CHAPTER 15: CLEARANCE - HUD.gov / U.S. Department of ... · Interpret results by comparing them to the HUD Interim Clearance Standards ... keep turbulence and re-entrainment of particu-late

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Chapter 15: Clearance

CHAPTER 15: CLEARANCE

Step-by-Step Summary ............................................................................................ 15–3

I. Introduction ......................................................................................................... 15–5

A. Purpose of Clearance ........................................................................................ 15–5

B. Clearance as the Endpoint ................................................................................ 15–5

C. Conflicts of Interest .......................................................................................... 15–5

II. Time Between Completion of Cleanup and Clearance ...................... 15–6

III. Visual Examination Procedures ................................................................... 15–6

A. Determination of Completed Work ................................................................. 15–6

1. Paint Removal and Repainting .................................................................... 15–7

2. Building Component Removal and Replacement........................................ 15–8

3. Enclosures ..................................................................................................... 15–8

4. Soil Treatments ............................................................................................. 15–8

5. Encapsulants ................................................................................................. 15–8

6. Interim Controls ........................................................................................... 15–8

B. Visual Examination for Settled Dust and Debris ............................................ 15–8

IV. Clearance Dust Sampling ............................................................................... 15–9

A. Multifamily Housing (20 or More Units) ..................................................... 15–10

B. Single-Family Housing and Multifamily Housing(Fewer Than 20 Units) .................................................................................. 15–11

C. Clearance Dust Sampling and Floor Sealant Application ............................. 15–11

D. Location and Number of Clearance Dust Samples ....................................... 15–11

1. Single-Surface Sampling ............................................................................. 15–11

2. Composite Clearance Dust Sampling ......................................................... 15–13

V. Clearance Soil Sampling ............................................................................... 15–15

A. Multifamily Housing (20 or More Units) ..................................................... 15–15

B. Single-Family Housing .................................................................................... 15–16

C. Number and Location of Clearance Soil Samples at Each Building ............ 15–16

VI. Clearance Paint Testing ................................................................................ 15–16

VII. Interpretation of Clearance Testing Results ...................................... 15–16

A. Visual Examination Results ............................................................................ 15–16

B. Dust Results .................................................................................................... 15–17

C. Soil Results ...................................................................................................... 15–18

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VIII. Recordkeeping and Issuance of Statementof Lead-Based Paint Compliance ........................................................... 15–18

A. Recordkeeping Responsibilities ................................................................... 15–18

B. Record Content ............................................................................................ 15–18

C. Length of Time ............................................................................................. 15–19

IX. Clearance and Reevaluation Procedures ............................................... 15–19

Form 15.1 Lead Hazard Control Visual Clearance Form ....................................... 15–20

Form 15.2 Lead Hazard Control Clearance Dust Sampling Form(Single-Surface Sampling) ...................................................................................... 15–21

Form 15.2a Lead Hazard Control Clearance Dust Sampling Form(Composite Sampling) ............................................................................................ 15–22

Form 15.3 Lead Hazard Control Clearance Soil Sampling Form(Composite Sampling Only) .................................................................................. 15–23

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Clearance: How To Do It

Step-by-Step Summary

1. Decide who will conduct clearance. Clearance on all abatement projects and federally funded interim con-trol work must be done by a certified risk assessor or inspector technician. The U.S. Department of Housingand Urban Development (HUD) strongly recommends the use of a certified risk assessor or inspector techni-cian who is completely independent of the lead hazard control contractor to eliminate conflicts of interest.Some local jurisdictions may require a license to conduct clearance.

2. Finish the lead hazard control and cleanup effort. Seal floors before clearance testing (if necessary).

3. Wait 1 hour to allow any airborne dust to settle. Do not enter the work area during that hour.

4. Conduct visual examination.

a. Determine if all required work has been completed and all lead-based paint hazards have beencontrolled.

b. Determine if there is visible settled dust, paint chips, or debris in the interior or around the exterior.

5. Complete the Visual Clearance Form contained in this chapter; if all specified work was not completed,inform the owner and order completion of work and repeated cleanup, if necessary.

6. Conduct clearance dust sampling of floors, interior window sills, and window troughs using the protocolin this chapter.

7. Conduct clearance soil sampling if bare soil is present that was not sampled previously, or if exterior paintwork was completed as part of the lead hazard control effort. Whenever exterior work has been done, it maybe necessary to take samples from soil that is not bare to determine if contamination has occurred. If resultsare above 2,000 µg/g (or 400 µg/g in high contact play areas), compare the results to baseline soil samplingresults to determine what additional measures are needed.

8. Complete the Dust and Soil Sampling Clearance Form contained in this chapter.

9. Submit samples to a U.S. Environmental Protection Agency (EPA) recognized laboratory participating inthe National Lead Laboratory Accreditation Program (NLLAP) for analysis.

10. Interpret results by comparing them to the HUD Interim Clearance Standards contained in this chapter(until EPA issues its health-based leaded dust standards).

11. If clearance is achieved, go to step 15.

12. Order repeated cleaning or soil treatments if results are above applicable standards. Clean all surfaces thesample represents.

13. Continue sampling and repeated cleaning until the dwelling achieves compliance with all clearancestandards.

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14. Complete any related construction work that does not disturb a surface with lead-based paint (all workthat does disturb painted surfaces or that could generate leaded dust should be completed as part of the leadhazard control effort).

15. Issue any necessary statements of lead-based paint compliance or releases and maintain appropriate records.

16. Permit residents into the cleared work area.

Step-by-Step Summary (continued)

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Chapter 15: ClearanceI. Introduction

A. Purpose of Clearance

Clearance refers to the various environmentalevaluation procedures used to determine if:

✦ The lead hazard control work was actuallycompleted as specified.

✦ The area is safe for unprotected workers toenter.

✦ The area is a safe place for residents andyoung children to live.

Since most lead hazard control work generates aconsiderable amount of leaded dust, and sinceprevious studies have indicated that cleaningcan be accomplished only with great care andskill (HUD, 1991), it is necessary to determineif the cleaning was successful. Some type ofclearance is required for all forms of lead hazardcontrol. Certified risk assessors or certified in-spector technicians (clearance examiners) canbest recommend the exact type of clearancetesting to be employed on a specific project.The process outlined in this chapter provides ameans of determining if lead hazards have beencontrolled.

B. Clearance as the Endpoint

If clearance criteria are met, the contractor whoperformed the work can conclude that the job iscomplete. However, if the clearance criteria arenot met, the contractor must complete the workand/or repeat the cleaning process until the areais clean enough to meet clearance criteria. Forexample, if the job included the removal andreplacement of all windows, but the clearanceexaminer determines that one window has beenoverlooked, the contractor must remove andreplace it as originally specified (in addition tocarrying out any necessary additional cleaningin that area). Similarly, if excessive leaded dustlevels remain, the contractor’s job cannot beconsidered complete until leaded dust levels

are below clearance standards. Normally, thefinal payment to the contractor is withhelduntil compliance with clearance standards isachieved.

The clearance examination described in thischapter is similar to the punchlist that follows atypical construction or repair job. The majordifference is that the normal visual check is al-most always augmented with environmentaltesting since leaded dust and soil hazards are notvisible to the naked eye.

The clearance examination protects all partiesinvolved—the job contractor, the owner, andthe resident. The process provides the contrac-tor with an objective determination that thejob was completed safely. The owner will haveassurance that the abatement job was successfulin correcting hazards and that the amount ofleaded dust left after the work was completed isat a safe level. The resident can be certain thatdangerous shortcuts were not taken during thework process and that resident children will besafe.

C. Conflicts of Interest

The owner should retain the services of a certi-fied risk assessor or a certified inspector techni-cian to determine compliance with clearancecriteria. The clearance examiner must not bepaid or employed, or otherwise compensated bythe lead hazard control contractor and shouldhave no vested interest in seeing that the job iscompleted on schedule. The clearance exam-iner’s only concern should be that compliancewith clearance standards has been achieved.

This does not mean that job supervisors shouldnot perform their own visual assessments of thequality of the cleanup job performed by theirworkers. Such assessments will help ensure thatclearance criteria are met the first time around.

Some owners of multiple dwelling units maywish to have lead hazard control work per-formed by their own trained crews, rather than

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contract for such services. In this case it isessential that clearance testing be performed byan independent third party whose payment isnot dependent on completion of the job withinany particular time period.

The clearance procedures contained in thischapter should always be included in the jobspecifications so that performance responsibili-ties are clear.

II. Time BetweenCompletion of Cleanupand Clearance

Clearance dust sampling should be performedno sooner than 1 hour after completion of thefinal cleanup to permit airborne leaded dust tosettle. Clearance dust sampling is for settledleaded dust, not airborne leaded dust, since themain source of lead exposure for children isthrough contact with contaminated surfacesfollowed by ingestion. Most children in theUnited States. are not lead poisoned by inhala-tion (ATSDR, 1988). Airborne leaded dustsampling is not recommended for clearancepurposes in lead hazard control work.

While often performed for asbestos abatementprojects, air sampling does not appear to be auseful tool for determining if clearance has beenachieved in lead hazard control work. Becauseasbestos fibers are known to have low settlingvelocities (that is, they take a long time to set-tle out of the air), air sampling can be used todetermine the effectiveness of the cleanup effortin asbestos abatement jobs. But because dustparticles typically generated during lead abate-ment jobs are larger, denser, more spherical,and heavier, settling time is much faster.

The U.S. Department of Housing and UrbanDevelopment’s (HUD’s) Interim Guidelines forHazard Identification and Abatement in Public andIndian Housing recommended 24 hours as theminimum waiting period to allow airborne lead-contaminated particles to settle, although nojustification for the 24-hour waiting period wasprovided (HUD, 1990a). The reduction in thewaiting period before sampling from 24 hours

to 1 hour marks an important change in thenew recommendations. The current Guidelinesrecommend 1 hour because the additionalamount of leaded dust that would settle ontofloors after 1 hour is negligible. The analysissupporting this finding is summarized below.(A full description of the analysis can be foundin Appendix 11.)

Analysis of the settling velocity of airborneleaded particulate has demonstrated that nearlyall particulate greater than 5 µm in diameterwill have settled out of the air within an hour.It is estimated that any remaining airborne par-ticulate less than 5 µm would contribute nomore than an additional 5 µg/ft2 of lead to sur-face dust, even if all of it were to settle out ofthe air. This is well below the HUD InterimClearance Standard for floors (100 µg/ft2) andalso well below the routine limit of quantitationfor wipe sampling (25 µg/ft2). Therefore, a re-duction in the waiting period to 1 hour is justi-fied. This change will contribute to significantcost savings by cutting 1 day off the length ofthe abatement job (reducing relocation costsand job delays). Entry into the area should beprohibited during the 1-hour waiting period tokeep turbulence and re-entrainment of particu-late matter to a minimum.

III. Visual ExaminationProcedures

Clearance occurs in two main phases: visualexamination and environmental sampling(dust and, if exterior work was conducted, soilsampling). A standard Visual Clearance Formcan be found at the end of this chapter (seeForm 15.1).

A. Determination ofCompleted Work

A visual examination determines whether thework on all interior and exterior surfaces to betreated was in fact completed and to ensure thatno visible settled leaded dust or debris are pre-sent. Visual clearance is a relatively straightfor-ward process requiring an understanding of thescope of the job and a keen eye for detail. It is

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essential that clearance examiners have fullknowledge of the extent of the work and spe-cifically which surfaces did not require treat-ment. The clearance examiner should have ac-cess to any risk assessment or paint inspectionreport as well as the job scope of work or specifi-cations and a report from the owner or contrac-tor that the work has been completed.

The visual examination of completed workshould be done on a room-by-room basis to en-sure that all areas are examined (this includesthe exterior and common areas). In most casesthe visual examination will be conducted by aclearance examiner when the environmentalsamples are collected.

When paint removal and repainting or soil re-moval and covering is planned, verification ofthe removal of the lead hazards will be neces-sary prior to the completion of work. In theseinstances the owner or a representative of theowner (which may be the hazard control con-tractor) may take responsibility for confirmingthat the hazard is removed prior to repaintingor covering. This allows the owner to avoidthe expense of having the clearance examinertravel to the job site twice—once to verify thehazard removal and again to collect environ-mental samples. On the other hand, ownersmay choose to have the clearance examinerconfirm that the work was actually completed.Regardless of who verifies the hazard removal,verification should be documented onForm 15.1.

In multifamily housing of similar construction,it is not necessary to perform a visual examina-tion of every single unit. Instead, a randomsample of abated units can be visually examinedbefore the paint is applied. The abatement con-tractor should not know ahead of time whichunits will be visually inspected prior to repaint-ing. The random sample size can be determinedby using the table for lead-based paint inspec-tions (Table 7.3). Random sampling of single-family dwellings is not possible due to the largevariability in construction and work. Therefore,each single-family dwelling should be clearedindividually.

In the case of a child with an elevated bloodlead level, local authorities may require that thetreatment of all indicated surfaces be verified bya government employee or certified third party,especially in cases where the abatement hasbeen ordered by local authorities. Clearanceexaminers should determine if the propertythey are investigating has been abated as a re-sult of a legal or regulatory proceeding. If so, theenforcement agency should be contacted to co-ordinate clearance procedures, prevent duplica-tion of effort and, most importantly, ensure thatthe private clearance process is not inadvert-ently overstepping the bounds of the normalpractices of the local health department orchildhood lead-poisoning prevention program.

1. Paint Removal and RepaintingAll surfaces where paint has been removedshould be visually examined prior to repainting.If clearance is conducted after new paint is ap-plied, it is often impossible to determine if theold paint was actually removed. Areas com-monly overlooked during paint removal projectsinclude the underside of interior window sillsand handrails, backside of radiator ribs, bottomedge of doors, top of doorframes, and the backedge of shelving.

For both onsite and offsite removal, the clear-ance examiner or the owner should examinethe bare surfaces to ensure that there is no vis-ible residue. If residue remains, the componentshould be cleaned prior to repainting orrefinishing.

Wipe sampling and x-ray fluorescence (XRF)testing are not appropriate tools for determiningthe effectiveness of paint removal from a par-ticular surface. Wipe sampling cannot dislodgeany leaded dust that may have been absorbedinto the substrate during the removal process,nor can it remove paint that is still bonded tothe substrate. Wipe sampling is appropriate formeasurement of settled leaded dust on floors,interior window sills, and window troughs. It isnot appropriate to apply the settled leaded dustclearance standard to these components sincethe bare surface will be sealed with new paint,

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thus rendering the dust inaccessible. Appendix1 describes how much lead-contaminated dustcan remain on a surface (at least 35,000 µg/ft2)before it would cause the newly applied paintto become lead-based paint (at 0.5 percent).

2. Building Component Removaland ReplacementIf building components coated with lead-basedpaint were removed as a lead hazard controlmeasure, the clearance examiner should havedetailed knowledge of the scope of the replace-ment activities so that actual removal can beverified. Each building component specified forreplacement should also be examined to deter-mine if it was overlooked during the lead hazardcontrol work.

3. EnclosuresComplete installation of enclosure systems,such as new drywall, paneling, or siding, can bebest evaluated by direct visual observation. Theclearance examiner should determine that themechanical fastening system used to hold theenclosure to the substrate is adequate. This isespecially important for ceilings. All seams andedges in the enclosure should be sealed to pro-vide a “dust-tight,” but not necessarily airtight,system.

4. Soil TreatmentsSoil treatments, which typically consist of someform of covering or removal and/or replace-ment, can be assessed by direct visual observa-tion to determine if the covering is present. Forexample, if sod or asphalt has been used as a soilcovering, the clearance examiner should deter-mine if all bare areas have been covered by thesod or asphalt, as specified.

No visible lead-based paint chips should beobserved in soil following lead hazard controlwork. It is not necessary to turn over or rake soilto look for paint chips. A visual examination ofthe surface is adequate.

If exterior work on lead-based paint has beenperformed, baseline soil samples should havebeen collected but not necessarily analyzed un-til clearance soil samples have been collected,

analyzed, and compared to clearance standards.It may be necessary to collect samples from soilthat is not bare to determine if contaminationhas occurred. If post-hazard control soil levelsare below applicable limits, the preabatementsamples need not be analyzed. The clearancelevel for most soil is 2,000 µg/g (400 µg/g forsmall, high-contact play areas). If post-hazardcontrol soil levels are greater than or equalto the applicable limits, the baseline samplesshould be analyzed to determine where addi-tional work is needed. If paint chips originatingfrom the work are identified in the soil, theyshould be picked up with a high-efficiencyparticulate air (HEPA) vacuum.

5. EncapsulantsAnother category of lead hazard control thatcan best be assessed visually is the applicationof encapsulants. Assuming that the encapsulantwas properly selected for the surface undergoingtreatment and that patch tests were conductedas recommended in Chapter 13, the clearanceexaminer can determine if the encapsulant isin fact present.

6. Interim ControlsVisual examination of the wide variety of in-terim control measures consists of a confirma-tion that all lead-based paint (either suspectedor identified through testing) is stabilized andthat any friction, impact, and other surfacesmarked for treatment in the risk assessmentreport or project specifications have all beenproperly treated. No known or suspected lead-based paint should be in a deteriorated condi-tion in a cleared dwelling.

B. Visual Examination forSettled Dust and Debris

There should be no evidence of settled dust fol-lowing a cleanup effort. If dust is observed, thecontractor must be required to repeat the clean-ing effort before clearance dust samples are col-lected to avoid conducting dust sampling twice.Any settled dust present following abatementor interim control work provides sufficientevidence that cleanup was not adequate (seeFigure 15.1).

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Figure 15.1 Visible Dust Indicates Cleaning ShouldBe Repeated.

Lead Tracking

Lead dust can be transported from one area toanother on shoes.

Tracking lead dust from one area to another is a bigproblem on lead hazard control jobs. Lead dust canbe tracked on shoes from the work area to the out-side. Sometimes lead dust from the outside soil istracked into the work area. Lead dust from a porchor nonwork area can get tracked into a cleaned area.When this happens, the whole area must be cleaned.

There are conflicting reports regarding the useof the so-called “white glove test” as part ofthe visual examination. Some housing agencieshave indicated that they find this to be a usefulpreliminary examination tool, while othersindicate that this test almost always showssome discoloration, even if surfaces have beencleaned well. Until it has been demonstrated toeffectively predict leaded dust levels, use of the“white glove test” is left to the discretion of theexaminer and is not recommended by HUD.The “white glove test” is not a substitute forlaboratory analysis of dust samples.

Finally, the grounds around the dwelling shouldalso be examined visually to make certain thatall waste and debris have been removed andthat leaded dust or paint chips were not trans-ferred outside the dwelling. For example, waste

should not be left at the curbside for trashpickup; all waste should be removed from thesite. The examiner should be particularly con-scientious about looking for paint chips whenexterior components have been disturbed.

IV. Clearance DustSampling

A visual examination alone is not adequatefor determining if a residence is safe for occu-pancy, since small dust particles are not visibleto the naked eye. A person with normal eye-sight cannot detect individual dust particlessmaller than 50 µm in diameter (Olishifski,1983). Data indicate that a significant percent-age of the dust generated during abatement issmaller than 50 µm (Mamane, 1994; NIOSH,

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1993b). Since these smaller dust particles areassociated with an increased risk of lead poison-ing, clearance dust testing is required to deter-mine if a leaded dust hazard remains followinglead hazard control work.

Unless U.S. Environmental Protection Agency(EPA) regulations establish different clearancelevels, the following HUD clearance standardsshould be used, based on wipe sampling:

✦ 100 µg/ft2 for floors.

✦ 500 µg/ft2 for interior window sills.

✦ 800 µg/ft2 for window troughs and exteriorconcrete or other rough surfaces.

There is no standard for vacuum sampling atthis time.

Portable XRF analyzers have not yet demon-strated a capacity to detect dust lead levels inthe range of interest. Wet chemical field testkits are also not sufficiently reliable for routineanalysis of leaded dust at this time and do notyield quantitative data that can be comparedto clearance standards.

Dust samples must be analyzed by laboratorymethods such as atomic absorption spectro-scopy, inductively coupled plasma-emissionspectroscopy, laboratory XRF using standardmethods, or other equivalent analytical meth-ods (see Appendix 14). Only laboratories thatparticipate in a national proficiency testing pro-gram and are recognized by EPA should be used.

If the dust sample from any surface indicates aleaded dust level above the clearance standard,all similar surfaces in the dwelling that samplerepresents (e.g., all interior window sills orfloors) should be recleaned and retested. Onlythe similar components need to be recleaned,not necessarily the entire dwelling. If any suchsurface fails twice, the property owner shouldconsider additional hazard control measuresand/or further sealing of the surface. See sec-tions D and VII for further disussion interpret-ing dust sampling results.

A. Multifamily Housing(20 or More Units)

It is possible to conduct clearance dust samplingin a number of randomly selected dwelling unitsin multifamily housing where similar dwellingunits have undergone comparable types of leadhazard control activity. The random samplingcan be performed for a portion of the housingdevelopment or for all of it. In either case therandomly selected units represent a specifiedgroup of housing units. The contractor must notknow in advance which units will be sampledsince this would bias the results. In addition,it is necessary to choose an adequate numberof randomly selected units (Table 7.3). Signifi-cant cost savings could be realized with such asampling plan.

However, the implications of random clearancesampling should be understood fully before it isused. First, if the random sampling shows thatlevels of leaded dust are too high, it will be nec-essary to reclean not only the affected compo-nent in the selected dwelling unit, but also theaffected component in all the other units thatthe randomly selected unit was meant to repre-sent. Alternatively, all the units represented bythe randomly selected unit could be sampledindividually to determine which ones need re-cleaning. The costs of repeated sampling shouldbe compared with the costs of repeated clean-ing. Regardless of whether all the representedunits are sampled or recleaned, a further delayin permitting residents back into the area is pos-sible when using random clearance sampling.

Second, insurance carriers covering lead hazardcontrol work may demand a high degree of as-surance that the work was performed properlyin each and every dwelling. The extra cost ofdust sampling in all units is likely to be minorcompared to the liability of a child with an el-evated blood lead level in an abated unit thatwas not sampled but was later found to containhigh leaded dust levels.

Third, there has been a significant failure ratein attaining compliance with clearance duststandards in both the ongoing public housingprogram and the HUD Demonstration Project

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(HUD, 1991). In the latter study, failure rateson the initial wipe tests were 19 percent forfloors at 200 µg/ft2, 14 percent for window sills,and 33 percent for window troughs. In one largeabatement job for a public housing authority, 15percent of the housing units failed the clearancetests and required recleaning (Jacobs, 1993a).While this failure rate can be partially attrib-uted to abatement strategy, variable contractorperformance, and perhaps the inexperience ofthe abatement industry, the high rate of failureargues for more extensive unit-by-unit testing.

In spite of all these caveats, there is one specialsituation that may lend itself well to randomclearance sampling. A large vacant apartmentbuilding or housing development that will notbe immediately reoccupied following abatementcould conceivably be randomly sampled at theend of the project and, if necessary, completelyrecleaned. Alternatively, all units could besampled to determine which ones requirerecleaning.

Whether random clearance sampling or unit-by-unit clearance sampling is performed, re-peated sampling should always be performed inall units that required recleaning. In short, mostcases of lead hazard control will require thatclearance dust sampling be conducted in everyunit treated. With additional research and in-novative abatement and cleaning techniquesthat improve compliance rates with clearancedust standards, it may be possible to sample onlya fraction of the units treated.

B. Single-Family Housing andMultifamily Housing (FewerThan 20 Units)

Clearance dust sampling should be conductedin every single-family dwelling unit and in allmultifamily housing with fewer than 20 units.Because treatment and housing conditionsvary so greatly in these housing units, randomsampling is inappropriate.

C. Clearance Dust Samplingand Floor Sealant Application

Wipe samples should be collected after applica-tion of a floor sealant, not before. In lead hazard

control programs, coating floors with a sealantis often one of the final measures completed.The purpose of sealing floors is not to trapleaded dust underneath the sealant, but to pro-vide a surface that can be cleaned effectivelyby the resident. The type of flooring determinesthe type of sealant. Wooden floors should eitherbe painted with a deck enamel or coated withpolyurethane, concrete floors should be sealedwith a concrete sealant, and tile floors shouldbe sealed with appropriate wax.

The maintenance and monitoring systemshould check the integrity of the floor sealantat least yearly.

D. Location and Number ofClearance Dust Samples

Clearance dust samples should be taken eitherfrom specific locations near the area where thelead hazard control treatment was done, fromnearby high-traffic areas (around doorways, forexample), or from other areas. The clearanceexaminer may determine which specific siteis best based on the type of treatment, visualobservation, and professional judgment. Theabatement contractor must not know exactlywhere the clearance samples will be collected.

The number of clearance samples depends onwhether composite or single-surface samplesare collected.

1. Single-Surface SamplingSingle-surface sampling can be conducted usingessentially the same methodology as that de-scribed in Chapter 5 and Appendix 13. How-ever, the number and location of clearancesamples is based on the type of containmentused and the number of rooms treated, not onthe use pattern of the room (as is the case forrisk assessment purposes). The three buildingcomponents that should be tested are floors,interior window sills, and window troughs. Awindow trough is the part of the window inwhich both sashes sit when lowered. An inte-rior window sill (sometimes called the stool) isthe part of the window ledge facing the interiorof the room (see Figure 15.2 for an illustrationof areas to be sampled).

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Figure 15.2 Window Locations for Dust Sampling.

Courtesy: Warren Friedman

C

A

C

A B

1. Sectional view of window (with no storm window) showing window trough area, A, to be tested. Trough is the surfacewhere both window sashes can touch the sill when lowered. The interior window sill (stool) is shown as area C. Interiorwindow sills and window troughs should be sampled separately.

2. Sectional view of window (including storm window) showing window trough area, A and B, to be tested. Trough extendsout to storm window frame. The interior window sill (stool) is shown as area C. Interior window sills and window troughsshould be sampled separately.

Interior Exterior

Interior Exterior

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2. Composite Clearance DustSamplingWhen lead hazard control treatments are simi-lar in multiple rooms of the same dwelling,composite samples may be collected. For com-posite sampling each room treated must be in-cluded. The total number of required sampleswill depend on the number of rooms treatedand whether those treatments are similar (seeTable 15.1). Wipe samples are composited inthe field, not in the laboratory, by inserting upto four wipes from four surfaces into the sametube. The laboratory analyzes all four wipes asone sample using a modified analytical proce-dure (see Appendix 13).

An example of a composite sampling schemecan be found in the example below. Fieldsampling data can be recorded on Form 15.2a.

The rules for combining subsamples into asin-gle composite sample described in Chapter 5for risk assessment also apply to clearancesampling. Those rules are as follows:

✦ Separate composite samples are requiredfrom carpeted and hard surfaces (e.g., asingle composite sample should not be col-lected from both carpeted and bare floors).

✦ Separate composite samples are requiredfrom each different component sampled(e.g., a composite sample should not becollected from both floors and interiorwindow sills).

✦ Separate composite samples are requiredfor each dwelling.

✦ Floor surface areas sampled in each roomshould be approximately the same size (ap-proximately 1 ft2). Interior window sill andwindow trough sampling sizes are dependenton window characteristics, but should alsobe similar from room to room, if possible(e.g., the surface sampling area should notbe skewed so that one room is oversampled).

✦ For composite wipe samples, a separate wipemust be used for each spot sampled (eachsubsample).

The field sampling and analytical methods forcollecting and analyzing wipe dust samples arein Appendixes 13 and 14, respectively. Untilthe EPA standards and protocols are estab-lished, wipe sampling should be performedon all surfaces. While vacuum samples can becollected, neither HUD nor EPA can providestandards to interpret vacuum sampling resultsat this time. Until vacuum sampling standardshave been established, wipe sampling is thepreferred method.

Readers should note that these Guidelines rec-ommend the following precautions when con-ducting dust sampling (see Appendix 13.1):

✦ A standard sampling motion should be used.

✦ Only certain brands of wipes can be used(unless equivalence is demonstrated throughside-by-side field sampling).

✦ Whatman™ filters and thick diaper wipesshould not be used (Whatman™ filters arenot sufficiently durable and some thick dia-per wipes are too difficult for the laboratoryto digest).

✦ Field-spiked wipe samples will need to beincluded in the sample stream in a blindfashion (i.e., the lab should not know theamount of lead spiked onto the wipe) toascertain the efficiency of the laboratorydigestion procedure.

✦ Hard-shelled containers (not plastic bags)must be used to contain wipe samples, sincethe container must be rinsed thoroughlyand quantitatively. A nonsterilized 50-mlpolypropylene centrifuge tube works well.

The minimum number of clearance samplesrecommended in each room is shown in Table15.1. Field sampling data can be recorded onForm 15.2.

Further information on wipe sampling tech-nique can be obtained from ASTM StandardES–30–94.

15

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Ch

apter 1

5: C

learance

1 Interior treatments

No containment withindwelling

2 Interior treatments

With containment(plastic sheeting asairlock on doorsbetween treated anduntreated areas)

3 Exterior treatments

4 Routine maintenancework

5 Soil treatment

Clearance Category Number and Location of Single-Surface Number and Location ofCategory Description Wipe Samples in Each Area 1 Composite Wipe Samples

Two dust samples from at least four rooms indwelling (whether treated or untreated):

✦ One interior window sill or window trough,alternating between rooms.

✦ One floor.

AND

✦ For common areas, one for every 2,000 ft2 of acommon area room floor (if present).

Same as Category 1 but only in every treated room(up to four rooms)

AND

One floor sample outside the containment area butwithin 10 feet of the airlock to determine the effec-tiveness of the containment system. This extrasingle-surface sample is recommended in 20 per-cent of the treated dwellings in multifamily housingand all single-family homes.

✦ For common areas, one floor sample forevery 2,000 ft2 and one floor sample outsidecontainment.

Two dust samples as follows:

✦ At least one dust sample on a horizontal surfacein part of the outdoor living area (e.g., a porchfloor or entryway).

✦ One window trough sample on each floor whereexterior work was performed. An additionaltrough sample should be collected from a fewlower floors to determine if troughs below thearea were contaminated by the work above.

At least 1 floor dust sample for every 20 high-hazardjobs near the work area (see Chapter 17 for defini-tion of “high hazard”).

One dust sample from the entryway.

Three composite samples for every batch of fourrooms (whether treated or untreated):

✦ One floor composite.

✦ One interior window sill composite.

✦ One window trough composite.

AND

✦ For common areas, one floor subsample forevery 2,000 ft2 (if present); up to 8,000 ft2 canbe sampled for each composite.

Same as Category 1 but only in every treatedroom

AND

One floor sample outside the containment areabut within 10 feet of the airlock to determine theeffectiveness of the containment system. Thisextra single-surface sample is recommended in20 percent of the treated dwellings in multifamilyhousing and all single-family homes.

✦ For common areas, one floor subsamplefor every 2,000 ft2 (up to 8,000 ft2 for eachcomposite) and one floor sample outsidecontainment.

Two dust samples as follows:

✦ One composite on a horizontal surface in partof the outdoor living area (e.g., a porch flooror entryway).

✦ One window trough composite for every fourfloors where exterior work was performed,including lower floors where exterior work wasnot done, if present.

Same as single-surface sampling.

One dust sample from the entryway.

Table 15.1 Recommended Minimum Number and Location of Single-Surface Dust Samples

1 A room includes a hallway or a stairway. If no window is present, collect just one floor sample. When a closet is treated, the room to which it isattached should be tested. A closet is not considered to be a separate room. If all rooms received similar treatments and cleaning, only fourrooms need to be sampled for clearance purposes. More rooms may need to be sampled in larger dwellings. The room to be sampled shouldbe selected based on where most of the dust-generating work was done or in the judgment of the clearance examiner.

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✦ The same wipe should not be used to sampletwo different spots. All subsamples shouldbe inserted into the same tube. No morethan four different wipes should be insertedinto a single container for a compositesample. Acceptable recovery rates havebeen found when no more than four wipesare analyzed as a single sample (Jacobs,1993b).

Because composite sampling requires fewersamples than single-surface sampling, samplingcosts may be reduced. Also, more surfaces areoften sampled than would be possible for single-surface sampling. The drawback to compositesampling, however, is that if only one of thecomposite samples fails, all similar componentsin each room will have to be recleaned or eachroom will need to be sampled individually. Incontrast, if one of the single-surface samplesfails, only one room will have to be recleaned.

Composite samples should not be taken fromrooms that have dramatically different condi-tions. For example, if the clearance examinerhas some reason to believe that cleanup was notperformed adequately in a room, a single-surfacesample should be collected there. In some casesboth single-surface samples and compositesamples may be needed.

V. Clearance Soil Sampling

If no exterior lead hazard control work was per-formed, it is not necessary to conduct any soilsampling. Clearance soil sampling should beconducted following any abatement or interimcontrol treatment on the exterior of a house orsoil treatment. The purpose of such testing is toensure that the treatment did not contaminatesoil surrounding the dwelling.

Clearance soil sampling is typically conductedaround the foundation of the house, althoughit is also important to collect samples in playareas that could have been contaminated asa result of the work. All soil samples shouldbe composite samples. If the exterior workinvolved covering bare soil areas only, clear-ance soil samples are not needed; a visual ex-amination is adequate. A detailed protocolfor soil sampling is provided in Appendix 13

and ASTM ES–29–94. Sampling data can berecorded on Form 15.3.

There is evidence that soil lead levels can in-crease following abatement if proper precau-tions are not taken. For example, in one study,6 percent of the dwellings had statistically sig-nificant increases in soil lead levels when com-pared to pre-abatement soil lead levels(NIOSH, 1990).

There should be no visible paint chips on thesurface of the soil near the foundation. How-ever, soil sampling near the foundations ofdwellings is often complicated by the presenceof paint chips embedded in or under the soilsurface from previous repainting efforts. Thehazard associated with these paint chips in thesoil is difficult to assess since it is often notpractical to sample all the different paint chipsthat may be present. Therefore, these paintchips should be considered a part of the soil.They should not be sampled preferentially orexcluded when collecting or analyzing the soil.Laboratories should be instructed to disaggre-gate (force) paint chips through the soil sieveas part of the analytical process.

If the paint chips were generated by hazardcontrol work, they should be picked up with aHEPA vacuum. A visual examination is usuallyadequate. If the clearance soil samples are above2,000 µg/g in the yard (or 400 µg/g in bare, high-contact play areas), the baseline soil samplesshould be analyzed to determine if soil lead lev-els were already high before the work began.Soil samples collected during risk assessments(if one was performed) can be used for thispurpose.

A. Multifamily Housing(20 or More Units)

If a large complex of multifamily housing hasundergone similar lead hazard control work,random sampling of the soil around the build-ings can be conducted using the samplingscheme for lead-based paint inspection. Thedrawbacks of conducting random clearancesampling are the same for soil as for dust (seethe section on clearance dust sampling earlierin this chapter).

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Example of Clearance Composite Sampling Scheme

A house has undergone an abatement job involving extensive interior paint removal (clearance category 1)and has passed a visual examination. The owner and the clearance examiner have agreed to use compositeclearance dust sampling to minimize expenses. The house has eight rooms that were treated, four of whichare carpeted, and all of which have windows.

At a minimum, the clearance examiner should collect the following samples:

No. Description

1 Composite carpeted floor sample (one subsample from each of the four carpeted rooms).

1 Composite hard floor sample (one subsample from each of the four uncarpeted rooms).1 Composite interior window sill sample, with a subsample collected from a location in four selected

rooms.

1 Composite window trough sample, using the same procedure as for interior window sills.

This results in a total of four composite samples for analysis. If single-surface sampling had been completedunder the recommendations in Table 15.1, it would have been necessary to collect eight samples (four roomsx two samples/room = eight samples/dwelling).

has been removed, removal should be assessedvisually prior to repainting. If for some reason itis not possible to visually determine that thepaint has been removed, then XRF readings canbe taken. The protocols described in Chapter 7apply.

Some forms of interim control involve paintfilm stabilization (repainting). In this case theclearance examiner must visually inspect allpainted surfaces to determine if they are allsealed, intact, smooth, and cleanable.

VII. Interpretation ofClearance Testing Results

A. Visual Examination Results

Interpreting the results of the visual examina-tion is a straightforward process. If there is vi-sual evidence that work on building compo-nents or soil is incomplete, the clearanceexaminer should inform the owner and contrac-tor and ensure that the work is completed beforecollecting any dust or soil samples. In situationswhere job specifications are used, they shouldclearly state that failure to pass the clearancevisual examination means failure to complywith clearance standards.

B. Single-Family Housing

If exterior lead hazard control work was done,composite soil samples should be collected nearthe building foundation close to the work areaand in nearby play areas that could have beencontaminated by the work. All single-familyhousing units should be cleared.

C. Number and Location ofClearance Soil Samples at EachBuilding

One composite soil sample should be collectedaround the perimeter of the building. If onlyselected faces of the building were treated, thesamples should come from those faces.

A second composite soil sample should becollected from any nearby play areas.

In both cases bare soil should be sampled prefer-entially. If there is no bare soil, the soil coveringshould be sampled to determine if it has beencontaminated by the lead hazard control work.

VI. Clearance Paint Testing

XRF testing of surfaces that have been strippedand repainted is not recommended. If the paint

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Table 15.2 Interim HUD Clearance Dust Standards (Wipe Sampling Only)1

Surface Leaded Dust Leaded DustLoading ( µg/ft 2) Loading (mg/m 2)2

Bare and carpeted floors 100 1.08

Interior window sills 500 5.38

Window troughs 800 8.61

Exterior concrete or other 800 8.61rough surfaces

1 No clearance standards are currently available for vacuum sampling.2 To convert from µg/ft2 to mg/m2, multiply by 0.01076.

B. Dust Results

Interim HUD clearance dust standards areshown in Table 15.2. These may be revisedsubject to EPA’s issuance of regulations.

No standard method has been developed tocorrelate the wide variety of vacuum methodsavailable with the wipe sampling standards.Until and unless EPA regulations state other-wise, all hard surfaces should be tested with wetwipe samples. While vacuum sampling is ac-ceptable, there is no HUD Interim ClearanceStandard for vacuum sampling at this time,making interpretation of vacuum sampling re-sults against recognized standards impossible.

The results of dust samples collected using avacuum method may be reported in lead con-centration (µg/g) and loading (µg/ft2); wipe sam-pling results are reported in loading only. Forclearance purposes, however, the lead concen-tration cannot be used to determine the effec-tiveness of the cleanup. It is possible to removenearly all leaded dust from a surface, but notchange its concentration significantly, sincemost cleaning methods do not preferentiallyremove lead from the dust. However, addinglead-free soil or dust to the area will reduce theconcentration, even in the absence of cleaning.In short, leaded dust loading (not leaded dustconcentration) should be used to determine ifan adequate cleanup job has been completed. Ifleaded dust levels exceed those given in Table15.2, the contractor must repeat the cleaninguntil compliance is achieved.

The recleaning should be focused on those sur-faces where the sampling results indicate thatthe first round of cleaning was inadequate. Forexample, if floor leaded dust levels are abovethe standard, but interior window sills andwindow troughs are below the standard, onlythe floors need to be recleaned. Similarly, ifsingle-surface samples fail in one room, thenonly that room and any rooms not sampledneed to be recleaned. If composite samples fail,then all the surfaces the composite representsneed to be recleaned (or resampled individuallyto determine which ones require recleaning).For example, consider the two examples shownin Tables 15.3 and 15.4.

In Table 15.3, only the floors in Rooms 1 and 2require recleaning (assuming a four-room unit).In Table 15.4 the window troughs should berecleaned in all four rooms and any rooms notsampled. While the window troughs could con-ceivably be sampled individually to determinewhich ones require recleaning, it is likely to befar more cost-effective to simply reclean all ofthem. When cleaning troughs, the sills shouldalso be cleared, even if they were not originallycontaminated. In both examples, repeated sam-pling of the recleaned surfaces should be com-pleted to ensure that the recleaning wassufficiently effective.

For composite sampling the HUD InterimClearance Standard should not be reduced bydividing the standard by the number of sub-samples in the composite. The purpose of the

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composite sample is to average the lead loadingin all rooms sampled to determine if all therooms require additional cleaning. Compositesampling is used to determine the average leadloading in a group of rooms, not individualrooms. Since composite sampling is done inunits with the same hazard control techniqueand since the method of correction is alwaysthe same (i.e., recleaning), it is not necessary todetermine the leaded dust level in each room.Even a single-surface sample only represents asmall area on a larger surface, in much the sameway as a composite represents many surfacesover a larger area, e.g., all floors within a unit.For paint chip sampling, however, it is necessaryto know the concentration on each surfacesampled, making it necessary to divide the paintstandard by the number of subsamples con-tained in a composite sample (see Chapter 5).

C. Soil Results

If clearance sampling shows that post-abatement soil samples are more than2,000 µg/g, additional soil treatment should berequired. If the area sampled is a high-contactplay area, the soil should be no more than400 µg/g.

VIII. Recordkeeping andIssuance of Statementof Lead-Based PaintCompliance

A. RecordkeepingResponsibilities

Three parties should maintain records of allabatement, interim control, risk assessment,inspection, and clearance results:

✦ Property owner.

✦ Contractor.

✦ Clearance examiner.

Some jurisdictions will also require submissionof such records to an enforcement agency or alead-safe housing registry.

B. Record Content

The records should include all laboratory re-sults, quality control/quality assurance proce-dures, dates of both visual examination andenvironmental sampling, completed forms,

Table 15.3 Hypothetical Example of Single-Surface Clearance Dust Sampling Data

Room Floors ( µg/ft 2) Interior Sills ( µg/ft 2) Window Troughs ( µg/ft 2)

1 475 40 60

2 878 65 90

3 30 70 75

4 50 40 80

Table 15.4 Hypothetical Example of Composite Clearance Dust Sampling Data

Surface Rooms Included in Composite Leaded Dust ( µg/ft 2)

Floors 1, 2, 3, 4 30

Interior window sills 1, 2, 3, 4 129

Window troughs 1, 2, 3, 4 3,695

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and appropriate identifiers for the property—the owner, inspector, job contractor, andresident(s).

Depending on the jurisdiction and the type ofabatement or interim control work undertaken,the owner may be awarded a Statement of Lead-Based Paint Compliance. One State now issuesa statement indicating that the property is“Lead-Free” when all lead-based paint is re-moved and all other lead hazards are corrected.The property is “Lead-Safe” when all lead-basedpaint hazards have been rectified (Rhode Island,1993).

C. Length of Time

Statements of lead-based paint compliance andrecords of all clearance testing should be keptfor the duration of the life of the building, sinceit is to the benefit of the owners to retain thisinformation.

IX. Clearance andReevaluation Procedures

The clearance process evaluates the effective-ness of the lead hazard control efforts immedi-ately following cleanup. Reevaluation deter-mines the continued effectiveness of all leadhazard control treatments (except completeremoval of all lead-based paint). Reevaluationalso determines whether any new lead-basedpaint hazards have appeared. Because mostforms of lead hazard control have limited life-spans, they will require ongoing monitoringby the owner and a reevaluation by a certifiedrisk assessor based on the reevaluation schedulefor the specific property. The method and fre-quency of reevaluation is detailed in Chapter 6.

In those cases where the owner did not have arisk assessment or inspection before hazard con-trol, the clearance examiner should conduct arisk assessment at the time of clearance to en-sure that all lead-based paint hazards were, infact, addressed.

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Form 15.1Lead Hazard Control Visual Clearance Form

Date _______________________________________________________________

Name of clearance examiner ____________________________________________

License no. (if applicable) ______________________________________________

Name of property owner ________________________________________________

Property address ____________________________________ Apt. no.___________

Date cleanup completed ________________________________________________

Time cleanup completed ________________________________________________

Abatement/interim control contractor name ________________________________

Address ________________________________

Telephone no. ___________________________

Check if repeat clearance examination __________

Room List all building compo- Work on each Visible paint Visible Additionalidentifier nents required to be component chips seen? settled work

treated in each room completed? (yes or no) dust seen? required?(yes or no) (yes or no)

Exterior soil _____Treated _____Not treated

If treated, is bare soil present? _____Yes _____No

Was contaminated soil removed? _____Yes _____No

Is additional soil treatment required? _____Yes _____No

NOTES:

Signature _______________________________________

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Area (ft 2)(can be

completedby lab)

Form 15.2Lead Hazard Control Clearance Dust Sampling Form (Single-Surface Sampling)

Date __________________________________________________

Name of clearance examiner _____________________________

License no. (if applicable) ________________________________

Name of property owner ________________________________

Property address ________________________ Apt. no. ________

Clearance categories:

1. Interior treatments without containment.

2. Interior teatments with containment.

3. Exterior work on painted surfaces.

4. Routine maintenance.

5. Soil work.

Samplenumber

Roomnumber

oridentifier

Surface type(floor, interiorwindow sill,

windowtrough)

Clearancecategorynumber

Dimensionsof sample

area (inches)

Passor

Fail

Result oflab analysis

(µg/ft 2)(can be

completedby lab)

Total number of samples on this page________

Page _________ of _________

Date of sample collection ____/____/____ Date shipped to lab ____/____/____

Shipped by ________________________________ Received by ________________________________ (Signature) (Signature)

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Form 15.2aLead Hazard Control Clearance Dust Sampling Form (Composite Sampling)

Date ______________________________________________

Name of clearance examiner ___________________________

License no. (if applicable) _____________________________

Name of property owner ______________________________

Property address ____________________ Apt. no.___________

Clearance categories:

1. Interior treatments without containment.

2. Interior treatments with containment.

3. Exterior work on painted surfaces.

4. Routine maintenance.

5. Soil work.

Dimensions ofsurface sampledin each room(inches x inches)

Samplenumber

Name ofroom oridentifiersincludedin sample

Totalsurface

areasampled

(ft 2)

Type of sur-face sampled(smooth floors,carpetedfloors, interiorwindow sills,windowtroughs)

Clearancecategorynumber

Lab result(µg/ft 2)

Passorfail

________ ______ X ______________ ______ X ______________ ______ X ______________ ______ X ______

________ ______ X ______________ ______ X ______________ ______ X ______________ ______ X ______

________ ______ X ______________ ______ X ______________ ______ X ______________ ______ X ______

________ ______ X ______________ ______ X ______________ ______ X ______________ ______ X ______

Total number of samples on this page ________

Page _________ of _________


Shipped by ________________________________ Received by ________________________________(Signature) (Signature)

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Form 15.3Lead Hazard Control Clearance Soil Sampling Form (Composite Sampling Only)

Date ___________________________________________

Name of clearance examiner ________________________

License no. (if applicable) ___________________________

Name of property owner____________________________

Property address ____________________ Apt. no._______

Sample number Location Bare or covered Lab result ( µg/g)

building perimeter

building perimeter

Sketch soil sampling plot plan. Collect only the top 1/2” of soil.

Total number of samples on this page ________

Page _________ of _________


Shipped by ________________________________ Received by ________________________________(Signature) (Signature)

Documents

CHAPTER 15: CLEARANCE - HUD.gov / U.S. Department of ... · Interpret results by comparing them to the HUD Interim Clearance Standards ... keep turbulence and re-entrainment of particu-late