Introduction Electron cloud, mitigation, SPS requirements Thin film coating of amorphous carbon
Table of Contents - cdn.ymaws.com€¦ · requirements. Some states, such as California, have low...
Transcript of Table of Contents - cdn.ymaws.com€¦ · requirements. Some states, such as California, have low...
2
How to Estimate the Cost of Lead Abatement by Abrasive Blast Cleaning and Painting of Complex Industrial Structures
Table of Contents
Section 1 Introduction Page 3 Section 2 Type and Methods of Measurements Page 4 Section 3 Unique Project Characteristics that Effect Pricing and Take-off Page 6 Section 4 Project Costs and Mark-up Approach Page 11 Section 5 Special Risk Considerations Page 13 Section 6 Ratios and Estimate Analysis Page 14 Section 7 Miscellaneous Pertinent Information Page 14 Section 8 Structure Framing Plan Page 16 Section 9 Structure Take-off and Estimate Page 17 Section 10
Terminology Page 24
Section 11
References Page 25
3
Section 1 – Introduction
The objective of this technical paper is to provide estimators with a general understanding of the
many elements and complexities involved with the containment, lead abatement, and painting of complex
steel 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 was approximately $276 billion dollars.
Steel structures, such as bridges, are abrasive blasted to replace failing and aging protective coatings.
Most importantly, the structures are repainted after the surface preparation with high performance
protective coatings that, if properly applied, will protect the structure from corrosion. Preventative
maintenance is critical to protecting and maintaining our nation’s assets and infrastructure from corrosion.
Corrosion is a natural electrochemical process that occurs when a corrosion cell is formed on the
steel. A corrosion cell is comprised of an anode, cathode, electrolyte, and metallic pathway—corrosion
cannot occur without all four elements. Modes of protection from corrosion by protective coatings
include: barrier (impedes the ingress of oxygen, water, and soluble salts), inhibitive (slows down the
reaction at the anode, cathode, or both), or sacrificial (provides cathodic protection).
The infamous lead based protective coatings were excellent at reducing the development of
corrosion by acting both as a barrier, protecting the steel from environmental conditions, and by inhibiting
the reaction at the anode and/or cathode. On the other hand, it was later shown that lead based coatings
had a harmful effect on human health and the environment. Consequently, lead-based protective coatings
are now removed by abrasive blasting and replaced with protective coatings that provide comparable
performance without the risks.
MAIN CSI DIVISION
Division 9 – Finishes
MAIN CSI SUBDIVISION
Subdivision 09900 – Paints and Coatings
4
BRIEF DESCRIPTION
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
over the active travel lanes. The platform will function as part of the containment system. The structure
parapet wall is concrete, and the railing is galvanized steel. These bridge members are not included 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 and support personnel (tenders).
Section 2 – Types and Methods of Measurements
As with many different types of construction estimates, the quantity take-off is one of the most
critical junctures in producing an accurate industrial painting estimate. All of the permanent materials
required for the project will be derived directly from the steel surface area take-off. The temporary
containment materials will be quantified from the work platform area beneath the structure (fascia girder
to fascia girder—abutment to abutment). This section will focus on the various types and measurement
approaches for the two major functions of the work.
Constructing access to the steel and erecting the containment system to contain the hazardous
dust created by the abrasive blasting and overspray from the painting is critical. Moreover, the quality of
the access directly correlates to the production of the abrasive blasting, abrasive recovery (vacuuming),
and painting. The components of the containment system can be flexible, rigged, or a combination of
both.
The containment platform, which will suspend below the bottom flange of the structure, is
constructed by a combination of materials. Heavy-duty termination plates (EA) are anchored to the
bridge abutments; then main termination cables (LF) are stretched and tensioned from plate to plate and
5
secured by shackles (EA) . Vertical cable chokers (LF) are then suspended from bridge members, such
as diaphragms or beam flanges, and are attached to the main termination cable via shackles (EA) to
prevent the deck from deflecting. The rigid floor, typically a galvanized corrugated steel deck (SQ FT),
is positioned perpendicularly on the cables to inherently create the work platform. The estimator must
account for the additional deck materials required as a result of the deck sheet overlap. The deck overlap
will be a minimum required figure defined by the design engineer. Light duty steel plates (EA) are
anchored to the bridge parapet wall to secure the cantilevered deck sections. Vertical choker cables (LF)
are attached from the parapet wall plates to the outside main termination cables with shackles (EA) .
The structure can be sealed (contained) once the corrugate metal deck is installed and the vertical
chokers positioned and adjusted per the approved design. Lumber (2x4), which is included under the
containment expendables (SQ FT) , is anchored lengthwise along the parapet wall bottom edge and the
rigid work platform edge. Fire retardant tarpaulins (SQ FT) are draped and fastened from the bridge
parapet wall lumber to the platform edge lumber to enclose the containment outside walls. Other
containment expendables (SQ FT) including plywood, spray foam, fasteners, and caulk are used to close
seams and small openings to ensure dust and paint overspray do not escape the containment during the
blasting and painting operations.
Platform load requirements will be typically defined in the specification. Load requirements will
vary depending on the work to be performed. 25 PSF (lbs/ft2) is a common value specified; however, 50
PSF (lbs/ft2) or more can be specified if concrete or steel repairs are required in the contract. The
estimator must consult the design engineer for cable, shackle and plate size requirements, and for the
spacing of the components. The spacing and deck component sizes directly correlates to the deck load
capacity.
The costs for the abrasive blasting and painting of the structural steel are derived by applying
production rates to the area of the steel (SQ FT) . Many painting contracts also require the application of
a waterproof membrane to the horizontal and vertical faces of concrete abutment walls and bridge pier
seats after coating the steel. The concrete surfaces are effectively roughened by lightly brush-off blasting
6
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 completed within the containment after the
steel surface preparation operations. The surface preparation and coating of the concrete is measured by
(SQ FT) . Lastly, a high performance one-part elastomeric sealant/adhesive is caulked and tooled around
the bridge bearing perimeter (LF) and the bearings are lubricated.
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—this is also known
as economies of scale. Fundamentally, the rigging and containment crew will be able to install the
containments and work platforms faster once they have completed several similar spans. Additionally, the
abrasive blasting and painting crew will steadily improve production as they become accustomed to the
structure and develop a ‘rhythm’. Likewise, the estimator will be able to negotiate lower materials costs
and favorable credit terms due to the larger volume of materials required.
Alternatively, depending on the scope of work (containment requirements, level of cleanliness,
and coating system specified) the mobilization and containment setup costs can surpass the cost of
cleaning and painting smaller bridge structures. This is due to the considerable labor, material, and
equipment expense associated with mobilizing and installing the containments and preparing for the
abrasive blasting operations. The estimator along with management must consider this when reviewing
and selecting prospective projects, and either adjust cost and OH&P margins accordingly, or forgo
bidding altogether if financial objectives cannot be realized without considerable risk.
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 the living and travel expenses if a select crew is to travel to and live near the prospective project.
7
The atmospheric environmental conditions at the geographic location of the structure must also
be taken into consideration. Structures adjacent to salt water sources and/or industrialized areas require
special attention. Acid rain, chemicals from manufacturing plants, and chlorides in coastal areas all
increase corrosion rates. 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
manufacturer’s specified limits before abrasive blasting and painting. Contaminants can become
embedded or spread widely across the steel if they are not removed prior to abrasive blasting. Painting
over a contaminated surface may result in coating defects such as osmotic blistering. Contaminants must
be removed from the steel surface by solvent cleaning as defined by SSPC SP 1.
The climate in the project region should also be considered. The northeast may have a drier
climate, but containments may require heat in the winter to ensure the applied coating will cure. The
southeast climate is moist and may require dehumidification/refrigeration systems in the summer to
prevent flash rusting of newly blasted steel and to ensure coatings cure appropriately. These engineered
environmental control 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, have low coating volatile organic compound (VOC)
requirements. Conventional methods of coating application, such as airless spray, may not be permitted.
Alternative 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 considered when preparing the estimate.
SEASONAL EFFECT ON WORK
For the most part, the painting season is marked by the beginning of spring and ends the
beginning of winter. However, contractors can utilize heat or a combination of dehumidification and
refrigeration to extend the winter or summer (humid) seasons, respectively. High performance protective
coatings have very specific application guidelines that must be strictly adhered to. The coating type and
cure mechanism will dictate the surface preparation and application requirements.
8
AVAILABILITY OF INFORMATION
Many times the bid package does not include the bridge working drawings. At minimum, the
estimator will require the bridge framing plans to complete an accurate quantity take-off of the steel area.
The estimator must 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, the
drawings provided by the owner are for a structure that was widened or reinforced many years after its
completion. The estimator must verify all structure working drawings for completeness and accuracy to
avoid errors in the quantity take-off that will translate into fatal errors in the bid.
SPECIAL FACTORS
The estimator must be available the day of the project walk-through and should have a camera
handy. Experienced estimators will be able to recognize potential problems that can result in
unanticipated costs during the lifespan 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 a written addendum. Major items that must be addressed include,
but are not limited to:
Level of cleanliness: The specification will indicate the level of abrasive blast cleanliness
required. 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. Bridge painting contracts that necessitate the complete
removal of the existing coating by abrasive blasting will more than likely specify 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 random staining from the previous coating, mill scale, and other
corrosion products on the steel is limited to 5.00 percent each 9.00 square inches. The difference
in production on the above two levels of cleanliness can be as much as 20% percent or more
depending on the existing condition of the steel and the adhesion of the coating to be removed.
9
If not already specified, choosing the correct abrasive is critical. Five parameters that will
determine the performance of an abrasive are: shape, hardness, density, size, and velocity.
Abrasive selection will typically be dictated by environmental constraints, degree of cleanliness
required, and the coating system surface profile requirements. The performance of the abrasive is
directly correlated to the abrasive blast production—the most costly function of a coating project.
Cleaning and painting of drainage troughs and downspouts: Often drainage troughs and
downspouts are packed with dirt and debris. The estimator must account for the time a small crew
will require to remove and dispose of the debris. At the conclusion of the project the contractor
may be required to demonstrate to the Engineer that the system is free and clear of debris from
the construction activities.
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: Grease and cutting oils must be removed from the structure before abrasive blasting
by solvent or steam cleaning. If oil or/and grease is not removed prior to abrasive blasting, the
contaminants can be spread widely over the entire work surface and contaminate the abrasive.
Steel surface imperfections, such as sharp fins, sharp edges, and weld splatter must be ground
smooth before abrasive blasting and painting. Breaks or discontinuities in the coating film, known
as holidays, can occur 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 conduits, and fiber optics must be protected
before abrasive blasting. Conduit and pipe continuing outside of the containment structure can
make it difficult to create a complete seal of the containment. Also, these members will require
additional time for the application of the stripe coat to bolts, rivets, and edges.
The availability of adequate staging for the blasting and painting equipment is imperative.
10
Hard level ground will be required for the placement of the heavy machinery and the storage of
the hazardous materials. The estimator may need to address the need for leased property adjacent
to the 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. Consult the project plans for vertical clearance restrictions.
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, state, 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 existing protective coatings are identical. A long-standing, weathered coating that is brittle
and peeling will be much easier to remove than a more recently applied well adhering coating.
Blast production rates must be adjusted accordingly after inspecting the structure and existing
coating.
Work over navigable waterways 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 Coast 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 required.
11
Additional costs for flagmen services and railroad protective liability insurance must be added to
the estimate when working over railroads. Also, many times the work hours are stipulated and
vertical clearance requirements defined. The estimator must consider these requirements when
preparing the estimate.
Abrasive blasting and painting production will be limited to the local roadway and highway lane
closure work hours. Lane closure hours and work restrictions must be reviewed thoroughly when
preparing the estimate.
The estimator must identify bridge box girders and bridge interior cells that are within the scope
of work. These locations are considered confined spaces and have unique safety, containment,
ventilation, and access requirements.
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. Further, any coating defects found during the warranty inspection will
require access and repair to the satisfaction of the Engineer.
Responsibility for Hazardous Waste: The estimator must read the specification thoroughly and
identify if the contractor will be considered a co-generator of the hazardous waste under the
Resource Conservation and Recovery Act (RCRA).
Contractors must take care when working adjacent to galvanized steel. The ricochet from the
abrasive blasting can damage the galvanized coating on steel members such as stay-in-place
forms, rails, and special structural members. Metalizing in the field is difficult and very costly.
The estimator must be aware of special protection requirements.
Section 4 – Project Costs and Mark-up Approach
The estimator must have an exhaustive understanding of the work and must be able to identify
potential pitfalls before they materialize. With this knowledge the estimator will be able to compile the
project costs carefully and accurately. Abrasive blast and painting production rates from previously
completed contracts must be maintained in a well-organized manner to reference in the future. Also, a
12
good habit when preparing a new estimate is to review the scope of work thoroughly with crew foremen
and visit the structure to discuss the project requirements. Previous project production rates can then be
adjusted and applied to the new work accordingly.
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 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 non-work 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.
A common abrasive blasting and painting crew setup consists of 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. If utilizing
recycled abrasives, such as steel grit, the operation will require an abrasive blast and recovery unit, up to
two 1,600 CFM compressors per blast unit, a dust collector ranging from 15-60,000CFM or more
depending on the containment size, and material handling equipment.
13
The major materials for the project will include the rigging, containment, and the paint materials.
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 to seal the structure. 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. The complexity of a given prospective project 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. Well-designed access will
provide better production and better quality work. Inventive containment systems may be
required to overcome access/containment difficulties, and may come at a considerable expense.
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 containment walls during storms or high winds if
the structure is in a storm prone area.
14
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 system 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 especially important for the
estimator to request an explanation of the escalation expenses from the paint manufacturer.
Typically, a manufacturer will apply a markup that is percentage based on indices such as the US
Bureau of Labor and Statistics (BLS) or the London Metal Exchange (LME). 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. 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 costs. Generally, the new project containment, surface
preparation, and painting figures should be in-line with prior comparable projects.
Section 7 – Miscellaneous Pertinent Information
15
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, a Health and Safety Officer, a Coating Application Specialist (CAS), and a Quality
Control Technician on each-job site.
16
Section 8 – Bridge Structure Framing Plan
FIGURE 1: SIMPLE 2-SPAN STRUCTURE
17
Section 9 – Sample Take-off and Estimate
18
19
ASSUMPTIONS AND EXPLANATIONS:
Being able to accurately estimate 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
financial consequences. The most important figure to understand is the percent volume solids (%V.S) 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) dry film thickness will remain after a 68% volume solids coating is applied at 4.00 mils
(WFT) wet film thickness after it 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 influences 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, material
delivery lead time, overall comfort with the product, performance track record, application variables, and
quality all are taken into account when selecting a coating system.
20
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 floor beam, stringer, and diaphragm structures will have a
lower loss rate due to the simple flat surfaces. Complex steel configurations, such as stiffeners, riveted
steel or open lattice work, will have greater loss rates.
21
(c) Loss due to Paint Distribution: No painter can provide a perfectly uniform paint
thickness across the steel surface. Dry film thickness (DFT) will vary from area to area due to technique
and fatigue. Additional paint may be required to achieve the minimum specified dry film thickness in low
film thickness areas. The estimator must account for the loss due to the additional required 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.
22
FIGURE 7: TYPICAL CONTAINMENT COMPONENTS INSTALLED ON A
STRUCTURE
23
24
25
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.
Holiday A coating “holiday” is a skip, discontinuity or missed area on the
structure. Laitance A weak layer of cement and aggregate fines on a concrete surface that is
usually caused by an over wet or over worked 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
26
Section 11 – References
US Federal Highway Administration, Corrosion Costs and Preventive Strategies in the United States,
Report FHWA RD-01-156