Section 15 — Inspection

Liquid Penetrant Examination

IPE Engineering Practice IPE-EP-15-2-3

Document number: IPE-EP-15-2-3 · Section: 15 — Inspection

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SCOPE

This practice covers the minimum requirements to perform and monitor the liquid penetrant Inspection method by Inflection Point Engineering, LLC Inspectors and contractors.

Inspection contractors, whose Liquid Penetrant procedures have been submitted and approved by Inflection Point Engineering, LLC Inspection personnel may perform Liquid Penetrant Inspections.

Any deviation to this practice shall be approved by the procedure described in EP 1–1–3.

An asterisk ( * ) indicates that a decision by the Owner’s Level III or Inspection Authority is required or that additional information is furnished by the Purchaser.

REFERENCES

The latest edition of the following standards and publications are referred to herein.

STANDARDS AND PUBLICATIONS

DEFINITIONS

• Black Light – Black light as specified herein shall be applied to the invisible radiant energy in that portion of the spectrum just beyond the blue of the visible spectrum and shall have wave length of between 3,300 and 3,900 angstrom units.
• Developers - The developers used herein shall be either wet or dry. They shall draw or absorb penetrant from surface indications to such an extent that the indications can be visible under natural, white or black light as applicable to the type of penetrant being used.
• Emulsifier – An agent which will, when added or applied to an oil–like penetrant material, make the penetrant water washable.

• Fluorescence – A term used to describe the effects produced by certain chemical products which exhibit a property of emitting visible light by the activation of black light. These materials absorb the invisible energy, alter its wavelength, and emit the energy in the form of light which is visible to the eye.
• Manufacturer - The recipient of a direct or indirect purchase order for materials and/or equipment. In this context, a direct order is one issued to a manufacturer by a contractor or the Owner. An indirect order is one issued to a manufacturer by a vendor (recipient of a direct order) for materials, fabricated components, or subassemblies.
• Owner - Inflection Point Engineering, LLC.
• Penetrant Remover – A solvent–type liquid which is used to clean visible dye penetrants from the surface of the material.
• Post – Emulsifiable – A liquid penetrant which after application to the surface, can be made water–washable by application of an emulsifier.
• Purchaser - The party placing a direct purchase order. The purchaser is the Owner’s designated representative.
• Plant Inspection Authority - That person or body appointed by Management to be responsible for examination and certification of equipment utilized within the plant. Management may appoint more than one Inspection Authority in order to cover specialized equipment such as rotating, instrumentation and electrical equipment.
• Self-Emulsifiable – A liquid penetrant containing an emulsifying agent which will make it water– washable as applied.
• Solvent Removable - Liquid pentrant formulated so that most of the surface excess can be removed by wiping with a lint-free cloth, with remaining surface penetrant traces removed by further wiping with a lint-free cloth lightly dampened with solvent remover.

DESCRIPTION OF METHODS

• This procedure states that the color contrast or fluorescent penetrant method may be used. For each technique there are three types of penetrant. An overview is provided in the following Figures.

Water Washable (Type A- Figure 1) Post–Emulsifying (Type B/D – Figure 2) Solvent Removable (Type C – Figure 3)Figure 1Figure 2Figure 3)

RESPONSIBILITY

• The Contractor’s or Inflection Point Engineering, LLC Level III shall be responsible for the content of this procedure and subsequent revisions.
• The Inspection Authority shall be responsible to assure that only certified personnel perform these examinations.

CERTIFICATION

• Personnel performing examinations to this procedure, shall be certified to the requirements of EP 15–3–2 or an approved contractor’s written practice that meets the requirements of ASNT- TC-1A.
• This procedure or an approved contractor’s procedure shall be available on–site during these examinations.

SAFETY

• Penetrant materials should not be heated or used near an open flame.
• Penetrant materials and cleaners shall be used cautiously in accordance with manufacturer’s recommendations.
• Some are highly volatile and flammable and their vapors may be hazardous.
• Good ventilation shall be maintained at all times. If needed, cartridge respirators shall be used.
• The liquid is a primary skin irritant and prolonged contact with the liquid should be avoided.
• Rubber gloves must be worn in cases of repeated exposure or prolonged contact.
• The hands should be washed thoroughly after contact with any of the penetrant test liquids.
• The Material Safety Data Sheets and Product Data Sheets shall be read and understood by the inspector prior to using penetrant materials .
• When using a black light for fluorescent pentrant examinations, or other AC powered lighting equipment, the inspector should take care to avoid electrical shock. Ground fault circuit breakers should always be used along with explosion proof connectors where required in operating facilities. Worn electrical cords and other equipment should be discarded.
• All applicable plant safety rules shall be followed when performing testing.

CONTROL OF CONTAMINANTS

• Certification of Materials – Certification of contaminant content (sulfur, chlorine, fluorine) for all liquid penetrant materials used on nickel based alloys, austenitic stainless steels, and stainless steels, shall be obtained from the manufacturer. The Manufacturer’s certificate of compliance shall state the batch number and compliance with the requirements set forth in ASME Section V.
• Penetrant materials as used in the above specifications are intended to include all penetrants, solvents or cleansing agents, developers, etc., used in the examination procedure.

SURFACE PREPARATION

• In general, satisfactory results may be obtained when the surface is in the as–welded, as– rolled, as–cast, or as–forged condition; however surface preparation by grinding or machining or other methods may be necessary in some instances where surface irregularities could otherwise mask indications of unacceptable discontinuities.

• (*) Blasting with shot or dull sand may peen discontinuities at the surface and shall not be used without subsequent etching of the test surface to re-open closed discontinuities. The method for etching and neutralizing shall be approved by the Inspection Authority.
• Prior to liquid penetrant examination, the surface to be examined and all adjacent areas within at least 1 inch shall be dry and free of any dirt, grease, lint, scale, welding flux, weld spatter, oil or other extraneous matter that could obscure surface openings or otherwise interfere with the examination.
• Typical cleaning agents which may be used are detergent and water, organic solvents, descaling solutions, and paint removers. Degreasing and ultrasonic cleaning methods may also be used.
• Cleaning solvents shall meet the requirements of paragraph 8.1.
• Drying, after pre-cleaning of the surface to be examined, shall be accomplished by normal evaporation or with forced hot air, as appropriate. A minimum drying time of five (5) minutes shall be required.
• Residues from the cleaning process such as strong alkalis, pickling solution and chromates, in particular, may adversely react with penetrant and reduce its sensitivity and performance. Before application of the penetrant, final cleaning shall be performed with a cleaner of the manufacturer, group and batch and compatible to the penetrant material.

EXAMINATION REQUIREMENTS

• Temperature - The temperature of the penetrant and the part to be processed shall not be below 60oF nor above 100oF throughout the examination period. Local heating or cooling is permitted, provided the part temperature remains in the ambient temperature range during the examination. Penetrant inspections performed outside these temperature ranges shall be qualified in accordance with ASTM E-165, or ASME Section V, Article 6, whichever is applicable.
• Penetrant Application - The Penetrant may be applied by dipping, brushing, or spraying. If the penetrant is applied by spraying, using compressed air type apparatus, filters shall be placed on the upstream side near the air inlet to preclude contamination of the penetrant by oil, water or sediment that may have collected in the lines.
• The minimum penetrant dwell times for this procedure are established in Table 1. Penetrant shall be re–applied as required to prevent drying.
• Excess Penetrant Removal - After the specified penetration time, penetrant remaining on the surface shall be removed, taking care to minimize the removal of penetrant from discontinuities.

WATER WASHABLE PENETRANTS

• Excess water washable penetrant shall be removed with a soft water wash. The water pressure shall not exceed 30 psi, the water temperature should be 50oF to 100oF and the rinse time shall not exceed 120 seconds. Care shall be taken to avoid over washing. The rinse water shall contact the test specimen surface at an angle of not greater than 45 degrees.

• Water–washable – The surface may be dried by blotting with clean absorbent paper, cloth, or by using circulating warm air, provided the temperature of the test surface is not raised above 125oF.
• Perform the washing / rinsing operation under a black light when using fluorescent penetrants so that it can be determined when the surface penetrant has been adequately removed.

POST EMULSIFYING PENETRANTS

• With post–emulsifying penetrants, the emulsifier shall be applied by spraying or dipping. Emulsification time is critical. Emulsification dwell times start as soon as the emulsifier is applied and must be determined experimentally for each specific application. After the required emulsification period, the emulsified penetrant shall be removed by a water wash using the same procedure as for water washable penetrants.
• Drying - Drying using circulating warm air is acceptable provided the temperature of the surface is not raised above 125oF. When test specimens are dipped using Hydrophilic Emulsification, a pre-rinse to remove excess penetrant, is recommended prior to emulsification to reduce contamination of emulsifier.. The temperature of the rinse water shall be within a range of 50oF to 100oF, water pressure shall remain within 25 to 40 psi and maximum rinse time shall be 60 seconds.

SOLVENT REMOVABLE PENETRANTS

• With solvent removable penetrants, excess penetrant, insofar as possible, shall be removed by wiping with a cloth or absorbent paper, repeating the operation until most traces of penetrant have been removed. The remaining traces shall be removed by wiping the surface lightly with a cloth or absorbent paper moistened with solvent. To minimize removal of penetrant from discontinuities, care shall be taken to avoid the use of excess solvent. Flushing or spraying the surface with solvent, following the application of the penetrant and prior to developing, is prohibited.
• Drying - For the solvent removable method, the drying of the test surfaces after the removal of excess penetrant shall be by normal evaporation. The time for surface drying, after removal of the excess penetrant and prior to application of the developer will vary with atmospheric conditions. The drying time shall not exceed 30 minutes.

DEVELOPING

• The developer shall be applied as soon as possible after penetrant removal and drying. The minimum developer dwell time is established in Table 1.
• Dry Developer Application – Dry developer shall be applied only to a dry surface using a soft brush , a hand powder bulb, or a powder gun, enclosed dust chamber, or by other means, provided the powder is dusted evenly over the entire surface being examined.
• Wet Developer Application – Prior to applying suspension type wet developer to the surface, the developer must be thoroughly agitated to ensure adequate dispersion of suspended particles.

• Aqueous Developer Application – Aqueous developer may be applied to either a wet or dry surface. It shall be applied by brushing, spraying or other means provided a thin coating is obtained over the entire surface being examined. Drying time may be decreased by using warm air, provided the surface temperature of the part is not raised above the requirements of

9.1. Blotting is not permitted.

• Nonaqueous Developer Application – Nonaqueous developer shall be applied only to a dry surface. It shall be applied by spraying, except where safety or restricted access precludes it. Under such conditions, developer may be applied by brushing. Drying shall be by normal evaporation.

EXAMINATION

• The true size and type of a discontinuity is difficult to evaluate if the penetrant bleeds excessively in the developer. Consequently, it is good practice to observe and detect the nature of any indications which tend to bleed, allowing the penetrant to bleed out as per Table 1 with a maximum of 30 minutes. If bleed out does not alter the examination results, longer periods are permitted. If the surface to be examined is so large as to preclude complete examination within the prescribed time, only portions of the surface shall be examined at any time.
• Color Contrast Penetrants – When using color contrast penetrants, the test area shall be adequately illuminated to ensure proper evaluation of the indications revealed on the test surfaces. Visible penetrant indications can be inspected in either natural or artificial white light. A minimum light intensity at the inspection surface of 100 foot candles (fc) shall be used. A two- cell flash light (”D” batteries) with reasonably fresh batteries will emit 150 fc @ 12”.
• With color contrast penetrants, the developer forms a more or less uniform white coating. Surface discontinuities are indicated by bleeding–out of the penetrants which is normally of a deep red color staining the developer. Indications with a light pink color may indicate excessive cleaning. Inadequate cleaning may leave an excessive background making interpretation difficult.
• Fluorescent Penetrants – With fluorescent penetrants, the process is essentially the same as with color contrast penetrants with the exception that the examination is performed using an ultraviolet light called a black light. The examination shall be performed as follows:
• The examination shall be performed in a darkened area.
• The technician shall be in a darkened area for at least 5 minutes prior to performing the examination to enable his eyes to adapt to dark viewing. If the technician wears glasses or lenses, they shall not be photosensitive.
• The black light shall be allowed to warm up for a minimum of 10 minutes prior to use or measurement of the intensity of the ultraviolet light emitted.
• The black light intensity shall be measured with a calibrated black light meter. A minimum of 1000 (w/cm2 on the surface of the part being examined shall be required. The black light intensity shall be measured prior to use, at least once every 8 hours, and whenever the work station is changed.

NOTE: Fluorescent penetrant inspection SHALL NOT follow a color contrast examination.

EVALUATION OF INDICATIONS (DOCUMENTATION)

• Discontinuities at the surface will be indicated by bleed–out of the penetrant; however, localized surface irregularities due to machining marks or other surface conditions may produce false indications.
• Broad areas of fluorescence or pigmentation which could mask indications of discontinuities are unacceptable; such areas shall be cleaned and re–examined.
• (*) Acceptance Criteria – For determination of the appropriate criteria, the inspector shall review the required engineering documentation, Code / Standard or EP.
• Documentation – Table 2 –A Liquid Penetrant Inspection Report shall be completed for every code examination performed by Inflection Point Engineering, LLC Inspectors . NDT Contractors may use the forms that were approved with their procedures.Table 2

DISPOSAL OF PENETRANT MATERIALS

• Empty spray cans shall be properly disposed of in accordance with plant procedures.
• Rags or paper towels used in the penetrant process shall be properly disposed of in approved containers.

18.0 TABLES

TABLE 1

MINIMUM PENETRANT DWELL TIMES

TABLE 2

INFLECTION POINT ENGINEERING, LLC LIQUID PENETRANT INSPECTION REPORT

19.0 FIGURES

FIGURE 1 WATER WASHABLE PENETRANT TYPE - A

FIGURE 2

POST EMULSIFIABLE PENETRANT TYPE - B/D

FIGURE 3

SOLVENT REMOVABLE PENETRANT TYPE - C

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