LIQUID PENETRANT TESTING
6.0 TYPE OF PENETRANT MATERIAL
11.0 ACCEPTANCE CRITERIA
This procedure describes the method and techniques used in Liquid Penetrant Inspection, LPI using solvent removable or water washable, colour contrast, visible in day light or artificial light.
This procedure establishes minimum requirement for “Solvent Removable - Visible Liquid Penetrant Inspection” to detect crack and other discontinuities that are open to the surface such as crack, seams, laps, cold shuts, lamination, and lack of fusion and are applicable to in process, final and maintenance examination.
ASME SEC V, A6 Non-destructive testing (ASME Boiler and Pressure vessel code -2004)
API 1104 Standard for Welding Pipelines and related facilities-20th Edition 2005, (REAFFIRMED Apr. 2010).
ASTM E 165 Standard Test Method for Liquid Penetrant Testing.
SNT-TC-1A Recommended practice for the qualification and certification of Non-destructive testing Personnel
QP 02 Control of Quality records
QPS 01 Project Quality Plan
QP 7.6 Control of Measuring and Monitoring Devices
QA-062.02 SOTAM Written Practice for Personnel Qualification
QP 6.4 General Health & Safety Procedure
5.0 PERSONNEL QUALIFICATIONS
Personnel performing LPI/DPI Examinations of welds shall be qualified to a minimum of ASNT Level I or Level II. Interpretation and evaluation done by Level II
All materials used in performing liquid penetrant inspection shall be of the type, or equivalent to, that specified in the contract
Materials used in performing the inspection shall be identifiable by a serial number or batch number, which is traceable to the manufactures Certificate of Conformity. These numbers shall be recorded on all applicable inspection reports to provide traceability.
Penetrant shall be of the colour contrast, either solvent removable type or water washable type or both.
The family of Liquid Penetrant examination materials used as per this procedure.
Or examination materials accepted as per international standard and Contractor.
Developer shall be of the wet solvent suspension or dry powder type, suitable for application by spraying.
Contaminant content shall not exceed that specified in ASME BPV Code, Section V Non-Destructive Examination, Article 6, T-625.
8.1 All SOTAM employees shall respect and work in accordance with the safety requirements of the SOTAM General health & safety manual QP 6.4 at all times.
Appropriate personal protective equipment for the task being carried out shall be worn. consideration shall be given to the working environment for example
- Construction site
- Fabrication shop activities
- Those associated with the material being used, note manufacture’s instruction.
- Those associated with the equipment being used and electrical connection etc
Minimum period of evaporation time for the cleaning solution should be at least 10 seconds. The operator / technician shall visually check and ensure that the cleaning solution has completely evaporated and the surface to be inspected has completely dried prior to penetrant application.
9.2 PENETRANT APPLICATION
Penetrant shall be applied by spray evenly to the test area in accordance with the manufacturer’s instructions. The temperature of surface under examination shall be between 16 to 52 degrees C. Outside of this range the adequacy of the products shall be checked by conducting a preliminary test.
The test area shall remain wet for approximately 10 minutes, soak period, in accordance with the manufacturer’s instructions.
EXCESS SURFACE PENETRANT REMOVAL
Excess surface penetrant shall be removed by wiping with a lint free cloth or absorbent paper, repeating the operation until most traces of penetrant have been removed. The remaining traces shall be removed by lightly wiping the surface with cloth or absorbent paper moistened with solvent.
To minimize the removal of penetrant from discontinuities, care shall be taken to avoid the use of excess solvent. Flushing the surface with the solvent, following of the application of penetrant and prior to developing, is prohibited.
9.5 DEVELOPER APPLICATION
Developer shall be applied uniformly in a thin coating to the test surface as soon as possible and shall not exceed 5 minutes after removal of penetrant. Thick coatings and pools of wet developer shall be avoided.
9.6 DEVELOPING TIME
The developing time, length of time the developer is to remain on the part prior to examination to allow for bleed out of penetrant from discontinuities into the developer coating. The developing time shall not be less than 7 minutes for steel welds. Developing time begins as soon as the wet developer coating is dry.
The examination procedure to identify any surface breaking discontinuities shall be in accordance with ASME BPV Code, Section V, Article 6 and shall be reported in accordance with this procedure
Penetrant indications may be inspected in either natural or artificial white light. A minimum light intensity of 500 lux or 50 foot candles is required to ensure sensitivity during examination and evaluation of indication (ASME V, Art. 6, T-676.3).
All traces of penetrant and developer shall be removed using a suitable solvent or water (in case of water washable dye).
Discontinuities at the surface will be indicated by bleed out of penetrant however localized surface irregularities due to grinding marks / machining marks or other surface conditions may produce false indications.
Broad area of pigmentation which could mask indications of discontinuities are unacceptable, and such area shall be cleaned and reexamined.
11.0 ACCEPTANCE CRITERIA
The Liquid penetrant Indication interpretation shall be based on API 1104 Sect. 9.5
Any indication with a maximum dimension of 1/16 inch (1.6 mm) or less shall be classified as non-relevant.
Relevant Indications shall be unacceptable should any of the following condition exist.
Linear Indication evaluated as crater cracks or star cracks and exceed 5/32 in. (4 mm) in length.
Linear Indications evaluated as Incomplete Fusion (IF) and exceed 1 in. (25 mm) in total length in a continuous 12 in. (300 mm) length of weld or 8% of weld length
Linear indications are evaluated as cracks other than crater cracks or star cracks..
Rounded Indications shall be interpreted as per table below
The maximum dimension of a rounded indication shall be considered as its size.
The Liquid Penetrant Test Report shall be completed using the format attached, QC-009-12.1Identification method shall be established which will enable the test report, the component and the area tested to be identified with respect to each other at any time.
The report shall consist of the following as a minimum
Contract number, job number, identification of the weld, test object.
Surface condition, method of Examination
Standard in which the test was done, accept, and reject criteria.
Name, sign, level of inspector & date of test.
Finding and result (Accept or Reject)
Batch number of Penetrant & Developer
DPI Report SOTAM-QC-009-12.1
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