API 510 Pressure Vessel Inspector

API 510 Pressure Vessel Inspector

Chapter 1

Interpreting ASME and API Codes Passing the API ICP examination is, unfortunately, all about interpreting codes. As with any other written form of words, codes are open to interpretation. To complicate the issue, different forms of interpretation exist between code types; API and ASME are separate organizations so their codes are structured differently, and written in quite different styles.

1.1 Codes and the real world

Both API and ASME codes are meant to apply to the real world, but in significantly different ways. The difficulty comes when, in using these codes in the context of the API ICP examinations, it is necessary to distil both approaches down to a single style of ICP examination question (always of multiple choice, single-answer format).

1.2 ASME construction codes

ASME construction codes (VIII, V and IX) represent the art of the possible, rather than the ultimate in fitness for service (FFS) criteria or technical perfection. They share the common feature that they are written entirely from a new construction viewpoint and hence are relevant up to the point of handover or putting into use of a piece of equipment. Strictly, they are not written with in-service inspection or repair in mind. This linking with the restricted activity of new construction means that these codes can be prescriptive, sharp-edged and in most cases fairly definitive about the technical requirements that they set. It is difficult to agree that their content is not black and white, even if you do not
agree with the technical requirements or acceptance criteria, etc., that they impose. Do not make the mistake of confusing the definitive
requirements of construction codes as being the formal arbiter of FFS. It is technically possible, in fact common-place, to use an item safely that is outside code requirements as long as its integrity is demonstrated by a recognized FFS assessment method.

1.3 API inspection codes

API inspection codes (e.g. API 510 Pressure Vessel Inspector) and their supporting recommended practice documents (e.g. API RP 572 and 576) are very different. They are not construction codes and so do not share the prescriptive and ‘black and white’ approach of construction codes. There are three reasons for this:
. They are based around accumulated expertise from a wide variety of equipment applications and situations.
. The technical areas that they address (corrosion, equipment lifetimes, etc.) can be diverse and uncertain.
. They deal with technical opinion, as well as fact.

Taken together, these make for technical documents that are more of a technical way of looking at the world than a solution, unique or otherwise, to a technical problem. In such a situation you can expect opinion to predominate.
Like other trade associations and institutions, API (and ASME) operate using a structure of technical committees. It is committees that decide the scope of codes, call for content, review submissions and review the pros and cons of what should be included in their content. It follows therefore that the content and flavour of the finalized code documents are the product of committees. The output of committees is no secret – they produce fairly well-informed opinion based on an accumulation of experience, tempered, so as not to appear too opinionated or controversial, by having the technical edges taken off. Within these constraints there is no doubt that API 510 Pressure Vessel Inspector API codes do provide sound and fairly balanced technical opinion. Do not be surprised, however, if this opinion does not necessarily match your own.

1.3.1 Terminology

API and ASME documents use terminology that occasionally differs from that used in European and other codes. Non-destructive examination (NDE), for example, is normally referred to as non-destructive testing (NDT) in Europe and API work on the concept that an operative who
performs NDE is known as the examiner rather than by the term technician used in other countries. Most of the differences are not particularly significant in a technical sense – they just take a little getting used to. In some cases, meanings can differ between ASME and API codes (pressure and leak testing are two examples).API 510 Pressure Vessel Inspector  API codes benefit from their principle of having a separate section (see API 510 section 3) containing definitions. These definitions are selective rather than complete (try and find an accurate explanation of the difference between the terms approve and authorize, for example). Questions from the ICP examination papers are based solely on the terminology and definitions understood by the referenced codes. That is the end of the matter.

1.3.2 Calculations

Historically, both API and ASME codes were based on the United States Customary System (USCS) family of units. There are practical differences between this and the European SI system of units. SI is a consistent system of units, in which equations are expressed using a combination of base units. For example: Stress = pressure X diameter / 2 X  thickness In SI units all the parameters would be stated in their base units, i.e.
Stress: N/m2 (Pa)
Pressure: N/m2 (Pa)
Diameter: m
Thickness: m
Compare this with the USCS system in which parameters may be expressed in several different ‘base’ units, combined with a multiplying factor. For example the equation for determining the minimum allowable corroded shell thickness of storage tanks is:
tmin =  (2.6H –  1)DG/SE
where tmin is in inches, fill height (H) is in feet, tank diameter (D) is in feet, G is specific gravity, S is allowable stress and E is joint efficiency.
Note how, instead of stating dimensions in a single base unit (e.g. inches) the dimensions are stated in the most convenient dimension for measurement, i.e. shell thickness in inches and tank diameter and fill height in feet. Remember that:
. This gives the same answer; the difference is simply in the method of expression.
. In many cases this can be easier to use than the more rigorous SI system – it avoids awkward exponential (106, 106, etc.) factors that have to be written in and subsequently cancelled out.
. The written terms tend to be smaller and more convenient.

1.3.3 Trends in code units

Until fairly recently, ASME and API codes were written exclusively in USCS units. The trend is increasing, however, to develop them to express all units in dual terms USCS(SI), i.e. the USCS term followed by the SI term in brackets. Note the results of this trend:
. Not all codes have been converted at once; there is an inevitable process of progressive change.
. ASME and API, being different organizations, will inevitably introduce their changes at different rates, as their codes are revised and updated to their own schedules.
. Unit conversions bring with them the problem of rounding errors. The USCS system, unlike the SI system, has never adapted well to a consistent system of rounding (e.g. to one, two or three significant figures) so errors do creep in.
The results of all these is a small but significant effect on the form of examination questions used in the ICP examination and a few more opportunities for errors of expression, calculation and rounding to creep in. On balance, ICP examination questions seem to respond better to being treated using pure USCS units (for which they were intended). They do not respond particularly well to SI units, which can cause problems with conversion factors and rounding errors.

1.4 Code revisions

Both API and ASME review and amend their codes on a regular basis. There are various differences in their approach but the basic idea is that a code undergoes several addenda additions to the existing edition, before being reissued as a new edition. Timescales vary – some change regularly and others hardly at all. Owing to the complexity of the interlinking and crossreferencing between codes (particularly referencing from API to ASME codes) occasional mismatches may exist temporarily. Mismatches are usually minor and unlikely to cause any problems in interpreting the codes. It is rare that code revisions are very dramatic; think of them more as a general process of updating and correction. On occasion, fundamental changes are made to material allowable stresses (specified in ASME II-D), as a result of experience with material test results, failures or advances in manufacturing processes.

1.5 Code illustrations

The philosophy on figures and illustrations differs significantly between ASME and API codes as follows:
. ASME codes (e.g. ASME VIII), being construction-based,contain numerous engineering-drawing style figures and
tables. Their content is designed to be precise, leading to clear engineering interpretation.
. API codes are not heavily illustrated, relying more on text. Both API 510 Pressure Vessel Inspector and its partner pipework inspection code, API 570, contain only a handful of illustrations between them.
. API Recommended Practice (RP) documents are better illustrated than their associated API codes but tend to be less formal and rigorous in their approach. This makes sense, as they are intended to be used as technical information documents rather than strict codes, as such. API RP 572 is a typical example containing photographs, tables and drawings (sketch format) of a fairly general nature. In some cases this can actually make RP documents more practically useful than codes.

1.6 New construction versus repair activity
This is one of the more difficult areas to understand when dealing with ASME and API codes. The difficulty comes from the fact that, although ASME VIII was written exclusively from the viewpoint of new construction, it is referred to by API 510 Pressure Vessel Inspector  in the context of in-service repair and,to a lesser extent, re-rating. The ground rules (set by API) to manage this potential contradiction are as follows (see Fig 1.1).
. For new construction, ASME VIII is used – and API 510 Pressure Vessel Inspector plays no part.
. For repair, API 510 Pressure Vessel Inspector is the ‘driving’ code. In areas where it references ‘the construction codes’ (e.g. ASME VIII), this is followed when it can be (because API 510 Pressure Vessel Inspector has no content that contradicts it).
. For repair activities where API 510 Pressure Vessel Inspector and ASME VIII contradict, then API 510 Pressure Vessel Inspector takes priority. Remember that these contradictions are to some extent false – they only exist because API 510 Pressure Vessel Inspector is dealing with on-site repairs, while

 

 

 

 

 

 

 

 

 

 

 

ASME VIII was not written with that in mind. API 510 Pressure Vessel Inspector Two areas where this is an issue are:
. some types of repair weld specification (material, fillet size, electrode size, etc.);
. how and when vessels are pressure tested.

1.7 Conclusion:

interpreting API and ASME codes In summary, then, the API and ASME set of codes are a fairly comprehensive technical resource, with direct application to plant and equipment used in the petroleum industry. They are perhaps far from perfect but, in reality, are much more comprehensive and technically consistent than manyothers. Most national trade associations and institutions do not have any in-service inspection codes at all, so industry has to rely on a fragmented collection from overseas sources or nothing at all. The API ICP scheme relies on these ASME and API 510 Pressure Vessel Inspector API codes for its selection of subject matter (the so-called ‘body of knowledge’), multiple exam questions and their answers. One of the difficulties is shoe-horning the different approach and style of the ASME codes (V,VIII and IX) into the same style of questions and answers that fall out of the relevant API documents (in the case of the API 510 Pressure Vessel Inspector ICP these are API 571/572/576/577). Figure 1.2 shows the situations. It reads differently, of course, depending on whether you are looking for reasons for difference or seeking some justification for
similarity. You can see the effect of this in the style of many of the examination questions and their ‘correct’ answers. Difficulties apart, there is no question that the API 510 Pressure Vessel Inspector API ICP examinations are all about understanding and interpreting the relevant ASME and API codes. Remember, again, that while these codes are based on engineering experience, do not expect that this experience necessarily has to coincide with your own. Accumulated experience is incredibly wide and complex, and yours is only a small part of it.

Non Destructive Testing

 

Non Destructive Testing  is the use of noninvasive techniques to determine the integrity of a material, component or structure or quantitatively measure some characteristics of an object. It is the testing of materials, for surface or internal flaws or metallurgical condition, without interfering in any way with the integrity of the material or its suitability for service.

i.e. Inspect or measure without doing harm.

Importance of Non Destructive Testing (NDT)

1.Non Destructive Testing (NDT) increases the safety and reliability of the product during operation.

2.It decreases the cost of the product by reducing scrap and conserving materials, labor and energy.

3.It enhances the reputation of the manufacturer as a  producer of quality goods. All of the above factors boost the sales of the product which bring more economical benefits for the manufacturer.

4.Non Destructive Testing (NDT) is also used widely for routine or periodic determination of quality of the plants and structures during service.

5.This not only increases the safety of operation but also eliminates any forced shut down of the plants.

Six Most Common Non Destructive Testing (NDT) Methods:

1. Visual Testing (VT)
2. Dye Penetrant Testing (DPT)
3. Magnetic Particle Testing (MPT)
4. Ultrasonic Testing (UT)
5. Eddy Current Testing (ECT)
6. Radiography Testing (RT)

Visual testing is the most basic and common inspection method involves in using of human eyes to look for defects. But now it is done by the use special tools such as video scopes, magnifying glasses, mirrors, or borescopes to gain access and more closely inspect the subject area.

Visual Testing Equipments:

• Mirrors (especially small, angled mirrors),
• Magnifying glasses,
• Microscopes (optical and electron),
• Borescopes and fiber optic borescopes,
• Closed circuit television (CCTV) systems,
• Videoscope.

Visual Testing Equipments

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Dye Penetrant Testing

This method is commonly used for detect the surface cracks or defects. Dye penetrant Testing (DPT) is one of the most widely used Non Destructive Testing (NDT) methods. DPT can be used to inspect almost any material provided that its surface is not extremely rough.

Dye Penetrant Testing Process

Three liquids are used in this method.

1.Cleaner

2.Penetrant

3.Developer

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Dye Penetrant Testing of a Boiler

 

 

 

 

 

 

 

 

 

 

 

 

 

At first the surface of the material that is to be tested is cleaned by a liquid. The liquid is called cleaner.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Then a liquid with high surface wetting characteristics is applied to the surface of the part and allowed time to seep into surface breaking defects. This liquid is called penetrant. After five or ten minutes the excess penetrant is removed from the surface.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Then another liquid is applied to pull the trapped penetrant out the defect and spread it on the surface where it can be seen. This liquid is called deveoper.

Findings

After Dye Penetrant Testing there are two surface cracks are Detected.

 

 

 

 

 

 

 

 

 

 

 

 

Advantages of Dye Penetrant  Testing

• This method has high sensitivity to small surface discontinuities.
• Large areas and large volumes of parts/materials can be inspected rapidly and at low cost.
• Indications are produced directly on the surface of the part and constitute a visual representation of the flaw.
• Aerosol spray can make penetrant materials very portable.
• Penetrant materials and associated equipments are relatively inexpensive.

Limitations of Dye Penetrant  Testing

• Only surface breaking defects can be detected.
• Precleaning is critical since contaminants can mask defects.
• The inspector must have direct access to the surface being inspected.
• Surface finish and roughness can affect inspection sensitivity.
• Post cleaning of acceptable parts or materials is required.
• Chemical handling and proper disposal is required.

Magnetic Particle Testing

This method is suitable for the detection of surface and near surface discontinuities in magnetic material, mainly ferrite steel and iron. Magnetic particle Testing (MPT) is a nondestructive testing method used for defect detection. MPT is fast and relatively easy to apply, and material surface preparation is not as critical as it is for some other Non-Destructive Testing (NDT) methods.

 

 

 

 

 

 

 

 

 

 

 

 

Basic Principle of MPT

 

 

 

 

 

 

In the first figure the magnetized metal has no crack and there only two poles that is north pole and south pole. And in second figure the magnetized metal has a crack and at the crack point there creates another north and south pole for the magnetic flux leakage.

Magnetic Particle Testing Process

The first step in a magnetic particle testing is to magnetize the  test component by a MPT equipment. If there any defects on the surface or near to the surface are present, the defects will create a leakage field.

Then finely milled iron particles coated with a dye pigment are applied to the specimen. These particles are attracted to magnetic flux leakage fields and will cluster to form an indication directly over the defects. This indication can be visually detected under proper lighting conditions.

 

 

 

 

 

 

 

 

Magnetic Particle Testing in Superheater Pipe Welding

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

First the welding joint is magnetized by MPT equipment. Then finely milled iron particles are applied to the magnetized weld joint.

Magnetic Particle Testing in Gas Pipe Welding:

Iron particles make a cluster at the welding joint for magnetic flux leakage because of welding defects.

Advantages Magnetic Particle Testing:

• It does not need very stringent pre-cleaning operation.
• It is the best method for the detection of surface and near to the surface cracks in ferromagnetic materials.
• Fast and relatively simple Non Destructive Testing (NDT)  method.
• Generally inexpensive.
• Will work through thin coating.
• Highly portable NDT method.
• It is quicker.

Limitations of Magnetic Particle Testing:

• Material must be ferromagnetic.
• Orientation and strength of magnetic field is critical.
• Detects surface and near-to-surface discontinuities only.
• Large currents sometimes require.

Ultrasonic Testing

This technique is used for the detection of internal surface (particularly distant surface) defects in sound conducting materials. In this method high frequency sound waves are introduced into a material and they are reflected back from surface and flaws. Reflected sound energy is displayed versus time, and inspector can visualize a cross section of the specimen showing the depth of features.

 

 

 

 

 

 

 

 

Basic Principle of Ultrasonic Testing

A typical UT system consists of several functional units, such as the pulser/receiver, piezoelectric transducer, and display devices. A pulser/receiver is an electronic device that can produce high voltage electrical pulses. Driven by the pulser, the transducer generates high frequency ultrasonic energy. The sound energy is introduced and propagates through the materials in the form of waves. When there is a discontinuity (such as a crack) in the wave path, part of the energy will be reflected back from the flaw surface. The reflected wave signal is transformed into an electrical signal by the piezoelectrical transducer and is displayed on a screen.

In the figure below, the reflected signal strength is displayed versus the time from signal generation, when a echo was received. Signal travel time can be directly related to the distance. From the signal, information about the reflector location, size, orientation and other features can sometimes be gained.

 

NON DESTRUCTIVE TESTING NDT

NON DESTRUCTIVE TESTING NDT:

• Introduction to NON DESTRUCTIVE TESTING NDT
• Overview of Six Most
• Common NDT Methods
• Principle, Working & Application

INTRODUCTION:

• What is  NON DESTRUCTIVE TESTING  NDT ?

                           The use of noninvasive techniques to determine the integrity of a material, component or structure or quantitatively measure some characteristic of an object.

i.e. Inspect or measure without doing harm.

What are Some Uses  of NON DESTRUCTIVE TESTING NDT Methods:

• Flaw Detection and Evaluation
• Leak Detection
• Location Determination
• Dimensional Measurements
• Structure and Microstructure Characterization
• Estimation of Mechanical and Physical Properties
• Stress (Strain) and Dynamic Response Measurements
• Material Sorting and Chemical Composition Determination

When are NON DESTRUCTIVE TESTING NDT Methods Used?

                There are NON DESTRUCTIVE TESTING NDT application at almost any stage in the production or life cycle of a component.

–To assist in product development

–To monitor, improve or control manufacturing processes

–To verify proper processing such as heat treating

–Fatigue and Creep damage prediction

–To inspect fitness-for-service evaluation

Major types of NON DESTRUCTIVE TESTING  NDT:

• Detection of surface flaws

1. Visual
2. Magnetic Particle Inspection
3. Fluorescent Dye Penetrant Inspection

• Detection of internal flaws

1. Radiography
2. Ultrasonic Testing
3. Eddy current Testing

Visual Inspection:

1. Most basic and common inspection method.
2. Visual inspection refers to an NON DESTRUCTIVE TESTING  NDT method which uses eyes, either aided or non-aided to detect, locate and assess discontinuities or defects that appear on the surface of material under test.
3. Tools include fiberscope’s, borescopes, magnifying glasses and mirrors.
4. Defects such as corrosion in boiler tube, which cannot be seen with naked eyes can easily be detected and recorded by using such equipment.

APPLICATIONS:

1. Portable video inspection unit with zoom allows inspection of large tanks and vessels, railroad tank cars, sewer lines.
2. Remote visual inspection using a robotic crawler.
3. Robotic crawlers permit observation in hazardous or tight areas, such as air ducts, reactors, pipelines

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Advantages :-

• Cheapest NON DESTRUCTIVE TESTING NDT method
• Applicable at all stages of construction or manufacturing
• Do not require extensive training
• Capable of giving instantaneous results

Limitation :-

• Limited to only surface inspection
• Require good lighting
• Require good eyesight

 

 

 

 

 

API 570 Question

1.For 8” ND Sch 40 and   8” ND Sch 80 pipes,

1. OD for both pipes will be same
2. IDs and ODs for both pipes will be different
3. Average pipe diameters for both will be same
4. ID for both pipes will be same

 

2.Hot tapping is best described by statement:

1. It is technique of heating the pipe to specified temperature and gently tapping with 1 lb. rounded hammer to detect thinning of pipe wall
2. It is technique of providing a tapping connection while pipe system is in operation
3. It is technique of fixing a water tap on hot water lines for use during winter
4. It is act of using the tap and die for threading the pipe when the pipe is hot

 

3.Which of the following defines the term hold point?

1. The point at which a pipe hanger is attached to a pipe.
2. A point at which a U-clamp is fixed on the pipe.
3. A point at pipe beyond which work may not proceed until inspections have been performed and documented
4. A trunnion, or sliding shoe used for piping support systems

 

4.Which of the following statements is true?

1. Flange rating indicates flange diameter.
2. Other factors remaining same, ERW pipes can withstand higher pressure than seamless pipes.
3. Deadlegs means pipes with broken supports.
4. API 570 is applicable for metallic pipes only.

 

5.Post weld heat treatment is carried out

1. To increase Hardness
2. To increase Tensile strength
3. To release locked-up stresses in the weld
4. None of above.

 

6.What section of the ASME boiler and pressure vessel code is the basic document for welding procedure qualification?

1. Section III
2. Section VIII
3. Section IX
4. ASME Section II C

 

7.What can be caused to ferrous metals by the low operating temperatures?

1. Increase of ductility
2. Loss of ductility and toughness
3. Increase in plasticity or deformation
4. Decrease in yield strength

 

8.API 570 is intended to apply to:

1. New piping in the chemical Industry
2. Piping that has been placed in service
3. New piping in the Petroleum Refinery
4. New piping in the Paper Industry

 

9.If a welder is to be qualified in all positions he must pass test in which positions?

1. 1G, 2G, 3G and 4G
2. 5G and 4G
3. 6G
4. 5G and 4G

 

10.ASTM A 106 Gr B pipes belong to which type?

1. Seamless only
2. ERW only
3. Seamless or ERW depending on type of Grade
4. None of above

 

 

Welder Training

TRAINING MODULES OF ESL:

• SMAW – ARC (1G to 4G)
• GTAW – TIG (1G to 6G)
• GMAW – MIG (1G to 4G)

WHAT IS WELDING?

Welding is nothing more than the art of joining metals together. It is one of the most valuable technologies that played a huge part in the industrial revolution, and is the back bone to the world’s militaries. Welding today is comprised of three main ingredients which are required to join metals together.

WPQ (Welder Performance Qualification)

WPQ will be performed as per ASME Sec IX/AWS D1.1 code with welder ID continuity record will be provided

ARC WELDING:

ARC Welding is a slang term commonly used for Shielded Metal Arc Welding or “SMAW”. Arc welding is the most basic and common type of welding processes used. It is also the first process learned in any welding school. Arc is the most trouble free of all of the welding processes and is the fundamental basis for all the skills needed to learn how to weld.

TIG WELDING:

TIG Welding is also a slang term commonly used for Gas Tungsten Arc Welding or “GTAW”. TIG welding also goes by the term HeliArc welding. TIG welding is the most difficult of the processes to learn, and is the most versatile when it comes to different metals. This process is slow but when done right it produces the highest quality weld! TIG welding is mostly used for critical weld joints, welding metals other than common steel, and where precise, small welds are needed.

MIG WELDING

MIG Welding is a slang term that stands for Metal Inert Gas Welding, the proper name is Gas Metal Arc Welding or “GMAW”, and it is also commonly referred to as “Wire Wheel Welding” by Unions. MIG Welding is commonly used in shops and factories. It is a high production welding process that is mostly used indoors.

POSITION REQUIRED:

PROCESS	MATERIAL	JOINT	POSITION
SMAW (ARC)	PLATE	GROOVE/ FILLET	1G TO 4G
GTAW (TIG)	PIPE/ TUBE	GROOVE/ FILLET	1G TO 6G
GMAW (MIG)	PLATE	GROOVE/ FILLET	1G TO 4G

 

 

 

 

 

API 510 Questions

 

1. A PQR was qualified in SG position using a new welder. But production welding is to be done by   the same welder in 3G position. Which of the following are applicable as a minimum?

1. Both procedure and welder shall be re-qualified in 2G position.
2. The qualified procedure can be used, only welder needs to be re-qualified in 3G position.
3. The welder is qualified, but the procedure needs re­-qualification.
4. Both procedure and welder need not be re-qualified.

2. A procedure is required with preheat temp = 2S0oF. Two WPS were made based on this PQR. All other parameters being same WPS (A) showed preheat temp = 280°F and WPS (B) showed preheat temp = 140°F, will you:

1. Reject (A) & (B)
2. Accept (A) only
3. Accept (B) only
4. Accept both

3. In a certain PQR for SMAW, the electrodes used for all passes were of AWS classification (E7018). Corresponding WPS also showed filler materials as E 7018. Now the manufacturer proposes to change the filler material in WPS to E 701S. Will you ask manufacturer to:

1. Quality new PQR with E 7015 electrodes.
2. Revise only WPS showing the change from E 7018 to E7015 and submit WPS as a new    revision.
3. Revise only the PQR showing the change and resubmit for approval.
4. Revise both WPS and PQR showing the change and resubmit for approval.

4. A PQR in GTAW process was qualified with PWHT with A 516 grade 70 materials, ¾” thick. The thickness for production welds is 1.0”, but without PWHT. The manufacturer claims that same PQR will be O.K. What is your assessment?

1. It qualifies required conditions hence no new PQR is required.
2. It qualifies thickness but not It does not qualify “No PWHT” condition, hence new PQR is   required.
3. It qualifies “no PWHT” condition, but not thickness. New PQR is required.
4. It does not qualify both thickness as well as “No PWHT” – condition, hence new PQR is    required. ­

5. For 515 grade 60 material, the following results were obtained for two tensile test specimen during   a PQR qualification.

Specimen T1: failed in B.M. at 57,400 psi

Specimen T2: failed in weld metal, at 59,500 psi

Your assessment is:

1. PQR test is OK since both are within acceptance criteria
2. PQR test is rejected as both T1 and T2 are not within the acceptance criteria
3. PQR in rejected because T1 is OK but T2 has failed
4. PQR in rejected because T1 is failed thoughT2 is OK

6. A procedure is qualified with Base metal THK. = 20mm. Two WPS were made based on this PQR. Other parameters being same, WPS (A) showed Base Metal Thk. = 38 mm and WPS (B) showed Base Metal Thk. = 6mm.  

Your assessment is

1. Reject (A) & (B)
2. Accept (A) only
3. Accept (B) only
4. Accept both

7. A welder has made 25 SMAW groove welds, but the guided bend test for the welder’s qualification was never performed. In order to avoid cutting out all of the production welds made by this welder, which of the following minimum steps would be taken to validate the qualification?

1. Radiograph the welder’s first production weld and accept the qualification based on acceptable weld quality by radiography.
2. There is no alternative to qualifying a welder by the guided bend test.
3. Have the welder prepare a test coupon and have the bend test done on that. If bend test is okay,    accept the welds already made.
4. Radiograph all 25 welds, regardless of the governing specifications for sample selection.

8. In a radiographic examination of butt weld (Thk= 3.5 in.) the Geometric un-sharpness shall not exceed?

1. 0.02″
2. 0.04″
3. 0.03″
4. None of above

9. Select suitable Hole Type (Source Side) penetrameter for following weld joint:

Base Mertal Thk. = 7/8”

Backing Strip Thk. = 3/16”

Weld Re-enforcement Thk. = 1/8”

1. No. 20
2. No. 25
3. No. 30
4. None of the above

10. If type of penetrameter in above question is changed to wire type what shall be the wire designation                                                 (wire diameter In  Inch)?

1. 0.025 dia. (No.10)
2. 0.016 dia. (No. 8)
3. 0.032 dia. (No.11)
4. None of the above

11. For steel plates and welds to be checked by LPI what shall be the penetration time for the Penetrant?

1. 10 min for weld, 5 min for plate
2. 5 min for both
3. 10 min for both
4. 5 min for weld, 10 min for plate

12. After applying the developer the examiner checked four welds for surface defects after following period,                                       weld A after 5 minute,weld B after 10 minutes, weld C was checked after 30 minutes and welds D                                                       after 65 minutes. Which of the welds were checked wrongly?

1. Weld A and B
2. Weld C and D
3. Weld D only
4. Weld A and D

13. For MT examination by Prod Technique the spacing between prods shall be between?

1. 4 inch to 12 inch
2. 4 inch to 10 inch
3. 3 inch to 10 inch
4. 3 inch to 8 inch

14. Calculate estimated inspection period for external and internal inspection for a vessel whose remaining                                         life is estimated as 12 years?

1. Internal = 6 years, external = 10 years
2. Internal = 6 years, external = 5 years
3. Internal = 5 years, external = 10 years
4. None of the above

15.As per WPS the material used is SAS16 Gr.70 and the electrode used is E-7018. What are the P. No. and F No.?

1. 1 and 4
2. 4 and 1
3. 2 and 4
4. 4 and 2

 

­

 

­Q. NO.	ANSWER
1	4
2	2
3	2
4	2
5	3
6	4
7	1
8	2
9	2
10	4
11	4
12	4
13	4
14	2
15	1

 

 

 

EDDY CURRENT

1. In a feed through encircling coil eddy current system, what would be the purpose of running a calibration defect several times but in various positions (such as top, bottom, left and right)?

a.To check the phase selectivity

b.To ensure proper centring of the material in the test coil

c.To select the modulation analysis setting

d.To select the proper operation speed

2.In a feed through encircling coil eddy current system, a calibration standard may be used to:

a.Insure repeatability of the setup

b.Calibrate the approximate depth of the detectable flaws

c.Both a and b

d.Measure the test frequency

3.A calibration standard may be used with a spinning probe eddy current instrument to:

a.Produce an indication relative to the depth of the flaw

b.Check the instrument for reliability and freedom from drift

c.Check probe coil for possible damage

d.All of the above

4.Spinning probe type eddy-type eddy current instruments are most useful in:

a.Detection of surface and subsurface inclusions

b.Detection of surface defects such as overlaps and seams

c.Detection of internal piping or burst

d.All of the above

5.A product can be viewed in terms of electrical magnetic effects. A diameter change of the product in an encircling coil is:

a.An electrical effect

b.A conductivity effect

c.A magnetic effect

d.All of the above

6.In figure 9, AC flowing through a primary coil set-up a magnetic field and causes a flow of eddy currents in the rod. The voltage of the secondary coil is dependent upon:

a.These eddy currents

b.The primary coil

c.The generator

d.All of the above

7.Which of the following is not a method that may be used to improve the signal-to-noise ratio?

a.Change to test frequency that will decrease the noise

b.Increase the amplification of the test instrument

c.Improve the fill factor

d.Add filter circuits to the instruments

8.In eddy current testing, the theoretical maximum testing speed is determined by the:

a.Magnetic flux density

b.Testing frequency

c.Conveyor drive

d.Test coil impedance

9.In eddy current testing of ferromagnetic materials, the dc saturating field may be provided by :

a.An encircling solenoid

b.A magnetic yoke

c.Both a and b

d.None of the above

10.Which of the following is a property of eddy currents induced in a conductor by an encircling coil?

a.The magnitude of eddy current flow is large compared to the current flow in the coil

b.The eddy current flow is affected by permeability variation in the samples

c.The eddy current flow dissipates no power in the conductor

d.None of the above

11.Which of the following is a property of eddy currents induced in a homogeneous conductor by an encircling coil?

a.They are weakest on the conductor surface

b.The phase of the eddy currents varies through out the conductor

c.They travel in straight lines

d.They are maximum along the coil axis.

12.Which factor does not affect the phase shift between the transmitted signal and the reflected signal for a reflection type coil(assuming the part is nonferromagnetic)?

a.The conductivity of the sample

b.The magnitude of the transmitted signal

c.The signal of the sample

d.The presence of defects in the sample

13.Lift-off certainly reduces the amplitude of the flux leakage signal. The other significant effect it has on the signal is a change in:

a.Phase

b.Frequency

c.Increasing lift-off which reduces the apparent width of the defect

d.None of the above

14.The tubular product parameter having the greatest influence on the flux density of the magnetic field in the part (assuming the magnetizing force, H, remains constant)is the :

a.Surface roughness of the product

b.Diameter of the product

c.Wall thickness of the product

d.Length of the product

15.Any handling of equipment used in an eddy current system must take into consideration:

a.The operator ‘s abilities

b.The use of the product being tested

c.Speed, frequency of test, sorting speed, and physical control of the product

d.All of the above

16An eddy current system lends itself to quality ratings such as “Quality Number” where the product being inspected:

a.Is not defective

b.Does not allow defective areas to be removed

c.Is of inferior quality

d.Has inconsistent quality

17.When inspecting material with eddy currents in an automatic handling system, it is advisable to calibrate and adjust the sensitivity levels to:

a.Some electroic source

b.Another NDT method

c.An NBS standard

d.An actual testpart being inspected

18.A distinct advantage of using handling equipment in an eddy current test system is to reduce the error caused by:

a.Instrument drift

b.Lift-off

c.Skin effect

d.All of the above

e.None of the above

19.Decreased coupling or fill factor results in decreased test sensitivity because:

a.Reduced coupling between the driver coil and the specimen induces less eddy current flow in the specimen

b.Reduced coupling between the specimen and the pickup coil results in smaller voltages across the pickup coil

c.Electrical circuits designed to provide fill factor compensation may prove to be inadequate, depending upon the extent of fill factor loss

d.All of the above

20.Why is it desirable to hold the factor or lift-off constant?

a.To avoid arcing between the coil and the specimen

b.To minimize tester output signal changes that are not relevant to conditions with in the specimen to be tested.

c.A fill factor or lift-off change will shift the operating frequency

d.To minimize the load on the constant current ac excitation circuits

21.The reactance component is decreased by placing a conducting object in the coil’s electromagnetic field. Why is this so?

a.The secondary field is exactly in phase with the primary field

b.The secondary field is at precisely 90 degrees with the primary field

c.The phase angle between the two field components is always greater than 90 degrees which partially cances the primary field

d.The secondary field is 180 degrees out of phase with the primary field which causes a large phase shift

22.Test coils may be shielded with conducting material or magnetic material to:

a.Shape field

b.Increase sensitivity

c.Increase resolution

d.All of the above

e.None of the above

23.When a magnetic bar is placed in the coil’s electromagnetic field,the coil’s reactance is increased. What causes this phenomena?

a.The coil becomes magnetic ally saturated

b.The permeability raises the inductance of the test coil

c.The magnetic test sample’s conductivity increases the reactance value of the coil

d.This effect is described mathematically by thr equation B/H=μ

24.When an excitation voltage is applied to a primary winding, only the magnetic flux is in phase and the secondary magnetic flux is minor. When a test object is inserted in this coil, what action takes place?

a.The object gets hot and no information is available

b.Insertion of the object cancels all information

c.The insertion of the test object intensifies the secondary magnetic flux producing a new total magnetic flux which can be used to supply test information

d.By subtracting the primary voltage from the secondary voltage, the net voltage is obtained

25.The test coil excitation current should be held constant so that the test piece information obtained by an eddy current system will:

a.Contain only flaw information and not indicate variations in magnetic field strength

b.Not contain signals generated by cross talk

c.Not contain electrical noise

d.All of the above

26.Eddy currents flowing in the test object at any depth produce magnetic fields at greater depths, which oppose the primary field, thus breducing its effect and causing what kind of change in current flow as depth increases?

a.A decrease

b.An increase

c.A frequency change

d.None of the above

27.Skin effect causes eddy currents to tend to flow near the surface of the test piece. Which of the following factors alter the skin effect?

a.Testing frequency

b.Test piece temperature

c.Test piece hardness

d.Test piece permeability

e.None of the above

28.Which of the following is not a common undesirable effect to the test caused by the testing environment?

a.Temperature variation

b.Crack in test sample

c.Test object making contact with test coil

d.Foreign object in the test coil field

e.Test coil vibration

29.There is one function that responds to variations in eddy current flaw and magnetic field conditions. This function actually produces the output signal from the coil. What is this function?

a.Phasing

b.Resistance

c.Reactance

d.Impedance

30.The inductive reactance of a test coil, which is one of the most importance impedance quantities, depends upon which of the following?

a.Frequency, coil inductance, coil resistance

b.Coil inductance only

c.Coil resistance and coil inductance only

d.Frequency and coil resistance only

e.Frequency and coil inductance only

31.An ac current produces eddy currents in a test object. The vector Hp represents the secondary ac field in the test piece. What function occurs to produce a workable test situation? (See figure 10)

a.Changes in the test specimen such as a crack, metallurgical and dimensional change alter the secondary field phase and amplitude

b.The primary ac current must be 60 cycles to produce this effect

c.A temperature raise in the specimen

d.A mismatch of the Hp and Hs fields produces a change in the output

32.To separate cracks and diameter effects for steel cylinders, the optimum frequencies correspond to f/fg ratios of less than (see figure 11)

a.10

b.15

c.50

d.100

e.150

33.Thin –walled tubes should be tested for cracks, alloy or wall thickness at frequency ratios between(see Figure 12):

a.0.1 and 0.4

b.0.4 and 2.4

c.2.4 and 4.0

d.4.0 and 10

34.Figure 13 indicates that the largest eddy current indicates from subsurface cracks will occur when the frequency ratio(f/fg) is:

a.5 or less

b.15

c.50

d.150 or more

35.Figure 13 indicates that the magnitude of a signal from a surface crack will increase when the frequency ratio(f/fg):

a.Remains the same

b.Decreases

c.Increases

d.None of the above

36.Figure 14 indicates that when inspecting for surface cracks in nonferromagnetic cylinders, the optimum frequency ratio (f/fg) is between :

a.5 and 10

b.10 and 50

c.50 and 100

d.100 and 150

37.An operating frequency of 100 khz will have the deepest penetration in:

a.Titanium

b.Copper

c.Stainless steel

d.Aluminum

38.As the operating frequency is increased, the impedance of the empty coil:

a.Increases

b.Decreases

c.Remains the same

d.None of the above

39.Disadvantage of using a surface probe coil for the inspection of small diameter tubing include:

a.Inability to detect small discontinuities

b.Slow inspection speed

c.Inherent mechanical problem

d.Both a and c

e.Both b and c

40.Differntial coil system can be of which of the following types? (See figure 15)

a.Sketch no. 1

b.Sketch no. 2

c.Sketch no. 3

d.All of the above

e.Both a and b

EDDY CURRENT QB 1

ANSWERS

Q.NO	ANSWERS	Q.NO	ANSWERS
1	B	21	C
2	A	22	D
3	D	23	B
4	A	24	C
5	C	25	A
6	D	26	A
7	B	27	E
8	B	28	B
9	C	29	D
10	B	30	E
11	B	31	A
12	B	32	A
13	B	33	B
14	C	34	A
15	D	35	B
16	B	36	B
17	D	37	C
18	B	38	A
19	D	39	E
20	B	40	D

RBI Risk Based Inspection

 

Chapter 3

Basic Concepts

What is Risk?

• Risk is something that we live with on a day-to-day basis
• What is a Risk Decision?
• Examples from every day life

An Example of a Risky Decision

 

Acceptance of Risk

• We accept risk because the probability of a serious catastrophe is sufficiently low to make it acceptable

Risk

• Risk is the combination of the probability of an event occurring during some time period and the consequence (generally negative) associated with the event

Risk = Probability x Consequence

Perception of Risk Versus Reality

Management      Perception

Engineers

Supervisors

Operators

Craftsman         Reality

A Perception of a Risky Decision

Risky Decision Event Tree

Risk Management and Risk Reduction

• Not really synonymous
• Risk reduction is a part of risk management

1. Act of mitigating a known risk to a lower level

• Risk Management is a process

1. To assess risk
2. To determine if risk reduction is required
3. To develop a plan to maintain risks at an acceptable level
4. Some risks may be identified as acceptable
5. Some risks may be inherent

Management of Risk Using RBI

Evolution of Inspection Intervals

• Inspection programs are established to detect and evaluate deterioration due to in-service operations
• Periodic verification of equipment integrity evolved as “calendar-based” intervals
• Effectiveness varied widely

Evolution of Inspection Approach

• Better understanding of type and rate of deterioration
• Intervals became more dependent on equipment condition
• Codes and standards evolved

1. Percentage of equipment life interval
2. On-stream in lieu of internal inspection
3. Process environment induced cracking
4. Consequence based inspection intervals

Traditional Equipment Inspection

RBI – The Next Generation

• Ultimate Goal of Inspection

1. Safety and Reliability of Operating Facilities

• RBI Approach

1. Focuses attention specifically on equipment and associated deterioration mechanisms representing the most risk to the facility

Inspection Optimization

• Optimization for planning and implementing a risk based inspection program needs information on:

1. Risk associated with equipment
2. Relative effectiveness of inspection techniques to reduce risk

• Not all inspection programs are equally effective in detecting in-service deterioration and reducing risks
• Various inspection techniques are usually available to detect any given deterioration mechanism
• Each method will have a different effectiveness.

Relative Risk vs. Absolute Risk

• Complexity of risk calculation is function of factors affecting risk

1. Absolute risk is virtually impossible to determine because of too many uncertainties

• RBI is focused on a systematic determination of relative risk
• Risk acceptance may be evaluated by sensitivity analysis

RISK BASED INSPECTION RBI

CHAPTER II

Definitions and Acronyms in RISK BASED INSPECTION

Consequence

• Consequence: Outcome from an event. There may be one or more consequences from an event. Consequences may range from positive to negative. However, consequences are always negative for safety aspects. Consequences may be expressed qualitatively or quantitatively.

Damage Tolerance and Deterioration

• Damage Tolerance: The amount of deterioration that a component can withstand without failing.

• Deterioration: The reduction in the ability of a component to provide its intended purpose of containment of fluids. This is caused by various deterioration mechanisms (e.g. thinning, cracking, mechanical). Damage or degradation may be used in place of deterioration.

Event and Event Tree in risk based inspection

• Event: Occurrence of a particular set of circumstances. The event may be certain or uncertain. The event may be singular or multiple. The probability associated with the event is estimated for a given period of time.
• Event Tree: A tool that organizes potential accidents in a logical manner. The event tree begins with identification of potential initiating events. Subsequent possible resulting events are then displayed as the second level of the event tree. This process is continued to develop pathways or scenarios from the initiating events to potential outcomes.

External Event

• External Event: External events are usually beyond the direct or indirect control of persons employed at or by the facility. Events resulting from forces of nature, acts of Allah or sabotage, or neighboring events fires or explosions, hazardous releases, electrical power failures, climatic catastrophes, earthquakes, and intrusions.

Failure and Failure Mode

• Failure: Termination of the ability of a system, structure, or component to perform its required function of containment of fluid (i.e. loss of containment). Failures may be unannounced and undetected until the next inspection (unannounced failure), or they may be announced and detected by any number of methods at the instance of occurrence (announced failure).
• Failure Mode: The manner of failure. For Risk Based Inspection, the failure of concern is loss of containment of pressurized equipment items. Examples of failure modes are small hole, crack, and rupture.

Source and Hazard in risk based inspection

• Source: Thing or activity with a potential for consequence. Source in a safety context is a hazard.
• Hazard: A physical condition or a release of a hazardous material that could result from component failure and result in human injury or death, loss or damage, or environmental degradation. Hazard is the source of harm. Components that are used to transport, store, or process a hazardous material are a source of hazard. Human error and external events can also create a hazard.

Hazard and Operability Study

• Hazard and Operability (HAZOP) Study: A form of failure modes and effects analysis, which uses systematic techniques to identify hazards and operability issues.
• Identifying unforeseen design, process, or operational hazards.
• The basic objectives are:

1. To produce a full description of the facility or process, including the intended design conditions.
2. To systematically review every part to discover how deviations from the intention of the design can occur.
3. To decide whether deviations can lead to hazards or operability issues.
4. To assess effectiveness of safeguards.

Likelihood and Probability

• Likelihood: Probability.
• Probability: Extent to which an event is likely to occur within a time frame. Probability is “a real number from 0 to 1 attached to a random event”. Probability is related to long-run relative frequency or degree of belief in an occurrence. Frequency rather than probability is used. Degrees of belief is chosen as classes or ranks.

1. “Rare/unlikely/moderate/likely/almost certain” or “incredible/improbable/remote/ occasional/probable/frequent”.

Qualitative Risk Analysis in risk based inspection

• Qualitative Risk Analysis (Assessment): Method that uses engineering judgment and experience as the basis for analysis of probabilities and consequences of failure.

1. Results of qualitative risk analyses are dependent on the background and expertise of the analysts and the objectives of the analysis.
2. Failure Modes, Effects, and Criticality Analysis (FMECA) and HAZOPs are examples of qualitative risk analysis techniques that become quantitative risk analysis methods when consequence and failure probability values are estimated along with the respective descriptive input.
3. Identifies and delineates the combinations of events that, if they occur, will lead to a severe accident (e.g. major explosion) or any other undesired event.
4. Estimates the frequency of occurrence for each combination.
5. Estimates the consequences.

• Quantitative risk analysis integrates into a uniform methodology the relevant information about design, operating practices and history, reliability, human actions, physical progression of accidents, and potential health and environmental effects, as realistically as possible.

Risk
Relative, Absolute, and Residual

• Risk: Combination of probability of an event and its consequence. In some cases, risk is a deviation from the expected. When probability and consequence are expressed numerically, risk is the product.
• Relative Risk: The comparative risk of a facility, process unit, system, or equipment to other facilities, process units, systems, or equipment, respectively.
• Absolute Risk: An ideal description of quantification risk.
• Residual Risk: The risk remaining after mitigation.

Risk
Analysis, Assessment, and Acceptance

• Risk Analysis: Systematic use of information to identify sources and to estimate the risk

1. Risk analysis provides a basis for risk evaluation and risk acceptance. Information can include historical data, analysis, informed opinions and concerns of stakeholders.

• Risk Assessment: Overall process of risk analysis and risk evaluation.
• Risk Acceptance: A decision to accept a risk. Risk acceptance depends on risk criteria.

Risk
Criteria and Identification

• Risk Criteria: Terms of reference by which the significance of risk is assessed. Risk criteria may include associated cost and benefits, legal and statutory requirements, socio-economic and environmental aspects, concerns of stakeholders, priorities and other inputs to the assessment.
• Risk Identification: Process to find, list, and characterize elements of risk. Elements may include; source, event, consequence, probability. Risk identification may also identify stakeholder concerns.

Risk
Estimation and Evaluation

• Risk Estimation: Process used to assign values to the probability and consequence of a risk. Risk estimation may consider cost, benefits, stakeholder concerns and other variables, as appropriate for risk evaluation.
• Risk Evaluation: Process used to compare the estimated risk against given risk criteria to determine the significance of the risk. Risk evaluation may be used to assist in the acceptance or treatment decision.

Mitigation

• Mitigation: Limitation of any negative consequence or reduction in probability of a particular event.