The Pressure Vessel Inspections article provides you information about the inspection of pressure vessels and pressure vessel tests in a manufacturing shop. You may want to review the pressure vessel inspection procedure and corresponding inspection and test plan.
Pressure Vessel Definition – Based on the ASME Code Section VIII, pressure vessels are containers for the containment of pressure, either internal or external.
It means there is a defect if interpreted based on the full radiography criteria in UW-51, and it might be rejected, but if it is interpreted by the spot radiography criteria in UW-52, it might be accepted. Pressure Vessel RT Test - What is the Important Spot Radiography Requirement? One spot shall be examined on each vessel for each 50 ft. As per ASME, there are four types of Radiography test (RT), i.e. RT1, RT2, RT3 and RT4. Joint efficiency is the number used to define welded joint strength which basically depends on the RT type. This Joint efficiency plays a vital role in determining the thickness of the pressure vessel components in Mechanical calculation.
This pressure may be obtained from an external source, or by the application of heat from a direct or indirect source, or any combination thereof.
Click on the above link for detailed information about pressure vessel definition, scope, and boundaries based on ASME and API codes which specifically focus on pressure vessel inspections.
Figure 2.Sample vessel illustrating joint locations for RT-4 that will improve the shell long seam joint efficiency. Since circumferential stress governs cylindrical shell design, performing spot radiography on long seams is the easiest way to improve joint efficiency and thus reduce shell thickness. By CT and chest radiography, to better evaluate laryngeal. (rT3, rT4) or a histologically. Supracricoid partial laryngectomies were performed for rT1 and rT2 with suboptimal endoscopic. シートカバー,クロスロード シートカバー rt1 rt2 rt3 rt4 一台分 クラッツィオ eh-0461 クラッツィオ エアー air 内装 送料無料 - artofthenegrospiritual.com.
ASME Code Section 8 – ASME Code Section 8 is the construction code for Pressure Vessels.
This Code section addresses mandatory requirements, specific prohibitions, and non-mandatory guidance for pressure vessel materials, design, fabrication, examination, inspection, testing, certification, and pressure relief.
You may know that ASME Code Section 8 has three divisions. Division 1 covers pressure up to 3,000 psi, Division 2 has an alternative rule and covers up to 10,000 psi, and Division 3 can be used for pressure higher than 10,000 psi.
This section is divided into three parts: subsections, mandatory appendices, and non-mandatory appendices.
Subsection A consists of Part UG, covering the general requirements applicable to all pressure vessels.
Subsection B covers specific requirements that are applicable to the various methods used in the fabrication of pressure vessels. It consists of Parts UW, UF, and UB, and deals with welded, forged, and brazed methods, respectively.
Subsection C covers specific requirements applicable to the several classes of materials used in pressure vessel construction.
It consists of Parts UCS, UNF, UHA, UCI, UCL, UCD, UHT, ULW, and ULT dealing with carbon and low alloy steels, nonferrous metals, high alloy steels, cast iron, clad and lined material, cast ductile iron, ferritic steels with properties enhanced by heat treatment, layered construction, and low temperature materials, respectively.
Click on the above link for detailed information about ASME code section 8, which specifically focuses on pressure vessel inspections.
Pressure Vessel Plate Material – You have to be careful when choosing Pressure Vessel Plate Materials; there are lots of requirements and specific prohibitions in the ASME code.
Some of these requirements are ASME and Non ASME plate material, plate specification, inspection requirement and material test report.
ASME Code Sec VIII DIV 1 requires that materials that used for pressure containing parts are one of the materials specified in ASME section II, but with some restrictions which are stated in ASME Code Sec VIII Div 1 in subsection C e.g. UCS, UHF, UNF.
For example, SA 283 plate material is listed in ASME Sec II, but when you refer to subsection C in Sec VIII Div 1, you see it is not allowed to be used for lethal substance services as well as for unfired steam boilers. Also, you cannot use this material when you need your thickness to be greater than 5/8 of an inch.
Click on the above link for detailed information about pressure vessel plate materials which are specifically focused on pressure vessel inspections.
ASME Pressure Vessel Joint Efficiencies – You may know ASME Pressure Vessel Joint Efficiencies are linked to the radiography testing grades, and there is concession for full radiography testing per the UW-11(a) (5) (b) clause, which it is a little bit confusing.
Based on ASME Code requirements, manufacturers have to mark the type of RT, e.g. RT1, RT2, RT3 and RT4, in the pressure vessel name plate and state the same in the Pressure Vessel Data Report.
We have seen many professionals including inspectors and quality control engineers who are confused between RT1 and RT2, specifically when they see that the ASME Pressure Vessel Joint Efficiencies for both RT1 and RT2 is the same and is equal to 1(E=1);
They say both RT1 and RT2 are categorized in the “Full Radiography” part in UW-11 clause. So why are some joints in RT2 radiographed in spot? We are doing spot radiography, but it is categorized in full radiography!!!
Click on the above link to answer to this question, which specifically focuses on pressure vessel inspections.
ASME Impact Test Requirement – You need to take care about ASME Impact Test Requirement. Suggest you have pressure vessel in the design process and construction has not started yet.
Based on ASME impact test requirements, you need to make an assessment to see that either your pressure vessel is exempted from impact testing or you need to carry out the test.
There are 4 steps for impact test exemption assessment. You need to go through these steps, and you might be exempted in the first, second or third steps, and might not be exempted in step 4;
So if you are in step 4 and you have not exempted, then you need to carry out the test. This article explains you this assessment process.
First, you have to keep your pressure vessel design data available and then refer to UG-20 (f), if you are exempted from this clause, you do not need proceed anymore.
But if you are not exempted by UG-20 (f), you have to proceed to UCS-66(a). Again if you are exempted, there is no need for more assessment.
But if not, you have to proceed to UCS-66(b). If you are exempted now, no need for more assessment, otherwise you have to proceed to UCS-68(c). Again, if you are still not exempted; you have to carry out impact testing.
It means for some cases we might be exempted from ASME impact test requirement in first stage in UG-20 (f), in others in UCS-66(a) or UCS-66(b) or UCS-68(c) or might not be exempted and must prepare for doing this costly test.
This test would be more costly out of the US because of the Laboratory Accreditation requirement. The Accredited Laboratory based US accreditation system is not used too much in Europe, the Middle East and other locations.
Click on the above link for detailed information about the ASME Impact Test Requirement, which specifically focuses on pressure vessel inspections.
Pressure Vessel Dimension Inspection – Do you know what the Pressure Vessel Dimension Inspection requirement is? You may know some fabrication tolerances have not been addressed in ASME Code Section VIII.
So you need to refer to other sources for inspection. Most dimensional controls of Pressure Vessels are either addressed or not addressed in the ASME Code. They consists of the following items:
Pressure Vessel Inspections – Dimension
- Mill Undertolerance of Plates and Pipes
- Tolerances for Formed Heads
- Out of Roundness of Shell
- Nozzles and Attachments Orientation
- Nozzles and Attachments Projection
- Nozzles and Attachments elevation
- Nozzles and Attachments levelness
- Weld Mismatch
- Weld Reinforcement
Click on the above link for detailed information about Pressure Vessel Dimension Inspection, which specifically focuses on pressure vessel inspections.
Pressure Vessel RT Test – Do you know what your Pressure Vessel RT Tests Requirements are? Is full radiography mandatory for your vessel? When the full radiography is mandatory? What the acceptance criteria are? What the RT symbols are?
When one of following condition is existing, you need to do full radiography:
- All butt welds in vessels used to contain lethal substances
- All butt welds in vessels in which the nominal thickness exceeds specified values
- All butt welds in unfired steam boilers with design pressure > 50 psi
- All category A and D butt welds in a vessel when “Full Radiography” is optionally selected
As you see, the item numbers 1, 2 and 3 are really mandatory for the full RT test;
But the pressure vessel manufacturer may make an optional decision for full radiography in item number 4.
Why would pressure vessel manufacturers want to spent more money for full radiography in item Number 4?
Because joint efficiency in full radiography condition is 1, and the higher joint efficiency in the pressure vessel wall thickness formula causes less wall thickness, so the manufacturer might save lots of money with a lower thickness plate material.
But code has given some bonuses to the manufacturer in item 4, because it is not mandated to do really full radiography in all butt welds. The manufacturer can do spot radiography in B and C joints with the same joint efficiency of 1.
Click on the above link for detailed information about Pressure Vessel RT Tests which are specifically focuses on pressure vessel inspections.
Vessel Pressure Testing – You need to do a hydro-static test after the completion of construction process, but before the internal parts assembly, and also before the painting process.
Please note that performing the pneumatic test instead of the hydro-static testing is not allowed and it can be replaced only when it is not possible due to design and process.
Vessel Pressure Testing requirements have been addressed in UG-99 and UG-100 in ASME Code Section VIII Div. 1.
The activities are done in 3 stages; the activities before start of the test, the activities during test and the activities after the test.
Click on the above link for detailed information about pressure vessel hydro-static testing which is specifically focuses on pressure vessel inspections.
Pressure Vessel Certification – Do you know what the pressure vessel certification process is? How Pressure Vessel Manufacturers can be ASME Stamp Holders? How Third Party inspection companies can be certified by ASME and be Authorized Inspection Agencies? What is a “U” Stamped Pressure Vessel?
You may know pressure vessel manufacture certification is the same as the Authorization for the ASME Stamp.
The pressure vessel manufacturers can implement the ASME Quality Control System and then apply for ASME Stamp.
It means that if a manufacture accredited by the ASME organization for pressure vessel per ASME Code Section VIII Div. 1 can stamp the letter “U” in the pressure vessel nameplate. These are the processes for ASME Stamp Accreditation:
- Obtain Application Forms from ASME
- Sign a Service Agreement with an Authorized Inspection Agency (AIA) – Authorized inspection Agencies are Third Party Inspection Companies that have been accredited by the ASME organization and their inspectors certified by the National Board Inspection Code (NBIC).These Inspectors are named Authorized Inspectors and hold Commission Cards issued by the NBIC organization. Summary: AIAs are accredited by ASME, but the inspectors are certified by NBIC.
- Submit Application Forms to ASME and Transfer Fees
- Purchase ASME Code Books
- Describe a QC-System according to the ASME Code Quality Control manual and have the procedures prepared by the manufacturer.
- Prepare a Demonstration Item – A representative demo pressure vessel needs to be constructed and all drawings, calculations, parts lists, purchase orders, material test reports, fabrications, inspections, tests and reports should be based on the ASME code section VIII requirement.
- Qualify Procedures and Personnel – Quality Control Procedures and Personnel also need to be approved by manufacture.
- Pre-Joint Review by the Supervisor of AIA – It takes almost 4 months to fulfill the above requirements. Then an audit needs to be conducted by a supervisor authorized inspector, which is designated by the authorized inspection agency, which is under contract with the manufacturer. This auditor would report non-conformities found in the audit process, and then manufacturer would have some time to correct them.
- Joint Review (Audit) with ASME Designee, Inspector and Supervisor – Finally the Audit would be conducted by an ASME designated Person, Supervisor Authorized Inspector and Authorized Inspector. That is the reason this audit is called a joint review.
- Issuance of Certificate and Stamp by ASME
If the result of the audit was satisfactory, the certificate would be issued by ASME, and then the manufacturer would be authorized to stamps nameplates with the “U” Stamp.
Click on the above link for detailed information about Pressure Vessel Certification, which is specifically focuses on pressure vessel inspections. Kiss x sis watch online english dub cast.
Pressure Vessel Heads – How many standard Pressure Vessel Heads are in the ASME Code? What are their characteristics?
Ellipsoidal Head, Hemispherical Head and Torispherical Head are three types of ASME Pressure Vessel Dished Heads.
Under the same design conditions, such as design pressure, design temperature and material, your calculated wall thickness under internal pressure for ellipsoidal head will be approximately equal to the shell thickness. For a torispherical head, the thickness is equal to 1.77 times that of the ellipsoidal, and the shell thickness and for a hemispherical head is equal to half the shell thickness.
For example, if you have calculated your shell thickness under internal pressure and obtained 12 mm, your thickness for an ellipsoidal head will be approximately 12 mm; for a torispherical head, 20.4 mm; and for hemispherical head, 6 mm.
Click on the above link for detailed information about Pressure Vessel Heads, which specifically focuses on pressure vessel inspections.
Third Party Inspection for Pressure Vessel – What is the third party inspection requirement for pressure vessel inspection in a manufacturing shop?
This article provides information about pressure vessel inspection from material inspection to final inspection and dispatch to site.
Inspection and Test Plan for Pressure Vessel – The Inspection and testing requirement is distributed in a different part of the construction code.
The inspection and test plan have a tabulated format and collect all these requirements in a simple table and determine the responsibly of each party, i.e. the manufacturer, third party inspector and purchaser.
Pressure Vessel Handbook – When there is ASME Code Section VIII, why do we need the Pressure Vessel Handbook? What are the applications? All design formulas and calculations methods have not been addressed in ASME Code, and also, there are no fabrication tolerances in ASME Code.
So the Pressure Vessel Handbook assists us in covering all these requirements.
The Pressure Vessel Handbook supports pressure vessel inspections engineers, designers, pressure vessel manufacturer quality control technicians and engineers, and any other people who deal with pressure vessels.
Click on the above link for detailed information about the Pressure Vessel Handbook, which specifically focuses on pressure vessel inspection.
Spherical Pressure Vessel – What is the construction Code for a Spherical Pressure Vessel? What is the In-Service Code for Spherical Pressure Vessel? What are the Spherical Vessel applications? What are the advantages?
Click on the above link to see the answer to the above questions, which is specifically focuses on pressure vessel inspections.
Maximum Allowable Working Pressure – This article describes the differenec between design pressure and vessel MAWP
Pressure Vessel Inspections and ASME IX
The ASME Code Section VIII refers to the ASME Code Section IX for welding procedure specification, procedure qualification record and welding performance qualification.
Essential variables are variables (such as P number, A number, F number) that directly affect the mechanical property of material so need the re-qualification of procedure qualification.
The nonessential variable is the variables that are not affecting the mechanical property. The WPS must be revised and no need to be re-qualified. The supplementary essential variable will be essential variable when construction code requires impact testing. An example of the supplementary essential variable is Group number.
More articles about ASME Section IX
ASME Section IX Tensile Test – Provides information about tension test acceptance criteria for welding procedure qualification.
ASME Section IX Bend Test – Provides information about bend test acceptance criteria for both Welding procedure qualification and welder performance qualification.
ASME Section IX Heat Input – The heat input calculation applicable to the WPS’s which impact test is a requirement by construction code e.g., ASME Section VIII Div. 1
ASME Section IX Radiography – ASME Section IX Radiography – The requirement only is applicable for welder and welding operator qualification.
The ASME Pressure Vessel Joint Efficiencies article provides you with information about pressure vessel joint efficiency requirements and their connection with radiography testing.
You may know Pressure Vessel Joint Efficiencies are linked to the radiography testing grades and there is a concession for full radiography testing as per the UW-11(a) (5) (b) clause which it is a little bit confusing.
This article provides you the ASME pressure vessel joint efficiencies requirements and guidelines for the above clause.
Based on the ASME Code requirement, manufacturers have to mark the type of RT i.e. RT1, RT2, RT3 and RT4 in the pressure vessel name plate and state the same in Pressure Vessel Data Report.
The ASME Training Course is 5 days training course and available online and the student that successfully pass the exam, receive I4I academy certificate with 40 hours training credit.
We have seen many professionals, from inspectors to quality control engineers who are confused between RT1 and RT2, specifically when they see ASME Pressure Vessel Joint Efficiencies for both RT1 and RT2 is the same and equal to 1(E=1).
They say both RT1 and RT2 are categorized in the “Full Radiography” part in UW-11 clause ..
So why are some joints in RT2 radiographed in spots?
We are making spot radiography, but it is categorized in full radiography!!!
So in this 'ASME Pressure Vessel Joint Efficiencies' article we want to answer this question in very simple way, but before this, we need review joint categories and summarize them as below:
- All longitudinal welds in shell and nozzles
- All welds in heads, Hemisph-head to shell weld joint
- All circumferential welds in shell and nozzles
- Head to shell joint (other than Hemisph.)
Category C and D are flange welds and nozzle attachment welds respectively
Longitudinal welds (Category A) are more critical than Circumferential welds (Category B) because they are under double stress.
This the reason why in different part of ASME code we have stringent rules in category A joint compared to category B joint.
See the following Fig. for joint categories:
Now let's get back to the ASME Pressure Vessel Joint Efficiencies subject, to remove the above confusion about RT1 and RT2.
Rt1 Rt2 Rt3 Rt4 Radiography Test
We need to know:
When and where is there a code requirement for full radiography?
Item 1: All butt welds in vessels used to contain a lethal substance (UW-11(a)).Lethal substances have specific definitions in ASME Code in UW-2 and it is the responsibility of the end user to determine if they ordered a vessel that contains lethal substances.
Item 2: All butt welds in vessels in which the nominal thickness exceeds specified values (UW-11(a). You can find these values in subsection C, in UCS-57, UNF-57, etc. For example, this value for P-No.1 in UCS-57 is 1 ¼ inch.
Item 3: All butt welds in an unfired steam boiler with design pressure > 50 psi (UW-11(a)).
Item 4: All category A and D butt welds in vessel when “Full Radiography” optionally selected from table UW-12(column (a) in this table is selected); and categories B and C which intersect Category A shall meet the spot radiography requirement (UW-11(a) (5) (b)).
The point is this: items 1, 2 and 3 are similar, but item 4 is completely different. In items 1, 2 and 3 it is mandated by code; to do full radiography in all butt welds in vessel so it means it is mandatory for designer to select column (a) in UW-12 table.
Rt1 Rt2 Rt3 Rt4 Radiography Review
But in item 4, there is no mandating rule. A manufacturer with its own decision has chosen to use column (a) in table UW-12 for full radiography.
So here there is a concession or bonus to manufacturers for categories B and C.
What is concept behind this concession or bonus in pressure vessel RT test?
If you review item 1, 2 and 3 one more time, you will see that the pressure vessel RT tests are related to the type of welds and services.
You can see the pressure vessels in these items are critical from a safety point of view, one contains a lethal substance, the other one has a high thickness, which implicates high pressure, and the last one is an unfired steam boiler. But item 4 has no criticality like the other items have.
But you should note all 4 items have been categorized in full radiography clause( U-11(a)), so to differentiate item 1, 2 and 3 from item 4, the RT symbols are used in Code (UG-116).
RT 1: Items 1, 2 and 3, (E=1), All butt welds-full length radiography
RT 2: Item 4 (E=1), Category A and D butt welds full length radiography and category B and C butt welds spot Radiography
RT 3: (E=0.85), Spot radiography butt welds
RT 4: (E=0.7), Partial / No radiography
You need to consider the hemispherical head joint to shell as category A, but ellipsoidal and torispherical head joint to shell as category B;
Do you know why? Why ASME considered the stringent rule for pressure vessel RT test in hemispherical head joint?
It is because this joint is more critical, because the thickness obtained from the formula for hemispherical head approximately would be half of the shell thickness;
It means if the shell thickness is 1 inch, the hemispherical head thickness would be 0.5 inch.
For more detail, you may review the Pressure Vessel Heads article.
ASME Pressure Vessel Joint Efficiencies for welded Heads
For Welded Heads, the joint efficiency of the vessel will be 1(E=1), if all welds within the head's full length are radiographed (since they are all Cat. A welds). See above figure.
ASME Pressure Vessel Joint Efficiencies for Seamless Heads
For seamless heads, the joint efficiency of the vessel will be 1(E=1) if the head to shell weld is fully radiographed for the hemispherical Head (Cat A);
See the following Figure for RT types:
Spot radiographed for ellipsoidal and torispherical heads(Cat. B).
Here is some clarification about the different type of welds that have specific definitions in ASME Code SEC VIII DIV 1 and related to the pressure vessel RT test.
The concept is to define the different types and then introduce some restriction for using them.
For example, a Type 1 weld is defined as a full penetration weld, typically double welded and Type 2 is welds with backing strips.
So when you go to service restriction for a vessel containing a lethal substance, you see there is a restriction there that says all category A joints shall be weld Type 1 and Category B and C shall be type 1 or type 2.
You should take this point in to account, which is this: the same joint category with different weld types have different joint efficiencies.
Summary of weld types:
Type 1: Full penetration welds (Typically Double welded)
Type 2: Welds with backing strip
Type 3: Single welded partial penetration welds
Type 4, 5 and 6: Various Lap welds (rarely used)
Pressure Vessel Definition, Pressure Vessel Certification, Pressure Vessel Heads, Pressure Vessel Handbook, Spherical Pressure Vessel, Pressure Vessel Plate Material, ASME Code Section 8, ASME Impact Test Requirement, Pressure Vessel RT Test , Vessel Pressure Testing, Third Party Inspection for Pressure Vessel, Inspection and Test Plan for Pressure Vessel
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