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How to Estimate the Cost of Lead Abatement by Abrasive Blast Cleaning

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The objective of this technical paper is to provide estimators with a general understanding of the many variables and complexities involved with the containment, lead abatement and painting of complex structures, such as bridges.  
In 2002, the U.S. Federal Highway Administration (FHWA) released a report on a 2-year study that estimated the annual cost of corrosion in the United States is approximately $276 billion.

We abrasive blast and recoat structures to replace failing and aging coatings, which is due to corrosion. Corrosion is an electrochemical process that occurs when a corrosion cell is created. A corrosion cell consists of an anode, cathode, electrolyte and metallic pathway—corrosion cannot occur without all four elements. Lead based protective coatings were excellent at reducing the development of corrosion by acting both as a barrier, reducing or eliminating the electrolyte, and by reducing the reaction at anode and cathode.

On the other hand, we learned later on that the lead based coatings presented many environmental and health risks. As a result, these original coatings are now removed by abrasive blasting and replaced with protective coatings that provide excellent performance for Owners. Preventive maintenance is critical to protecting and maintaining our nation’s assets and infrastructure.

MAIN CSI DIVISION
Division 9 – Finishes
MAIN CSI SUBDIVISION
Subdivision 09900 – Paints and Coatings

The purpose of this paper is to provide estimators with the information required to systematically produce a detailed bridge painting estimate for competitive bidding purposes. The structure presented for containment, abrasive blasting and painting is a simple two-span overpass over a quiet suburban road. It is assumed that the structure has the necessary vertical clearance required to install a rigid work platform. The platform will serve as part of the containment system. The structure parapet wall is concrete, and the protective railing galvanized steel. These bridge members are not in the scope of work. Additionally, adequate staging for materials and equipment is available adjacent to the structure. The project is a public Federal-Aid project subject to general wage determinations issued under the Davis-Bacon Act. The estimate will be prepared assuming all work will be completed without the use of subcontractors. All work will be performed by bridge painters.

Section 2 – Types and Methods of Measurements
As with many different types of construction estimates the take-off is one of the most critical junctures in producing an accurate estimate. All of the permanent materials required for the project will be derived directly from the steel area take-off. The temporary containment materials will be quantified from the area beneath the structure (fascia girder to fascia girder and abutment to abutment). This section will concentrate on the various types and measurement methods for the two major functions of the work.

Creating access to the steel and building the containment system to contain the hazardous dust created by the abrasive blasting operations is critical. The quality of the access directly correlates to the production of the abrasive blasting. This is the most costly phase of the work. The components of the containment system can be flexible, rigged or both.
The containment platform, which will suspend below the bottom flange of the structure, is created by a combination of materials. Termination plates (EACH) are anchored to the bridge abutments and main termination cables (LF) are stretched from plate to plate and held by shackles (EACH). Then vertical chokers (LF) are suspended from bridge members, such as diaphragms or stringers/floorbeams, and are affixed to the main termination cable via shackles (EACH) to prevent the deck from deflecting. The rigid floor, typically a galvanized corrugated steel deck (SQ FT), is positioned on the cables to create the access/work platform. The estimator must account for the necessary overlap of the sheets, which will by a minimum figure defined by the design engineer. Light duty steel plates (EA) are anchored to the bridge parapet wall and cables (LF) attached to the fascia cables via shackles (EA) where the deck cantilevers. Platform load requirements are typically defined in the specification. Load requirements will vary depending on the Owner and the work to be performed. 25 PSF (lbs/ft2) is a typical requirements; however, 50 PSF or more can be specified. The estimator must pay special attention to the requirements. The design engineer will provide the cable, shackle and plate size requirements, and will also provide the spacing of the components. The spacing and member sizes directly correlate to the deck load rating.

The structure can be sealed (contained) once the work platform is complete. Lumber (2x4), which is included under containment expendables (SQ FT), is anchored length wise along the structure fascia to the parapet wall and the rigid work platform edge. Fire retardant tarpaulins (SQ FT) are draped from the bridge parapet wall down to the corrugated structure edge and fastened to enclose the containment completely. Other containment expendables (SQ FT) include plywood, 2x4s, spray foam, fasteners and caulk are used to close seams and small openings to ensure dust and paint overspray does not escape from the containment during the blasting and painting operations.

The costs for the abrasive blasting and painting of the structural steel are derived by applying production rates to the area of the steel that requires cleaning and painting by (SQ FT). In many cases, contractors are required to also apply waterproof membranes to the horizontal and vertical faces of abutment walls and bridge piers after coating the steel. The concrete is typically roughened by lightly brush-off blasting to achieve a laitance and contaminant free surface prior to applying a two-component, moisture tolerant 100% solid epoxy coating. The concrete surface preparation is done within the containment during the steel surface preparation operations. The surface preparation and coating of the concrete is figured by (SQ FT). Lastly, a high performance one-part elastomeric sealant/adhesive is caulked and tooled around the bridge bearings (EA).

Section 3 – Unique Project Characteristics that Effect Pricing and Take-off

SMALL V. LARGE QUANTITIES
Basic economic theory establishes that larger projects will have an effect on pricing due to the reduction in unit cost as a result of production efficiency and material pricing power. For the most part, no two bridges are alike. The rigging and containment crew will be able to more quickly install the containments and work platforms once they have completed several similar spans. Additionally, the abrasive blasting and painting crew will steadily improve production as they become accustom to the structure. The estimator may be able to negotiate lower materials costs due to the larger volume of materials that will be required.

Mobilization and setup costs can outweigh the cost of actually cleaning and painting the structure when producing estimates for smaller structures. This is due to the substantial labor, material and equipment expense involved with mobilizing and installing the containments.

GEOGRAPHIC LOCATION
Geographic location will certainly play a role in producing estimates when considering the costs. A skilled workforce and labor rates can vary greatly from region to region. The estimator must account for living and travel expenses if a specific company crew is to travel to and live near the prospective project.

The geographic location of the structure must also be taken into consideration. Structures adjacent to salt water sources require additional attention. The estimator must account for the additional time required to clean soluble contaminants, such as chlorides, nitrates and sulfates. Contaminants must be below the project and/or manufacturers specified limits before abrasive blasting. Contaminants can become embedded in the steel if they are not removed before abrasive blasting. Painting over a contaminated surface may cause coating defects such as blisters or complete coating delamination.

Contaminants must be removed from the steel surface by solvent cleaning as defined by SSPC SP 1.
The climate in the project region must be accounted for. Structures in the Northeast may have a drier climate, but containments may require heat in the winter to aid the cure of the coating. Structures in the Southeast may require dehumidification/refrigeration systems in the summer to prevent flash rusting of newly blasted steel, and to ensure coatings cure properly. Engineered environmental systems have high initial and operating costs.

Estimators must also pay close attention to the coating material and coating application requirements. Some states, such as California, may have low coating volatile organic compound (VOC) requirements. Conventional methods of coating application, such as airless spray may not be allowed. Alternate spray methods, such as high-volume low pressure (HVLP) or plural component spray systems may be required to comply with VOC and transfer efficiency requirements. Coating application production rates may differ greatly, and must be adjusted accordingly.

SEASONAL EFFECT ON WORK
The painting season is marked by the beginning of spring and ends the middle of winter. High performance protective coatings have specific application guidelines that must be adhered to. The coating type and cure mechanism will dictate surface preparation and application requirements. If necessary, contractors can utilize heat and dehumidification/refrigeration systems to extend the coating season. The estimator must account for the additional equipment and operating costs.

AVAILABILITY OF INFORMATION
On occasion, the bid package will not include the bridge working drawings. At minimum, the estimator will require the bridge framing plans to complete an accurate takeoff of the steel area. Prior to the bid, the estimator should obtain these drawings from the Owner. More importantly, the estimator must confirm that the acquired drawings he or she has been given represent the existing conditions. At times, drawings provided by the Owner are for a structure that was widened many years after its completion. The estimator must verify all structure working drawings for completeness and accuracy.

SPECIAL FACTORS
The estimator should be available the day of the project walk-through, and should have a camera handy. Experienced estimators will be able to identify potential problems that can result in unanticipated costs during the life of the project. Ambiguities in the contract and/or specification and differing site conditions should be identified by the estimator. The findings must be formally presented in writing to the Owner for clarification via an addendum prior to the bid. Major items that must be addressed include, but are not limited to:

  • Level of cleanliness specified: Specifications will identify the level of cleanliness required by the Owner. The highest achievable level of cleanliness is an SSPC-SP 5/NACE No. 1 (White Metal Blast Cleaning). The steel must be free of all existing coatings, mill scale, oxides, corrosion products, and other foreign matter. More likely, the specification will require an SSPC-SP 10/NACE No. 2 (Near-White Metal Blast Cleaning). This level of cleanliness is similar to the SSPC-SP 5/NACE No. 1, but allows 5 percent staining of the previous coating, mill scale and other corrosion products. The estimator must account for the difference in production. The variance on the above two levels of cleanliness can be as much as 30% percent or more depending on the existing condition of the steel.
     
  •  Cleaning and painting of drainage troughs: Often drainage troughs are packed with dirt and debris. The estimator must account for the time a small crew will need to remove and dispose of the debris.
     
  •  Pack rust is a form of localized corrosion that must be removed from gaps and crevices prior to abrasive blasting. Pack rust is removed by hand and/or power tools, and can be a time and labor intensive process.
     
  •  Degreasing: Cutting oils and greases must be removed from the structure before abrasive blasting. This is done by solvent cleaning. This is typical ailment on projects that have steel repairs.
     
  •  Surface imperfections, such as sharp fins, sharp edges, and weld splatter, must be grinded smooth before abrasive blasting and painting. Breaks or discontinuities in the coating film, known as holidays, can exist if the applicator does not have a uniform surface to apply to. Moisture can penetrate through a coating holiday to the steel, and can create a corrosion cell.
     
  • Utilities such as water pipes, gas pipes, electrical, and fiber optics must be protected before blasting and painting. Groups of conduit and pipe extending outside of the containment structure can make it difficult to create a complete seal of the containment.
     
  • The availability of adequate staging for the blasting and painting equipment is very important. The estimator may need to account for leased property adjacent to a structure for the period of time it will take to complete the work.
     
  • Sometimes it is not possible to install a rigid containment system below the structure due to vertical clearance restrictions. Production will suffer if the containment system must be installed and dismantled on a daily basis.
     
  • Many projects require a stripe coat on edges, crevices, bolts and rivets. Often these locations are the weakest link for the coating system, and a major source of coating holidays. The estimator must inspect the structure and ensure the cost to complete this work is accounted for in the estimate.
     
  •  The project work location must be surveyed, and the proximity to sensitive locations, such as schools and parks, identified. Additional environmental protection and air monitoring may be required to comply with project and state regulations and federal requirements, such as 40 CFR 60, App. A Method 22 (Visual Determination of Fugitive Emissions from Material Sources and Smoke Emissions from Fires).
     
  • Not all protective coatings are alike. An old weathered coating that is brittle and already peeling off will be much easier to remove than a well adhering coating. Blast production rates must be adjusted accordingly after inspecting the structure.
     
  • Work over navigable water ways must be approved by the United States Coast Guard. The estimator must know the vertical clearance restrictions, any black-out dates during Holidays and other project requirements to be in compliance with the USCG. The United States Coat Guard Bridge Administration Manual COMDTINST M16590.5C should be reviewed thoroughly for construction requirements, such as permits, minimum lighting requirements and signage that may be needed. 
     
  • Additional costs for flagmen services and railroad protective liability insurance must be added to the estimate when working over railroads. Furthermore, many times work hours are stipulated and vertical clearance requirements defined. The estimator must consider these requirements.
     
  • Production will be limited to local roadway and highway lane closure hours. Lane closure hours and restriction must be reviewed thoroughly.
     
  •  The estimator must identify bridge box girders and bridge interior cells that are considered confined spaces and difficult to access. Unique safety, containment, ventilation and access requirements may be costly.
     
  •  A maintenance warranty inspection may be required after a specified period of time. A crew must be priced into the estimate along with equipment, small tools and materials to complete the warranty inspection.

Section 4 – Project Costs and Mark-up Approach
The estimator must have a very good understanding about all aspects of the work. With this understanding the estimator will be able to compile the project costs accurately. It is important to maintain production rates from previously completed contracts in a well-organized manner. A good habit when preparing a new estimate is to review the scope of work thoroughly with crew foremen and visit the work site to discuss the work and prepare notes. Previous project production rates can then be adjusted and applied to the new work.

The project costs can be divided into three major activities: (1) support, (2) rigging/containment, (3) abrasive blasting and painting. The included sample estimate will divide the major costs—labor, materials and equipment—per these three major activities. Prevailing wages rates and fringe benefits on public work projects are based on collective bargaining agreements established for the trade in the given region where the work is to be performed.

The support crew is responsible for mobilizing equipment, preparing blast lines, air hoses, recovering (vacuuming) abrasive media, handling materials and handling the traffic control. The crew size will vary depending on the size of the project. A common practice is to assign 1 tender to every 2 blasters during the abrasive blasting operations to ensure the abrasive media is being recovered into the blast machine (to be reused), and to prevent exceeding the containment deck loads.

The rigging/containment crew specializes in the installation and dismantling of the rigging and containments. On-highway work can include the installation and removal of bulkheads to partition work lane containments from travel lanes. Off-highway work can include the installation and removal of simple or complex work platforms and containments. Work platforms can be as small as 5,000 ft2 or as large as 500,000 ft2. The crew size and equipment requirements will vary depending on factors such as: on-highway work, off-highway work, size and complexity of the containment/work platform, working over water, project size and schedule.

The abrasive blasting and painting portion of the project is the most costly. A common abrasive blasting and painting crew setup is 6 blasters, 1 machine operator (foreman) and 1 or more supporting the foreman depending on the size of the project and schedule. The equipment and operating expenses required come at a substantial expense. The abrasive blasting operation requires an abrasive blast and recovery unit, up to two 1,600 CFM compressors per unit, a dust collector ranging from 15-60,000CFM or more depending on the containment, and material handling equipment.

The major materials for the project will include the rigging and containment materials and the paint. At minimum, the estimator will need the structure framing plan and all applicable details to complete an area take-off. From the framing plan the estimator can easily quantify the area of the platform by multiplying the length by the width. It is important to take into account irregular areas that may require additional materials. Inventory of containment materials in good condition can be reused several times as long as it is not lead contaminated. Paint materials are measured through simple calculations as described in Section 9.

Management will review the current backlog and apply a reasonable margin for markup once all direct and indirect costs have been estimated. Additionally, the complexity of a given contract will necessitate a higher markup due to the inherent risks. Conversely, routine projects will have more competitive markup rates applied.

Section 5 – Special Risk Considerations
Many special risk considerations must be accounted for when preparing an estimate including access, health and safety, weather, contract time, quality control, pollution control and escalation. For example:

  •  Installing the containment work platform to access the steel is critical. Good access will provide for increase production and better quality work. Some structures may limit the ability to install a particular containment system. Innovative systems may be required to overcome access/containment difficulties, and may come at a considerable expense. An example would be when the containment main cables cannot be fastened to the bridge abutments. Proprietary access systems that do not use cables to create the work platform base would be required.
     
  •  Bridge painting is an inherently dangerous business. General and lead health and safety personal protective equipment must be in place. The estimator must account for the cost required to be in compliance with Federal Regulations, such as 29 CFR 1926 (Occupational Safety and Health Regulations for Construction) and 29 CFR 1910 (Occupational Safety and Health Standards).
     
  •  Weather is a major concern on painting contracts. High performance coatings have strict application conditions that must be adhered to. Furthermore, many specifications require the contractor to dismantle containment walls when winds exceed a certain velocity. The estimator should add an incidental cost for dismantling containments walls during storms or high winds if the structure is storm prone area.
     
  • Contracts that fall behind schedule can become subject to substantial liquidated damages. Liquidated damages should be included in the costs if the estimator believes the contract time frame is unreasonable.
     
  • A solid quality control system and excellent quality control personnel will ensure the coatings are applied per the manufacturer’s recommendations. The cost of repairing a failed coating system can be more than the original cost of applying the coating initially.
     
  • Abrasive blasting operations produce lead dust and other hazardous heavy metals from the original coating and the steel. Engineered pollution control systems must be in place and constantly monitored and maintained to ensure good working order.
     
  • Projects that extend into multiple seasons can have exposure to cost escalations. Labor, paint materials, steel and fuel are all subject to cost escalations. It is important for the estimator to request from paint manufacturers an escalation clause. Typically, a manufacturer will apply a percentage based on indices such as the US Bureau of Labor and Statistics (BLS) or to the London Metal Exchange (LME), which can be adjusted every 3 months. If steel will be required in year 2 of the project the estimator should apply a conservative escalation rate to the steel cost. Most importantly, labor escalation should be applied if a project is expected to extend into multiple years.

Section 6 – Ratios and Estimate Analysis
Every bridge painting contract is unique. Square foot prices fluctuate depending on the complexity of the work, geographic region and the competitive environment. After compiling the costs the estimator should review the estimate thoroughly for errors and completeness. The estimator can then review previous comparable contracts to check for consistency on the containment cost per square foot and blasting and painting cost per square foot figures. Again, every project is unique. However, the estimator can assess current estimates for accuracy against previous completed projects after adjusting labor rates, production rates, material costs and equipment cost. Generally, the new project containment, surface preparation and painting figures should be in-line with prior contracts.

Section 7 – Miscellaneous Pertinent Information
The estimator must be aware that many state transportation authorities have a prerequisite that the bidder be a certified SSPC QP 1 (Field Application to Complex Industrial Structures) and SSPC QP 2 (Field Removal of Hazardous Coatings) contractor. These qualifications are awarded by the Society for Protective Coatings (SSPC) to industrial and marine painting contractors that have demonstrated the technical capability to perform the work, competency to manage the work safely and ability to comply with environmental laws and regulations. Contractors must adhere to the program requirements to be in compliance with the SSPC, and to maintain the certifications. This includes, but is not limited to: a Project Manager on each job-site, a Health and Safety Officer on each job-site and a Quality Control Technician on each-job site.

Section 8 – Bridge Structure Framing Plan

FIGURE 1: SIMPLE 2-SPAN STRUCTURE

Section 9 – Sample Take-off and Estimate

ASSUMPTIONS AND EXPLANATIONS:
Estimating accurately the volume of paint required for a project is critical for an estimator. This section will identify the major variables that must be accounted for to prevent potential pitfalls. The most important figure to understand is the percent volume solids of a coating. Often, inexperienced estimators do not take into account the percent volume solids of a coating. This figure is provided by the coating manufacturer in the Product Data Sheets. The percent volume solids of a coating is the ratio of nonvolatile content (solids) in relation the volatile content (wet). The nonvolatile content (solids) portion of the coating will remain after the coating has cured. For example, 2.72 mils (DFT) will remain after a 68% volume solids coating applied at 4.00 mils (WFT) has cured. It is very important to understand percent volume solids when selecting a coating system for a project. The coatings that are the least expensive (unit price per gallon) may not necessarily be the least expensive overall. The example below shows how the percent volume solids effect the overall cost of a coating system. Coating System No. 1 appears to be the most expensive on a unit cost per gallon basis. However, Coat System No. 1 is actually the most budget friendly after taking into consideration the percent volume solids. It is important to note however that the selection of a coating system is not necessarily dictated by the price. Product technical support, lead time, overall comfort with the product, application variables and quality all are taken into account when selecting a coating system.

QUANTIFYING MATERIAL LOSS
(a) Surface Profile: The anchor or surface profile is produced when the (1) steel is abrasive blasted with a sharp (angular) media, such as steel grit. The steel becomes (2) textured, which will provide the adhesion properties for the (3) prime coat. The surface area of the steel increases, thus the estimator must account for the additional required paint material.

FIGURE 5: STEEL SURFACE PROFILE
(b) Loss due to Paint Application: The estimator must account for loss from the paint application activities. For example, paint lost from a dripping brush or roller, or paint lost during the spray application. Simple configurations, such as floorbeam, stringer and diaphragm structures will have a lower loss rate due to the flat surfaces. Complex steel configurations, such as stiffeners or open lattice work, will have a greater loss rates.
(c) Loss due to Paint Distribution: No painter can provide a perfectly consistent paint thickness across the steel. Dry film thickness (DFT) will vary from area to area due to technique and fatigue. Additional paint may be required to achieve the specified dry film thickness in low film thickness areas.

The estimator must account for the loss due to the additional paint distribution across the steel surface.
(d) Loss due to Paint Wastage: Paint wastage is one of the largest factors an estimator must account for. This is paint not utilized, such as paint mixed but not applied, paint flushed from spray lines at the end of the work day and paint not applied that has exceed the manufacturer’s pot life.

STEEL MATERIALS REQUIRED TO CONSTRUCTION CONTAINMENT PLATFORM
The estimator must have experience quantifying the material requirements for a rigid access platform. Experience is gained reviewing previous containment plans that were designed by qualified engineers. The estimator can use containment plans previously submitted and approved if the containment is similar. A schedule of materials required was prepared to coincide with the sample containment platform.

John P. Psarianos, CPE is an Estimator and Project Manager in New Jersey. John began his career as a financial analyst after graduating from the New Jersey Institute of Technology. He then took a position with a painting and structural steel repair company in 2005. During that period he worked as an Assistant Estimator/Project Manager on various major bridge painting and rehabilitation projects in New York and New Jersey. John is now the Estimator and Project Manager for Anka Painting Co., Inc. The company specializes in bridge painting contracts for entities such as the New Jersey Department of Transportation and the New Jersey Turnpike Authority. John is a NACE Certified Coatings Inspector—Level 3 and a SSPC Protective Coating Specialist.

FIGURE 7: TYPICAL CONTAINMENT COMPONENTS INSTALLED ON A STRUCTURE

Section 10 – Terminology

Davis-Bacon Act of 1931 A United States federal law which established the requirement for paying prevailing wages on public works projects.

Laitance A weak layer of cement and aggregate fines on a concrete surface that is usually caused by an overwet or overworked mixture.

Mils A unit of measurement equal to one thousandth of an inch. 1 mil is equal to 25.4 micron.

Pack Rust A form of localized corrosion that typically affects joints, crevices and back-to-back steel members.

SSPC The Society for Protective Coatings

SSPC Class 1A Containment The highest containment class for emission control of abrasive blasting operations specified in the SSPC Technology Guide No. 6.

SSPC SP 1 SSPC standard for solvent cleaning of steel surfaces.

SSPC QP 1 The SSPC QP 1 is a certification procedure that evaluates the qualifications of industrial field painting Contractors. It is a commonly specified requirement for Owners of complex industrial structures.

SSPC QP 2 The SSPC QP 2 is a certification procedure that evaluates the qualifications of industrial field painting Contractors to remove hazardous coatings. It is a commonly specified requirement for Owners of complex industrial structures.

NACE National Association of Corrosion Engineers

Section 11 – References
US Federal Highway Administration, Corrosion Costs and Preventive Strategies in the United States, Report FHWA RD-01-156

Section 12 – Signed Copy of ASPE Paper Topic Acceptance Letter
Facsimile Transmission: 02/2

Tags: Costs, Estimating Construction, Davis-Bacon Wages



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