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Thursday
Apr082010

Controlling Asbestos Exposures

      The OSHA {Occupational Safety and Health Standards} regulate two {2} kinds of materials installed in buildings. 1] Asbestos-containing material {ACM} and 2] presumed asbestos-containing material {PACM}. ACMs’ are any material containing more than one {1%} percent asbestos by weight. PACMs’ are materials that must be treated as ACM until tests prove they are not. OSHA guidelines specify three {3} types of PACM. 1] Thermal system insulation {TSI} and surfacing ACM, 2] resilient flooring installed no later than 1980, and 3] dust or debris near powdery or visibly damaged ACM or PACM. Thermal system insulation and surface ACM are considered “high risk” materials as they are very “friable” and are easily damaged, powdery, resulting in higher amounts of airborne “fibrils” than other ACMs.

    Because airborne exposure is difficult to measure reliably, OSHA groups work operations, exposure levels, and risks into four {4} classes. 1] Class 1-work operations pertain to “high risk” ACM and PACMs such as, TSI and sprayed on or troweled-on surfacing material. 2] Class 2 work operations cover removal of “lower-risk” ACM and PACM such as wallboard, roofing, shingles, and resilient flooring. 3] Class 3 work operations involve repair and maintenance that may “fibrilize”, thus disturbs, any previously installed ACM. This includes work to boilers, valves, and piping, or replacing light fixtures and ceiling tiles. 4] Class 4 work operations cover custodial operations after any class 1, 2, or 3 ACM work has been performed as well as, the clean-up of construction or debris waste from the installation of new ACM. Stripping and buffing resilient flooring, sweeping, dusting or vacuuming asbestos containing dust from surfaces or carpeting is also class 4 work.

     The OSHA standards, which should be in your “HazCom” {Hazard Communication} if you work with or around ACM, have PELs’ {permissible exposure limits} that define the maximum employee exposure during any, work activity. There are two {2} types of asbestos PELs’. 1] TWA or Time Weighted Average limits and 2] excursion limit. The TWA is based upon a normal 8-hour work shift and may not exceed 1/10th of a fiber, per cubic centimeter of air over 8 hours. An “excursion” is a short-term severe rise in airborne fiber concentrations above one {1} fiber per cubic centimeter of air, averaged over 30 minutes. Work operations that exceed either of these limits require worker PPE {personal protective equipment}. This includes respiratory protection along with other prescribed protective clothing and engineering controls. If the asbestos work in question does not qualify in either class, you must utilize the more severe work class. This thought thoroughly protects the worker from ACM exposure and contamination.

     Once protected, the worker employs three basic “tactics” in the performance of his duties. 1] Utilize “wet” methods for clean-up. This encompasses wiping up the ACM with moist cleaning rags. They in turn must be properly cleaned for future use or disposed of as asbestos waste. 2] HEPA {High Efficiency Particulate Air} filtered vacuums or vacuum systems. 3] Promptness in all waste and debris removal that contains ACM or PACM.

     Another stipulation in the standard is regulated areas. Employers must establish clear indication of areas involved with ACM work. They must have a shield of Demarcation to prevent ACM from migrating off-site. Access must be strictly regulated and enforced. All personnel entering MUST have the appropriate respiratory protection. Lastly, to prevent ACM from entering your body, no smoking, drinking, or eating is allowed in ACM areas.

     An OSHA “competent person” must supervise all ACM work within an area. These workers are specially trained to assess hazards in an area while monitoring for increased levels inside an asbestos work site. Their monitoring skills prevent the aforementioned PELs' from being violated. If you work with ACM, advanced medical surveillance must be provided by your employer at his expense, on a time-regulated basis. Asbestos workers must be trained in asbestos “abatement” procedures before begin work, just as hazardous materials responders are trained before they begin responding to emergencies.

     As hazardous materials responders, you may be called to respond to an AFRE {asbestos fiber release episode}. The federal standards “paramatize” these episodes. A minor release involves three {3} square or linear feet of ACM. A major fiber release involves more than three {3} square or linear feet of ACM. The proper response must be pre-planned by your haz-mat team leader that should be your most accredited person. Wetting down the ACM before containment, with manual clean-up tactics is the safest option.

                                          Haz Mat Mike

 

 



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