May 27, 2009
    Illinois Pollution Control Board
    Clerk’s Office
    James R. Thompson Center
    100 West Randolph Board, Suite 11-500
    Chicago, Illinois 60601
    And participants on the Service List (via First Class Mail)
    Re:
    Case No
    : R2009-009
    Case Name:
    In the Matter of: Proposed Amendments to Tiered Approach to
    Corrective Action Objectives (35 Ill Adm. Code 742)
    Board Member:
    Johnson, T.E.
    Hearing Officer:
    McGill, R.
    Dear Board Members:
    CETCO has prepared the following responses to questions posed at the March 17, 2009
    hearing held in Chicago, IL.
    Question from Gary King, Illinois Environmental Protection Agency (IEPA): IEPA is
    concerned about the feasibility of installing a 60-mil liner in a crawl space. I was
    wondering if you could comment on that.
    Response: CETCO 60-mil spray applied membrane has been installed in three existing
    basements: Wesleyan U, Middleton, CT; Belgravia Redevelopment, South Haven, MI
    and Residential Basement, Biddeford, ME. A typical installation cross section is shown
    in following detail G3.1 with overlaying geotextile and a minimum 2-inch topping slab.
    Electronic Filing - Received, Clerk's Office, May 27, 2009
    * * * * * PC #3 * * * * *
    The 60-mil membrane could also be installed over a prepared dirt crawl space with
    similar overlaying geotextile and topping slap.
    Question from Mr. Anand Rao, IPCB: You indicated that GeoKinetics had significant
    experience and you mentioned thousands of sites that they have handled. I was
    wondering if you have any information in a database as to what kind of issues were dealt
    with related to (a 60-mil) membrane, 6-mil membrane or other membrane that were
    evaluated as part of this experience.
    Response: Per Glen Tofani, GeoKinetics, they do not have a database. However, based
    upon their plans on file and billing records of VOC and methane vapor intrusion
    mitigation projects, he made the following estimate:
    •
    minimum 60-mil: 90%
    •
    minimum 12-mil: 10%
    •
    <12-mil: 0%
    The <60-mil vapor barriers were for low concentration VOC or methane projects dating
    back to the mid-1990s and earlier. More recent projects were all minimum 60-mil vapor
    barriers.
    Question from Ms. Kimberly Geving, IEPA: If you are spray (applying) how do you
    make sure it’s all the same thickness? Do you do periodic measurements after it’s
    sprayed on once it’s dry?
    Response: Yes, current CETCO brownfield membrane/liner specification guidelines
    state the following: “The membrane must be cured at least overnight before inspecting
    for dry-thickness. ON CONCRETE/SHOTCRETE/MASONRY & OTHER HARD
    SURFACES Membrane may be checked for proper thickness with a blunt-nose depth
    gauge, taking one reading every 500 square feet. Record the readings. Mark the test area
    for repair, if necessary. If necessary, test areas are to be patched over with LIQUID
    BOOT® to a 60 mils minimum dry thickness, extending a minimum of one inch (1")
    beyond the test perimeter. DIRT AND OTHER SOFT SUBSTRATES. Samples may be
    cut from the membrane and geotextile sandwich to a maximum area of 2 square inches.
    Measure the thickness with a mil-reading caliper, per 500 square feet. Deduct the plain
    geotextile thickness to determine the thickness of LIQUID BOOT® membrane. Mark the
    test area for repair. Voids left by sampling are to be patched with geotextile overlapping
    the void by a minimum of two inches (2"). Apply a thin tack coat of LIQUID BOOT®
    under the geotextile patch. Then spray or trowel apply LIQUID BOOT® to an 60 mils
    minimum dry thickness, extending at least three inches (3") beyond geotextile patch.”
    Electronic Filing - Received, Clerk's Office, May 27, 2009
    * * * * * PC #3 * * * * *
    Thank you for the opportunity to present at the March 17
    th
    hearing. Please do not hesitate
    to contact me if you have any further questions.
    Sincerely,
    James T. Olsta, P.E.
    Technical Manager
    CETCO Remediation Technologies
    2870 Forbs Ave.
    Hoffman Estates, IL 60192

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