In order to protect structural steel from corroding, it is necessary to apply a protective coating system. The coating system consists of three coats. On existing steel all three coats are applied in the field. On new steel, normally inorganic zinc primer is applied in the fabrication shop and the remaining two coats are applied in the field.
When applying coating systems it is very important for the Contractor to constantly monitor the quality of the work. Due to his many duties and responsibilities, the foreman is not able to properly monitor the quality of the work. Therefore, the Contractor is required to assign one person the duties of a Quality Control Specialist (QCS). If there is no QCS on the project, the Contractor is not allowed to proceed with any production work.
This person must be formally trained as a QCS. Prior to allowing the QCS to begin working, the Engineer should confirm that the QCS appears on the approved list maintained by the Office of Construction Administration (OCA). This list can be viewed on their website.
The QCS is only to be involved in quality control work while production work is going on. He is not to be a foreman or a member of the Contractor’s production staff. He is not allowed to abrasive blast, apply coating, recover spent abrasive, mix paint, run errands, set up or maintain the traffic control, run or work on the equipment, etc. It is also imperative that the QCS does not perform supervisory duties on the production staff. If the QCS is not performing his duties or is involved in any work other than quality control while production work is proceeding, the violation should be documented and remedied. It should then be determined based on the disqualification guidelines in the specification if the violation(s) warrants disqualification of the QCS. If the project staff feels that the criteria for disqualification have been met, all documentation of the violation(s) is then sent to the Office of Construction Administration for review. The QCS should be allowed to continue to work during this review process. If the Office of Construction Administration determines violations are substantiated, the QCS will be permanently disqualified. The Office of Construction Administration will inform the project staff of the disqualification and QCS should then be relieved of his duties.
The quality control specialist must be properly equipped with all the necessary testing equipment, and able to climb to all parts of the structural steel. He is to have the authority to stop the Contractor’s work if necessary, and to inform the foreman of all work that does not meet the requirement of the specifications.
The purpose for the quality control points is to mandate points in the process where the product being produced can be inspected to help insure compliance with the specifications. It is important that the QCS signs off at all QCPs that the work being inspected has been checked and is in complete compliance with the specifications. This sign-off puts the accountability for quality on the QCS. Only after receiving the QCS sign off should the formal joint inspection begin.
The testing equipment listed in the specification must always be available for use by the Inspector. If the equipment is not available or in good working order, all production work should be halted. For electric equipment to be in good working order they must have batteries and bulbs. The tables and visual standards must be legible. There must also be film or printing consumables available.
The list in the specification indicates the testing equipment that must be supplied by the contractor, but it in no way limits the means by which the inspector may inspect the work. This may include, but is not limited to, mirrors and larger lights. Note that magnification is not allowed to be used for the determination of SSPC-SP10 blast condition.
Abrasive blasting and painting is to be done between April 1, and October 31. The Contractor should plan his work to ensure that he is an acceptable stopping point on October 31. This date is not to be waived without concurrence from the Office of Construction Administration.
Paint, except for inorganic zinc, must be applied when the temperature of the air within the enclosure, steel surface, or paint is 50° F (10° C) or higher and is expected to remain above 50° F (10° C) for the times noted in the table shown in 514.06.A. It should be noted that the times shown in the table are NOT recoat times. They simply dictate the required time a particular temperature must be maintained after the coating is applied. At lower temperatures the paint will not cure and in some cases the paint may not resume curing when the temperatures warm up. It becomes important to pay closer attention to the temperature in the early spring and the late fall. During the early spring and the late fall, the temperatures will be above 50° F (10° C) during the day, but the temperature will drop during the early evening hours before the paint has had enough time to properly cure.
The surface temperature of the steel should be taken in the area that is the coldest. This is not always the same on every structure (i.e. the fascia beam bottom flange). If you cannot tell where the coldest area is by running your hand over the steel, then it may be necessary to take readings in multiple areas.
For inorganic zinc, apply when the air, steel surface and paint is 40° F (4° C) or higher.
Paint must be applied when the temperature of the steel is at least 5° F (3° C) above the dew point. Applying paint to steel at temperatures below 5° F (3° C) above the dew point could result in condensation on the surface of the steel. The dew point is to be determined by using the psychrometer and the psychrometric tables. The psychrometer should be used in the area to be painted or blasted (i.e. in containment up near the beams). Note, if the barometric pressure is unknown when using the psychrometric tables, it is acceptable to assume a barometric pressure equal to 30 inches.
Abrasive blasting must be performed when the steel is at least 5° F (3°) above the dew point. This is due to the possibility of condensation. The Contractor will be required to reblast the steel if this requirement is not met.
Heated enclosures may be used to maintain the temperatures above the minimum specified temperatures. If combustion type heating units are used, the exhaust fumes must not be permitted in the enclosure, but should be vented away from the enclosure. If exhaust fumes are not properly vented, they can leave a deposit on the surface that could affect the ability of remaining coats of paint to properly bond to the steel or the previous coats of paint. These exhaust deposits could also contaminate the freshly applied paint.
A recording thermometer should be used to insure that the minimum temperature is maintained until the coating has cured. The thermometer should be placed close to the perimeter of the enclosure since this is the area subject to cooler temperatures. The paper graph generated by the recording thermometer should be copied and filed as part of the QCP documentation.
Special note should be made to address the handling storage and disposal of hazardous materials used during construction. Handling, storage and disposal of any volatile product is of particular concern. These would normally include thinners, reducers and solvents. Common types of volatile used in a painting operation may include methyl ethyl ketone (MEK), xylene and toluene based materials.
When these types of items are onsite it is important that the Contractor 1) submit MSDS sheets for each product 2) maintain a current inventory sheet as to the quantity of each product 3) properly label usable product and hazardous waste created by the use of these products 4) properly containerize and store these products and wastes so as to not create a health and safety hazard or exposure to the environment 5) waste containers must be managed in such a way that hazardous waste and non-hazardous waste are properly stored and kept separate.
Proper inspection cannot be accomplished unless the inspector has access to every surface to be painted.
To accomplish this, the Contractor is required to provide, erect, and move scaffolding and all other equipment necessary to provide the inspector access to closely inspect the work. On bridges with tall girders, placing scaffolding only under the girders is not adequate to provide proper access to the work. The inspector should not climb around on the structural steel to inspect the work. If the Contractor fails to provide proper access to inspect the work, he should not be allowed to continue since proper inspection cannot be performed.
All scaffolding of any width, whether it is supported by a wire rope, mounted on the back of a truck, or supported by any other means, that is at least 21 inches (533 mm) or more below the surface to be painted must have guard rail placed on all sides. It is not necessary for scaffolding that is less than 21 inches (533 mm) below the surface to be painted to have guardrail on the two sides bounded by the structural steel, but in this case the scaffolding must be at least 28 inches (711 mm) wide.
One row of guardrail is required to be placed around the scaffolding when it is at least 21 inches (533 mm) but less than 43 inches (1092 mm) below the surface to be painted. Two rows of guardrail are required when the scaffolding is placed 43 inches (1092 mm) or more below the surface to be painted.
Remember you should never utilize a means of inspection access that you do not foresee as being safe.
Prior to production blasting it is imperative that a test section be blasted and the job site visual standards be agreed upon and documented. A comparison to these standards will be utilized for the rest of the project to accept the surface preparation of the steel. The test section also allows the Contractor to adjust his grit size / blast pressure combination to maximize his production, while producing work that is within the specifications.
Note in the event of a dispute SSPC-VIS 1 will govern.
One of the most important items of work is surface preparation. It is also the most labor intensive and expensive phase of the work.
Prior to abrasive blasting, areas that contain asphalt cement, oil, grease, or diesel fuel deposits must be solvent cleaned. It is not necessary for the Contractor to solvent clean the entire surface of the steel to be coated, but only those areas that contain asphalt cement, oil, grease, or diesel fuel deposits.
Solvent cleaning per SSPC-SP1 requires the removal of foreign material (other grease and oil) prior to solvent cleaning. This can be done by one or a combination of the following: wire brushes, abrade, scrape, or clean with solutions of appropriate cleaners followed by a fresh water rinse.
Make sure that all solvent brought on site are accompanied by a current MSDS for that product.
All solvent cleaning should be completed prior to the start of the abrasive blasting operation. If this is not accomplished, the abrasive blasting operation will not remove the asphalt cement, oil, grease, or diesel fuel deposits but drive them into the steel.
In order to remove all residual solvent, asphalt cement, oil, grease, or diesel fuel deposits after the solvent cleaning, all solvent-cleaned areas are to be washed with water at a pressure of at least 1,000 PSI (7 Mpa). In order to be effective, the nozzle must be held no further than 12 inches (300 mm) from the surface being washed.
The specification require that bottom flange edges of all beams are to be rounded to a radius of 1/8 ± 1/16 inch. This includes both rolled beams and girders. It is impossible for an edge to be given a radius with one straight pass of a grinder. It requires multiple straight passes or the use rounding motion.
The radius is necessary to allow the application of the proper coating thickness. The sharp edge splits the spray of paint which results in only a thin coating of paint being deposited along that edge.
The prime coat contains zinc that protects the steel by reacting chemically with the surface of the steel. Therefore, it is important to remove all foreign material from the surface of the steel to allow the zinc particles to come in contact with the bare steel. It is also important to roughen up or produce a profile on the surface of the steel. The profile aids the coating in adhering to the surface of the steel.
Steel surfaces to be painted are to be abrasively blasted to a near white metal, SSPC-SP10. SSPC-SP10 is generically defined as white metal with an allowable 5% staining. This allowable staining is a discoloration. It does not have any noticeable thickness. It should be noted that SSPC-SP10 does not allow magnification for this determination. During inspection, pay special attention to areas that are more difficult to blast or areas that might be difficult to inspect. These areas include under cross frames, around bolt heads and nuts, end dams, cross frames next to or close to back walls, and any other areas of limited access. After the steel is blasted, it must be maintained in that condition until it is painted. The backside of cross frame assemblies that are 3 inches (75 mm) or closer to backwalls may be commercial blast cleaned according to SSPC-SP6. SSPC-SP6 in generically defined as white metal with an allowable 33% staining. Again this staining does not have any noticeable thickness. It is not a residue or film.
The abrasive used in the field must be steel grit. The abrasive must be recycled to minimize the volume of waste material placed into landfills. The size or gradation of the grit is not specified, but must provide a profile of between 1.5 mils to 3.5 mils. G40 and G50 size grit are commonly used by Contractors for abrasive blasting in the field. The profile should be continuously monitored during the blasting operation since the size of the abrasive can be reduced due to being recycled, which can in turn reduce the size of the profile. The size of the profile can also be reduced if the air pressure at the blasting nozzle is reduced. The profile should be monitored by the use of extra-course replica tape and a spring micrometer. Make sure the replica tape is extra-course as this is the appropriate tape to measure our specified profile range of 1.5 mils to 3.5 mils. It is also necessary to account for the 2.0 mil adjustment required for the thickness of the replica tape. This adjustment can be subtracted from every reading or the micrometer can be zeroed to -2.0 mils which results in a direct reading being taken from the micrometer.
Some abrasives, when received by the Contractor, can be contaminated with oil. Therefore the abrasives should be checked to insure that they are free of oil. This check should be made by placing a small amount of abrasives in a jar with tap water. The abrasives and water should then be stirred or shook up. The top of the water should then be checked for signs of oil. If oil is detected, the abrasives should not be used.
Apply a prime coat to the steel that is blast cleaned in the field within 12 hours of the beginning of abrasive blasting. This requires that the time and location the blasting was started is accurately documented. This requirement is extended to 24 hours for shop blasted steel as it is a more controlled environment.
After abrasive blasting is completed, all abrasive and dust must be removed from the surface to be painted. Dust and abrasive must also to be removed from any adjacent painted surface that also includes any adjacent structure. Dust and abrasive should be removed as soon as possible to prevent rust staining of adjacent surfaces. Rust stains can be very difficult to remove.
Occasionally the compressed air used to propel the abrasive can become contaminated with oil or water from the compressor. This oil or water, if deposited on the surface of the steel to be painted, can be detrimental to the coating system. To prevent this problem, the quality control specialist must blow air from a nozzle for 30 seconds onto a white cloth or blotter held in a rigid frame. This testing must be done at the start of each shift, and at 4-hour intervals. If any oil, water, or other contaminates are present on the cloth or blotter, the blasting operation must be suspended until the problem is corrected. After the operation is corrected, and before the blasting operation is permitted to proceed, another test should be made to insure that the problem has been corrected.
The Contractor MUST comply with all Federal, State, and Local laws, rules, regulations and ordinances.
Due to the possibility of the existing coating containing lead or chromium, which are considered hazardous substances, the Contractor is required to erect an enclosure to completely surround the area where the existing coating will be removed. Not only should the enclosure be placed vertically around the sides of the blasting operation, it should also be placed on the ground under the blasting operation. In addition to containing potentially hazardous debris, the enclosure also prevents fugitive dust from escaping into the environment.
The enclosure must be constructed of materials that are free of tears, cuts, or holes to prevent dust and lead from escaping into the environment. Holes, cuts, or tears that do occur should be repaired immediately. The perimeter of the enclosure should also extend up between the beams to the bottom of the concrete deck. All seams should be fastened or lapped in a manner that insures a seal and does not allow any openings between the screens or materials of the enclosure. The area where workers enter and exit the enclosure should also be sealed.
In addition to placing an enclosure around the blasting operations, the Contractor must also place ground covers under all equipment. This ground cover must be placed under the equipment for its entire length, not just a portion of its length. If the ground is not properly covered, there is the possibility that it could become contaminated. These ground covers are also intended to reduce the impact of equipment leaking oil, fuel or hydraulic fluid.
All abrasive blasting debris is to be picked up at the end of the day and must be stored in steel containers that have the lids locked. Normally the Contractor will store the debris in 55-gallon drums with lids. The lids have a ring around them that are capable of being locked. Normally, the Contractor will lock the lids by means of a bolt. This method is acceptable as long as there is a nut placed on the bolt and tightened by the use of a wrench. Many times all of the lids are not properly locked at the end of the day. They should be checked at the end of the day or the first thing in the morning to insure that the Contractor is locking the lids at the end of the day. The use of tie wire, zip ties or duct tape are not acceptable as a means for locking the lids. If the Contractor chooses to use a large roll-off container to store abrasive blasting debris, the requirement for providing a means for locking the lid of the containers must still be enforced.
Within the first week of production blasting the Contractor must sample the abrasive blasting debris and have it sent out for testing. If the samples come back with lead, chromium, cadmium or arsenic contents higher than the limits shown in the table in Section 514.13.D.1 of the Construction and Materials Specifications, the abrasive blasting debris is considered hazardous. Note that parts per million for these items is equivalent to mg/L. The Contractor must dispose of the abrasive blasting debris within 60 days after it is generated. The 60 days starts as soon as the Contractor generates the debris, not after the completion of the abrasive blasting operation. If the debris remains on the project site over 90 days, the State and the Contractor could be cited by the Environmental Protection Agency. On smaller structures the debris can be removed in one operation. However, on larger structures where the abrasive blasting operation extends over a period of several months, it will be necessary to make several trips in order to comply with the 60-day limit. If after the 60 days, the Contractor has not properly disposed of the debris, all abrasive blasting and painting of the structural steel on the project must immediately cease until the waste is properly disposed of. At this time, the Department must cease processing all pay estimates and send notification to the Contractor’s surety that he has breached the contract.
Note that the date of manufacture does not show up on all container labels. Some manufacturers show a code number in lieu of a date of manufacture. You will need to call the manufacturer and give them this code number and they will in turn give you the date of manufacture.
Prior to applying paint it is necessary to thoroughly mix all the ingredients together. This is to be accomplished with a high shear mixer. Paddle mixers are not allowed due to the fact that they will not do an adequate job of mixing the different ingredients together. Using compressed air to cause a stream of bubbles in the paint and paint shakers also is not allowed since it will not properly mix the ingredients.
During the application of the primer, it is important that it be continuously mixed. If it is not continuously mixed, the zinc particles in the primer will settle to the bottom of the container and will not be applied to the structural steel. To insure that the mixing process is not interrupted, it is also important that the mixer be an automated mixer, and not a hand held mixer.
Normally thinning of the paint is not required. However if the Contractor elects to thin the paint, it is important that it be thinned with the correct type and volume of thinner. In order to insure that the Contractor is using the proper type of thinner, only use thinner recommended and supplied by the paint manufacturer. The maximum rate of thinner is to be as per the manufacture’s printed instructions. If the paint manufacturer’s printed instructions do not list a maximum proportion of thinner, the manufacturer should be contacted to obtain their recommendation. Note that the manufacturer may recommend different thinners based on humidity or temperature. All thinning should be done in the presence of the Engineer or Inspector.
In an effort to insure that the thinner the Contractor is using is the thinner recommended and supplied by the manufacture, only use thinner that has been supplied to the project in unopened containers with the labels intact. The amount of thinner used from each container should be monitored to prevent refilling of the container with other types of thinner.
The above restrictions do not apply to the thinners that the Contractor uses to clean his equipment. Be aware that methyl ethyl ketone (MEK) is sometimes used as both a reducer and a cleaner.
Paint is only to be applied by the use of brush or spray equipment. Rollers can cause bubbling and other irregularities in the coating and are only permitted where cross frame angles are located within 2 inches (50 mm) of the bottom flanges, where end cross frames are within 6 inches (150 mm) of the backwall, the bottom of the bottom flanges around bearings that are less than 6 inches (150 mm) in height and other areas as determined by the Engineer.
The specification states that each spray operator shall demonstrate to the Engineer or Inspector the ability to apply the paint as specified. This allows the project staff to remove a painter that is unable or unwilling to produce work within the specification requirements.
All surfaces to be painted shall be free of dust, dirt and moisture. If these or other contaminants are left on the surface they can cause multiple types of defects including adhesion failures and accelerated rusting. Simply blowing down with compressed air is not always sufficient. It is sometimes necessary to wipe the surface down, use a vacuum system, or some other means to adequately prepare the surface to receive paint. This cleanliness requirement includes both the blasted steel surface as well as previously applied coats of paint.
Apply a prime coat to steel that is blast cleaned in the field within 12 hours of the beginning of abrasive blasting. This requires that the time and location the blasting was started is accurately documented. This requirement is extended to 24 hours for shop blasted steel as it is a more controlled environment.
The maximum elapsed time allowed between the application of any portion of the prime coat and the application of the intermediate coat is 30 days. The maximum elapsed time allowed between the application of any portion of the intermediate coat and the application of the finish coat is 13 days. The maximum recoat times shall also not exceed the maximum recommended by the manufacture. Extending the time beyond that mentioned above could adversely affect the bond of the coating. No additional time is allowed due to weather related delays. Any coat that has been allowed to cure more than the above allotted time is to be removed and the steel reblasted to SP10.
During spray application of the paint the operation is to be totally enclosed. The enclosure must be identical to the enclosure used during the abrasive blasting operation. Failure to properly utilize the enclosure could result in overspray damage to private property including automobiles, the ground, public property, vegetation, streams, lakes, etc. The enclosure is not required if the paint is being applied by brush or roller.
Each coat of paint is to be applied as a continuous film of uniform thickness. It is to be free of all defects such as holidays, runs, sags, etc.
Many time holidays in the form of pinholes are difficult to detect. The best way to view pinholes is with the aid of a flashlight. The flashlight should be placed to shine a beam of light parallel to the painted surface. If pinholes are present in the top coat, they will appear as small white specs about the size of the end of a needle. If they are present in the intermediate coat they will appear as small dark specs.
Note that if you are painting over an inorganic zinc primer you should play close attention to pinholes appearing in the intermediate coat. The inorganic zinc has an inherent characteristic of “outgassing” due to its porous nature. The released gas pushes up through the intermediate coat and causes the pinholes. To avoid the majority of pinholes in this situation the Contractor should properly apply one, or multiple, mist coats of intermediate paint prior to the remaining full application.
Repairing pinholes can be very difficult. Applying another coat of paint over the pinholes will only result in the pinhole reflecting through the additional coat of paint. It is the Contractor’s responsibility to repair the pinholes. The best way to correct pinholes is by removing the coating at least down to the prime coat of paint. If the prime coat is not removed, measurements should be taken to insure that the required minimum thickness of prime paint is still present. If the Contractor elects to attempt to leave the prime coat, he will probably remove the topcoats with sand paper. If a large area needs to be repaired, it will probably be more prudent for the Contractor to abrasively blast the coating down to bare metal and reapply it.
Runs and sags are normally prevalent around bolts and areas of limited access. This is sometimes due to the fact the Contractor tries to paint these areas using a spray gun only (i.e. without the use of a brush). These defects should be corrected after each coat is applied. If not the defect will just translate into the next coat and the repair will be more extensive.
This item is paid for by the man hour. The quantity of man hours eligible for payment are not to include the superintendent or the QCS, but only the personnel actually performing the work.
All gaps greater than 1/8 inch need to be caulked. Normally caulking is used to seal gaps around the perimeter of adjacent steel plates and angles. This void is normally caused by rust forming between the plates or angles and forcing them apart to the extent that it is not possible to seal the void with paint.
Caulking materials appear the qualified product list (QPL) maintained by the Office of Material Management (OMM).
Prior to measuring coating thickness it is necessary to determine the effect of the blasted surface of the steel on the paint gage. Due to the fact that the steel has received a profile of between 1.5 to 3.5 mils (40 to 90 μm), this profile will cause the paint gage to read high. To compensate for this additional height it will first be necessary to take a reading on the blasted surface immediately prior to applying the prime coat. Preferably three or more readings should be taken and averaged out. This average reading should then be subtracted from all paint film thickness readings. As an alternate to subtracting the thickness attributed to the surface profile from the paint film thickness, recalibrating the paint gage to read 0 mils on the blasted steel is also acceptable.
It is very important to determine the coating thickness by taking the average thickness in the manner specified in the specifications. This involves taking 5 spot readings for each type of member (i.e. webs, bottom of top flange, top of bottom flange, bottom of bottom flange, crossframes, stiffeners, etc.) over an area of one hundred square feet. A spot reading is comprised of the average of three closely-spaced individual readings. The average reading for this one hundred square feet area may be used to represent up to one thousand square feet of painted steel surface. The number of one hundred square feet areas to be measured is determined by the area of steel painted. Form CA-S1 should be used to tabulate the results.
The spot averages are to be within 80% to 150% of specified minimum and maximum thicknesses, respectively. The area averages must fall within the actual specified minimum and maximum values.
There are provisions in the specification for addressing areas with a film thickness greater than the maximum specified. If a Contractor chooses to have the certified testing done as described in the specification make sure the preparation of the panels mirrors the actual field installation of the paint in question. This includes paint thickness, multiple or mist coats as well as type and quantity of thinner used.
The purpose of the final inspection is to ensure the quality of the surface preparation and coating thickness are witnessed by a third party. This third party could be the project engineer, area engineer or other District personnel.
The Engineer will select the locations and take the dry film thickness (DFT) readings. The Contractor will then perform the removals. The 9 square inches required by the specification is the minimum “clean” area of steel. It normally takes about a 6 inch by 6 inch square to get 9 square inches of “clean” steel. The contractor will normally use Methylene Chloride and MEK as a chemical stripper/solvent. These chemicals are both corrosive and the safety precautions found on the MSDS sheets and manufacturer’s literature need to be followed.
A common stripping procedure is as follows:
1. Spray surface with stripper
2. Wait 5-10 minutes to allow the stripper to work
3. Use a scraper or putty knife to remove top coat and intermediate coat. It may take multiple applications of the stripper to accomplish this.
4. Spray the exposed primer with stripper and allow time to work
5. Scrape off majority of primer with being careful not to damage the substrate.
6. Repeatedly apply solvent or stripper and rub with a rag until steel substrate is clean.
This process takes about 15 minutes for each stripped area, if you are working on other areas while the stripper is allowed to sit. It is imperative that the Engineer observe the removal process as the stripper and a scraper can remove lead paint as well as the new paint.
The engineer will evaluate the stripped area and document his findings on Form CA-S-18.
If the surface in the stripped area is not found to be in complete conformance with the contract documents additional locations may be tested. Note the Contractor is only paid for stripped areas that are found to be in conformance with the contract documents.
Once all the required tests have been performed and the progressive project data has been reviewed the Engineer should complete Form CA-S-19,
Destructive test locations shall be repaired per 514.22
If it is necessary to make repairs, the intent of the specifications is that the repair be made in a manner that the repaired areas will blend in with the surrounding area so that it is not evident that a repair was made.
If the area to be repaired does not cover a large area, abrasively blasting the surface may not be advisable due to the fact that it will damage the surrounding coating that does not need to be removed. In lieu of using abrasives, the engineer may allow alternate methods of preparing the surface. This might include the use of power tools with abrasive bits or hand tools. However, whatever method is used, it is still necessary to prepare the surface in a manner that will give a surface profile of between 1.5 to 3.5 mils (40 to 90 μm).
In order to produce a smooth transition, it is necessary to feather the adjacent coatings. This cannot be accomplished through the use of abrasives. The new coat of paint should only applied to the same coat as was feathered, i.e. the prime coat should only be applied to the feathered prime coat, the intermediate coat should only be applied to the feathered intermediate coat, and the finish coat should only be applied to the feathered finish coat. Applying the finish coat to existing finish coat that has not been feathered or in any other way abraded will result in finish with a dull, frosty appearance in lieu of a bright glossy finish.
Since surface preparation is being performed and paint is being applied, all work limitation and documentation requirements are in effect.
1. Document Dry Film Paint Thicknesses on Form CA-S-2
2. The Quality Control Specialist must fill out and sign form CA-S-7 prior to all Quality Control Point inspections
3. Document the Quality Control Specialist’s information and the Job Site Visual Standards on Form CA-S-11
4. Document Solvent Cleaning (QCP#1) and Grinding of Flange Edges (QCP#2) on Form CA-S-12
5. Document Abrasive Blasting (QCP#3) on Form CA-S-13
6. Document Waste Disposal (QCP#4) on Form CA-S-14
7. Document Prime Coat Application (QCP#5) on Form CA-S-15
8. Document Grinding Fins and Slivers (QCP#6) and Caulking (QCP#9) on Form CA-S-16
9. Document Intermediate Coat Application (QCP#8) or Finish Coat Application (QCP#10) on Form CA-S-17
10. Document the Final Destructive Tests on Form CA-S-18
11. Document the Final Acceptance (QCP#11) on Form CA-S-19