ASTM E1208-21

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E1208 − 16 E1208 − 21
Standard Practice for
Fluorescent Liquid Penetrant Testing Using the Lipophilic
Post-Emulsification Process
This standard is issued under the fixed designation E1208; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This practice covers procedures for fluorescent liquid penetrant examination utilizing the lipophilic post-emulsification
process. It is a nondestructive testing method for detecting discontinuities that are open to the surface such as cracks, seams, laps,
cold shuts, laminations, through leaks, or lack of fusion and is applicable to in-process, final, and maintenance examination. It can
be effectively used in the examination of nonporous, metallic materials, both ferrous and of nonmetallic materials such as glazed
or fully densified ceramics and certain nonporous plastics and glass.
1.2 This practice also provides a reference:
1.2.1 By which a fluorescent liquid penetrant examination, lipophilic post-emulsification process recommended or required by
individual organizations can be reviewed to ascertain its applicability and completeness.
1.2.2 For use in the preparation of process specifications dealing with the fluorescent penetrant examination of materials and parts
using the lipophilic post-emulsification process. Agreement by the purchaser and the manufacturer regarding specific techniques
is strongly recommended.
1.2.3 For use in the organization of the facilities and personnel concerned with the liquid penetrant examination.
1.3 This practice does not indicate or suggest standards for evaluation of the indications obtained. It should be pointed out,
however, that indications must be interpreted or classified and then evaluated. For this purpose there must be a separate code or
specification or a specific agreement to define the type, size, location, and direction of indications considered acceptable, and those
considered unacceptable.
1.3.1 The user is encouraged to use materials and processing parameters necessary to detect conditions of a type or severity which
could affect the evaluation of the product.
1.4 Units—The values stated in inch-pound units are to be regarded as standard. SI unitsThe values given in parentheses are for
information only.mathematical conversions to SI units that are provided for information only and are not considered standard.
1.5 All areas of this document may be open to agreement between the cognizant engineering organization and the supplier, or
specific direction from the cognizant engineering organization.
This practice is under the jurisdiction of ASTM Committee E07 on Nondestructive Testing and is the direct responsibility of Subcommittee E07.03 on Liquid Penetrant
and Magnetic Particle Methods.
Current edition approved June 1, 2016July 1, 2021. Published June 2016August 2021. Originally approved in 1987. Last previous edition approved in 20102016 as
E1208 - 10.E1208 – 16. DOI: 10.1520/E1208-16.10.1520/E1208-21.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1208 − 21
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.7 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D129 Test Method for Sulfur in Petroleum Products (General High Pressure Decomposition Device Method)
D516 Test Method for Sulfate Ion in Water
D808 Test Method for Chlorine in New and Used Petroleum Products (High Pressure Decomposition Device Method)
D1552 Test Method for Sulfur in Petroleum Products by High Temperature Combustion and Infrared (IR) Detection or Thermal
Conductivity Detection (TCD)
E165/E165M Practice for Liquid Penetrant Testing for General Industry
E433 Reference Photographs for Liquid Penetrant Inspection
E543 Specification for Agencies Performing Nondestructive Testing
E1316 Terminology for Nondestructive Examinations
E2297 Guide for Use of UV-A and Visible Light Sources and Meters used in the Liquid Penetrant and Magnetic Particle Methods
E3022 Practice for Measurement of Emission Characteristics and Requirements for LED UV-A Lamps Used in Fluorescent
Penetrant and Magnetic Particle Testing
2.2 ASNT Documents:
Recommended Practice SNT-TC-1A Personnel Qualification and Certification in Nondestructive Testing
ANSI/ASNT-CP-189 Qualification and Certification of NDT Personnel
2.3 AIA Standard:
NAS 410NAS410 Certification and Qualification of Nondestructive Test Personnel
2.4 ISO Standards
ISO 9712 Nondestructive Testing—Qualification and Certification of NDT Personnel—General Principles
2.5 Department of Defense (DoD) Contracts—Unless otherwise specified, the issue of the documents that are DoD adopted are
those listed in the issue of the DoDISS (Department of Defense Index of Specifications and Standards) cited in the solicitation.
2.6 Order of Precedence—In the event of conflict between the text of this practice and the references cited herein, the text of
this practice takes precedence.
3. Terminology
3.1 Definitions—The definitions relating to liquid penetrant examination, which appear in Terminology E1316, shall apply to
the terms used in this practice.
ThroughoutThroughout this practice, the term “black light” has been changed to “UV-A” to conform with the latest terminology
in E1316. “Black light” can mean a broad range of ultraviolet radiation; fluorescent penetrant inspection only uses the UV-A range.
4. Summary of Practice
4.1 A post-emulsifiable, liquid, fluorescent penetrant is applied evenly over the surface being tested and allowed to enter open
discontinuities. After a suitable dwell time, the excess surface penetrant is removed by applying the lipophilic emulsifier and the
part is water-rinsed and dried. If an aqueous developer is to be employed, the developer is applied prior to the drying step. A
developer is applied to draw the entrapped penetrant out of the discontinuity and stain the developer. The test surface is then
examined visually using a UV-A source in a darkened area to determine the presence or absence of indications. (Warning—
Fluorescent penetrant examination shall not follow a visible penetrant examination unless the procedure has been qualified in
accordance with 9.2, because visible dyes may cause deterioration or quenching of fluorescent dyes.)
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from The American Society for Nondestructive Testing (ASNT), P.O. Box 28518, 1711 Arlingate Lane, Columbus, OH 43228-0518.
Available from the Aerospace Industries Association of America, Inc., 1250 Eye Street, N.W., Washington, DC 20005.
Available from International Organization for Standardization (ISO), ISO Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier, Geneva,
Switzerland, http://www.iso.org.
E1208 − 21
NOTE 1—The developer may be omitted by agreement between purchaser and supplier.
4.2 Processing parameters, such as precleaning, penetration time, emulsification time, etc., are determined by the specific materials
used, the nature of the part under examination (that is, size, shape, surface condition, alloy), type of discontinuities expected, etc.
5. Significance and Use
5.1 Liquid penetrant examination methods indicate the presence, location, and, to a limited extent, the nature and magnitude of
the detected discontinuities. This practice is normally used for production examination of critical components or structures when
(a) removal of excessive amounts of penetrant from discontinuities using a water-washable process can be a problem and (b) the
use of a hydrophilic remover is impractical.
6. Reagents and Materials
6.1 Liquid Penetrant Testing Materials, for use in the lipophilic post-emulsification process (see Note 2) consist of a family of
post-emulsifiable fluorescent penetrant, lipophilic emulsifier, and are classified as Type I Fluorescent, Method B—Post-
Emulsifiable, Lipophilic. Each penetrant and emulsifier are approved together as a pair. Intermixing of materials from various
manufacturers is not recommended. (Warning—While approved penetrant materials will not adversely affect common metallic
materials, some plastics or rubbers may be swollen or stained by certain penetrants.)
NOTE 2—Refer to 8.1 for special requirements for sulfur, halogen, and alkali metal content.
6.2 Post-Emulsifiable Penetrants are designed to be insoluble in water and cannot be removed with water rinsing alone. They are
designed to be selectively removed from the surface by the use of a separate emulsifier. The lipophilic emulsifier, properly applied
and given a proper emulsification time, combines with the excess surface penetrant to form a water-washable mixture, which can
then be rinsed from the surface, leaving the surface free of fluorescent background. Proper emulsification time must be
experimentally established and maintained to assure that over emulsification does not occur, resulting in loss of indications.
6.3 Lipophilic Emulsifiers are oil-base liquids used to emulsify the oily penetrant on the surface of the part, rendering it water
washable. The rate of diffusion establishes the emulsion time. They are either slow- or fast-acting, depending on both their viscosity
and chemical composition, and the surface roughness of the area being examined (see 7.1.5.1).
6.4 Developers—Development of penetrant indications is the process of bringing the penetrant out of open discontinuities through
blotting action of the applied developer, thus increasing the visibility of the penetrant indications. Several types of developers are
suitable for use with the lipophilic penetrant process. (Warning—Aqueous developers may cause stripping of indications if not
properly applied and controlled. The procedure should be qualified in accordance with 9.2.)
6.4.1 Dry Powder Developers are used as supplied (that is, free-flowing, noncaking powder) in accordance with 7.1.8.1(a). Care
should be taken not to contaminate the developer with fluorescent penetrant, as the penetrant specks can appear as indications.
6.4.2 Aqueous Developers are normally supplied as dry powder particles to be either suspended or dissolved (soluble) in water.
The concentration, use, and maintenance shall be in accordance with manufacturer’s recommendations (see 7.1.8.1(b)).
6.4.3 Nonaqueous, Wet Developers are supplied as suspensions of developer particles in a nonaqueous solvent carrier ready for
use as supplied. Nonaqueous, wet developers form a coating on the surface of the part when dried, which serves as the developing
medium for fluorescent penetrants (see 7.1.8.1(c)). (Warning—This type of developer is intended for application by spray only.)
6.4.4 Liquid Film Developers are solutions or colloidal suspensions of resins/polymer in a suitable carrier. These developers will
form a transparent or translucent coating on the surface of the part. Certain types of film developer may be stripped from the part
and retained for record purposes (see 7.1.8.1(d)).
7. Procedure
7.1 The following general procedure applies to the fluorescent liquid penetrant examination, lipophilic post-emulsification process
method (see Fig. 1).
7.1.1 Temperature Limits—The temperature of the penetrant materials and the surface of the part to be processed should be
E1208 − 21
Incoming Parts
PRECLEAN Alkaline Steam Vapor Solvent Acid
(See 7.1.3.1) Degrease Wash Etch
Mechanical Paint Ultrasonic Detergent
Stripper
DRY
(See 7.1.3.2)
Dry
PENETRANT Apply Post-
APPLICATION Emulsifiable
(See 7.1.4) Penetrant
LIPOPHILIC Apply
EMULSIFIER Lipophilic
(See 7.1.5) Emulsifier
FINAL RINSE Water
(See 7.1.6) Wash
DRY Dry Developer
(See 7.1.7) (Aqueous)
DEVELOP
(See 7.1.8)
DEVELOP Developer Dry, Dry
(See 7.1.8) Nonaqueous DEVELOP Developer Dry
DRY or Liquid Film (See Dry,
(See 7.1.7) 7.1.8) Nonaque-
DRY ous
(See
7.1.7)
EXAMINE Examine
(See 7.1.9)
Water Detergent Mechanical
Rinse Wash
POST CLEAN Dry
(See 7.1.11 and Practice
E165/E165M,
Annex on Post Cleaning.)
Vapor Solvent Ultrasonic
Degrease Soak Clean
Outgoing Parts
FIG. 1 General Procedure Flowsheet for Fluorescent Penetrant Examination Using the Lipophilic Post-Emulsification Process
between 40 and 125°F125 °F (4 and 52°C).52 °C). Where it is not practical to comply with these temperature limitations, qualify
the procedure at the temperature of intended use as described in 9.2.
7.1.2 Surface Conditioning Prior to Penetrant Inspection—Satisfactory results may be obtained on surfaces in the as-welded,
as-rolled, as-cast, or as-forged conditions or for ceramics in the densified condition. These sensitive penetrants are generally less
easily rinsed away and are therefore less suitable for rougher surfaces. When only loose surface residuals are present, these may
be removed by wiping the surface with clean lint-free cloths. However, precleaning of metals to remove processing residuals such
as oil, graphite, scale, insulating materials, coatings, and so forth, should be done using cleaning solvents, vapor degreasing or
chemical removing processes. Surface conditioning by grinding, machining, polishing or etching shall follow shot, sand, grit and
vapor blasting to remove the peened skin and when penetrant entrapment in surface irregularities might mask the indications of
unacceptable discontinuities or otherwise interfere with the effectiveness of the examination. For metals, unless otherwise
specified, etching shall be performed when evidence exists that previous cleaning, surface treatments, or service usage have
produced a surface condition that degrades the effectiveness of the examination. (See Annex on Cleaning Parts and Materials in
Practice E165/E165M for general precautions relative to surface preparation.) (Warning—Sand or shot blasting may possibly
close indications. Extreme care should be used with grinding and machining operations.)
NOTE 3—When agreed between purchaser and supplier, grit blasting without subsequent etching may be an acceptable cleaning method.
E1208 − 21
NOTE 4—For structural or electronic ceramics, surface preparation by grinding, sand blasting and etching for penetrant examination is not recommended
because of the potential for damage.
7.1.3 Removal of Surface Contaminants:
7.1.3.1 Precleaning—The success of any penetrant examination procedure is greatly dependent upon the surface and discontinuity
being free of any contaminant (solid or liquid) that might interfere with the penetrant process. All parts or areas of parts to be
inspected must be clean and dry before the penetrant is applied. If only a section of a part, such as a weld including the heat-affected
zone, is to be examined, all contaminants shall be removed from the area being examined as defined by the contracting parties.
“Clean” is intended to mean that the surface must be free of any rust, scale, welding flux, spatter, grease, paint, oily films, dirt,
etc., that might interfere with penetration. All of these contaminants can prevent the penetrant from entering discontinuities (see
Annex on Cleaning of Parts and Materials in Practice E165/E165M for more detailed cleaning methods). (Warning—Residues
from cleaning processes such as strong alkalies,alkalis, pickling solutions, and chromates, in particular, may adversely react with
the penetrant and reduce its sensitivity and performance.)
7.1.3.2 Drying after Cleaning—It is essential that the surface parts be thoroughly dry after cleaning, since any liquid residue will
hinder the entrance of the penetrant. Drying may be accomplished by warming the parts in drying ovens, with infrared lamps,
forced hot or cold air, or exposure to ambient temperature.
7.1.4 Penetrant Application—After the part has been cleaned, dried, and is within the specified temperature range, apply the
penetrant to the surface to be inspected so that the entire part or area under examination is completely covered with penetrant.
7.1.4.1 Modes of Application—There are various modes of effective application of penetrant such as dipping, brushing, flooding,
or spraying. Small parts are quite often placed in suitable baskets and dipped into a tank of penetrant. On larger parts, and those
with complex geometries, penetrant can be applied effectively by brushing or spraying. Both conventional and electrostatic spray
guns are effective means of applying liquid penetrants to the part surfaces. Electrostatic spray application can eliminate excess
liquid buildup of penetrant on the part, minimize overspray, and minimize the amount of penetrant entering hollow-cored passages
which might serve as penetrant reservoirs, causing severe bleedout problems during examination. Aerosol sprays are conveniently
portable and suitable for local application. (Warning—Not all penetrant materials are suitable for electrostatic spray applications.)
(Warning—With spray applications, it is impor
...