ITEM 25570.9663xx - BLAST CLEANING AND ZINC THERMAL SPRAYING OF STRUCTURAL STEEL
1. DESCRIPTION: (cont'd)
1.07 Submittals
A. The Contractor shall provide the following written submittals
before starting any work:
1. MSDS sheets.
2. Documentation of previous similar work experience.
3. Documentation of SSPC QP1 and QP2 qualification.
4. Work schedule.
5. QA/QC Plan including the application process. This should
include equipment capabilities, materials, application
procedures, and quality control checkpoints for (a)
surface-preparation, (b) spraying, (c) adhesion, (d) coating
thickness measurements.
1.08 Definitions:
A. Thermal spray shall include the surface preparation and
application of a Zinc-Aluminum alloy coating to metal surfaces.
Zinc-Aluminum (85-15) Thermal Spraying will be referred to as
spraying.
B. White Metal Blast Cleaning shall mean the preparation of surfaces
to be coated in accordance with standards and specifications for
"White-Metal Blast Cleaning," SSPC-SP5 as published by the Steel
Structures Painting Council.
C. Hand Tool Cleaning shall mean the preparation of all surfaces to
be coated in accordance with standards and specifications for
"Hand Tool Cleaning," SSPC-SP2 as published by the Steel
Structures Painting Council.
D. Power Tool Cleaning shall mean the preparation of all surfaces to
be coated in accordance with standards and specifications for
"Power Tool Cleaning," SSPC-SP3 and "Power Tool Cleaning to Bare
Metal" SSPC-SPl1.
E. Paint and sealers if required shall be as specified in the
contract documents.
F. Surface Preparation shall mean the cleaning and/or pretreating of
surfaces to be sprayed as specified in the contract documents and
shall include the removal of all debris.
G. Field Spraying shall mean the coating of metal surfaces at the
construction site.
H. Zinc-Aluminum Coating shall include cleaning and preparing the
entire surface, recoating all steel on existing installations or
structures in service, and sealing the sprayed coating if
specified.
I. Steel Structures Painting Council (SSPC) - Surface Preparation
(SP). Specifications referred to herein may be obtained through
the Council at SSPC, Melon Institute, 4400 5th Avenue,
Pittsburgh, PA 15213.
J. Environmental Protection shall mean the containment, collection,
and removal of existing paint chips, corrosion residues, spent
abrasives, and any newly applied paint (herein after referred to
as waste materials) that result from blasting and other cleaning
and coating operations performed in the field.
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ITEM 25570.9663XX - BLAST CLEANING AND ZINC THERMAL SPRAYING OF STRUCTURAL STEEL
1. DESCRIPTION: (cont'd)
1.08 Definitions: (cont'd)
K. Inaccessibility shall mean the inability to use a standard
application method because of restrictions such as reduced
clearance, insufficient hand space or too narrow an opening. It
shall not mean that the element is too high or that the rigging
or scaffolding will be difficult. The Engineer will make a final
determination as to what will be deemed inaccessible.
L. Debris shall mean anything on the structure that isn't an
inherent part of the structure or coating system.
M. Flush Rusting - Rusting that occurs on metal within minutes to a
few hours after blast-cleaning or other cleaning is completed.
The speed with which flash-rusting occurs may be indicative of
soluble-salt contaminants on the surface, high humidity, or both.
2. MATERIALS:
2.01 All equipment used for cleaning and spraying shall meet the
requirements as specified in the Contract. Zinc-Aluminum alloy shall
be manufactured for thermal spraying and shall be of the following
composition:
Fe - 0.020% Max.
Cu - 0.004% Max.
Cd - 0.004% Max.
Pb - 0.004% Max.
Al - 14.0 - 16.0%
Ti - 0.002% Max.
Zn - Balance
The Contractor shall provide certificates of alloy composition for the
wire.
2.02 The coating shall be as specified in the Contract and shall be applied
according to same or the manufacturer's recommendations, whichever is
more restrictive.
2.03 The abrasive selected for blast cleaning shall be identified by the
Contractor and approved by the Engineer prior to use. The abrasive
shall be certified to be of fine to extra fine gradation. The abrasive
shall have a sharp, hard cutting surface and shall be clean, dry and
free of oil or soluble salt contaminants. Silica sand and/or shot are
not allowed:
2.04 All material shall be delivered to the site in sealed, original,
labeled containers and stored in accordance with the manufacturer's
recommendations.
2.05 All material and equipment used for environmental protection shall be
approved by the Engineer. Any material or equipment that is determined
to be deficient or that becomes damaged to the extent that it no
longer fulfills the requirements of this specification shall be
replaced or repaired to the satisfaction of the Engineer, at the
Contractor's expense, with the replacement material and/or equipment
meeting the requirements of the contract documents.
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ITEM 25570.9663XX - BLAST CLEANING AND ZINC THERMAL SPRAYING OF STRUCTURAL STEEL
3. CONSTRUCTION DETAILS: (cont'd)
3.04 Spraying Application (cont'd)
B. Surface Cleanliness - All surfaces to be coated shall be
thoroughly cleaned prior to each application to remove dirt,
dust, or other interference material. Cleaning methods shall be
by vacuuming only, unless other means are approved by the
Engineer. Special worker protection and containment measures will
be required to avoid health and safety problems associated with
lead contamination.
C. Grease/Oil - If grease or oil are/or become deposited on the
surface, they shall be removed by solvent cleaning in accordance
with SSPC-SPl prior to the application of the next coat.
D. Ambient/Weather Conditions - Coatings shall not be applied to
surfaces containing frost or applied in rain, fog, or similar
conditions. Coatings shall be applied in accordance with the
coating manufacturer's written recommendations.
E. Zinc-Aluminum Coating Application Methods
1. The coating shall be applied in a neat and workmanlike
manner and shall be applied uniformly and shall be free of
ridges or other defects. The coating shall be applied by
thermal spray employing multiple passes to achieve a
thickness of 0.008 to 0.010 inches (8-10 mils) as specified
in the contract documents. No single pass shall deposit more
than 0.004 inches. Thickness measurements shall be taken
frequently.
2. The coating, when applied, shall be even and uniform. All
subsequent coats shall be perpendicular to previous coats.
3. On the areas which are inaccessible to the thermal spray
equipment, a zinc silicate coating shall be applied as close
in proximity to the area as possible.
F. Spraying
1. Thermal Spray equipment shall be capable of applying
Zinc-Aluminum (85-15) in a fine, even spray so as to produce
a uniform film at the specified thickness. Spray equipment
shall be as recommended by the Contractor.
2. Spray coating shall be done by experienced and qualified
applicators. Thermal spray operators shall apply the coating
in a manner that promotes uniform coverage and prevents
discontinuity of the applied coating. The spray gun shall be
moved uniformly across and perpendicular (90 degrees) to the
receiving surface. To insure a uniform coating, each spray
pass should lap the other by 50%. Any defects shall be
immediately corrected.
3. Spraying distance should be between 5 and 8 inches from the
substrate.
4. Special care shall be exercised to avoid contamination of
surrounding areas or property by over spraying. Containment
tarps should be used when spray application is performed.
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ITEM 2557O.9663XX - BLAST CLEANING AND ZINC THERMAL SPRAYING OF STRUCTURAL STEEL
3. CONSTRUCTION DETAILS: (cont'd)
3.04 Spraying Application (cont'd)
F. Spraying (cont'd)
G. Adhesion - Adhesion strength shall be 700 psi minimum with
approved measuring equipment as per ASTM D4541. All adhesion test
locations shall be re-metalized in accordance with this
specification at no additional cost. Measurements shall be taken
every 500 feet. If adhesion is less than 700 psi, the coating
shall be removed and re-applied at the Contractor's expense.
H. Ventilation - The work area shall be properly ventilated to
assure proper worker protection and safety.
3.05 Termination of Coating Operations
The Engineer is empowered to terminate coating operations, temporarily
or permanently, if the Engineer determines that any of the following
conditions exist:
A. Satisfactory results are not being obtained.
B. The measured film thickness is not within the required range.
C. Areas not specifically designated to be coated are likely to be
or are being affected by the application method.
D. The application method is causing damage to public or private
property.
If the Engineer permanently terminates coating operations, he may do
so by verbal order but he shall notify the Contractor, in writing of
his reasons for termination, within 48 hours of termination. The
Engineer may temporarily terminate coating operations by verbal
orders. Coating operations which are terminated due to damage to
public or private property shall not be resumed until the Contractor
takes appropriate measures to protect such property and demonstrates
to the Engineer's satisfaction that such property damage will not
reoccur.
3.06 No coating shall begin until cleaned steel surfaces have been
inspected and approved by the Engineer or Inspector. All structural
steel members, railings, fascia, downspouts, and other miscellaneous
steel items which have been previously coated shall be cleaned and
coated in accordance with these specifications unless specifically
excluded by the plans, or specifications, or by the Engineer.
3.07 The coating of metal surfaces shall include, but not be limited to the
following:
A. The proper preparation of all surfaces.
B. The application and protection of the coating.
C. The protection from spatter or spillage of pedestrians vehicular,
marine or other traffic upon, beneath or adjacent to the coated
surfaces. Payment for this work will be made under the item
Environmental Ground Protection and/or Environmental Waterway
Protection.
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