514 Field Painting of Structural Steel

514 Field Painting of Structural Steel

Description (514.01)

Quality Control (514.04)

Testing Equipment (514.05)

Work Limitations (514.06)

Pollution Control (514.08)

Inspection Access (514.10)

Job Site Visual Standards (514.11)

Surface Preparation (514.13)

Handling (514.15)

Mixing and Thinning (514.16)

Coating Application (514.17)

Removing Fins, Tears, or Slivers (514.18)

Caulking (514.19)

Dry Film Thickness (514.20)

Final Inspection (514.21)

Repair Procedures (514.22)

Documentation Requirements – 514 Field Painting of Structural Steel

Description (514.01)

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.

Quality Control (514.04)

Quality Control Specialist

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.

Quality Control Points

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.

Testing Equipment (514.05)

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.

Work Limitations (514.06)

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.

Temperature

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.

Pollution Control (514.08)

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.

Inspection Access (514.10)

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.

Job Site Visual Standards (514.11)

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.

Surface Preparation (514.13)

One of the most important items of work is surface preparation. It is also the most labor intensive and expensive phase of the work.

Solvent Cleaning

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.

Grinding Flange Edges

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.

Abrasive Blasting

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.