INSPECTION OF PAINTING OPERATIONS
9.1 Scope of Section. This section describes the duties of an inspector, general inspection procedures, and specific inspection methods used in inspecting painting operations. Depending upon the job and the contract requirements, quality – control inspectors may be contractor-supplied (that is, contractor quality control – CQC) or Government personnel. In either case, the contracting officer is responsible for ensuring the quality of the job. The intent of this section is to describe proper inspection procedures so that Government personnel will know either how to inspect a painting operation or to ensure that someone else has done it correctly.
9.2 Importance of Inspection. The success of a painting job depends upon the specification requirements being met for surface preparation, application and materials. Most coating failures are the result of contract requirements not being met. Inspection procedures are designed to detect situations when the requirements of the contract are not being met. Thus, inspection is a key factor in obtaining the performance and durability built into the specification.
9.3 Contractor Quality Control Inspection. In Government painting, quality control inspection is often provided by the contractor. For large jobs, a contractor usually hires an inspector. For smaller jobs (less than $200,000), a contractor’s superintendent may carry out the quality control inspection. If deemed necessary because of the size or difficulty of a job, or because of the crucial function of a structure, the contract specification can require the contractor to hire a certified inspector (e. g., NACE has a certification program). In this way, the contractor’s inspector may be more independent of the contractor and may have better inspection skills. Although this requirement may increase inspection costs, the increased cost of proper inspection as opposed to none or poor inspection has been found by the private sector to be cost effective. Quality control inspectors should report deviances from the contract specification in writing to the contracting officer. Appropriate governmental action in response to these reports is essential in obtaining the quality of the job built into the specification.
9.4 Duties of an Inspector. The duties of an inspector include understanding the contract specification requirements, making sure that the specification requirements are met by the contractor, and keeping good records. Record keeping is a very important part of inspection. It should occur during all phases of the job. Records form an important part of the permanent record on each building, and provide key information in the case of contract disputes.
9.4.1 Record Keeping. Inspectors should keep records in a
bound book (logbook). Each page should be initialed by the inspector and dated. The record book should contain:
a) Written records of verbal agreements made between the contracting officer or the inspector and the contractor.
b) Daily descriptions of the type of equipment and number of workers on the job site.
c) Descriptions of the coating materials that are on
d) Records of the rate of work progression.
e) Measurements of ambient conditions.
f) Results and observations of the surface preparation inspection.
g) Measurements and observations of coating application, including time between surface preparation and coating application, and times between coats.
h) Results of the final and warranty acceptance inspections.
It is especially important that agreements between the contracting officer (or designee) and the contractor that modify the contract specification be in writing and be signed to minimize future disputes.
9.5 Inspection Equipment. A description of equipment used
in typical inspections is summarized in Table 15. Instructions on its use are provided in Section 10 and in the equipment manufacturer’s literature. Some of the equipment is readily available from local hardware or variety stores but some is specialized equipment for painting operations. Suppliers of specialized equipment are listed in:
a) ASTM, 1916 Race Street, Philadelphia, PA 19103.
b) NACE, P. O. Box 218340, Houston, TX 77218.
c) SSPC, 516 Henry Street, Suit 301, Pittsburgh, PA 15213-3738.
d) Paul N. Gardner Company, Inc., Gardner Building, P. O. Box 10688, Pompano Beach, FL 33060-6688.
e) KTA-TATOR, Inc., 115 Technology Drive, Pittsburgh,
f) ZORELCO, P. O. Box 25500, Cleveland, OH 44125.
g) Pacific Scientific, 2431 Linden Lane, Silver Spring, MD 20910.
h) S. G. Pinney & Associates, 2500 S. E. Midport Road, P. O. Box 9220, Port St. Luice, FL 34952.
9.6 Inspection Steps. The inspector’s tasks can be divided
into eight general steps, which are summarized in Table 16 and discussed in more detail below. Special equipment required in each of these steps is also listed in the table. A form that may be useful in reviewing the contract is provided in Figure 21, and one for organizing inspection data is provided in Figure 22.
9.6.1 Review Specification and Correct Deficiencies, If Any. The first part of any inspector’s job is to read and understand the contract specification. If deficiencies are found, resolution of the deficiencies between the contracting officer and the contractor is needed prior to start of work. Any changes in the contract specification must be documented in writing and signed by the two parties or their representatives. Copies of these agreements should be kept in the inspector’s records. In addition to reviewing the specification, the inspector must also review the contract submittal. The form shown in Figure 21 may help an inspector to identify key specification requirements and essential information from the submittals, and to prepare for the preconstruction conference. Note that at this time, all the information needed to complete the form may not be available. However, the information should be available before the start of the job.
9.6.2 Visit Job Site. It is important for the contractor to visit the job site with an inspector prior to the preconstruction conference so that the scope of the job and any constraints are understood. Potential problems that are found, such as difficulty with access to the job site, can then be resolved at the preconstruction conference. Such visits have been shown to be effective in reducing problems during the job.
Equipment for Inspecting Painting Operations
9.6.3 Conduct Pre-Construction Conference. At the beginning of each new contract or work order before the start of any surface preparation or coating application, a meeting should be held with the contractor, contracting officer, inspector, and other key people. Figure 21 may be helpful in this discussion. During this conference, agreement should be reached on details of the specification and the procedures and expectations of the inspector. For example, the number and locations for inspecting surface preparation and coating thickness should be determined. Scheduling, job sequencing, job stops for inspection, and other job-related issues should be discussed. Differences between contractor and contracting officer should be resolved at this time to avoid future misunderstandings and job delays.
Agreements that result in a change of the contract should be made in writing, signed and included in the record book.
9.6.4 Inspect Job Site After Pre-Surface Preparation. Prior to surface preparation or coating application, it is necessary to be certain that requirements in the specification relating to readying a surface or area for painting are carried out. These may include protecting adjoining surfaces, removing weld splatter, ensuring that surfaces are free of oil and grease, grinding sharp metal edges, protecting plants and other shrubbery, replacing rotted wood, caulking joints, and the like.
9.6.5 Inspect Coating Materials. Coating materials must be inspected at the job site to identify deficiencies that could result in failure of the paint film. The following checklist can be used:
a) Read labels on the coatings to verify that the coatings are the ones specified or approved.
b) Take one representative 1-quart sample in accordance with the specification. Retain the sample for a period of 1 year from the date of final approval of the contract work in case of coating film failures or contract disputes.
c) Ensure that coating materials are in sealed, unbroken containers that plainly show that the date of manufacture is within 1 year. The label should display the manufacturer’s name, specification number/or designated name, batch number, and FED-STD-595 color.
d) Inspect the paint after stirring for homogeneity, weight, viscosity, color, and smell. If deficiencies are suspected from these tests, the paint should be sent to a laboratory for testing. A kit developed by the Army Construction
Engineering Research Laboratory (Champaign, IL 61802, 1-800-USA-CERL) is available that will assist the inspector in field inspection of latex and oil-based paints.
e) Count the cans of paint on the job site to determine that a sufficient quantity is available to complete the job as specified. For multi-component paints, confirm that the proper ratio of materials for each specific coating is present.
To estimate the paint required for a job, use the nomograph reproduced from a Naval Facilities Engineering Service Center (Port Hueneme, CA 93043) Techdata Sheet shown in Figure 23.
f) Ensure that the paint is stored on site in an approved building or area.
g) Record number of cans and paint condition in record
9.6.6 Measure Ambient Conditions. Most coating systems will
not dry or cure properly under extremes of temperature or humidity, nor will they adhere well if applied over damp surfaces. For example, specifications often require that the substrate surface temperature be 5 degrees F above the dew point and rising. For these reasons painting contracts have requirements for air and surface temperature, dew point, and, perhaps, additional environmental conditions. The paint manufacturer’s technical data sheet will also have limits for acceptable environmental conditions. (If the limits are in conflict, agreement on the limits should be reached during the preconstruction conference.) Because temperature and dew point may vary considerably within a small area, temperature and dew point should be measured in the immediate vicinity of the work being done. Surfaces being painted may be colder than the atmospheric temperature and their temperatures should be measured in addition to atmospheric temperatures. Dew point at the surface being painted may also be different from that in the air away from the surface. Thus, dew point should be measured near the surface. Ambient condition measurements should be made about every 4 hours. These times should include before start of job, after breaks, and after sudden changes in environmental conditions. Sudden changes in environmental conditions should also be recorded in the logbook. In addition, do not paint in rain, snow, fog, or mist, or when the surface is covered with frost.
220.127.116.11 Relative Humidity and Dew Point. These conditions are measured using a psychrometer. Most psychrometers consist of a wet bulb thermometer, a dry bulb thermometer, and a standard psychometric table. Using the table, the relative humidity is obtained from the two temperature readings. More detailed information is provided in Section 10.
18.104.22.168 Surface Temperature. Surface temperature is measured using a special thermometer in which the temperature sensing element is designed to come into intimate contact with the surface and to be shielded from the surrounding air. The surface temperature of the coldest and warmest surfaces should be within the limits of the specification. The location, temperature and time of the measurement should be recorded in the record book.
9.6.7 Inspect Surface Preparation. Surface preparation
inspection procedures include inspecting equipment, and associated materials (e. g., blasting medium and chemicals), as well as the cleaned surface itself. Proper surface preparation, as described in the specification, must be completed to obtain a durable coating film. Additional information on surface preparation is presented in Section 6. Many of the surface preparation requirements involve visual inspection of the surface, and some are subjective. For example, the specification may require removal of loose paint (for example, paint that can be removed by a dull putty knife), removal of surface chalk to some specified level and feathering of edges on the remaining paint film. To help avoid conflicts between the contractor and the inspector, it may be useful to have the contractor prepare a test surface about 4 by 4 feet that can then be used as a standard for surface preparation. Photographs of the test surface could be part of the inspection record. For steel, the test surface should be protected by a clear coating.
When blast cleaning is part of the surface preparation, it should be performed in a manner so that no damage is done to partially or entirely completed portions of the work, adjacent surfaces, or equipment. Usually blast cleaning should progress from the top towards the bottom of a structure, should be carried on downwind from any recently painted structures, and should not scatter abrasive on or into surrounding buildings or equipment. All dust from blasting operations must be removed by brushing, blowing, or vacuuming before painting.
22.214.171.124 Abrasive-Blasting Surface Preparation Equipment and Supplies
a) Air Cleanliness. Routinely (at least two times a day or every 4 hours) inspect air supply lines for both blast cleaning or paint spray application to ensure that the air supply is clean and dry. A blotter test as described in ASTM D 4285 can be used to determine whether the air supply is free of oil and moisture. In this test, a clean white blotter is held downstream about 19 inches from the nozzle for 2 minutes. It should remain clean and dry.
b) Abrasive. Each batch or shipment of abrasive should be checked for oil contamination and, if required, soluble salts. Either can contaminate a cleaned surface and reduce the service life of the coating. A commonly used test to check for oil contamination is to take a small random sample of the abrasive, place it together with clean water in a small bottle or vial, shake the bottle for a minute and examine the surface of the water. There should be no sheen of oil on the surface of the water. Soluble ionic contaminants can be detected using the electrical conductivity test described in ASTM D 4940. In addition, the abrasive should feel dry to the touch when it is placed in the abrasive blasting machine. Recycled abrasives break down after several cycles, and the number of cycles depend upon the type of the abrasive. The abrasive should be replaced when it no longer meets the requirements of the specification.
c) Blast Hoses and Nozzles. Blast hoses should be in good condition and kept as short as possible. The nozzle pressure and diameter of the nozzle orifice both affect the cleaning rate. A nozzle orifice gage is used to determine the orifice size. Air pressure at the nozzle is measured using a hypodermic needle air pressure gage and should be from 90 to 100 psi for optimum efficiency. Usually these parameters are measured at the start of a job and when production rates are decreasing. An increase of nozzle size of more than 1/8-inch causes loss of cleaning efficiency because of the increased pressure drop. Increased nozzle size also causes increased use of abrasive. Profile should be inspected when major changes in cleaning efficiency are noted.
d) Safety. Special safety precautions are required during abrasive blasting. Refer to Section 13 for more information. These precautions include use of external couplings on blast hoses and dead man controls, and electrical grounding of equipment.
126.96.36.199 Water Blasting. Since contaminants, such as salts and oils, in the blasting water will be left behind on the blast – cleaned surface and may adversely affect the adhesion of the coating to be applied, water should be essentially free of contaminants. If cleaning agents are added to the water used for blasting and cleaning, the surfaces must be thoroughly rinsed with clear water. An exception is the use of flash-rusting control agents when cleaning steel. These agents should only be used in accordance with the contract specification and the coating manufacturer’s recommendations. As for abrasive blasting, hoses should be in good condition and kept as short as possible. Special safety precautions, similar to those used in abrasive-blast cleaning, also need to be taken. In addition, consideration should be given to the slipperiness of wet surfaces. More information on safety is provided in Section 13.
188.8.131.52 Frequency of Inspecting Cleaned Surfaces. The objective of the inspection is to ensure that the entire surface was prepared in accordance with the specification. The inspection report should provide a representative description of the cleaned surface. The specific number and location of places at which surfaces should be inspected must be in accordance with the contract specification. If not detailed in the specification, SSPC PA 2 can be used as a guide. Additional inspection sites that should be considered include those where the existing paint was failing, in hard-to-reach areas where surface preparation is difficult, and where major changes in equipment were made.
184.108.40.206 Inspecting Prepared Steel Surfaces
a) Cleanliness. If a small representative sample of surface was not prepared to use as the standard for surface preparation, the degree of blast or tool cleaning should be compared to the description given in the SSPC or NACE specification referred to in the contract specification. The appearance should correspond with the specified pictorial standards of SSPC VIS 1, SSPC VIS 3, or a NACE panel. Complete descriptions of the degrees of cleanliness are found in Section 6. After blasting, blast-cleaned surfaces must be cleaned (e. g., vacuum, air blast, or brushing) to remove traces of blast products from the surface or pitted areas. One of two tests for cleanliness can be used. In one, a white glove or other clean cloth is rubbed over the surface and examined for soiling or debris, and in the other, a piece of clear adhesive tape is applied to the surface, removed and the adhesive side examined for debris.
b) Profile. Profile is measured using one of three
pieces of equipment: comparator, depth micrometer, or replica
tape. It should be noted that the three techniques may give slightly different results. Complete descriptions of standard methods for each of these techniques are described in ASTM D 4417, Field Measurement of Surface Profile of Blast Cleaned Steel and in Section 10.
220.127.116.11 Inspecting Concrete, Masonry, Wood, Plaster, Wallboard, Old Paint. On these surfaces, specifications may have requirements for measurements of moisture content and residual chalk, as well as visual condition. The specification should state how moisture is to be measured, since the different methods provide different types of data. Moisture content can be measured either using a plastic sheet test (ASTM D 4263) or an electric moisture meter. In the plastic sheet test, a piece of plastic film is taped (all edges) to the surface. After 24 hours, the film is removed and the underside is examined for the presence of condensed water. Prior to application of most coatings, the sheet should be free of condensed water. This is because accumulation of water at the concrete/primer interface will usually lead to delamination of the primer. To use a moisture meter on hard surfaces, small holes must drilled for the electrodes. These holes should be repaired after the measurements are completed. The contract should state a moisture requirement. Residual chalk is usually measured using a piece of cloth of contrasting color, in accordance with ASTM D 4214.
Other procedures are also described in ASTM D 4214. In the cloth method, a piece of cloth is wrapped around the index finger, placed against the surface and then rotated 180 degrees. The spot of chalk on the fabric is compared with a photographic reference standard. Chalk readings of 8 or more indicate adequate chalk removal providing reasonable assurance that the new coating should not fail because of application to a chalky surface.
9.6.8 Inspect Coating Application. Proper application is
another essential factor in determining paint performance, and the requirements of the specification must be followed. General guidance on paint application is presented in Section 7 and SSPC PA-1. Inspectors should assess ambient conditions, application equipment, ventilation, mixing, film thickness, and drying and curing conditions to ensure that they are within the limits of the specification and the technical data sheets for the paints.
It is especially important that the paints be applied and cure within the temperature and relative humidity limits of the specification, since these conditions affect film formation. A properly dried and cured film is essential for satisfactory paint performance, and deviations from these limits may prevent proper film formation. For two-component systems, the inspector should ensure that the materials were mixed together and in the proper ratio. For all materials, thinning should only be allowed in accordance with the manufacturer’s data sheet.
18.104.22.168 Application Equipment. Equipment to apply the coating must be in acceptable working condition. When spraying, the spray pattern should be oval and uniform, the gun should be held at the proper angle and distance from the surface, and each spray pass should overlap the previous one by 50 percent. Proper techniques should also be used for brushing, rolling, or other application procedures. Refer to Section 6. Special safety requirements for paint application are described in Section 13.
22.214.171.124 Ventilation. The ventilation of tanks and other enclosed areas where paint is to be applied and cured must meet the requirements of OSHA’s Confined Space Regulation, and the contractor’s safety plan required by contract specification.
Good ventilation is also necessary for proper coating cure.
126.96.36.199 Mixing/Thinning. Paints must be properly mixed as described in Section 7. Paint solids often settle out during storage and must be completely blended into the paint vehicle, resulting in homogeneous mixture. For multi-component paints, the inspector should ensure that all components have been mixed in the proper proportion, that the mixing is thorough and that the resulting paint is uniform in appearance. Required induction times must also be met to obtain satisfactory application and film properties. Although the paint manufacturer prepares paint to produce a consistency for brushing, rolling, or spraying, sometimes additional thinning is permitted in the specification. Thinning of the paint must follow manufacturer’s instructions for both type and amount of solvent. A thinned paint will cover more surface area but the dry film thickness will be less and may not meet the requirements of the specification.
188.8.131.52 Film Thickness. Contract specifications may require a minimum and/or a maximum dry film thickness for each coating application. Wet film thickness measurements made at the time of paint application are used to estimate dry film thickness so that appropriate adjustments in the application procedure can be made to meet the specification. Wet film thicknesses are not used in meeting contract requirements because of the many factors (solvent evaporation, wetting energies) that affect the measurement. Procedures for making wet film thickness are described in ASTM D 4414, Wet Film Thickness by Notch Gages and in Section 10. The dry film thickness is estimated from the wet film thickness according to:
Dry Film Thickness = Wet Film Thickness x Percent Volume Solids
The percent volume solids is available from the coating manufacturer’s data and should be part of the inspector’s records. Dry film measurements are made after the coating has hardened. For steel surfaces, thickness measurements can be made according to SSPC PA 2 or ASTM D 1186 or ASTM D 1400, Nondestructive Measurement of Dry Film Thickness of Nonconductive Coatings Applied to a Nonferrous Metal Base. (There are some differences in calibration procedures between SSPC PA 2 and the ASTM standards. If the contract specification does not specify the exact procedures to be used, the procedures should be agreed upon, and the agreement documented, during the preconstruction conference.) ASTM D 4128, Identification of Organic Compounds in Water by Combined Gas Chromatography and Electron Impact Mass Spectrometry describes a destructive procedure for measuring coating thickness on non-metallic substrates using a Tooke gage (refer to Section 10). If the contract specification requires minimum film thicknesses for each layer, the measurements must be made after each layer has cured, taking care not to depress soft coatings during measurements.
184.108.40.206 Drying. The inspector should ensure that a previous coat has dried or cured as required by the contract specification before another coat is applied. For most thermosetting coatings, manufacturers specify a maximum, as well as a minimum, curing time before application of the next coat. In some situations, a coating manufacturer may require use of a methyl ethyl ketone (MEK) rub test to assess curing prior to application of another layer. The inspector’s record should provide information so that the dry/cure time for each layer can be determined.
9.6.9 Final Approval Procedures. The final approval
inspection is very important since it determines whether the contract requirements have been met, and whether identified deficiencies have been corrected. Since most coatings function as a barrier and since the protection of a surface is usually directly related to coating thickness and continuity, inspection of coating thickness and film continuity are essential. The following checklist can be used to inspect the final job:
a) Examine, as required by the specification, the cured coating system for visual defects, such as runs, sags, blistering, orange peel, spray contaminants, mechanical damage, color and gloss uniformity, and incomplete coverage. Note any areas of rusting, or other evidence of premature failure of the coating system.
b) If defects are observed, bring them to the attention of the contractor for correction. If resolution of the corrective action cannot be reached with the contractor, bring the matter to the attention of the contracting officer. Dated photographs of the defects could become part of the inspector’s records, if deemed appropriate.
c) Measure and record the total dry film thickness using appropriate gages. When the Tooke gage is used, the coating must later be repaired.
d) Measure adhesion as required in the contract specification. Adhesion measurements vary from those made with a knife (ASTM D 3359, Measuring Adhesion by Tape) to those that determine the amount of force needed to remove a dolly (Section 10 and ASTM D 4541, Pull-Off Strength of Coatings Using Portable Adhesion Testers) that has been cemented to the surface.
e) Examine the coatings on steel structures for pinholes using a holiday detector as described in NACE RP0188 and Section 10, if required in the contract specification.
f) Record the results of observations in the record book. Document photographs taken and retain in the record book.
9.6.10 Year Warranty Inspection. The warranty inspection includes a visual inspection of the film, and may involve a chalk, film thickness, and adhesion measurements. Since the film was found to be essentially free of defects upon completion of the job, a goal of the inspection is to identify contractually unacceptable defects that have formed during the course of the year. Resolution of film deficiencies should follow the same steps as for the final inspection. Deficiencies should be recorded in the logbook. Documented photographs (date, location, and photographer) should be included if deemed necessary to resolve contract disputes.