Difference between revisions of "715 - Cleaning and Coating Existing Structural Steel"

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Zinc primer will be continuously agitated during application process. Application of the primer must be done with spray painting equipment.
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Zinc primer will be continuously agitated to prevent settling of zinc during application prcoess |-
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* '''Air:        '''50 °F (10 °C)+
 
* '''Air:        '''50 °F (10 °C)+
 
* '''Steel:'''    50 °F (10 °C)+
 
* '''Steel:'''    50 °F (10 °C)+
* Steel surface temperature at least 5 °F (3 °C) above''' dew point''' to insure that the surface is dry.
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*Temperature limitations must be maintained for 24 hours minimum.
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* Steel surface temperature must be at least 5 °F (3 °C) above''' dew point''' to insure that the surface is dry.
 
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Zinc primer will be spray-applied only, according to paint manufacturer’s instructions.
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Zinc primer will be spray-applied per paint manufacturer’s instructions.
 
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'''Primer Coating thickness:'''  4 mils (100 ųm) minimum; 10 mils maximum
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'''Primer Coating thickness:'''  4 mils minimum; 10 mils maximum
 
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Minimum cure times will meet the requirements of subsection [http://mdotcf.state.mi.us/public/specbook/files/2012/915%20Bridge%20Coating%20Systems.pdf 915.04A] of the Standard Specifications.
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Minimum cure times for zinc primer are 24 hours - field application, 16 hours - shop application.
 
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Follow the manufacturer’s recommended cure time except that there shall be no more than 21 days between zinc-primer coating and the intermediate coating.  If the 21 days are exceeded, the Contractor must reblast and repaint at his/her own expense.
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Follow the manufacturer’s recommended maximum cure time except that there must be no more than 21 days between zinc-primer coating and the intermediate coating.  If the 21 days are exceeded, the Contractor must reblast and repaint at their own expense.
 
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Revision as of 13:33, 7 July 2014

715
Cleaning and Coating Existing Structural Steel
2012 STANDARD SPECIFICATIONS FOR CONSTRUCTION - SECTION 715


Contents

GENERAL

MDOT has two standard painting systems. New structural steel is completely shop painted with a three-coat system, referred to as Type 4S. Existing structural steel is blast cleaned and field coated with a similar three-coat system, referred to as Type 4. The following guidelines should be strictly followed in inspecting these systems.

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Health and Safety

The Contractor will provide the equipment and the training necessary to insure the safety of the personnel that are required to do the work and inspection required for the removal of lead-based coatings from existing structural steel bridges.

The equipment and the training will, as a minimum, provide employees with respirators including fit testing, respirator training and a respirator program. Protective clothing and equipment, change areas, showers, eating facilities and hand washing facilities are also required.

All bridge painting inspectors and the Resident/Project/Delivery Engineers must be familiar with Part 603 Lead Exposure in Construction (a MIOSHA regulation) and MDOT Hazard Communication Procedure, commonly referred to as “Right to Know”.

Respiratory Protection and Protective Equipment

Do not enter the containment until the air has visibly cleared of dust. All bridge paint inspectors must wear appropriate respirators and protective equipment when inside containments or when exposed to dust containing lead or solvent and paint fumes. At a minimum, MDOT is required to provide a medical evaluation to determine the employee’s ability to wear a respirator. A pulmonary function test is required at least once to determine if the employee’s breathing capacity can tolerate the use of a respirator. See Part 603 Lead Exposure in Construction and Part 451 Respiratory Protection, (MIOSHA).

Medical Surveillance

Per Part 603 Lead Exposure in Construction and Part 451 Respiratory Protection, (MIOSHA), all employees performing bridge paint inspection will be required to have blood sampling and analysis for lead and zinc protoporphyrin before the project begins and every 2 months until the project is completed, and at the completion of the project. All MDOT employees’ medical surveillance records must be forwarded and marked “Confidential” to the MDOT Safety Administration and to the employee. MDOT Safety Administration will notify the Engineer of the employee test results.

Exposure Monitoring

The Engineer must forward the exposure assessment marked “Confidential” of a designated MDOT Employee results directly to:

MDOT, Safety Administration Van Wagoner Building P.O. Box 30050, Lansing, MI 48909

Hygiene Facilities

All bridge paint inspectors who enter containments shall use the contractor provided hygiene facilities for hand and face washing and/or showers.

Lead Awareness Training

All bridge paint inspectors and engineers entering enclosures must attend a lead awareness training prior to performing bridge paint inspection. The training is required annually. The painting contractor provides lead awareness training per the contract special provision 12SP715(B) PROVIDING EXPOSURE ASSESSMENTS, EXPOSURE MONITORING, EQUIPMENT, HYGIENE FACILITIES, AND TRAINING.

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MATERIALS

Type 4S - Shop Painted Steel

Requirements

Shop coating is done in accordance with section 716 of the Standard Specifications for Construction. This is done prior to the steel elements arriving on site; however, it is important to visually inspect coated steel for damage that may have occurred during shipment.

If there is any evidence of faulty painting, damage from transportation or damage from handling, the damage must be document and the Contractor should be notified.

The pay item for repair of damaged coating covers all damage repairs, but the Contractor should separate the shipping damage caused by the fabricator from the bridge erection damage. Good documentation may eliminate future claims.

All shop painted steel elements must be handled with padded slings, chains or hooks and must be stored on cushioning pads above the ground so that no mud or water is deposited on the steel elements.

Special attention must be given to cleaning all bolted surfaces of dirt or mud before erecting the pieces.


After bridge erection is complete, the field repair of coating will be done in accordance section 716 of the Standard Specifications for Construction.

Special attention should be given to the requirements for cleaning surfaces to be painted and the minimum temperature and maximum humidity requirements.

The Construction Field Services Division (CFS) maintains a recommended procedure guide for damaged coating repair that depends on the exact system and paint manufacturer being used. Contact the Bridge Construction Engineer or the staff painting technician for a current copy.

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Procedures for Field Repair of Shop Coated (New) Structural Steel

Ensure all adhering scale, dirt, grease or other foreign material is removed by appropriate means.

All rusted or uncoated areas are to be cleaned to a near-white finish. A strip & clean wheel (abrasive embedded in an adhesive coated wheel) is an example of what can be used to clean the rusted areas. This wheel, used on a power drill, will feather the edges of the existing coatings surrounding the repair areas.

The area around the repair will be cleaned and primed using the original coating system. The primer will be spray applied.

Before the intermediate coating is applied, the primer that was oversprayed on the existing coating around the repair area must be wiped off.

The intermediate coating is spray applied; this coating must be the same as the original coating system.

The topcoat will be spray applied and be part of the original coating system.

The curing times between applications of the three different coatings will be the same as the Type 4 coating system.

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Type 4 - Field Painted Steel

Requirements

Abrasive blast cleaning of existing steel structures requires environmental controls.

Special attention should be given to the provisions in the proposal for removal of lead-based paint from bridges.

Any violation of requirements could lead to citations and severe penalties from Michigan Department of Environmental Quality (MDEQ) or the Department of Consumer and Industry Services.

The inspector should be especially cautious of the handling and storage of spent blasting materials that have been designated as hazardous waste by the Environmental Protection Agency (EPA) toxicity test.Ensure a Hazardous Waste Manifest is properly filled out noting the structure number and the Environmental Protection Agency (EPA) waste generator number. Hazardous Waste Manifests must be kept on file for 3 years from the date of shipment. A copy of the Generator Manifest must be sent to the MDEQ before the 10th of the following month. Mail copies to:

DEQ, Waste and Hazardous Material Division PO BOX 30038 Lansing, MI 48909-7538


All portions of the structure that could be damaged by abrasive blasting and/or coating operations will be protected by covering or shielding.

During the abrasive blasting operations, provisions will be taken by the Contractor to protect existing vehicuular traffic, waterway traffic and pedestrians.

During the coating operations, the Contractor will take necessary measures to prevent paint spray from reaching vehicles on the roadway, waterway or other private property. The required measures will probably include tarping around the area being coated.

The Contractor will select a blasting abrasive from the Qualified Products List (QPL) for low dusting abrasive.

The Contractor will select a complete coating system from the QPL, 915. Color number will be as called for in the proposal or on the plans. Ensure the Contractor provides the Engineer with product data sheets before any coating is started.

Sealing the Perimeter of Beam Plates - See Section 713 of the Standard Specifications for Construction.

Beams plates must be sealed after the intermediate coat has dried (may be applied prior to cure of the intermediate). The polyurethane top coat will be applied over the sealant.

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Steel Preparation

Cleaning Requirements

Ensure the top of the bottom flange is scraped to remove accumulated dirt and debris.

Ensure areas of oil and grease on surfaces to be sandblasted are cleaned with clean petroleum solvents before sandblasting operations begin.

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Containment

A method to contain all spent material, dust and other debris generated during the blast cleaning or subsequent vacuuming of the structure in preparation for coating must be used. The containment design, the air flow (negative pressure) equipment and dust filtering equipment is the Contractor’s responsibility.


The containment consists of tarpaulins or other approved sheet material. The tarpaulins will be made of an airtight material and will be tightly and continuously secured at the seams.

The containment will extend from the deck bottom to ground level and will be fastened securely to prevent lifting or opening by wind.

Ground cloths will be placed under the enclosed area and will extend at least 10 feet (3 m) beyond the containment edges. The ground cloth will be continuous within the containment with all seams and overlaps adequate to hold all spent material.

The containment will have air-moving equipment attached which will be capable of creating a negative pressure condition within the enclosure.

For painting tops of bridge beams during deck replacement or other instances the deck may be exposed such as deck patching or joint replacement, contractors are required to provide proper containment and immediately clean up any released spent materials outside the enclosure as specified in Section 715 of the Standard Specifications for Construction.

When replacing entire deck, the beam tops and edges must be cleaned per Section 715 (SSPC-SP 10 or SSPC-SP 11) and coated with zinc rich primer. When exposing beam tops during deck patching or expansion joint replacement, the beam tops and edges must be cleaned per SSPC-SP 3and coated with aluminum filled epoxy mastic.


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Spent Material

Spent material includes spent abrasive, bag house dust, shower water, and solvents. This also includes spent material from abrasive blast cleaning beam tops during bridge deck replacement or during joint removal and replacement.

The spent material will be collected daily and stored in suitable waste disposal containers located at the structure in accordance with subsection 715.03.A.7 of the Standard Specifications for Construction.

The waste containers must be kept covered with a waterproof cover. The waste containers will not be disposed of until authorized by the Engineer.

Spent material collected and stored on the structure site will be sampled and tested by the Contractor’s laboratory personnel in accordance with the EPA Toxicity Characteristic Leaching Procedure (TCLP) test. Ensure the sampling is conducted by a Society of Protective Coatings (SSPC) Competent Person, and is witnessed by the Engineer.

Spent material classified as hazardous waste by the TLCP test must be disposed of at a licensed hazardous waste disposal facility. All spent material is assumed hazardous and must be labeled accordingly, until laboratory testing proves otherwise.

Spent material that is nonhazardous will be disposed of at a Type II landfill.

Witness the contractor’s laboratory personnel sample the spent abrasive, shower water, solvent, and bag house dust. The laboratory must be approved and certified by the Michigan Department of Environmental Quality (MDEQ). Record the witness date and time in the “Comments” section of the Inspector’s Daily Report for Bridge Painting. Place copies of the chain of custody and test results in the project files.

Solvent - see 713.03.D.6 of the Standard Specifications for Construction for Solvent Reuse Determination Procedures.

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Structural Steel Surface Abrasive Blasting Requirements

Near-white finish (SSPC-SP10). Visual standards are in paint inspection kits available at Construction Field Services. See SSPC VIS 1 Pictorial Standards, Guide and Reference Photographs for Steel Surfaces Prepared by Dry Abrasive Blasting or SSPC Guide to Visual Standard No. 1.


Ensure fins, tears, slivers, burrs and sharp edges that appear during abrasive blasting operations are removed by grinding and the area reblasted.

The profile produced by the abrasive blasting should be within the range of 1.0 mil to 2.8 mils.

Spent abrasive and removed paint must be removed from an abrasive blasted surface with a good commercial vacuum cleaner with a brush-type cleaning tool. Horizontal surfaces should be inspected for debris and all debris must be removed prior to the prime coat.

The steel surface must be kept dust free and primed within 8 hours.


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Structures Over Waterways (Containment)

A floating boom must be stretched across the waterway within 200 ft of the work. The boom is used to collect the spent residue floating downstream in the event the containment fails.

Ensure the Contractor provides a barge in the water directly underneath the area being abrasive blasted to collect the spent residue. If the waterway is too shallow for a barge, the Contractor will provide some type of temporary platform. Tarpaulins must be draped from the abrasive blasting area to the barge or collection platform. The surface of the barge should be covered in ground clothes to expedite clean-up. The containment must prevent spillage into the waterway.

The Contractor must collect all surface water contaminants, all spent residue on the barge and/or temporary collection platform and all spent residue on the ground cloths on a daily basis.


Structures Over Railroad

Railroad containment systems must be able to accommodate the rail traffic. The contractor should design a system that can be quickly removed or opened over the tracks to allow for the passing of trains while still containing all dust and spent abrasive from entering the environment or railroad ballasts.



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CONSTRUCTION

Coating System

Coating must be done in three steps consisting of an organic-rich primer, an epoxy intermediate coat and a urethane top coat. The top coat color should be specified in the contract documents.

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Organic Zinc-Rich Primer

Step
Description
1

Mix with high-shear mixer according to manufacturer’s instructions.

2

A thoroughly mixed coating will be strained to prevent clogging of spray equipment.

3

Zinc primer will be continuously agitated to prevent settling of zinc during application prcoess |-

4

Temperature:

  • Air: 50 °F (10 °C)+
  • Steel: 50 °F (10 °C)+
  • Temperature limitations must be maintained for 24 hours minimum.
  • Steel surface temperature must be at least 5 °F (3 °C) above dew point to insure that the surface is dry.
5

Humidity:

  • Less than 90%.
  • Coating will not be applied when a combination of temperature and humidity cause moisture to condense on the steel surface.
6

Zinc primer will be spray-applied per paint manufacturer’s instructions.

7

Primer Coating thickness: 4 mils minimum; 10 mils maximum

8

Minimum cure times for zinc primer are 24 hours - field application, 16 hours - shop application.

9

Follow the manufacturer’s recommended maximum cure time except that there must be no more than 21 days between zinc-primer coating and the intermediate coating. If the 21 days are exceeded, the Contractor must reblast and repaint at their own expense.

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Intermediate Coat

Step
Description
1

Primed surface will be cleaned by vacuuming with a good commercial vacuum cleaner with a brush-type cleaning tool.

2

Mix with high-shear mixer according to manufacturer’s instructions.

3

Thoroughly mixed coating will be strained to prevent clogging of spray equipment.

4

Application of the intermediate coating must be done with spray painting equipment.

5

Temperature:

  • Air: 50 °F (10 °C)+
  • Steel: 50 °F (10 °C)+
  • These minimum temperatures must be maintained for at least 24 hours.
  • Steel surface temperature at least 5 °F (3 °C) above dew point to insure that the surface is dry.
6

Humidity:

  • Less than 90%.
  • Coating will not be applied when a combination of temperature and humidity causes moisture to condense on the steel.
7

Coating thickness:

  • minimum of 3.5 mils (90 ųm); maximum of 9 mils.
  • The intermediate coating application will be sufficient to provide complete coverage with uniform color and appearance.
8

Minimum cure times will meet the requirements of subsection 915.04A of the Standard Specifications.

9

Follow the manufacturer’s recommended cure time except that there shall be no more than 21 days between the application of the intermediate coating and the topcoat.

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Urethane Topcoat

Step

Description
1

Intermediate coating will be cleaned by vacuuming with a good commercial vacuum cleaner with a brush-type cleaning tool.

2

Mix with high-shear mixer according to manufacturer’s instructions.

3

Thoroughly mixed coating will be strained to prevent clogging of spray equipment.

4

Application of the topcoat must be done with spray equipment.

5

Temperature:

  • Air: 40 °F (5 °C)+
  • Steel: 40 °F (5 °C)+
  • These minimum temperatures must be maintained for at least 24 hrs.
  • Steel surface temperature at least 5 °F (3 °C) above dew point to insure that the surface is dry.
6

Humidity:

  • Less than 90%.
  • Coating will not be applied when a combination of temperature and humidity causes moisture to condense on the steel.
7

Coating thickness:

  • minimum of 1 mil (25 ųm).
  • The topcoat application will be sufficient to provide complete coverage with uniform color and appearance.
8

Minimum cure times will meet the requirements of subsection 915.04A of the standard specifications.

9

After completion of coating operations, the completion date (month and year) and the number of coating system types (four) will be stenciled on the structure in 4 inch (100 mm) numbers. Use black urethane spray paint for stenciling. (subsection 715.03.D.4 of the Standard Specifications for Construction for locations).

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Paint Warranty

See Proposal for Paint Warranty.

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Pin and Hangers

See Section 713 of the Standard Specifications for Construction.

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MEASUREMENT AND PAYMENT

-Reserved-

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