Pt Level Ii

Liquid Penetrant Testing Compiled for ASNT by David Quattlebaum, Jr. Quattlebaum Consultants

Level II Liquid Penetrant Testing

Lesson 5 Selection of Penetrant Testing Method

Introduction 1. Combinations of penetrant, emulsifiers, penetrant removal methods and forms of developers must be made in accordance with the penetrant material manufacturer’s recommendations and instructions or an applicable qualified products list.

Introduction 2. Penetrant type and method are sometimes decided by the contractor, customer, Level III technician or design engineer.

Selection of Penetrant Type Selection of a suitably efficient, cost effective penetrant type and process for a particular application depends on several factors. 1. Customer requirements.

2. Specification requirements. 3. Sensitivity required. 4. Size and number of test objects.

Selection of Penetrant Type 5. Surface condition of the test objects.

6. Configuration of the test objects. 7. Cost of equipment and materials.

8. Availability of water, electricity, compressed air and suitable testing area.

Advantages 1. The advantage of using fluorescent penetrant is that fluorescent indications are easier to see. 2. The advantage of the water removable penetrant is that it is much faster, safer, ecologically friendly and inexpensive.

Disadvantage 1. The disadvantage of water removable penetrant is the danger of over washing if the technician does not use proper techniques. Over cleaning can occur with any type, method or sensitivity level if technicians fail to follow the appropriate work practices.

Penetrant versus Other Methods 1. The penetrant method is limited to surface discontinuities.

2. The penetrant method is an economical, excellent field testing method.

Penetrant versus Other Methods 3. The penetrant method does not require special equipment, and does not always require electrical power. 4. The penetrant method has lower training and experience requirements than most other methods.

Penetrant Examination as a Complimentary Method 1. The penetrant method may be used as a primary method for detecting surface discontinuities. 2. The penetrant method is effective as a means of verifying surface indications detected by other methods.

Selection of Penetrant Method When selecting a penetrant method, the following information should be considered. 1. Material to be tested. 2. Location of testing. 3. Number, weight and size of the test objects.

Selection of Penetrant Method 4. Type of discontinuities. 5. Surface condition of the test object. 6. End use of the test objects. 7. Selection of developer. 8. Acceptance and rejection criteria.

Portability 1. Field liquid penetrant tests can be effectively and efficiently completed using portable, Type I (fluorescent) or Type II (visible) penetrant kits and either water or solvent wipe. 2. Aerosol liquid penetrant testing kits are portable, and if Type II solvent removable is chosen, no power or water supply is needed.

Portability 3. The advantage of aerosol kits is their portability, and very little set-up time is required. 4. The disadvantage of manual wipe is that the method is slow.

Postemulsification 1. When postemulsification processes are required, appropriately formulated penetrant materials and postemulsification methods must be used. 2. Small test objects can be dipped in a tank of Method B (lipophilic) emulsifier, the emulsification time monitored and excess penetrant rinsed off.

Postemulsification 3. For large test objects, equipment that sprays water and Method D (hydrophilic) emulsifier mix may be more efficient. 4. The advantage of the postemulsified method is the elimination of worry that penetrant may be rinsed out of shallow discontinuities.

Postemulsification 5. The disadvantage of the postemulsified method is the cost of the emulsifier and equipment, the extra timed step for emulsification and the maintenance checks for the emulsifier. 6. Method B (emulsification) method is not permitted by some industry specifications.

Postemulsification 7. The choice of developer for all the methods is regulated by specifications and the manufacturers’ recommendations.

Dry Developer 1. Dry developer is best for rough surfaces, such as castings or test objects with fine threads or corners, such as keyways. 2. Dry developer is also easy to handle and easy to apply.

Dry Developer 3. Dry developer leaves no film, thus no special cleaning is required for subsequent processing operations. 4. Excessive drying time should be avoided, as this will reduce sensitivity.

Dry Developer 5. Dry developer is the least sensitive type of developer and

should not be used for visible penetrant.

Wet Developers 1. Aqueous developers can be applied immediately after the water rinse, before drying. 2. Both water suspendible and water soluble developers may be applied by dipping, spraying or flowing.

Wet Developers 3. Aqueous developers give off no flammable vapors, no dust and have no odor. 4. Since aqueous developer leaves a thicker coverage, complete coverage with aqueous developer is easier to monitor than with dry developer.

Wet Developers 5. Both types of wet developers leave a thicker buildup of developer on rough surfaces, such as castings, or test objects with fine threads or corners, such as keyways.

Wet Developers 6. The water suspendible developer requires agitation, and both types require daily maintenance checks when used in tanks.

7. When a nonaqueous wet developer is used, the test object must be completely dry before the developer is applied.

Wet Developers 8. Nonaqueous wet developer is the most sensitive developer

because it can be sprayed in a very controlled, thin layer.

Wet Developers 9. The solvent carrier dissolves in the penetrant, slightly reducing the viscosity, increasing the volume of the penetrant in the discontinuities and leaching the indications to the surface as the volatile liquid evaporates.

Wet Developers 10. There are also wax and plastic film developers that absorb and fix penetrant indications to provide records. The selection and usage of these materials is largely dependent on the particular process used, the controlling specifications or standards and the company policy regarding recording of test indications.

Lesson 6 Interpretation and Evaluation of Indications

Discontinuity Categories Specific discontinuities are divided into three general categories.

1.Inherent. 2.Processing.

3.Service.

Discontinuity Categories No matter what type of discontinuity may be present in the test object, only those open to the surface may be detected with liquid penetrant testing.

Discontinuities 1. In metals, inherent discontinuities are those that are related to the

melting and original solidification of the molten metal, ingot or casting.

Discontinuities 2. Processing discontinuities are related to the various manufacturing processes, such as forging, machining, forming, extruding, rolling, welding, heat treating and plating. 3. Service discontinuities are related to inservice conditions of test objects.

Inherent Discontinuities Inherent discontinuities in ingots are formed during the processing and solidification process and include the following. 1. Inclusions (slag, impurities, etc.).

2. Porosity (entrapped gas). 3. Pipe (shrinkage). 4. Cracks.

Inherent Discontinuities Inherent cast discontinuities are those related to the melting, casting and solidification of the cast test object and include the following. 1. Porosity (entrapped gas).

2. Shrinkage. 3. Hot tears.

Inherent Discontinuities 4. Inclusions (slag, impurities, etc.). 5. Cracks. 6. Blowholes.

Processing Discontinuities Forging discontinuities include the following.

1. Burst: Appear as scaly, ragged cavities when open to the surface. 2. Laps: Folded flap of metal, forced on the surface. Appear as oddly-shaped cracks.

Processing Discontinuities 3. Cracks: Unlike laps, follow stress distribution. Appear as

thin, jagged, linear indications.

Processing Discontinuities Rolling discontinuities include the following.

1. Pipe (shrinkage): Normally result in internal lamination. 2. Porosity and inclusion: Result in internal laminations. 3. External seams, stringers or cracks.

Processing Discontinuities Lamination characteristics include the following. 1. They appear on the end of pipe and plate. 2. They are linear and parallel with top and bottom surfaces. 3. On rolled shapes (for example, I-beams), they are parallel to the rolling direction.

Processing Discontinuities Seam characteristics include the following.

1. They appear on the surface of the test object. 2. They follow the direction of rolling. 3. The appearance depends on the inherent discontinuity.

Processing Discontinuities Stringer characteristics include the following. 1. They appear on the surface of the test object. 2. They follow the direction of rolling. 3. The appearance depends on the inherent discontinuity. 4. They are usually deep in comparison to seams.

Processing Discontinuities Crack characteristics include the following.

1. They appear on the surface of the test object. 2. Those resulting from inherent discontinuities follow the rolling direction.

Processing Discontinuities Drawing, extruding and piercing discontinuities are visible on the surface. 1. Drawn products: Gross failure, normally through-wall. 2. Extrusions: Scabs (scraped or torn surface). 3. Piercing: Scoring or mandrel drag, sluggish.

Casting Discontinuities Even though casting is a primary process, casting discontinuities are inherent and include the following. 1. Inclusions. 2. Hot tears. 3. Porosity. 4. Unfused chills. 5. Unfused chaplets. 6. Cold shuts.

Service Induced Discontinuities Service discontinuities are related to service conditions

such as cycles of loading, stress corrosion, fatigue and wear.

Cracking There are many causes of cracking. 1. Material types. 2. Exposure circumstances. 3. Equipment type.

Cracking The stages of cracking include the following. 1. Initiation (crack forms). 2. Propagation (crack moves). 3. Final failure (overload due to loss of sound supporting material).

Typical Penetrant Indications

Large crack or opening

Tight crack or cold shut

Partially welded lap

Pits or porosity

Forming of Indications 1. After the proper precleaning, drying and application of penetrant for the proper dwell time (reference applicable procedure), capillary action forces the penetrant into the discontinuity.

Forming of Indications 2. The excess surface penetrant is removed either by wiping or with a water spray rinse, with the aid of an emulsifier for postemulsifiable penetrants.

Time for Indications to Appear 1. After removal of excess surface penetrant and application of developer, penetrant will migrate to the surface aided by capillary action and the blotting action of the developer.

Time for Indications to Appear 2. Deep indications will begin to appear first since indications with a large reservoir of penetrant will bleed out faster than a small indication with a smaller reservoir.

Time for Indications to Appear 3. Typical time to allow indications to form before measuring and evaluation is specified in the written procedure. 4. Standard times for evaluation are important so different technicians and testing facilities will get standard results.

Effects of Temperature 1. Colder temperatures will increase the viscosity of the penetrant and slow the capillary action. 2. Temperatures higher than approved may cause the penetrant to dry and reduce sensitivity.

Effects of Temperature 3. High temperature materials require special procedures and special training.

Lighting 1. The standard lighting, referred to as ambient (white) light, for

viewing and evaluating visible dye penetrant indications should be verified at the test surface using calibrated equipment.

Lighting 2. For fluorescent penetrant indications, the standard lighting

should be verified with a calibrated ultraviolet radiation meter at the test surface, and a darkened test area of less than 20 lux (2 ftc) ambient light.

Effects of Metal Smearing 1. Power wire brushing or sand blasting can smear metal and close the surface opening of discontinuities. 2. If allowed by the governing procedure, the surface should be etched to remove the smeared metal.

Sequence 1. Inservice tests are sometimes used for the root pass of welds, or before final machining. 2. Final liquid penetrant testing is performed on a test object in the final machined and/or heat treated condition after proper precleaning, as required.

Factors Affecting Indications Penetrant selection depends on the following factors.

1. Sensitivity requirements. 2. Component location. 3. Ultraviolet radiation availability.

4. Water availability. 5. Power availability.

Factors Affecting Indications Fluorescent indications are easier to see. The postemulsified

method is the most sensitive for small, shallow indications.

Prior Processing 1. The method of precleaning may depend on prior processing of the test object. 2. If a test object or weld has never been exposed to machine oils or lubricants, some specifications will allow reduction of penetrant dwell time.

Prior Processing 3. Ultrasonic testing using couplant should only be performed after final penetrant testing because the couplant may hinder penetrant penetration into discontinuities.

Prior Processing 4. Visible penetrant should never be used before a fluorescent penetrant test because the red penetrant may still be present in discontinuities and could interfere with indication luminosity.

Prior Processing Factors affecting indications also include the following.

1. Previous examinations. a. Magnetic particles may fill or bridge discontinuities.

b. Visible versus fluorescent penetrants. 2. Surface conditions.

Prior Processing 3. Temperature. 4. Dwell time.

5. Developer application. 6. Examination conditions.

Prior Processing 7. Surface conditions. a. Surface openings may be closed. b. Rough or porous area may retain penetrant.

Prior Processing c. Deposits on the surface or in openings may dilute the penetrant. d. Moisture within the discontinuity can prevent penetrant from entering.

Prior Processing 8. Temperature. a. Viscosity of most liquids increases at low temperatures. b. Volatile components may evaporate if too hot.

Prior Processing 9. Dwell time and washing. a. Fine indications could be caused by insufficient penetrant dwell time. b. Diffused indication may imply incomplete washing. c. Excessive washing can remove penetrant from large or shallow discontinuities, resulting in less intense indications.

Prior Processing 10.

Developer application.

a. Excessive developer may mask fine discontinuities. b. Contrast may be reduced.

Prior Processing 11.

Examination conditions.

a. Good eyesight is required.

b. Proper lighting. c. Darkened area for fluorescent penetrants.

Prior Processing d. Adequate ultraviolet radiation intensity for fluorescent penetrants. e. Adequate ambient light intensity for visible dye.

f. Allow eyes to adjust to booth according to specifications.

Crack Indications Cracks can occur as: 1. Solidification cracks.

2. Processing cracks. 3. Service cracks.

Indications from Specific Material Forms Surface indications can appear on many of the following processes. 1. Forgings. 2. Castings.

3. Plates. 4. Welds. 5. Extrusions.

Indications from Specific Material Forms Each indication requires evaluation against an approved

specification or procedure.

Indications from Discontinuities 1. Continuous linear indications. a. Cracks. b. Cold shuts. c. Forging laps.

d. Seams.

Indications from Discontinuities 2. Intermittent linear indications. a. Partially filled cracks, seams, or forging laps. 3. Rounded area indications. a. Gas holes.

b. Pin voids. c. Deep crater cracks.

Indications from Discontinuities 4. Small dot indications. a. Porosity.

b. Excessive coarse grains (castings).

Indications from Discontinuities 5. Diffused indications. a. Widespread porosity.

b. Excessive developer. c. Pockets or shrinkage that come to the surface. d. Wide cracks.

Indications from Discontinuities Insufficient cleaning/incomplete penetrant removal can also

cause diffused indications.

Evaluation of Indications To evaluate an indication is to decide if the indication is

acceptable, requires rework or causes the test object to be rejected.

Evaluation of Indications 1. Determine if the indication is linear or rounded by procedure definition. 2. Determine if the indication is a crack, seam, lap, porosity or lack of fusion. 3. Measure each indication and compare to acceptance criteria.

Evaluation of Indications 4. Create a detailed report. 5. Generate a sketch of the indication and location. 6. Identify the test object as acceptable or unacceptable, and segregate it from the lot.

False Indications 1. Poor washing of water washable and postemulsifiable penetrants.

2. Inadequate ultraviolet radiation during the washing process. 3. Poor technique.

False Indications 4. Contaminants a. Penetrant on the hands of the technician. b. Contamination of wet or dry developer.

False Indications c. Penetrant rubbing off of one test object to a clean portion of the surface of another test object. d. Penetrant spots on the testing table.

e. Improper handling techniques.

Relevant and Nonrelevant Indications 1. Relevant indications are true discontinuities.

2. Nonrelevant indications are accumulations of penetrant commonly caused by the following factors.

Relevant and Nonrelevant Indications a. Poor washing or cleaning. b. Test object configuration, features or irregularities. c. Press-fitted test objects.

Lesson 7 Liquid Penetrant Process Control

Introduction 1. The reliability of any penetrant test is determined in large part by the condition of the material used. 2. Inservice checks are used to test penetrant materials held in open tanks and subjected to contamination or evaporation.

Quality Control of Test Materials Many quality control procedures are required for determination of the following components. 1. Sulfur and chlorine content. 2. Liquid oxygen compatibility. 3. Temperature stability. 4. Water tolerance.

Quality Control of Test Materials 5. Viscosity. 6. Flash point. 7. Toxicity. 8. Developer precipitation rate.

Test Material Control Samples 1. Control samples are taken at the time penetrant materials are received from the supplier – this includes developers. 2. Samples are kept in sealed containers and stored where they are not subject to deterioration from heat, light or evaporation. 3. Samples should be sufficient for life of the penetrant materials.

Reference Blocks 1. Reference blocks, plates or panels are often specified in the procedures for quality control of liquid penetrant materials. 2. These standards are often called known defect test specimens (KDTS).

Reference Blocks 3. The materials used in the manufacture of reference blocks include aluminum, steel, nickel, glass and ceramic. 4. Some of the blocks are designed primarily for the following functions.

Reference Blocks a. Checking penetrant system sensitivity.

b. Performing comparison tests. c. Penetrant or emulsifier washability.

Test Panels 1. Cracked nickel-chromium plated panels.

2. Penetrant system monitor (PSM) panel. 3. Quench cracked aluminum block.

System Monitor Panels System monitor panels are commercially manufactured and can be used to detect major changes in the following. 1. Visible and fluorescent systems.

2. Water washable and postemulsified systems.

System Monitor Panels System monitor panel includes five crack centers of different sizes for evaluation of sensitivity and grit blast side for wash characteristics.

Aluminum Reference Blocks 1. Aluminum reference blocks measure about 5 by 7.5 cm (2 by 3 in.), and are cut from 0.8 cm (0.3 in.) thick bare 2024-T3 aluminum alloy plate, with the 7.5 cm (3 in.) dimension in the direction of rolling. The dimensions are for guidance only.

Aluminum Reference Blocks 2. The blocks are heated and water quenched to produce thermal cracks. This is accomplished by supporting the block in a frame and heating it nonuniformly with the flame of a gas burner or torch in the center on the underside of the block.

Aluminum Reference Blocks 3. A groove about 0.15 by 0.15 cm (0.06 by 0.06 in.) deep is cut in the 5 cm (2 in.) direction across the center of the heat affected zone. 4. This forms two test areas, and permits the side-by-side application and comparison of two penetrants without cross contamination.

Aluminum Reference Blocks 5. This type of block is widely used for comparing the performance of

penetrants in field conditions.

Aluminum Reference Blocks 6. After a reference block has been used, it is cleaned before reuse. The block is heated slowly with a gas burner to 426 °C (800 °F), as determined by a 426 °C (800 °F) temperature indicating medium, after which the block is quenched in cold water.

Aluminum Reference Blocks 7. It is then heated to about 71 °C (160 °F) for 30 min to drive off any moisture in the cracks, and is then allowed to cool to room temperature.

Aluminum Reference Blocks Typical aluminum 2024T3 reference block after heating/ quenching and grove cut. Note the HAZ in the center.

Ceramic Reference Blocks 1. Ceramic reference blocks are flat, circular disks of unglazed ceramic that, although quite solid and impervious to liquids, have micropit surfaces that entrap liquid penetrants.

Ceramic Reference Blocks 2. The micropit structure provides a range of pore sizes, and a performance comparison can be made of two or more penetrants merely by noting the number or distribution of porosity indications and their intensity in a side-byside comparison test.

Ceramic Reference Blocks 3. Indications appear as a large number of microscopic specks of fluorescence or color, the number increasing as the sensitivity of the penetrant increases.

Ceramic Reference Block Use 1. Using a small applicator, a drop of each penetrant to be tested is applied to the flat surface of the reference block. 2. Immediately following application, the penetrants are blotted with a piece of soft tissue by pressing the tissue against the block using a flat object.

Ceramic Reference Block Use 3. The tissue and cover also hold the penetrants in proper contact with the reference block and prevent excessive bleeding and possible cross contamination. 4. Following the required dwell period (usually 10 min), the penetrants are processed in accordance with the penetrant manufacturer’s recommendations.

Ceramic Reference Block Use 5. A developer is not used. 6. In making visual comparisons,

both the number of indications observed and the intensity of indications are noted.

Anodized and Plated Test Panels 1. Stress cracked anodized aluminum and chrome plated nickel test panels are frequently used for comparing penetrant sensitivity and washability. 2. The panels are classified according to the size cracks they contain. 3. The grades are coarse, medium and fine, providing low, medium and high sensitivity levels.

Anodized and Plated Test Panels

Coarse cracks

Medium cracks

Fine cracks

Plated Test Panels Usage 1. A line is usually drawn along the centerline (length) of the panel using a wax pencil or narrow vinyl tape. 2. This forms two test areas and permits the side-by-side application and comparison of penetrant materials without cross contamination.

Low Cycle Fatigue Blocks 1. Titanium or NiCrFe plates are commonly used to manufacture standards with low cycle fatigue blocks (LCF) cracks in various size ranges. 2. The cracks are started from electrical discharge machined (EDM) notches or spot welds, which are later ground away after the starter cracks are grown.

Low Cycle Fatigue Blocks 3. Tensile stressing or reverse bending of the plates achieves additional crack length extension. 4. Titanium or NiCrFe plates are commonly sold in a set of three plates, with a total of eighteen possible cracks in the set.

Low Cycle Fatigue Blocks Usage 1. Low cycle fatigue blocks are used like other known discontinuity standards, except that the total number of detected cracks per inspection of the plate set is recorded and monitored in a running summary per procedure supplied with the plates.

Low Cycle Fatigue Blocks Usage 2. When fewer cracks are detected, the technician is warned that something has shifted in the process capability, or that the cracks have been improperly cleaned.

Tests of Penetrant Materials Inservice quality of the materials used in liquid penetrant testing is determined by a check of the following components. 1. Sensitivity.

2. Water content. 3. Contamination.

Tests of Penetrant Materials 4. Washability. 5. Fading of the penetrant dyes (checked by a simple comparison test). 5. Fluorescent luminance.

Tests of Penetrant Materials a. The fluorescent luminance test is a comparison of the luminance of the control penetrant sample to the used penetrant in the tanks. b. Samples are alternately read on a fluorometer and the results compared.

Tests of Penetrant Materials c. If the fluorescent intensity of the penetrant should drop below

90% of the reference penetrant, the penetrant is discarded.

Emulsifier Tests Emulsifiers are usually tested for the following components.

1. Sensitivity. 2. Washability. 3. Water content. 4. Amount of contamination from penetrants.

Emulsifier Tests The sensitivity test, water washability test and the water

content test for emulsifiers are identical to the tests used for penetrants.

Dry Developer Tests 1. Dry developers used in open containers or chambers are usually tested by observation. 2. Dry developers are not hygroscopic, they do not absorb moisture from the air and they are relatively trouble free if they do not come in contact with water.

Dry Developer Tests 3. Any dry developer that is found lumpy or caked instead of light

and fluffy, or that shows any other sign of having been wet, is discarded.

Dry Developer Tests Dry developer is checked daily for the following.

1. Cracking. 2. Dirt.

Should either condition exist, the developer is discarded.

Wet Developer Tests 1. Wet (aqueous) developers are usually tested for proper concentration and possible contamination from dirt or penetrant.

2. Solution concentration is tested by measuring the specific gravity with a hydrometer.

Wet Developer Tests 3. If the hydrometer reading differs from manufacturer’s requirements, either powder or water is added to the developer in sufficient quantities to bring the concentration within acceptable limits.

Wet Developer Tests 4. A small, smooth test plate with no indications is dipped in the

developer tank and visually examined for dirt.

Wet Developer Tests 5. The tank and the plate are checked for fluorescence or

penetrant contamination under ultraviolet radiation. If either condition is evident, the developer is discarded.

Typical Hydrometer Ballast

Stem

Scale Body

Lesson 8 Test Procedures and Standards

Introduction There are three types of written documents that control penetrant

tests. 1. Standards.

2. Specifications. 3. Written practices.

Standards A reference document that controls and standardizes

generally accepted practices for a nondestructive testing method. Examples include the following.

Standards 1. MIL-STD-6866, Inspection, Liquid Penetrant.

2. ASTM E-1417, Standard Practice for Liquid Penetrant Examination.

Specifications 1. Specifications are written by a company for a specific process.

2. Specification is a tool used by engineering, management and purchasing for contractual documents and procedure development. They will normally contain the following sections.

Specifications a. Reference documents. b. Materials. c. Equipment. d. Personnel qualifications.

e. Process control. f. Written procedure requirements.

Written Practices Written practices provide specific guidance on the performance of the penetrant test and should contain the following information. 1. Penetrant materials to be used.

2. Details of precleaning the test object. 3. Complete processing parameter.

Written Practices 4. Testing and evaluation requirements.

5. Specific test object information. 6. Acceptance/rejection criteria. 7. Postcleaning procedures. 8. Documentation requirements. 9. Safety requirements.

Lesson 9 Safety, Health and Disposal

General Safety Precautions 1. Use eye and face protection. 2. Keep clothing free of penetrant material and change immediately if cloth is contaminated. 3. Clean penetrant material off skin as soon as possible. 4. Avoid or limit exposure to penetrant materials in confined areas.

General Safety Precautions 5. Wear safety shoes to protect feet.

6. Use proper lifting techniques. 7. Have proper fire extinguishers. 8. Wear proper protective clothing.

9. Know the direction of sprays. 10. Know the work environment.

General Safety Precautions 11. Observe all safety rules. 12. Know the proper method of disposal of aerosol cans. 13. Do not smoke around penetrant materials.

14. Properly dispose of used wiping cloths and paper towels.

Flammability 1. Only approved ultraviolet lights should be used in areas where flammable vapors are present. 2. Dispose of all cloths and paper towels in a metal container.

3. All penetrant materials should be stored away from sources of flame and heat.

Flammability: Flash Point 1. Lowest temperature at which the vapors in sufficient concentration will ignite in air if exposed to a source ignition. 2. Minimum of 200 °F OSHA established for liquids in open tanks without special ventilation. 3. Aerosol cans/materials can have a flash point as low as 40 °F.

Flammability: Penetrants Penetrant vapors may concentrate above the liquid penetrant surface.

Flammability: Emulsifiers 1. Emulsifiers have many of the same hazards as penetrant.

2. Check the Material Safety Data Sheet (MSDS) before use for safe handling.

Flammability: Solvent Removers 1. Solvent removers can have a very low flash point.

2. Do not spray around sources of flame such as welding and grinding operations.

Flammability: Dryers 3. Designed for drying parts. 4. Do not use combustible materials in dryers.

Skin Irritation and Allergies 1. When used according to the manufacturers’ instructions, penetrant materials do not normally pose any problems. 2. In most cases, skin irritation is a form of dermatitis that appears on the hands and arms. 3. Rubber gloves will prevent most cases of skin irritation.

Respiratory Considerations 1. Respiratory equipment is not normally needed as long as adequate ventilation for fumes and vapors is maintained. 2. Dry developers should only be applied in hood equipment or adequately ventilated work areas.

Physiological Effects of Ultraviolet Radiation 1. The National Institute for Occupational Safety and Health (NIOSH) recommends personnel working with ultraviolet radiation between 310 to 400 nm limit exposure of their eyes and unprotected skin to 1000 µW/cm2.

Physiological Effects of Ultraviolet Radiation 2. Personnel using ultraviolet radiation bulbs should consider special yellow glasses that block most ultraviolet radiation.

Disposal of Penetrant Materials 1. Special rules set by federal, state and local laws must be followed. 2. General rule: Penetrant testing material cannot be disposed of through normal sewer lines.

Controlling Penetrant Usage 1. Use equipment that limits the amount of penetrant.

2. Increase penetrant drain time. 3. Use equipment that separates penetrant and emulsifier from the waste water. 4. Use biodegradable penetrants.