr alloys upon prolonged exposure to temperatures between about 1100 and 1475°F (593 and 800°C). Those austentic stainless steels containing higher alloy content, such as type 310 (25% Cr–20% Ni) are susceptible, as well as any grades that possess residual ferrite in their microstructure, a constituent which will transform to sigma,
preferentially at grain boundaries.

The most deterimental effect of sigma is reduction of toughness. Charpy Vnotch impact toughness can degrade to less than 10 ft • lb (14 joules) at room temperature if as much as 10 percent of the volume of material transforms. Toughness is usually not significantly degraded at higher temperatures, above about 1000°F (538°C).

Chemically, sigma is not as resistant to oxidizing media as the austenite, suchas acidic environments, thus, the materials will undergo intergranular attack. At normal metal operating temperatures in power plants, sigmatization of pressure piping made of these high-alloy materials takes very long times to form. Once formed, the phase can be redissolved by subjecting the material to an annealing heat treatment.

Graphitization on Piping Materials

Everything about Piping Systems will be explain in this blog, and Piping & Fabrication will continue now with Graphitization. Graphitization is a time- and temperature-dependent nucleation and growth process, in which iron carbide in the form of pearlite first spheroidizes, and later forms graphite nodules. There are two general types:
1. Formation of randomly, relatively uniformly distributed graphite nodules in the steel. This reduces the room temperature mechanical strength somewhat, but does not affect the creep-rupture strength at elevated temperature.
2. A concentrated formation of graphite most frequently along the edges of the heat-affected zone of weldments. This is referred to as chain graphite, since a plane of nodules exists paralleling the weld bead contours.

The formation of these nodules, when aligned through the wall of a pressure part, creates planes of weakness, subject to rupture. Fracture characteristically occurs without prior warning. The first graphitization failure of a low-carbon steam piping material occurred in the early 1940s. The failure occurred after five and a half years of service in a steam line made of aluminum-killed carbon-molydenum steel. The fracture surface was located approximately 1⁄₁₆ in (1.6 mm) from the fusion zone of a butt weld.

The failure precipitated numerous and extensive research programs to understand the key variables of the mechanism and to determine the steels which would resist graphitization. Research has helped in the understanding of the problem, and led to restrictions adopted by the various design codes on use of materials subject to graphitization. Carbon steel and carbon-molybdenum grades are the most susceptible to this degradation process, with the latter being more so. Relative susceptibility of these two grades is also dependent on the steel’s aluminum content; the more aluminum, the greater the susceptibility. Additions of chromium in amounts as low as 0.5 weight percent make the steel essentially immune to graphitization.

The ASME Code permits the use of carbon and carbon-molybdenum steels in ASME Section 1 boiler applications up to 1000_F (538_C). A cautionary note is provided in the allowable stress tables of Section I indicating the carbon steels and carbon-molybdenum steels may be susceptible to graphitization at temperatures above about 800 and 875_F (427 to 468_C), respectively. ASME B31.1 has a similar precautionary note specifying limits of 775 and 850_F (413 and 454_C), respectively.

Graphitization is a mechanism dependent on diffusion and is not associated with a precise temperature of initiation (it occurs sooner at higher temperatures). Thus, the differences between the design codes only reflect different levels of conservatism in dealing with the failure mode. Many manufacturers extend even more severe restrictions, some prohibiting the use of these steels in piping applications outside the boiler or pressure vessel where rupture creates a serious safety hazard. Substitution of chromium-containing steel grades, such as SA.335 P2(1/2 Cr-1/2Mo), P11 (1 1/4 Cr-1/2Mo), and P22 (2 ¼ Cr-1Mo), is normally recommended for these applications. Grade P91 (9Cr-1Mo-V) is increasingly being used in high-temperature applications where use of P11 and P22 is not desirable due to their reduced mechanical strength.

‘‘885°F’’ (474°C) Embrittlement

One of the limitations of ferritic stainless steels (those alloys of iron possessing greater than about 14 pecent chromium) has been the loss of toughness at room temperature that occurs after these materials are exposed for long times to temperatures in the range of 610 to 1000_F (320 to 538_C). This is commonly referred to as 885_F (474_C) embrittlement, corresponding approximately to the temperature at which many of the alloys degrade the fastest.

FIGURE A3.20 The classic Nelson diagram indicating the choice of steel warranted to avoid
hydrogen attack as a function of operating temperature and partial pressure of hydrogen. Austenitic
materials are satisfactory at all temperatures and pressure from hydrogen damage

 

The compositional effects in commercial alloys on 885_F (474_C) embrittlement have not been systematically investigated. However, it is clear that the degree of embrittlement increases as chromium content increases. The effects that other elements may have is not clear. Of these, most important is carbon, and it has been reported as having from no effect to a retarding effect on embrittlement.

This phenomenon results in increased hardness and strength, with a corresponding decrease in ductility, fracture toughness, and a decrease in corrosion resistance. Loss of toughness can be particularly severe, and in fact has tended to relegate the use of this class of alloy to temperature regimes below which significant embrittlement can occur.

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