Purple Book (Guide for Controlling ACM in Buildings) PDF

Repair is appropriate where the insulation has minor damage. Repair involves patching the damaged insulation or covering it with a new jacket. A more complete description of insulation removal and repair appears in Section 5.2. 4.2.3 Other Types of ACM A special O&M program is usually all that is n...

Repair is appropriate where the insulation has minor damage. Repair involves patching the damaged insulation or covering it with a new jacket. A more complete description of insulation removal and repair appears in Section 5.2. 4.2.3 Other Types of ACM A special O&M program is usually all that is needed for other types of ACM, since most ACM in this category is hard and nonfriable and should not readily release asbestos fibers. The only time abatement (primarily removal) should be considered is when it becomes necessary as part of building renovation or maintenance. The procedures in Section 5.3. should then be followed. 4.3 Further Considerations in Selecting a Schedule for Abatement Significant cost savings may be realized by coordinating asbestos abatement with other building activities. For example, when a commercial tenant moves, the space will be temporarily unoccupied and the new tenant may request changes such as moving walls and doors, installing dropped ceilings, or building rooms for specialized equipment. ACM will be disturbed by the renovation work, necessitating precautions to control fiber release. This investment in worker protection and site containment creates an opportunity to enclose, encapsulate, or remove ACM. On the other hand, when ACM needs immediate action, abatement may be a cost-effective time to improve building systems — for example, by upgrading electrical systems, repairing vents and ducts, or installing low-energy lights. Other considerations in scheduling asbestos abatement include the pattern of normal building operations, the long-term legal liability of the building owner, pressures brought by concerned parties, and the expected useful life of the building. ● The pattern of normal building operations. Extensive abatement activities will disrupt building operations. When possible, abatement should coincide with vacations or other periods of low activity. ● The long-term legal liability of the building owner. Some owners choose to remove all ACM as quickly as possible to reduce their liability. However, liability may actually increase if removal is performed by untrained or inexperienced contractors or without proper precautions. ● Pressures brought by workers, building occupants, and other affected parties. Building occupants and the public may have legitimate concerns about possible health risks. However, fear of asbestos often motivates them to call for action before the problem has been properly assessed. The public information program developed with the building survey should include descriptions of the assessment, its results, and a justification of the decision. This is especially important if abatement is not carried out immediately or if no further action will be taken. ● Expected useful life of the building. The comparative costs of removal versus a continuing special O&M program will depend on the expected life of the building. 4-12 CHAPTER 5. ABATEMENT METHODS: CHARACTERISTICS AND RECOMMENDED WORK PRACTICES This chapter provides more detailed information on the advantages, disadvantages, applicability, and relative costs of alternative abatement methods. Information is also given on recommended work practices for worker protection, work site containment, and project surveillance. This information is provided to help building owners determine which method is most appropriate for their situation and what the abatement effort will involve. It is not intended as an instruction manual for abatement. 5.1 Abatement Methods for Sprayed- or Troweled-on Surfacing Material Each abatement method (removal, enclosure or encapsulation) is a separate and distinct alternative. They share, however, several features. The first is the need to conduct a more detailed inspection of both the ACM to be treated and the underlying surface. Each separate, homogeneous area of ACM, usually a single room, hallway, or central space, should be reinspected. (Remember that seemingly homogeneous areas can be composed of different materials and thus require separate inspections.) It is especially important to inspect for hidden material above a suspended ceiling with lay-in panels (see Figure 9). A second round of material sampling in selected areas may help to confirm the presence of asbestos and better delineate areas needing further corrective action. The following information should be collected on each area with ACM: ● size of the area, since this affects the cost of abatement; ● type of ceiling construction if the ceiling is coated (for example, concrete joist and beam, concrete waffle slab, steel beam or bar joist, suspended metal lath, suspended lay-in panels, tile, metal, corrugated steel), since different construction types present different control problems; ● ceiling height, which may determine the practicality of enclosing the material; ● type of wall (for example, smooth or rough concrete, block or brick, plasterboard), which may indicate whether an encapsulant is needed if material is removed; ● average thickness of ACM (and variation in thickness), since encapsulant should not be applied to thick material. A form for collecting the necessary information was developed by EPA’s Region Vll Office and is included in Appendix I for illustrative purposes. The second common feature of the three abatement methods is the need for worker protection during abatement activities. Worker protection entails not only proper training and specified work practices, but also protective equipment (special coveralls and respirators) for the workers. The OSHA standards specify three different respirators depending on the expected concentration of fibers in the work area: (1) a full- or halfface mask with either a single-use or replaceable filter, (2) a full-face mask with replaceable filter and a pump to assist breathing, and (3) a full-face mask with a self-contained or remote air supply. NIOSH now recommends that the first type of respirator with a single-use filter not be used, because these filters have not been tested for effectiveness specifically against asbestos fibers and because they are difficult to seal properly around the face.1 Supplied air (type “C”) units offer the most protection. Respirators 1 A letter setting forth NIOSH’s concerns about these respirators was sent to respirator manufacturers on August 25, 1980. A copy of this letter appeared in the December 1980 issue of the Journal of the American Industrial Hygiene Association. An industrial hygienist or other appropriately trained professional should assist workers in fitting any type of respirators. 5-1 Figure 9. Asbestos-containing material located above a suspended ceiling. 5-2 are required for removal of ACM and are highly recommended for other abatement methods, since enclosure and encapsulation may also elevate fiber levels. The third common feature IS proper work area containment. Containment typically means construction of barriers with 6 mil polyethylene plastic sheets joined with folded seams, and with sealing tape at the seams and boundaries. Some contractors have had problems attaching plastic sheets to walls. Thinner sheets or a better attachment system (for example, stapling and taping sheets to furring strips fastened to walls) may be required. (Figure 10 shows the construction of a typical containment system. Note that respirators should be worn if the ACM will be disturbed during construct ion.) Air locks and worker decontamination facilities with showers are recommended, as well as negative air pressure systems, described in Section 5.1.1 below.2 All return air vents should be sealed to prevent asbestos contamination of the airhandling system. Without such containment measures, increased exposure for building occupants is likely. Once abatement begins, everyone not participating in the project should be kept out of the area. The fourth common feature is the need for a rigorous postabatement cleanup. This includes wet-mopping or HEPA-vacuuming all horizontal and vertical surfaces in the work area. (Wet mopheads and cloths should be discarded in sealed plastic bags and treated as asbestos-contaminated waste.) Cleaning of surfaces outside the work area is highly recommended. Two cleanings—the second after at least 24 hours when suspended fibers have settled—will provide better assurance of fiber reduction than a single cleaning. (Section 6.4 contains additional information on cleaning and inspecting the work site.) 5.1.1 Removal, Disposal, and Replacement Figure 11 is a photograph of a typical removal project. When removing ACM, observe the following requirements: ● The material must first be treated with a solution of water and a wetting agent to reduce fiber release. Some types of amosite-containing materials will not absorb either water or water combined with the wetting agent suggested by EPA (50% polyoxyethylene ester and 50% polyoxyethylene ether). Other wetting agents should be tested on the material for absorption. If the material will not absorb the wetting agent, undertake a dry removal using Type C respiratory protection. EPA must approve all dry removal operations. Get in touch with the NESHAPS contact in your region (see Appendix D). ● Friable ACM must be disposed of in “leak-tight containers," typically 6 mil polyethylene bags. Bags can be placed in 55-gallon drums for additional protection. Bags or drums must be labeled, as specified by NESHAPS (see Appendix C) or OSHA (see Appendix F). ● OSHA procedures for worker protection and decontamination, as well as for measurement of airborne asbestos, must be strictly followed (see Appendix F). While not required by law, EPA procedures for work area containment should also be folIowed to assure safe removal. Research on asbestos removal plus EPA’s experience with removal activities in schools since 1979 have pointed up several other important issues: ● 2 A tear in the containment barrier is a significant exposure hazard for building occupants and should be repaired immediately. The use of negative pressure systems together with HEPA filtration (that is, low speed exhaust fans with HEPA filters) to move air from within the work area OSHA decontamination requirements specify worker change rooms as a minimum provision for asbestos removal projects. If negative air systems are used, “air locks” should not be airtight. That is. make-up air should pass through the air lock. See Appendix J for additional information. 5-3 Figure 10. Construction of containment barriers. 5-4