- PURPOSE.
- REFERENCE STANDARDS.
- RESPONSIBILITY.
- The Site Manager
- The Quality Control Inspector
- Field Engineer
- Electrical Superintendent
- HSE Officer
- Vendor Representative
- MATERIALS AND CONTROL.
- RADIATION SAFETY.
- General
- Controlled areas
- Radioactive isotope
- QUALITY REQUIREMENTS.
- METHODS & GUIDELINES FOR RADIOGRAPHIC EXAMINATION TEST..
- Processing Requirements.
- Quality of radiographs
- Processing Manual (According to SE-94)
- Examination Procedure
- Surface Preparation
- RT request
- Controlled area
- Marking on the weld
- Film identification
- Location markers
- Direction of radiation
- Film handling
- Radiographic technique
- Single wall technique
- Double wall technique
- Geometric unsharpness
- IQI Selection
- Weld with reinforcements
- Weld without reinforcements
- Placement of penetrameters
- Source side penetrameter(s)
- Film side penetrameter(s)
- Penetrameter location for welds-hole penetrameters
- Penetrameter location for welds-wire penetrameters
- Number of penetrameters
- Multiple penetrameters
- Shims
- Evaluation
- Quality of radiographs
- Viewing facilities for radiographs
- Radiographic density
- Density Limitations
- Density variation
- IQI sensitivity
- Excessive scatter
- RECORDS
- ACCEPTANCE CRITERIA
- Processing Requirements.
- TOOLS AND EQUIPMENT
- INSPECTION
1 Radiographic Examination Procedure | Test Plan | Method Statement
This procedure covers the Test Plan pertaining to Radiographic Examination Test to be carried out in commercial buildings, plants and projects.
This procedure shall be applied to the method and criteria for installation work carried out by the Electrical Department. Field installation personnel must verify the feasibility of this procedure with the approved construction drawing, actual site condition and project specification. The purpose of this procedure is to ensure that the radiographic images produced are acceptable quality and that all radiographic examinations are performed in a safety policy, project specifications, quality control plan and applicable codes.
2 REFERENCE
2.1 ASME V Nondestructive Examination-Boiler & pressure vessel Code.
2.2 ASME B31.3 Process Piping.
2.3 ASMEIX Welding and Bracing Qualification.
2.4 API 650 Welded Steel Tanks for Oil Storage.
2.5 SNT-TC-IA Recommended Practice for Nondestructive Testing Personnel Qualification & Certification .
2.6 API 1104 Standard for welding pipelines and related facilities.
2.7 ANXI _4011-HSP-ABE-000-714-0001_Safety instructions.
2.8 INS-09-06 Radiography Operations.
3 RESPONSIBILITY
3.1 The Site Manager
Responsible for the Quality Procedure to ensure that construction work is carried out as per Project requirements. His Superintendent/Supervisor shall check that work is ready for inspection and prepare Internal Inspection Request. The Superintendent/Supervisor shall inform all parties concerned for any of inspection and the time schedule.
3.2 The Quality Control Inspector
Responsible for conducting surveillance and inspection duties for work and ensuring quality compliance and efficient. recording and reporting of results as required. He shall review all relevant documents, material confonnance certificates and non-confonnance reports and shall receive all internal requests for inspection from various sections of implementing work and prepare (RSI) Request for Site Inspection as per schedule work priorities and proceeds with the Quality inspection with the client, owner representative as required. He shall also prepare Witness / Hold Point inspection and the corresponding work releases by reviewing records and results as proof that work inspected confonns to contract requirements. He shall also be responsible to ensure that an approved detailed IFC/AFC or shop drawing is available prior to commencement of the work and all materials to be used are in compliance with the approved project specifications or requirements.
3.3 Field Engineer
Ensure that all related works are carried out in accordance with approved Issued for Construction drawings, specifications, schedule, quality and safety. Check Design and Construction details in reference with the project standard and specification. See to it that the design drawings provide adequate information for purchasing and site construction. Report to Site Manager.
3.4 Electrical Superintendent
Ensure that work once started is carried out as planned and that the applicable standards are complied with. Check working methods and precautions to be taken by the supervisors/foreman before commencing work. In charge of planning and preparation of manpower, materials, tools and equipment together with his supervisors prior to start of any activity. Monitors project completion schedule and the discipline supervisors under him.
3.5 HSE Officer
Supervise the project activities relating to health, safety and environmental compatibility. He shall carry out regular inspection at site and workplaces whether work is being carried out according to the given instructions and those personnel are wearing the necessary protective equipment (PPE). Perform, in co-operation with the Site Supervisors and Foremen regular Tool Box meetings. Report any adverse condition to health and safety.
3.6 Vendor Representative
Lead testing and commissioning activities for the equipment supplied in accordance to project specification and contract requirements. He shall ensure that project requirements are complied, with the necessary test to be performed and results are recorded and acceptable with the manufacturer’s data, project standards and specifications. The radiographic technician (radiographer) shall be fully trained / qualified, and shall be fully aware of the hazards of radiation.
4 MATERIALS AND CONTROL
a) Ensure that materials and equipment are stored and handled in accordance with project and vendor requirements.
b) Checked if all supplied materials are in conformance with Purchase Order or Specifications or Drawings. Any discrepancies will be reported immediately to Materials Department.
c) Receiving, off-loading, inspecting, storing and handling all material and equipment will be in general safety practice and manufacturer’s instruction.
d) Film – Radiographs shall be made using industrial radiographic films that are available to meet the required quality of radio graphs.
e) Identifying screen- The function of the lead intensifying screens is to reduce exposure times by the emission of electrons and secondary radiation in reaction to the primary radiation source and at the same time reduce film fogging by acting as a filter for the absorption of back scattered
radiation. The lead screens used shall be clean and in good condition, with required thickness, and shall be in direct contact with the radiographic film
I) IQI (Image Quality Indicator) – Pentameter shall be either the hole type or the wire type.
g) Radiation source – Iridium 192 will be used as a radiation source. Selection of the appropriate source is dependent upon variables regarding the weld being examined (material composition and thickness). The suitability of the source shall be demonstrated by attaining the required Image Quality Indicator (!QI) sensitivity and complying with all other requirements stipulated herein (film density and area of interest, density tolerances, etc.). The sources shall be Gamma ray. For the verification of source size, the manufacturer’s source certificate/decay chart documenting the actual physical source size shall be acceptable.
5 RADIATION SAFETY
5.1 General
Project safety procedure in Radiography Operation (INS-09-06) must be followed. Necessary work permit (X-ray) shall be utilized prior to the activity. The radiographic technician (radiographer) shall be fully trained / qualified, and shall be fully aware of the hazards of radiation. Human body tissue will be if severely damages they are over exposed to radiation and even small amount of exposure on a daily basis, with insufficient recovery periods, will eventually produce a serious deterioration in health. All possible safety precaution shall always be taken to avoid unnecessary exposure. Prior to commencing any radiation work on site, emergency procedures shall be established. The following are to be considered by discipline personnel who are involved with working with ionizing Radiation:
• Taking all reasonable safety precautions.
• Not knowingly expose either themselves or any other person to radiation greater than is absolutely necessary for the purposes of their work
• Make full and proper use of all personal protection equipment provided.
• Report any defects to radiographic equipment to his employer immediately upon discovery.
• Use of PPE (Idosimetric plate, radiation counter, safety footwear, safety helmet, reflective jacket)
• Valid certification of radiation equipment and good working condition
• Observe proper distance of working area restrictions
5.2 Controlled areas
Radiography shall only be undertaken in designated and clearly identified “controlled areas”. These areas shall be identified and sealed by the use of the following as a minimum
• Radiation tape Barriers-which surround and seal off the controlled area in its entirety.
• Radiation Hazard Warning Signs.
• These are positioned every 30 meters around the periphery of the controlled area.
• Flashing yellow lights to indicate radiation hazard area, these shall be positioned adjacent to warning signs.
Under no circumstances shall non radiographic discipline (unclassified) personnel cross or enter the barriers to a controlled area. Any infringement of this safety rule/ regulations concerning controlled areas will result in the immediate removal of the individual and expulsion from the Project.
5.3 Radioactive isotope
The container in which radioactive isotopes are housed shall be lockable and sealed. They shall be manufactured from expended uranium or similar materials, to international safety standards. These containers shall be re-certified as safe to use every of 26 months (maximum).The senior radiographic technician on site shall hold the keys at all times (other than usage).The whereabouts of all radioactive isotopes on site shall be logged and known at all times.
6 QUALITY REQUIREMENTS
An inspection of test equipment shall be conducted prior to any test activities. Each piece of the lest equipment shall have the calibration labels intact. Test equipment manual should be available and that calibration certificates are valid. All test equipment must be tested for proper operation before starting any test.
2 Defective test equipment must not be used.
It shall be isolated and removed for calibration of the approved third party Metrology Laboratory Company for re-calibration. Also, periodic checks of lest equipment will be conducted by QC Department to ensure that all equipment is within the calibration period and record shall be maintained and updated.
3 QUALIFICATION OF PERSONNEL
• Personnel using, handling, or transporting ionizing radiation producing equipment and radioactive sources are required to possess certificate to operate radiography equipment.
• The qualification of examination personnel shall be in accordance with project requirement or an alternative system specifically accepted by owner
7 METHODS AND GUIDELINES FOR RADIOGRAPHIC EXAMINATION TEST
7.1 Processing Requirements
7.1.1 Quality of radiographs
All radiographs shall be free from mechanical, chemical or other artifacts to be extent that they cannot mask or be confused with the image of any discontinuity in the object being radiographed. Such artifacts include but are not limited to:
• Fogging
• Processing defects such as water or chemical marks.
• Scratches, Finger marks, crimps, static smudges or tears
• Loss of details due to poor film Contrast.
• False indication due to defective screens.
7.1.2 Processing Manual (According to SE-94)
• Preparation – No more film should be processed that can be accommodated with a Minimum separation. Hangers are loaded and solutions stirred before starting development.
• Start of development – Start the timer and place the films into the developer tank. Separate to a minimum distance and agitate in two directions for about 15 seconds.
• Development – Normal development is 5 lo 8 minutes at 68° F (20° C)
• Agitation – Shake the film horizontally and vertically, ideally for a few seconds each minute during development. This will help develop evenly.
• Rinsing – Rinse the films with vigorous agitation in clear water
• Fixing – The Films must not touch one another in the fixer. Agitate the hangers vertically for about IO seconds and again at the end of the first minute, to ensure uniform and rapid fixation. Keep them in the fixer until fixation is complete (i.e. at least twice the clearing time), but not more than 15 minutes in relatively fresh fixer. Frequent agitation will shorten the time of fixation.
• Fixer Neutralizing – Use hypo eliminator or fixer neutralizer between fixation and washing.
• Washing – Washing is very slow below 60° F(l6° C).When washing at temperature above 85° F(30° C),care should be exercised not to leave films in the water too long. The films should be washed in batches without contamination from new film brought over from the fixer. If pressed for capacity, as more films are put in the wash, partially washed film should be moved in the direction of the inlet.
• Wetting Agent. – Dip the film for approx. 30 seconds in a wetting agent added clear water
• Drying – Take Precaution to tighten film on hangers, so that it cannot touch in the dryer. Too hot a Drying temperature at low humidity can result in uneven drying and should be avoided.
7.2 Examination Procedure
7.2.1 Surface Preparation
The weld ripples or welds surface irregularities on both the inside (where accessible) and outside shall be removed by any suitable process to such a degree that the resulting radiographic image due to any irregularities cannot mask or be confused with the image of any discontinuity.
7.2.2 RT request
Request for radiographic examination will be upon completion and visual acceptance of a weld that is subject to radiography. The request shall follow the project work safety instruction requirement and be coordinated to the Contractor/Client in fulfilling the requirements before the activity be conducted.
7 .2.3 Controlled area
Radiography shall only be performed at such times as the work site is clear of all non radiographic discipline personnel and the area of exposure shall be designated a’ controlled area’ Prior to commencing exposure of the isotope, all safety precautions and requirements as stated in radiation safety will be observed. The area in which the isotope is to be exposed shall be treated as a ‘controlled area’ and only classified personnel may enter. The boundaries of this ‘controlled area’ shall be identified with radiation tape barriers, warning signs (in both English and Hindi) and flashing lights.
7.2.4 Marking on the weld
The radiographer shall identify the weld to be radiographed and mark the weld.
7 .2.5 Film identification
Each radiograph will be uniquely identified by means of lead numbers and letters. The lead letters and numbers shall not encroach into the weld area and shall not interfere with the interpretation of the radiograph in any way. The following infonnation shall be displayed on each radiographic film as a minimum:
• Project name
• Company name
• Line number, drawing number or piece number.
• Weld number
• Repair identification number(where applicable)
• Welder identification number
• Date of radiograph
• Joint thickness and diameter
7 .2.6 Location markers
Location markers, which are to appear as radiographic images on the film, shall be placed on the part, not on the exposure holder. Their location shall be permanently marked on the surface of the part being radiographed when permitted, or on a map, in a manner permitting the area of interest on a radiographed to be accurately traceable to its location on the part
7.2.7 Direction of radiation
The direction of the central beam of radiation should be centered on the area of interest whenever practical.
7.2.8 Film handling
Care shall be taken to ensure that both exposed and unexposed films are kept segregated and are stored in such a manner as that they shall not be subjected to radiation, excessive heat, dirt, fumes, etc.
7 .2.9 Radiographic technique
7.2.9.1 Single wall technique – In the single wall technique, the radiation passes through only one wall of the weld, which is viewed for acceptance on the radiograph.
7.2.9.2 Double wall technique – When it is not practical to use a single wall technique, one of the following double wall techniques shall be used.
(a] Single wall viewing
For welds in components, technique may be used in which the radiation passes through two walls and only the weld on the film side wall is viewed for acceptance on the radiograph. When complete coverage is required for circumferential welds, minimum of three exposures taken 120 deg. to each other shall be made.
b) Double wall viewing
For welds in components 3.1/2 in. or less in nominal outside diameter, a technique may be used in which the radiation passes through two walls and the weld in both walls is viewed for acceptance on the same radiograph. For double wall viewing, only a source side penetrameter shall be used.
1) For welds, the radiation beam may be offset from the plane of the weld at an angle sufficient to separate the images of the source side and film side portions of the weld so that there is no overlap of the areas to be interpreted. When complete coverage is required, a minimum of two exposures taken 90 deg. To each other shall be made for each joint.
2) As alternative, the weld may be radiographed with the radiation beam positioned so that the images of both walls are superimposed. When complete coverage is required, a minimum of three exposures taken either at 60 degrees to 120 degrees. To each other shall be made for each joint.
7.2.10 Geometric unsharpness
Unless otherwise specified in the applicable job order or Contract, the geometric unsharpness should not exceed the following limits:
Material Thickness (in.) Ug Maximum (in.)
Under 2 0.020
2 trough 3 0.030
Over 3 trough 4 0.040
Greater than 4 0.070
7.2.11 IQI Selection
The designed hole penetrameter with essential hole or designed wire diameter shall be according to agreed project requirements.
7.2.11.1 Weld with reinforcements
The thickness on which the penetrameter is based is the nominal single wall thickness plus the estimated weld reinforcement not to exceed the maximum permitted by the referencing Code Section. Backing rings or strips are not be considered as part of the thickness in penetrameter selection. The actual measurement of the weld reinforcement is not required
7.2.11.2 Weld without reinforcements
The thickness on which the penetrameter is based is the nominal single wall thickness. Backing rings or strips are not to be considered as part of the thickness in penetrameter selection.
7.2.12 Placement of penetrameters
7.2.12.1 Source side penetrameter(s)
The penetrameter(s) will be placed on the source side of the part being examined, except as noted by the Client or the operator.
7.2.12.2 Film side penetrameter(s)
Where inaccessibility prevents hand placing the penetrameter(s) on the source side, the penetrameter(s) shall be placed on the film side in contact with the part being examined. A lead letter “F” , at least as high as the penetrameter indication number(s), shall be placed adjacent to or on the penetrameter(s), but shall not mask the essential hole where hole penetrameters are used.
7.2.12.3 Penetrameter location for welds-hole penetrameters
The penetrameter(s) may be placed adjacent to or on the weld. The identification number(s) and, when used, the lead letter “F” shall not be in the area of interest.
7 .2.12.4 Penetrameter location for welds-wire penetrameters
The penetrameter(s) shall be placed on the weld so that the length of the wires is perpendicular to the length of weld. The identification number(s) and, when used, the lead letter “F” shall not be in the area of interest.
7.2.13 Number of penetrameters
For components where one or more film holders are used for an exposure, at least one penetrameter image should appear on each radiographed except as outlined by the operator or the Client.
7.2.13.1 Multiple penetrameters
If the requirements are met by using more than one penetrameter, one shall be check of the lightest area of interest and the other the darkest area of interest: the intervening densities on the radiograph shall be considered as having acceptable density
7.2.14 Shims
A shim of material radiographically similar to the weld metal shall be placed between the part and the penetrameter, if needed, so that the radiographic density throughout the area of interest is no more than minus 15% from the radiographic density through the penetrameter. The shim dimensions shall exceeds the penetrameter dimensions such that the outline of at least three sides of the penetrameter image shall be visible in the radio graph.
7.3 Evaluation
7.3.1 Quality of radiographs
All radiographs shall be free of mechanical, chemical, handling related or other blemishes to the extent that they do not mask and are not confused with the image of any discontinuity in the area of interest of the object being radiographed. If any doubt exists as to the true nature of an indication exhibited by the film, the radiograph shall be rejected and re-shot.
7.3.2 Viewing facilities for radiographs
Viewing facilities shall provide subdued background lighting of an intensity that will not cause troublesome reflections, shadows or glare on the radiograph. Equipment used to view radiographs for interpretation shall provide a variable light source sufficient for the designated wire to be visible for the specified density range.
7.3.3 Radiographic density
7.3.3.1 Density Limitations
The transmitted film density through the radiographic image of the body of appropriate hole penetrameter or adjacent to the designated wire of a wire penetrameter and the area of interest will be 2.0 minimum and 4.0 maximum.
7.3.3.2 Density variation
[a] General
If the density of the radiograph anywhere through the area of interest varies by more than minus 15% or plus30 % from the density through the body of the hole penetrameter or adjacent to the designated wire of a wire penetrameter within density limitations, then an additional penetrameter shall be used for each exceptional area or areas and the radiograph taken.
b. With Shims
When shims are used the plus 30 % density restriction of[a] above may be exceeded, provided the required penetrameter sensitivity is displayed and the density limitation are not exceeded.
7.3.4 IQI sensitivity
Radiography shall be performed with a technique of sufficient sensitivity to display the hole penetrameter image and the specified hole, or the designated wire of a wire penetrameter, which are essential indication of the image quality of the radiograph. The quality levels required using wire. Penetrameters shall be equivalent to project requirements. The table T 276 Article 2 Sec V Provides a list of various hole type IQI’s and the diameter of the wires of corresponding EPS (Equivalent Penetrameter Sensitivity) with the applicable2T holes in the IQI.
7.3.5 Excessive scatter
A lead letter “B” shall be attached to the back of each film holder during each exposure to determine if backscatter radiation is exposing the film If a light image of the “B” appears on a darker background of the radiograph, protection from backscatter is insufficient and the radiograph shall be considered unacceptable. Client and/or company reserve the right to final interpretation and evaluation of radio graphs.
7.4 RECORDS
The following radiographic records will be maintained as agreed upon between the client and Visual:
a. Sketch
b. Weld repair documentation
c. Film used
d. Thickness of material
e. Source to film distance
f. Film interpretation record shall contain as the minimum following information
• Disposition of each radiograph (acceptable or rejected)
• If rejected, cause for rejection (slag, crack, Porosity, LOP,LOF etc.)
• Surface indication verified by visual examination (grinding marks, weld ripple, spatter etc.)
• Signature of the film interpreter
7.5 ACCEPTANCE CRITERIA
Radiographs shall be interpreted only in those areas in which Penetrameter(s) have established that a suitable radiographic technique has been used. Acceptance criteria will be applied according to applicable code section established by the Client.
8 TOOLS AND EQUIPMENT
a. Gamma Ray Camera
b. Radiation source and source size
c. Films
d. Intensifying screens
e. Dosimetric plate
f. Radiation Counter
g. Barricade, warning sign
h. Fire extinguisher
Note: Materials listed above must be verified for manufacturer/contractor supplied equipment or other requirements
9 INSPECTION
All inspections shall be coordinated by QA/QC Inspector, who will implement the inspection program and notify all parties involved in advance of the scheduled dates of inspection to enable them to participate. Relevant records shall be signed by all the required parties and originals kept by Site QA/QC Department. Inspections shall be done per level, area or drawings.
Radiography Examination shall be carried out in accordance with the Project specification and standards. Records must be maintained for each test. Acceptance criteria for inspection shall be within Project specification and standards and manufacturer’s specified criteria.
Step by Step Guide of Radiographic Examination Procedure
Explain in detail the steps that must be taken to ensure that the task is carried out safely (include drawing and sketches where required. include pre commencement of work activities and the work itself in a chronological manner).
A. Verify IFC drawings availability
B. Verify Documents of Radiation Equipment and Operator
C. Preparation of Tools and Equipment
D. Preparation of IPB Weld Surfaces
E. Perform of radiographic Test
A. Preparation of Tools and Equipment (Get approval to the security for access when transporting tools and equipment, follow site speed limits follow proper traffic signs & signals, tum on hazards light. only authorized operator and personnel to perform the task, ensure one flag man for traffic control during activity. Provide barricade with signage’s)
B. Preparation of IPB welds surfaces (Qualified and authorized personnel to perform the task. Ensure wearing of complete PPE (eye glass, dust mask, hard hat, safety shoes, reflective vest, hand gloves), fall protection when working at height, scaffold and ladder to be used are safe and inspected)
C. Radiographic Test (X-ray work permit and proper scheduling arrangement. Notification for all concerned personnel. Conduct tool box meeting before the start of work. Qualified and authorized personnel to perform the task, fall protection when working at height, scaffold and ladder to be used are safe and inspected. Equipment certification/calibration and in working condition including tools. Careful handling of materials and proper technique. Use of PPE dosimetric plate, radiation counter, hard hat, safety footwear, reflective jacket etc. Barricading the area in consideration with the required safe distance, installation of warning sign and watchman to control the entry of unauthorized person and not to leave it unguarded. Remote control unit is in a protected area. Recommended to be performed in non-working hours. Ensure area is clear from radiation before entry.)
D. Daily housekeeping (Full supervision on the area remind personnel for safe working and good housekeeping on the area should be done before and after the work )
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