chapter 13: encapsulation€“3 chapter 13: encapsulation encapsulation: how to do it step-by-step...

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Chapter 13: Encapsulation

CHAPTER 13: ENCAPSULATION

Step-by-Step Summary ............................................................................................ 13–3

I. Introduction ......................................................................................................... 13–5

A. Definition ........................................................................................................... 13–5

B. Standards and Acceptance ................................................................................ 13–5

C. Background ........................................................................................................ 13–6

II. Assessment of Surfaces and Components for Suitability ................. 13–6

A. Specific Surfaces and Components Not Suitable for Encapsulation ............. 13–6

B. All Other Surfaces ............................................................................................ 13–7

III. Encapsulant Classification ............................................................................. 13–8

IV. Minimum Performance Requirements for Encapsulants ................... 13–9

A. Safe Application ................................................................................................ 13–9

B. Adhesion ............................................................................................................ 13–9

C. Ability To Remain Intact ................................................................................ 13–10

1. Mechanical Properties ................................................................................ 13–10

2. Chemical Resistance Properties .................................................................. 13–10

3. Durability .................................................................................................... 13–10

D. Fire, Health, and Environmental Requirements ........................................... 13–10

V. Factors To Consider in Selecting and UsingEncapsulant Systems ..................................................................................... 13–11

A. Base Substrate ................................................................................................. 13–11

B. Lead-Based Paint Film Properties .................................................................. 13–11

C. Application and Installation Constraints ....................................................... 13–11

1. Skill Level ................................................................................................... 13–11

2. Method and Environmental Conditions .................................................... 13–11

3. Regulations ................................................................................................. 13–12

D. Environmental Service Conditions ................................................................ 13–12

E. Use Conditions ................................................................................................ 13–12

F. Encapsulant Service Life ................................................................................. 13–12

G. Safety Constraints and Information ............................................................... 13–12

H. Esthetics ........................................................................................................... 13–13

I. Repairability ..................................................................................................... 13–13

J. Cost .................................................................................................................. 13–13

K. Technical Assistance ....................................................................................... 13–14

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VI. Specific Encapsulant Products andSurface Preparation Procedure .................................................................. 13–14

A. Encapsulant Product Selection ....................................................................... 13–14

B. Surface Preparation ......................................................................................... 13–14

1. Cleaning ...................................................................................................... 13–14

2. Deglossing ................................................................................................... 13–14

3. Removal of Loose Paint .............................................................................. 13–15

4. Preparing Exposed Base Substrates ............................................................. 13–15

C. Field Patch Tests ............................................................................................. 13–15

1. Size of Patch Tests ....................................................................................... 13–15

2. Location of Patches ..................................................................................... 13–15

3. Surface Preparation for Patch Testing ........................................................ 13–15

4. Encapsulant Application and Installation .................................................. 13–16

5. Patch Preparation for Conducting a Lead-Based Paint Soundness Test .... 13–16

6. Visual and Adhesive Evaluation of Field Patch Tests ................................ 13–16

7. Documentation of Patch Test Results ........................................................ 13–18

VII. Application and Installation of the Encapsulation Systems ...... 13–18

A. Surface Preparation for Job ............................................................................ 13–18

B. Installation and Application of Encapsulant System .................................... 13–19

1. Nonreinforced and Reinforced Coatings .................................................... 13–19

2. Adhesively Bonded Coverings.................................................................... 13–19

C. Inspection of Encapsulant Systems ................................................................ 13–21

1. Tools ............................................................................................................ 13–21

2. Procedures ................................................................................................... 13–21

VIII. Periodic Monitoring and Reevaluation ............................................... 13–22

IX. Recordkeeping .................................................................................................. 13–22

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Encapsulation: How To Do It

Step-by-Step Summary

1. Determine if encapsulants can be used. Do not encapsulate the following surfaces:

✦ Friction surfaces, such as window jambs and door jambs.

✦ Surfaces that fail patch tests.

✦ Surfaces with substrates or existing coatings that have a high level of deterioration.

✦ Surfaces in which there is a known incompatibility between two existing paint layers.

✦ Surfaces that cannot support the additional weight stress of encapsulation due to existingpaint thickness.

✦ Metal surfaces that are prone to rust or corrosion.

2. Conduct field tests of surfaces to be encapsulated for paint film integrity.

3. Consider special use and environmental requirements (e.g., abrasion resistance and ability to span basesubstrate cracks).

4. Examine encapsulant performance test data supplied by the manufacturer.

5. Conduct at least one test patch on each type of building component where the encapsulant will be used.

6. For both nonreinforced and reinforced coatings, use a 6- by 6-inch test patch area. Prepare the surface inthe manner selected for the complete job. Prepared surfaces for patch testing should be at least 2 incheslarger in each direction than the patch area.

7. For fiber-reinforced wall coverings, use a 3- by 3-inch patch. For rigid coatings that cannot be cut with aknife, use a soundness test.

8. For liquid coating encapsulants, allow coating to cure and then visually examine it for wrinkling, blister-ing, cracking, bubbling, or other chemical reaction with the underlying paint. For all encapsulants, carryout the appropriate adhesion tests.

9. Record the results of all patch tests on Form 13.1.

10. Develop job specifications.

11. Implement a proper Worksite Preparation Level (see Chapter 8).

12. Repair all building components and substrates as needed, e.g., caulk cracks and repair sources of waterleaks.

13. Prepare surfaces. Remove all dirt, grease, chalking paint, mildew and other surface contaminants, remnantsof cleaning solutions, and loose paint. All surfaces should be deglossed, as needed.

14. Ventilate the containment area whenever volatile solvents or chemicals are used.

15. During encapsulant application or installation, monitor temperature and humidity. For liquid coatings,monitor coating thickness to ensure that the encapsulant manufacturer’s specifications are met.

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Chapter 13: EncapsulationStep-by-Step Summary (continued)

16. Conduct cleanup and clearance.

17. The owner should monitor the condition of the encapsulant after the first 6 months and at least annuallythereafter. Repairs should be made as necessary. Reevaluations should be completed according to the schedulein Chapter 6.

18. Provide information to residents on how to care for the encapsulation system properly and how to contact theowner to get repairs completed safely and quickly.

19. Maintain records on the exact detailed locations of encapsulant applications, concentration of lead in thepaint underneath the encapsulant, patch test specifications and results, reevaluations, product name, contrac-tor, and date of application or installation, along with a copy of the product label and a material safety datasheet (MSDS) for the product. Record failures and corrective measures, signs of wear and tear, and theidentity of the certified risk assessor.

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I. Introduction

This chapter provides information on (1) assess-ment of the suitability of a surface (i.e., the ex-isting paint film) and the building componentsubstrate for encapsulation; (2) types ofencapsulant systems; (3) considerations for se-lection and use of encapsulants; (4) field patchtesting; (5) general surface preparation and ap-plication procedures; and (6) procedures for on-going monitoring by the owner and reevalua-tion by a risk assessor.

A. Definition

Encapsulation is the process that makes lead-based paint inaccessible by providing a barrierbetween the lead-based paint and the environ-ment. This barrier is formed using a liquid-applied coating (with or without reinforcementmaterials) or an adhesively bonded coveringmaterial. While encapsulant systems may alsobe attached to a surface using mechanicalfasteners, the primary means of attachment foran encapsulant is bonding of the product to thesurface (either by itself or through the useof an adhesive).

Encapsulants should not be confused with en-closures, which are rigid barriers fastened bymechanical means to the base substrate (or thestructural members). Enclosures rely on me-chanical fasteners as the primary method ofattachment. Enclosures are addressed inChapter 12, Section␣III.

Encapsulation depends upon a successful bondbetween the surface of the existing paint filmand the encapsulant for performance. However,this condition alone is not sufficient for encap-sulation system success. All layers of the exist-ing paint film must adhere well to each other, aswell as to the base substrate. If not, the encap-sulation system may fail. Thus, proper assess-ment of the suitability of the surface and sub-strate for encapsulation is essential prior to theapplication and installation of the product.

The success of an encapsulation application alsodepends on successful patch testing in the field,proper completion of surface preparation andapplication procedures, ongoing monitoring bythe owner and resident, and periodic reevalua-tion by a risk assessor. These procedures arediscussed in detail in subsequent sections ofthis chapter.

B. Standards and Acceptance

At this time, there are no approved or prohib-ited encapsulants and no standards for their use.Standards for minimum performance character-istics are now being developed under the aus-pices of the American Society for Testing andMaterials (ASTM) Committee E06.23.30. Atleast one State (Massachusetts, 1994), alreadyhas such lead standards in place. Title X re-quires that encapsulant standards be completedby April 1996. In the interim, until such stan-dards are developed, encapsulation is consideredan acceptable method of federally supportedlead-based paint abatement or federally sup-ported lead-based paint hazard abatement,provided the following conditions, procedures,and precautions exist or are followed:

✦ The encapsulation product or system iswarranted by the manufacturer to performfor at least 20 years as a durable barrierbetween the lead-based paint and the envi-ronment in locations or conditions similarto those of the planned application.

✦ Selection and use of encapsulation productsor systems follow the manufacturer’s recom-mendations and the procedures and precau-tions described in this chapter of the Guide-lines and in other relevant chapters,including those on occupant protection,worker protection, cleanup, clearance, andwaste disposal.

✦ Patch testing is completed successfully.

✦ The property owner or local governmentagency conducts surface-by-surface visual

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monitoring of all encapsulant applications 1month and 6 months from the date ofcompletion of the application and at othertimes as specified for encapsulation inChapter 6 of these Guidelines and recordsthose results.

✦ Failures are repaired as soon as possible, andrepairs are made according to manufactur-ers’ recommendations and the proceduresand precautions recommended in this chap-ter and other relevant chapters of theseGuidelines, including those pertaining toresident protection, worker protection,cleanup, clearance, and waste disposal.

C. Background

Encapsulation technologies can offer safe andeffective control of lead-based paint hazards.Encapsulation can be less expensive thanother options and may be one of the only alter-natives that can be used in certain situations.Encapsulants may also be used in combinationwith other methods. Encapsulants can be ap-plied with only a moderate degree of trainingand, unless there is significant surface deteriora-tion, may generate low amounts of leaded dust.However, if the encapsulation system fails, re-pairing the damage, as well as covering the ex-posed lead-based paint surfaces, may result inhigh maintenance costs. The advantages anddisadvantages of using encapsulants are listed inTable 13.1.

A number of products currently being marketedspecifically for lead-based paint abatement havebeen used as specialty coatings and coveringsfor many years. However, there is limited fieldexperience in their use as lead-based paintencapsulants. Ongoing, but limited, field reex-amination and evaluation of coating systems arebeing conducted by the Massachusetts Depart-ment of Public Health and the Maryland De-partment of the Environment with fundingfrom the U.S. Environmental ProtectionAgency (EPA). Some sites with interior andexterior coatings have been found to remainintact for up to 3 years. On the other hand, thesame systems have been observed to fail imme-diately after application or within a period ofmonths due to inadequate surface preparation

or improper selection. Some failures have beenwidespread, in which the coating system sepa-rates completely from the substrate. Some havebeen more limited, in which cracks appear inthe coating or the product is abraded (rubbedaway) through normal wear and tear. The lim-ited failures have been attributed to use ofencapsulants on surfaces that were not suitablefor encapsulation, inadequate surface prepara-tion, or improper selection of product type.

The standards for minimum performance nowbeing developed by ASTM involve laboratorytesting of products applied to bare substratesunder controlled settings. Most commercialproducts have not been tested using the ASTMprotocols. Consequently, encapsulant systemshave not yet been subjected to rigorous perfor-mance testing. The ASTM standards, whenthey become available, specify minimum perfor-mance requirements. Specific use situations maywarrant more stringent performance require-ments for certain properties. The encapsulantuser will need to determine whether more rigor-ous performance is needed. Product selectionand use considerations are addressed later inthis chapter.

II. Assessment of Surfacesand Components forSuitability

Some surfaces and components are not suitablecandidates for encapsulation. In these situa-tions, a decision not to encapsulate can bemade without further consideration or testing.For all other surfaces and components, moreextensive field testing is recommended forencapsulation. Once the determination ismade that encapsulation is suitable, patch test-ing of candidate encapsulant systems (includinguse of the manufacturer’s recommended materi-als, surface preparation procedures, andapplication procedures) is essential.

A. Specific Surfaces andComponents Not Suitablefor Encapsulation

Friction surfaces. These surfaces include win-dow jambs and exterior wood flooring or stairs

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covered with lead-based paint. Some interiorfloor and stair surfaces may be suitable forencapsulating with a rigid floor covering(e.g., vinyl tile) that is adhesively bonded to thesurface.

Deteriorated components or paint films. Com-ponents must be sound and essentially free ofdeterioration to be suitable for encapsulation.Deteriorated components include rotten wood,rusted steel, spalled plaster, and masonry inneed of repointing. Use of encapsulants on steelstructures is especially difficult, since most donot have corrosion inhibitors and will fail if thesteel underneath rusts. Also, components af-fected by water leaks, poor moisture venting, orother moisture-associated problems should notbe encapsulated unless the moisture problem iscorrected first. Additional information on in-spection of components for damage associatedwith water penetration can be found inChapter 11.

Severely deteriorated paint films. Lead-basedpaint films that are severely deteriorated (e.g.,cracked and peeling over most of the surface)are not suitable for encapsulation.

Surfaces in which there is a known incompat-ibility between two existing coating layers.Usually this determination cannot be madewithout field testing. However, if available,historic records may reveal conditions knownto cause poor interlayer adhesion. For example,use of a flat latex paint over an improperly pre-pared, glossy oil-based enamel will likely resultin an existing paint system that is not suitablefor encapsulation.

B. All Other Surfaces

Surfaces of nondeteriorated substrates havingreasonably stable lead-based paint films can beconsidered for encapsulation. However, a deci-sion to encapsulate should be made only after afield evaluation of the condition of these filmsis conducted, using patch tests. A patch test is a

Table 13.1 Advantages and Disadvantages of Using Encapsulants

Advantages Disadvantages

Experience and information on long-termdurability is limited.

Use on friction surfaces is inappropriate.

Durability depends on condition of previouspaint layers.

Field compatibility testing of encapsulant withparticular lead-based painted surface isessential (patch testing).

Encapsulant system success depends on propersurface preparation.

Periodic monitoring and maintenance by the owneris required, since lead has not been removed.

Susceptible to water damage; system failurecan be extensive.

Application may be weather- and temperature-dependent and may require several coats.

Some systems may contain toxic ingredients.

Residents may not need to be relocated.

Minimal generation of leaded dust if surfacepreparation is minimal.

Moderate application training requirements.

Less costly and more timesaving than someother control techniques if surface preparationis minimal.

Wide range of product types available to meetspecial needs.

Finish carpentry work may not be required.

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field test procedure in which a small area of theexisting lead-based paint film is prepared andthe encapsulant product is applied or installedand cured in the manner intended for the large-scale job. A field evaluation should determinethe extent of deterioration, the condition of thesurface, and the integrity of the underlyingpaint layers. These factors should be consideredbecause an encapsulant is not mechanically fas-tened to the underlying base substrate. Somepaint films cannot support the additionalweight or stress of an encapsulant, because ofexisting film thickness, poor adhesion betweenpaint layers, or low cohesive strength within alayer. Existing film thickness can be measuredusing a dry film thickness gauge, such as aTooke gauge or a micrometer. Information onthe thickness of existing coatings can be pro-vided to an encapsulant manufacturer’s ordistributor’s technical representative to help inmaking appropriate recommendations.

The visual extent of deterioration, surfacedeterioration, and interfacial or cohesive filmweaknesses should be evaluated, before use ofencapsulants, in the following ways:

Visual Evaluation. Visual deterioration in-cludes peeling, flaking, blistering, and crackingof paint films. The level can be rated based onASTM photographic standards, such as ASTMD 610 for rusting, D 770 for blistering, etc. Anentire surface can usually be inspected for thesedefects. Often, both the extent of the surfacethat is deteriorated and level of deteriorationare assessed. For example, 5 percent of the sur-face may be deteriorated to a rating level of one(i.e., severe) or the entire surface may haveslight deterioration. Quantitative rating in thisfashion may be required by the encapsulantmanufacturer, but not by HUD at this time.

Surface Deterioration. Surface deteriorationincludes chalking, mildewing, and soiling. Stan-dard ASTM procedures can be used to rate thedegree of these conditions. Enough determina-tions need to be made to properly characterizethe surface. However, since this type of deterio-ration tends to be widespread and is usuallyrather uniform over large surface areas, determi-nation of two or three locations may adequatelydescribe the condition.

Interfacial and Other Film Integrity Proper-ties. Since most lead-based paint films are madeup of many paint layers, up to 1 or more milli-meters in thickness, a measure of how well thelayers are adhering to each other and the basesubstrate is needed prior to the use of anencapsulant. Also related to interfilm adhesionis cohesive strength within films. These proper-ties are usually assessed using a field adhesiontest, such as a crosshatch or “x-cut” test withtape, a pulloff adhesion test, or a probe of thefilm with a knife. Interfacial deterioration maynot be uniform over a large surface area (since itmay be defect-related) and will vary from loca-tion to location across a surface. Thus, it is im-portant to conduct enough interfacial integritytests to obtain a representative sampling of theentire area.

Surfaces with intact paint and good interfacialadhesion are good candidates for nonreinforcedencapsulants. Surfaces with peeling, flaking, orcracking paint films are usually not good candi-dates for nonreinforced encapsulants unless theloose coating can be removed. However, rein-forced encapsulants may be suitable if the areasof deterioration are localized and reasonablysmall. In these cases, the reinforced coating canspan the deteriorated areas. Adhesively bondedencapsulants may be suitable for either surfacetype.

III. EncapsulantClassification

Encapsulation technology is developing rapidly,and new material types and systems are con-tinually being introduced commercially, makingit difficult to classify encapsulants (Table 13.2).Within each of the three general classifications,there is a wide range of material types and prop-erties. Manufacturer’s data must be consulted toobtain specific information.

Residential paints, such as latex and alkyd-based paints and canvas-backed vinyl wallpaper,do not constitute encapsulant systems unlessthey pass the patch test and meet the perfor-mance requirements of this chapter and anyquantitative performance standards defined byASTM or other local, State, or Federal agency.

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IV. Minimum PerformanceRequirements forEncapsulants

Four general performance requirements forencapsulants are as follows:

✦ The encapsulant must be capable of beingapplied safely and must not contain toxicsubstances.

✦ The encapsulant must adhere to existingpaint films.

✦ The encapsulant must have the ability toremain intact for an extended period of timewhen exposed to the expected environmen-tal conditions and use patterns.

✦ The encapsulant and its application pro-cedure must comply with fire, health, andenvironmental regulations.

A. Safe Application

All encapsulants must be able to be appliedsafely, without excessive worker or occupantexposure to hazardous solvents, curing agents,or other chemicals in the encapsulant, either byinhalation or by contact with the skin.

B. Adhesion

An encapsulant must adhere to the existingpaint film. Adhesion can be measured usingpeel, tensile, or shear tests. However, adhesionof an encapsulant to the lead-based paint filmis not sufficient for success of the encapsulantsystem; the integrity of the underlying paintlayers is also crucial. Each of these layers mustadhere well to other layers and the base sub-strate. In addition, each layer must have suffi-cient cohesive strength to support the increasedinternal stresses caused by the addition of anencapsulant layer.

Table 13.2 Categories of Encapsulants

Encapsulant Category Application and CharacteristicsInstallation Method

Nonreinforced liquid coatings. Usually applied with brush, Interior and exterior products. Someroller, or spray. properties vary widely, such as

elongation (e.g., elastomeric withhigh elongation to rigid with limitedelongation), dry film thickness(0.05 mm to greater than 0.5 mm),hardness, dry/cure time, andcompatibility with existing painted surfaces.

Liquid coatings reinforced with Applied with brush, roller, Interior and exterior products.cloth, mat, fibers, etc. spray, or trowel. Usually Properties vary widely.

applied in two steps.

Materials adhered with an System is usually installed in Classification includes sheet vinyladhesive (e.g., fibermat, two steps: (1) adhesive systems, floor tile, wall systems, and othervinyl floor tile). application and (2) adhesively bonded systems.

encapsulant productinstallation.

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C. Ability To Remain Intact

The ability of a film to remain intact dependson many factors, some of which are specific tothe conditions in which the encapsulant is used.For example, an encapsulant may suffer impactand abrasion damage. It may also be exposed towater and other household chemicals, changingtemperatures, changing substrate dimensions,and other degrading environmental conditions.Laboratory procedures used to investigate theseproperties are loosely grouped into tests for me-chanical, chemical resistance, and durabilityproperties.

1. Mechanical PropertiesMechanical properties include tensile properties(elongation, tensile strength, modulus), flexibil-ity, abrasion resistance, and impact resistance.Most of these properties are interrelated andmay depend on temperature.

Mechanical properties of coatings should beconsidered in selecting an appropriate material.For example, more flexible materials may bemore likely to resist cracking when the substratemoves because of vibration, changes in tem-perature, changes in moisture content, or set-tling. If this mode of performance is important,the encapsulant must remain flexible over thecomplete range of exposure temperatures. Someelastomeric encapsulants have failed by crack-ing because they became brittle at low tempera-tures. Reinforced encapsulants may be morelikely to resist cracking over existing sub-strate cracks or new substrate cracks thannonreinforced encapsulants. This is becausestresses produced in a reinforced encapsulant asa result of substrate cracking or other move-ment are distributed over a larger area than fornonreinforced materials.

Abrasion resistance refers to the ability to resistwearing, such as from rubbing against a surfaceor from cleaning with abrasives. Examples ofsurfaces where abrasion is likely to occur in-clude railings, walls, moldings around door andwindow openings, and interior window sillswhere air conditioner units are installed andremoved.

Impact resistance is the ability of a coating toresist cracking or loss of adhesion upon directimpact by an object, such as a toy or tool. Goodimpact resistance is needed for surfaces adjacentto door openings and for walls in recreationrooms and entryways.

2. Chemical Resistance PropertiesChemical and water resistance is essential forlong-term stability of an encapsulant. Interiorencapsulants may be exposed for extended peri-ods of time to both water (steam, vapor, andliquid) and, in limited situations, chemicals. Forexample, on horizontal surfaces, water orchemicals (e.g., cola, cleaning solutions) maystand until evaporated. An encapsulant must beable to withstand such exposures without blis-tering, peeling, cracking, or losing film integrity.

3. DurabilityFor all encapsulants, it is essential that themechanical and chemical properties of the material remain essentially constant over time.For exterior exposures, this means that anencapsulant must also be resistant to degrada-tion by sunlight, moisture, and temperaturevariations. Until specific criteria are available,manufacturers should be asked to supply infor-mation and warranties on the durability of theirproducts.

D. Fire, Health, and Environ-mental Requirements

Encapsulants must meet all local fire coderequirements. Since their film thicknesses areoften much greater than that of paints, theremay be additional fire-related requirements.Building codes and material safety data sheets(MSDS) must be consulted to ensure safe appli-cation and to provide information on whenresidents can safely reenter the area. The MSDSwill also provide information on toxic substancecontent. In addition, environmental volatileorganic compound (VOC) regulations limit theVOC content of paints in many local regions.

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V. Factors To Consider inSelecting and UsingEncapsulant Systems

When encapsulation is suitable and is thedesired control strategy, a user has a wide rangeof systems from which to select. In addition tothe requirements of Section IV, the decision toselect a specific type or system should take intoaccount several other factors, including thoserelated to the type of lead-based paint film andbase substrate, service conditions, cost,liveability, and health and safety issues.

A. Base Substrate

The base substrate can be wood, plaster, steel,cement, masonry, stucco, or some other mate-rial. Thus, the movement and possible deterio-ration of the substrate vary and should be con-sidered. For example, wood will expand andcontract with changing water content and per-haps check and crack as it ages. Wood rot couldalso occur if water leaks or other moisture prob-lems are ignored. Stucco may develop cracks asit ages or the building settles. An encapsulantmust be able to move with the base substratewithout cracking or otherwise deteriorating.

Walls with extensive cracks and gaps that can-not be bridged by nonreinforced coatings maybe good candidates for reinforced coatings orwall coverings. For situations in which non-reinforced coatings can be used, cracks must befilled with a caulking or sealing compound com-patible with the encapsulant and the substrateto which it is applied.

Corrosion of metal substrates must be con-trolled by a proper primer prior to the use of anencapsulant. Uncontrolled rusting will quicklylead to delamination of an encapsulant. Thus, acorrosion-control primer is an essential part ofan encapsulant system for metal.

B. Lead-Based Paint FilmProperties

An encapsulant must be compatible with theexisting lead-based paint film. Both chemicaland physical properties of the film are impor-tant. A compatible encapsulant must form a

strong bond with the lead-based paint film butnot degrade the existing paint layers. Epoxies,polyurethanes, and other coatings having strongsolvents are often incompatible with oil/alkydsand latex paint films.

Physical properties of old films also affect per-formance of coatings and adhesives applied overthem. Water-based products tend to bond lesssuccessfully to glossy, smooth, chalky, dirty, oroily paint film surfaces than do compatiblesolvent-based materials.

Field patch testing is the best procedure fordetermining compatibility with the existinglead-based paint surface and early performanceproperties of the encapsulant.

C. Application and InstallationConstraints

Application constraints include the skill re-quired for application, the method of applica-tion and acceptable range of environmentalconditions, and regulations for worker safetyand environmental protection.

1. Skill LevelDifferent levels of skill are required for applica-tion of the various classes of encapsulants. Gen-erally, liquid nonreinforced coatings require thelowest skill level. Coatings having two compo-nents (requiring rapid, efficient application), orthose incorporating a mat, require more experi-ence and skill. Use of adhesively bonded mate-rials, such as tile and flexible wall coverings,also require an intermediate skill level for appli-cation (HUD, 1990b). Overall, skills requiredfor encapsulation are lower than those for en-closure and replacement. Nevertheless, specificknowledge and skills are critical for success inthe application of any encapsulant.

2. Method and EnvironmentalConditionsDepending on the specific encapsulant, applica-tion of the coating or adhesive may be by brush,roller, spray, or trowel; however, in certain situa-tions, some of these methods may not be fea-sible. For example, if spraying is not practical;an encapsulant that can be applied by another

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technique will be required. The acceptable en-vironmental conditions vary depending on thetype of encapsulant. For instance, temperaturesabove 40 °F and below 95 °F and relative hu-midity less than 85 percent are generally re-quired for water-based coatings. Moisture-curepolyurethanes may require a minimum relativehumidity. A manufacturer’s technical specifica-tions should be consulted for specificrequirements.

3. RegulationsWorker safety requirements vary dependingupon the material being applied. Themanufacturer’s MSDS should be consulted forappropriate controls. The VOC content ofcoatings is regulated in many regions of thecountry. In addition, a national EPA VOC rulefor all architectural coatings is expected to be-come effective in 1996. Consequently both lo-cal and national rules may place VOC limits onencapsulants.

D. Environmental ServiceConditions

The conditions under which the encapsulantwill be used are important when selecting anencapsulant. For exterior exposures, consider-ation must be given to an encapsulant’s abilityto withstand varying weather conditions, in-cluding temperature changes, temperature ex-tremes, water, moisture vapor, air pollutants,and ultraviolet radiation. For example, someelastomeric products can become brittle whenexposed to cold temperatures and may shatteron impact. Other materials, such as epoxies,prematurely chalk and erode because of ultra-violet deterioration.

Since some exterior—and even some interior—environments may be quite wet, encapsulantsmust not fail due to moisture. The water vaporpermeability should be considered, along withthe permeability of the component to be encap-sulated. An encapsulant with a low water vaporpermeability may peel because of a moisturegradient across the component. For example, inclimates with cold winters, an impermeableencapsulant applied to exterior walls lackingan internal vapor barrier may blister and fail

because of interior moisture passing through thebuilding envelope.

E. Use Conditions

If a lead-based paint surface is subject to fre-quent abuse (e.g., abrasion, impact, and rub-bing), especially careful consideration must begiven to selecting an encapsulant product. Also,the tolerance for increased coating thicknessvaries depending upon the component type. Forexample, reinforced coatings or fiber-reinforcedwall coverings having high abrasion resistanceare potential candidates for walls subject to ex-tensive abrasion and impact wear, such as inentrance hallways. Coatings having excellentchemical resistance (e.g., some epoxies) can begood candidates for surfaces containing largeamounts of hand oil, such as handrails andsurfaces around doorknobs. When use factorsare not considered, premature failures are likely.For example, elastomerics, which typicallyhave poorer chemical resistances than two-component coatings, have been reported to failprematurely when used on handrails (Maryland,1993).

F. Encapsulant Service Life

Epoxy paints, cementitious encapsulants, floortile, and flexible adhesively bonded wall cover-ings have been used for other purposes and tendto have relatively long lifespans. Some coatingshave qualities that may make them more du-rable than ordinary residential paints, e.g., apolyurethane binder is usually more abrasion-resistant than an oil binder. Since someencapsulants have been in use for a few years,field data may be available for some products.Also, the manufacturer’s warranty or guaranteeis an important consideration in product selec-tion. When the product is used for lead-basedpaint encapsulation, conditions of the warrantymay require prework inspections, surface prepa-ration inspections, in-process inspections, and afinal inspection.

G. Safety Constraints andInformation

Each encapsulation product has an MSDSavailable from the manufacturer, which should

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be obtained, reviewed, and filed as part of therecordkeeping procedure. The MSDS providesinformation on hazardous ingredients (specificchemical identities and common names); physi-cal and chemical characteristics (boiling point,water solubility, melting point, evaporationrate, specific gravity, vapor pressure); fire andexplosion hazard data (flashpoint, extinguishingmedia and firefighting procedures, and any un-usual fire/explosion hazards); reactivity (stabil-ity and incompatibility, hazardous decomposi-tion, or products); health hazard data (routes ofentry, acute and chronic health hazards, carci-nogenicity, signs and symptoms of exposure,medical conditions generally aggravated byexposure, and emergency and first-aid proce-dures); precautions for safe handling (wastedisposal, handling, and storing); and use andcontrol measures (respiratory protection, eyeprotection, protective gloves, ventilation,and other protective measures and hygienepractices).

Some MSDSs do not disclose the presence oftoxic substances under trade secret provisions. Ifan MSDS does not show chemical ingredientsand claims no hazardous ingredients are present,but still indicates eye and skin protection orventilation is necessary, the MSDS may be defi-cient. Occupational Safety and Health Admin-istration regulations require employers to main-tain current MSDSs for all products containinghazardous chemicals that are used by employees.

Until there are national performance standards,it may be useful to have a toxicologist or indus-trial hygienist review the MSDS and/or consultany of the available toxicology database sys-tems, such as the Hazardous Substance Data-base, Integrated Risk Information System(EPA), and Registry of Toxic Effects of Chemi-cal Exposures National Insitute of OccupationalSafety and Health (NIOSH). Both worker andresident safety should be taken into consider-ation. For example, residents and pets may beexposed to VOCs during the drying or curingprocess.

H. Esthetics

To maintain an acceptable appearance, thefinished product should be capable of being

painted, or otherwise coated, and maintained.Consideration should also be given to the im-portance of having a finished surface that issmooth or rough (textured) or soft or hard. Forexample, encapsulants that are either soft orhave a rough finish are not appropriate forhandrails and floors and may make cleaning ofwall surfaces more difficult. Also, soft coatingshave a greater tendency to adhere to or be im-printed by objects placed on them than doharder coatings. The final thickness of theencapsulant also affects the appearance of theproduct. For example, the final thickness ofmany elastomeric encapsulants (10 to 20 mil) isabout 10 times greater than a single layer ofpaint and can conceal desired detail on woodtrim and moldings.

If the existing coating is not intact or smoothand requires substantial sanding and feathering,then a nonreinforced liquid encapsulant maynot be the appropriate product type. Non-reinforced liquid encapsulants are less likely tohide surface imperfections than reinforcedliquid coatings or adhesively bonded wallcoverings.

I. Repairability

Repairability refers to the ease of repairs and theappearance of the affected areas. It is importantto determine if repairs can be performed only byoutside contractors with special equipment orskills or if they can be done by typical mainte-nance workers. Generally, all encapsulants arerepairable, although some types may be moredifficult to repair than others.

J. Cost

Depending upon the type of substrate to betreated, the life-cycle costs of encapsulationmethods may be less than for enclosure methods(HUD, 1991). Life-cycle costs include both theinitial costs and reexamination and mainte-nance costs. Initial per-unit costs (material pluslabor) associated with the various encapsulantproducts vary. Since labor may be a major partof the cost, encapsulant systems requiring morethan one layer or step may be more expensivethan those completed in one operation. In addi-tion, the total time required for application and

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cure is a cost-related factor if occupants need tobe housed away from the worksite during thistime. The length of time needed for theencapsulant to remain effective should also beincluded in life-cycle cost considerations.

K. Technical Assistance

For large projects, a technical representativefrom the product supplier or manufacturershould be involved in the choice and inspectionof the surface preparation procedure and theapplication processes. It is important to clarifythe nature and extent of any support that is be-ing offered. If no technical support is offered,consideration might be given to other productswhere support is available. The manufacturer’sinvolvement in quality assurance activities isdesirable, and every effort should be made tocooperate with those involved.

VI. Specific EncapsulantProducts and SurfacePreparation Procedure

A. Encapsulant ProductSelection

Once a surface has been found suitable for en-capsulation and a decision has been made toencapsulate, a specific product or product typeis selected, together with appropriate surfacepreparation and application procedures. Theprocedure for selecting a specific encapsulantproduct is to (1) obtain information from themanufacturer’s literature, users’ experiences, andany other credible knowledge base on the prod-ucts’ ability to meet the general performancerequirements and the factors listed previously inthis chapter; (2) select a group of candidateencapsulant products and surface preparationsusing this information; and (3) conduct fieldpatch tests with the candidate products on thesurfaces to be encapsulated.

B. Surface Preparation

After an encapsulant product or type has beenselected, surface preparation procedures need tobe identified. All encapsulant manufacturers

provide surface preparation recommendationsfor their products. In some instances, manufac-turers provide more than one specific recom-mendation. Thus, it is essential to select one ormore suitable specific procedures prior to appli-cation of the encapsulant. Consideration shouldbe given to identifying and testing more thanone specific surface preparation procedure be-cause the same encapsulant may be successfullyused with one procedure and not another. Costand time savings may be significant for someencapsulants if more than one surfacepreparation is tested at the same time. The curetime, and thus the test time, may be long.

General surface preparation requirements,which are similar for all encapsulants, are pre-sented below. Materials used and debris gener-ated during surface preparation may be hazard-ous and must be treated appropriately.

1. CleaningEncapsulants should not be applied over dirt,rust, oil, grease, mildew, chalk, or other surfacecontaminants. Surfaces should be cleaned withnonsudsy degreasers, such as trisodium phos-phate or other appropriate materials. Additionalcleaning agents may be needed for mildew orchalk removal. Cleaning can be done by handwith a sponge or rag or with the aid of powerwashing equipment. In either case, it is essentialto rinse the surface thoroughly with water toremove cleaning residue. Job specifications mayrequire that specific standards be met for re-moval of surface contaminants, e.g., ASTM D4214 for chalk. In situations where chalk can-not be removed to an acceptable level, the useof a primer or stabilizer may be needed. If a spe-cial primer is used, it is essential that it is onerecommended by the encapsulant manufacturer.

2. DeglossingThe surface of some lead-based paint films issmooth and glossy. Deglossing to roughen thesurface is usually recommended by manufactur-ers to improve adhesion of the encapsulantcoating. Often, specific deglossing materials willbe recommended, since they must be compat-ible with the encapsulant. For some very hard,chemically resistant surfaces, deglossers may not

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work, and wet sanding may be needed. Sincethe choice of deglossing materials or methodsaffects encapsulant adhesion, separate patchtests using different deglossers or methodsshould be considered.

3. Removal of Loose PaintLoose paint should be removed by wet scraping.

4. Preparing Exposed Base SubstratesThese substrates can warrant different surfacepreparation requirements than lead-based paintsurfaces. For example, the surface of bare woodexposed to sunlight should be wet sanded toremove the degraded surface layer. Corrodedmetal should be cleaned using HEPA-assistedpower tools or HEPA-vacuum blasting to re-move surface rust and contaminants. Bare con-crete and masonry materials should be washedto remove loose dirt, degraded materials, orother surface contaminants.

C. Field Patch Tests

A patch test evaluates the encapsulant on asmall area of the painted surface prior to thestart of work. When more than one surfacepreparation is being tested, each surface prepa-ration procedure, plus the encapsulant, is aseparate patch test. An encapsulant/surfacepreparation system that fails a patch test is notsuitable for use in the large-scale job.

Surface preparation and encapsulation applica-tions and installations can be done by certifiedcontractors or knowledgeable workers. Afterthe encapsulant has cured according to themanufacturer’s recommendations, an inspectortechnician performs the evaluation. In at leastone State (Maryland), a public agency inspectortechnician determines where the patches shouldbe placed, based on the plan submitted by theowner or contractor, and inspects the patch test(Maryland, 1988). Since other States may havesimilar requirements (e.g., Massachusetts has aformal procedure for approving encapsulants), itis important to contact local or State agenciesbefore starting work.

1. Size of Patch TestsFor liquid-applied systems, the recommendedtest patch size is about 6 by 6 inches. For narrowsurfaces such as doorframes, a differently shapedpatch may be needed but should be about thesame area. Smaller 3- by 3-inch patches may beused for fiber-reinforced wall coverings, sincethey may be impossible to remove and can bethick enough to show through a completedsystem.

2. Location of PatchesAt least one test patch should be applied toeach type of component in each room or exte-rior location representing different types ofpaint where the encapsulant is to be used. Forexample, if the encapsulant is to be used onwalls in both the kitchen and the living room, apatch test should be done on one wall in eachroom. Although the rooms may appear to havethe same surface paint, past painting practicesmay have been different; therefore, both roomsshould be tested. The paint testing protocolcontained in Chapter 7 also is based on the ideathat paint history and type is unique for eachroom. If localized areas of a surface or compo-nent are suspected of having underlying adhe-sion problems due to moisture, then the patchtest should be done in one of these areas. Outerwalls are good areas to test since they may bemore likely to experience moisture. Similarly,load-bearing walls are good areas for patch test-ing because they are subject to stress. For thick,reinforced coatings or wall-covering systems,patches should be placed in an inconspicuousplace, if possible. If it is known that one type ofcomponent has the same paint history in sev-eral rooms, only one patch test is needed forthat component type.

3. Surface Preparation for PatchTestingThe area prepared for the patch test should beat least 2 inches larger in each direction thanthe area to be encapsulated for the test, unlessthe shape of the component makes this impos-sible. The surfaces should be inspected

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following preparation to ensure that the prepa-ration was carried out properly. The inspectionresults should be documented separately foreach patch.

4. Encapsulant Application andInstallationThe encapsulant(s) should be applied in accor-dance with the manufacturer’s recommenda-tions. The application method, wet film thick-ness (if appropriate), and environmentalconditions should be documented for eachpatch, since they should be the same when usedon the target surface. For encapsulants that can-not be cut with a knife, consideration should begiven to substituting the soundness test de-scribed below. After the encapsulant has cured,the patch is examined for adhesion and compat-ibility with the existing lead-based paint film.Since the cure times of encapsulants range fromless than 24 hours to a period of months for acomplete cure, it may not always be possible toperform patch tests on completely curedpatches. Nevertheless, the patch test is still auseful method of assessing the likelihood of suc-cess with a given product on a given surface.

5. Patch Preparation for Conducting aLead-Based Paint Soundness TestThe following procedure has been employed inpast projects to prepare a patch test for sound-ness or integrity of the lead-based paint film/base substrate system. A 3/8- by 3-inch bead ofconstruction adhesive is applied to the centralportion of the face of an 8-inch-square piece ofgypsum wallboard. The wallboard square ispressed onto a 6- by 6-inch patch. The curingtime recommended by the adhesive manufac-turer should be observed. Evaluation of results isdiscussed below.

6. Visual and Adhesive Evaluation ofField Patch TestsThe encapsulant coating should be visually ex-amined for signs of incompatibility with thepaint film. These signs include wrinkling, blis-tering, cracking, cratering, and bubbling of theencapsulant. Solvent-based encapsulants (e.g.,epoxies, polyurethanes) may react with the

underlying paint layer and cause bubbling,disbonding, or other lead-based paint film dete-rioration. Bubbling or disbonding may be de-tected by scraping the surface of the patch, us-ing sufficient pressure to break any visible andnonvisible surface bubbles. Surface imperfec-tions may indicate that the encapsulant is in-compatible with the existing coating. Bubblesmay also form in liquid-coating encapsulantsbecause of foaming during application, solvententrapment during cure, and other conditions.If it can be established that the bubbles are as-sociated with chemical reactions between theencapsulant and the underlying paint film, orthe extent of bubbling is unacceptable, thepatch test is a failure. If deeper probing reveals aweakened layer of paint, the patch test is also afailure. If it has failed a patch test, the encap-sulant should not be applied to the targetsurface.

No standard method has been defined for fieldtesting encapsulant adhesion. The “X”-cut ad-hesion method, used by the Maryland Depart-ment of the Environment for some encapsulantssince 1988, is described here as an interimmethod that appears to be effective. A patch-edge method is also suggested for encapsulantsthat cannot be cut with a knife. Procedures forevaluating the soundness test are also providedin this section. The ASTM or another group oragency may provide additional technical stan-dards or guidelines in the future. While theASTM has two standard field methods for mea-suring adhesion of coatings—a tape test usingpressure-sensitive tape (ASTM D 3359) and aportable adhesion tester (ASTM D 4541), theyhave not been technically defined or used forfield patch testing of lead-based paintencapsulants.

“X”-Cut Adhesion Method. For the “X”-cutmethod, the inspector technician should take asharp cutting tool (e.g., a knife, razor blade, orscapel) in good condition and a hard metal ruler(as a cutting guide) and inscribe an “X” in thecenter of the patch after the encapsulant systemhas cured according to the manufacturer’s rec-ommendations. Each cut line should be 1 1/2to 2 inches long and should be made throughthe coating, the paint, and the patch all the

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way down to the substrate. A flashlight may benecessary to determine the depth of the cut. Ifthe cut does not go through the patch to thebase substrate, a second “X” cut should be madein a different location. The first cut should notbe deepened.

To evaluate the adhesion and integrity of thepaint film, the inspector technician should usethe point of the cutting tool to attempt to peelor lift the patch from the existing topcoat. Thepoint of the tool should be placed below theencapsulant layer at the intersection of the twocut lines. If the inspector technician can lift,peel, or tear a large (more than␣1/2␣inch- or1/2 inch-square) portion or section of the patchaway from the existing topcoat to which it wasapplied, then the encapsulant fails the patchtest. The inspector technician should expectthat a small piece of the patch will separatefrom the base substrate (up to 1/4 to 1/2 inch).This does not indicate failure of the patch test.Figure 13.1 shows one example of patch testfailure.

Patch-Edge Method. For the patch-edgemethod, the inspector technician should makea cut adjacent to the edge of the patch throughto the base substrate. If the thickness of theencapsulant does not change abruptly, butgradually decreases at the edge of the patch, thecut should be made through as thick a layer ofthe encapsulant as possible to the base sub-strate. The point of the knife should be placedunder the encapsulant at the cut, attempting topeel or lift the patch from the lead-based painttopcoat or locate other delaminated layerswithin the lead-based paint film. If a largeportion of the encapsulant can be lifted easily,then the patch test fails.

Soundness Method. For the soundness method,the inspector technician should attempt to pullthe wallboard square away from the painted sur-face. If the paper backing of the wallboard re-mains on the adhesive of the painted surface ofthe patch, the test is a success. The patch testfails if the adhesive is removed from the surfaceof lead-based paint or if the paint film splits.Failure at the adhesive/wallboard interface canperhaps be overcome by the use of a different

surface preparation procedure, as discussedbelow for the encapsulant patch test.

If failure occurs in any of these procedures, it isimportant to carefully examine the back of thedelaminated portion of the patch in order todetermine if the failure occurred at theencapsulant/paint film interface or in an under-lying layer of paint. As discussed below, encap-sulation may still be suitable—with a differentsystem or surface preparation—when the failureis interfacial but not when the failure is withinthe old paint film. It may be difficult to deter-mine the locus of failure if the paint layers andthe encapsulant coating are similar colors.

If a failure occurs, one of the following coursesof action must be taken, depending on thecause of failure:

The adhesion between two underlying layersof paint failed, causing delamination. Checkfor this condition by examining the back of thedelaminated portion of the patch for signs ofpaint. This result indicates a layer of paint thatbonded poorly and does not have sufficient ad-hesion. Poor bonding between underlying layersmay be due to inadequate deglossing, poor-

Figure 13.1 Encapsulant Failure.

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quality paint, or incompatible coatings. Theseconditions are usually not correctable. Sincemultiple patch tests are recommended, com-plete all patch tests before deciding upon a planof action. The encapsulant should not be usedon a surface or component that has failed patchtests.

The adhesion between the paint and the basesubstrate failed. Check for this by looking forsigns of bare substrate and paint adhering to theback of the delaminated portion of the patch.Failure may be due to a painting history thathas included so many layers of paint that theweight of the paint plus the encapsulant hasbegun to weaken the bond between the paintand the substrate. Moisture can also cause thistype of failure. This is usually not correctable,and the encapsulant should not be used.

The adhesion between the encapsulant coatingand the top layer failed. Check for this by ex-amining the back of the delaminated portion ofthe patch for lack of paint. Failure may be dueto:

✦ Application of the encapsulant to a glossysurface without adequate deglossing. It maybe possible to degloss the surface using a dif-ferent technique and apply a second patchtest to a different area on the same compo-nent. Wet sanding is permitted to deglossbut not dry sanding.

✦ Inadequate curing time or improper curingconditions. Manufacturer’s recommenda-tions for curing and application conditionsshould be consulted.

✦ Application of the encapsulant to a dirty orgreasy surface. The surface must be re-cleaned, and possibly deglossed before a sec-ond patch test is tried.

✦ Application of material to excessive thick-ness. This can cause failure due to internalstresses that cause the coating to pull awayfrom the substrate. The applicator should betrained according to the manufacturer’s in-structions and a wet film or dry film thick-ness gauge (sometimes referred to as a “mil”gauge) should be used during application.

Evaluation of Adhesively Bonded FlexibleSurface Covering Tests. A successful patch isone that cannot be easily removed. If the patchcannot be removed, the covering will have tobe installed over the patch. In such a case, asmaller patch in an inconspicuous place willminimize the irregularity in the appearance ofthe finished product.

7. Documentation of PatchTest ResultsPatch testing may involve multiple patches onmultiple surfaces. Therefore, documentation isvery important to be sure that the correctencapsulant systems (including surface prepara-tion) are applied to the target surfaces. If mul-tiple patch tests are performed in a dwelling, itis recommended that a schematic drawing beused to indicate the locations of the patches.Form 13.1 can be completed for this purpose.

VII. Application andInstallation of the Encap-sulation Systems

Upon successful completion of a patch test, theencapsulant system can be applied or installedto the targeted surface. The steps for a properapplication of an encapsulant system are sum-marized in Table␣13.2.

A. Surface Preparation for Job

The surface preparation must be the same onethat was used in the successful patch test andshould be conducted with the same thorough-ness and level of effort. The process of repairingcomponents and preparing surfaces for the ap-plication and installation of encapsulants cangenerate leaded dust and debris, so precautionsmust be taken. The type of precautions neededwill depend upon the methods used. The appro-priate Worksite Preparation Level should beselected from Chapter 8.

Repair of defective surfaces or components mayalso be necessary. The encapsulant manufac-turer should be asked to provide recommenda-tions for caulk and other filling compoundsthat are compatible with the encapsulant. To

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minimize future crack formation in theencapsulant, these materials should match theexpansion characteristics of the encapsulantand be compatible with the existing coatings.

For large jobs, it is advisable to have anencapsulant manufacturer’s representativeonsite to provide additional information on re-pair and surface preparation. When the repairwork and the surface preparation have beencompleted, the surface should be inspectedprior to application and installation of theencapsulant. Once the encapsulant is applied, itbecomes impossible to fix a poor surface prepa-ration or, in the case of a failure, to confirm thatsurface preparation was done properly.

B. Installation and Applicationof Encapsulant System

1. Nonreinforced and ReinforcedCoatingsThe application procedures and requirementsdepend upon the specific product type. Thesame application method should be used for thetargeted surface that was used in the patch test.

Several safety considerations are important inapplication: the applicator must have the ap-propriate MSDS documentation; personal pro-tective equipment may be needed and must bein compliance with NIOSH or OSHA regula-tions; and areas need to be properly ventilated.

Masking procedures should be carried out, asneeded. Surfaces to receive masking tape orother masking materials should be clean andfree from dirt, dust, grease, and oil to ensuregood contact. Loose edges of masking materialsshould be secured to avoid “flyaway,” if sprayapplication is being used. The time betweencoating application and masking materialremoval may depend upon the specificencapsulant being used.

The required environmental conditions for ap-plication depend upon the specific encapsulantbeing used. The manufacturer’s specificationsshould be followed. As noted previously, water-based systems generally should not be applied tosubstrates when temperatures are below 40 °F orabove 95 °F and the relative humidity is above

85 percent. For all encapsulants, applicationshould be done only when the surface is dry andthe temperature of the target surface is abovethe dewpoint.

Additional mixing and/or thinning of liquidencapsulants may be needed and should bedone in accordance with the manufacturer’s di-rections. Excessive thinning can cause prema-ture failure. For two-component coatings, it isessential that the proper ratio of materials bemixed according to the manufacturer’sdirections. Not all two-component products areto be mixed together in the same ratio. Two-component materials will have a limited “potlife.” That is, once the two components aremixed, a chemical reaction begins that can beslowed, but not stopped, by cooling. This meansthat the user has a limited period of time, i.e.,pot life, in which to apply the product and toclean tools. Two-component coatings may alsohave an “induction time” requirement. This is aperiod required after mixing but before applica-tion to allow time for initiation of the reactionbetween the two components.

Encapsulants should be applied according to themanufacturer’s recommended thicknesses. Wetfilm thickness gauges (sometimes called milgauges) should be used to ensure proper filmthickness. An encapsulant layer that is eithertoo thick or too thin can cause prematurefailure.

Reinforced liquid encapsulants can require theuse of a fabric. The manufacturer’s recommen-dations for application of the fabric and proce-dures for seaming should be followed.

For liquid coatings, cure times vary from prod-uct to product and can depend upon atmo-spheric conditions. Thick elastomeric coatingsmay take only a few hours to be dry to thetouch, but it may take several weeks for theirmechanical properties to reach optimum values.The time for two-component coatings to curedepends upon temperature but is generallyabout a day.

2. Adhesively Bonded CoveringsAdhesively bonded wall coverings are installedin a manner similar to that used for vinyl wall

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coverings (NBS, 1973). No special tools arerequired. The typical three-step procedure is toapply adhesive with a roller; align and trowelthe covering over the adhesive; and apply thetopcoat, if needed. There are two options forcoloring. The adhesive can be tinted the samecolor as the topcoat, which ensures two coatingswith color, or two topcoats with color can beapplied over untinted adhesive.

Some product manufacturers do not supply spe-cific adhesive and topcoat products but onlyprovide recommendations for choosing these

products. Generally, there are two types of ad-hesives—“permanent” clay-based adhesives andwater-based, heavy-duty, but strippable adhe-sives. Since the permanent clay-based adhesiveis more durable, it is preferred for lead-basedpaint encapsulation. However, removal of a wallsystem is difficult, if not impossible, when thepermanent adhesive is used. Water-based adhe-sives are more easily removed than permanentadhesives but may blister and fail when theycome in contact with moisture.

Form 13.1Encapsulant Patch Test Documentation

Name of Person Performing Patch Test ____________________________________

License or Certificate Number (If Applicable) ________________________________

Complete Address of Dwelling ____________________________________________

Date Patch Test Applied __________________ Curing Time ____________________

Date of Patch Test Evaluation ____________________

Temperature During Application and Curing _________

Humidity During Application and Curing ____________

Room Surface Substrate Type of Surface Name and Obser- Pass/Location Patch Test Preparation Formula- vations Fail

(X-cut or tion ofAdhesive Encapsulant

Wallboard)

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Table 13.3 Steps for Obtaining Proper Application and Installation of an Encapsulant System

Step Description

Complete patch test and other prejob procedures.

Adhesively bonded floor tile should be installedaccording to the manufacturer’s directions. Ifnew subflooring is installed, then the tile/subfloor system constitutes an enclosure. If ad-hesion alone is used, the tiles constitute anencapsulant.

C. Inspection of EncapsulantSystems

Proper application and installation ofencapsulant systems requires that the surfacepreparation and application procedures are car-ried out according to the manufacturer’s recom-mendations and in accordance with the jobspecifications, if any. Monitoring of surfacepreparation and application is essential, inaddition to conducting the final clearanceexamination.

1. ToolsTools that may be required are a dark cloth tocheck for chalk removal, copies of referenced

surface preparation standards, wet film and dryfilm thickness gauges, a moisture meter, surfaceand air thermometers, a relative-humiditymeter, pressure gauges, a timepiece, and an illu-minated viewing device. A logbook should beused to record all inspection data.

2. ProceduresSurface preparation and application inspectioncheckpoints and procedures are listed below:

✦ Prior to start of job—check equipment andencapsulant material.

✦ After preliminary cleanup and readying ofthe area prior to surface preparation—checkfor containment, protection of belongingsand property, and completion of surface re-pairs, such as caulking.

✦ After surface preparation—ensure that thesurface has been prepared in accordancewith the specification and in the same man-ner as used in the patch test.

Prepare complete job specifications. Describe all work to be done. Include alljob requirements (e.g., quality of surface preparation, dry film thickness).Reference standard procedures or equipment to the extent possible to avoidmisunderstandings.

Establish common understanding of amount and quality of work to be doneamong owner/specifier, contractor, and inspector technician. For example, allparties should agree on the extent of surface preparation. Document anychanges in writing to avoid future disputes. The contractor should be preparedto provide work (scheduling) plans, worker safety plans, lists of materials andthe amounts to be used, material manufacturer’s written technical data sheets,application instructions, MSDS, test reports, and other information required inthe job specification.

Inspect coating operations. This is essential in obtaining a durableencapsulant system. All inspection data should be recorded by the inspectortechnician in a daily logbook. Suggested “inspection checkpoints” are de-scribed in Section C.2.

Conduct final clearance testing as described in Chapter 15.

Develop jobspecification.

Hold prejob conference.

Conduct inspection.

Perform final clearanceinspection.

Identify hazard.

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✦ For liquid encapsulants, just prior to mate-rial application—observe mixing andthinning, if any, for compliance withmanufacturer’s written instructions. Ensurethat mixing ratio of two-component coat-ings is correct.

✦ During application of encapsulant—checkenvironmental conditions (temperature,relative humidity, etc.). For liquid coatings,check wet film thickness, color of material(different colors should be required for dif-ferent coats), and cure of previous coat be-fore application of next coat for compliancewith manufacturer’s written instructions.

✦ After job completion—check dry filmthickness and cure of liquid-applied coatingsand appearance for all encapsulants.

VIII. Periodic Monitoringand Reevaluation

Because of the limited experience with the useof encapsulant systems and because of their de-pendence upon the integrity of a lead-basedpaint film, the property owner or manager mustarrange for regular monitoring and repairs, asneeded. Visual monitoring should be performed1 month and 6 months after application and atthe schedule specified in Chapter 6. If signs ofwear or deterioration are apparent during anyreevaluation examination, the monitoringshould be increased to a quarterly basis for thenext 6 months, then annually thereafter. In ad-dition, residents should be instructed to notifymanagement of the need for repairs on a timelybasis. In some cities and States, regulatory reex-aminations may be required, including samplingof settled dust for lead analysis. For example,the Maryland Department of the Environmenthas the authority to inspect dwellings for a pe-riod of 1 year following application of anencapsulant. This is because encapsulants areapproved on a case-by-case basis, and the re-evaluation provides a means of documentingtheir performance (Maryland, 1988).

IX. Recordkeeping

The owner and contractor should both main-tain documentation of interim control or abate-ment measures. Since the lead is not removed,appropriate protective measures must be takenif the encapsulant fails or if the building is reno-vated or demolished. Although it would be pos-sible to label existing lead-based painted sur-faces prior to encapsulation, the warning wouldlikely be hidden, since it would be covered bythe encapsulant. A chemical reaction betweenthe marking substance and the encapsulantcould cause the encapsulant to fail. Therefore,drawings showing locations of lead-based paintshould be mounted on a wall of a basement,storage closet, or utility room. Records of boththe initial installation and reexaminationsshould be provided to a new owner at the timeof property transfer.

The following information describing the initialapplication should be included with the draw-ings kept in the building:

✦ Type of encapsulant and product name.

✦ Exact location of encapsulant.

✦ Product label and/or copy of manufacturer’stechnical product information.

✦ MSDS for all products used.

✦ Contractor name.

✦ Date of application.

The visual monitoring document should be keptby the owner or local agency. Each documentshould include the name of the person perform-ing the periodic visual monitoring, the date ofthe visual monitoring, the condition of coatingand signs of wear or deterioration, and results ofany leaded dust tests performed. If failure wasobserved or encapsulant had been repaired, thereasons for failure (if known), corrective actionsrecommended or taken to repair failures, andany other information pertinent to the mainte-nance of the encapsulant should be included.Form 13.2 may be used for this purpose.

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Form 13.2Lead-Based Paint Encapsulation Visual Monitoring Form

Name of Person Performing Visual Monitoring _________________________________

License or Certificate Number (If Applicable) __________________________________

Complete Address of Dwelling _____________________________________________

Date Encapsulant was Applied __________________

Date of Last Evaluation ________________________

Today’s Date ________________________________

Room Surface Substrate Name and/or Observations Pass/FailLocation Formulation of

Encapsulation

Signature ______________________________________________________

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