A very important major component of the Asbestos Safety Program is the written Asbestos Exposure Control Plan. This module will discuss some of the strategies in controlling exposure to airborne asbestos.
Controlling exposure to asbestos at work follows the same “Hierarchy of Controls” strategy that is common in all industries. Typically, a combination of these controls may be required in order to adequately manage and control worker exposure to asbestos.
If employees are exposed to asbestos above the PEL or EL, employers should protect those employees by using one or more of the following hierarchy of exposure controls:
Hazard controls: The first three controls focus on eliminating or reducing the asbestos hazard, itself:
Exposure controls: The next three control strategies do not do anything to the hazard, but they do influence behavior to eliminate or reduce exposure to the hazard:
Use or replace materials containing asbestos with non-asbestos-containing material. For instance:
Equipment design such as isolation through enclosure, encapsulating, or using wet methods.
Regulated areas are demarcated using warning signs.
Demarcation: A demarcation fixes a boundary or limits of something. The regulated area should be demarcated in any manner that minimizes the number of persons within the area and protects persons outside the area from exposure to airborne asbestos. Where critical barriers or negative pressure enclosures are used, they may demarcate the regulated area.
Warning Signs: Provide warning signs like that shown in the image to the right and display them at each regulated area. Here are some points to remember with warning signs:
Access: Access to regulated areas is limited to authorized persons and to persons authorized by OSHA standards.
Respirators: Supply all persons entering a regulated area where employees are required to wear respirators with a respirator selected in accordance with OSHA standards.
Prohibited activities: The employer should ensure employees do not eat, drink, smoke, chew tobacco or gum, or apply cosmetics in the regulated area.
Qualified Persons: The employer should have a qualified person supervise all asbestos work performed within regulated areas.
Administrative controls do not reduce or eliminate the hazard. Rather, they attempt to control behaviors with safety programs, training, policies, procedures, and rules. Administrative controls include:
All Class I, II and III asbestos work below should be conducted within regulated areas. Perform all other operations within a regulated area if airborne concentrations of asbestos exceed, or there is a reasonable possibility they may exceed a PEL.
Class I work is the most hazardous class of asbestos jobs because it releases asbestos fibers into the air. This work involves the removal, encapsulation, or enclosure of asbestos-containing material (ACM) or presumed asbestos-containing material (PACM).
Class 1 work usually involves removal of thermal insulation. Thermal insulation includes asbestos-containing materials applied to pipes, boilers, tanks, ducts, or other structural components to prevent heat loss or gain. Surfacing materials may include decorative plaster on ceilings, acoustical materials on decking, or fireproofing on structural members.
Employees performing work in a Class 1 regulated area should wear suits and respirators. A decontamination area should be at the containment site. Consider all waste materials as hazardous asbestos waste and carefully dispose of it.
Class II asbestos work includes the removal of ACMs other than thermal insulation, such as flooring and roofing materials. Removing intact incidental roofing materials such as cements, mastics, coatings, and flashings is not regulated as Class II. Examples of Class II work include removal of floor or ceiling tiles, siding, roofing, or transite panels.
When a designated competent person deems roofing material being removed as intact, the roofing contractor may make a negative exposure assessment and avoid initial monitoring if it meets the following conditions:
Class III asbestos work includes repair and maintenance operations where ACM or PACM are disturbed. The primary purpose of the work is not to remove or disturb asbestos, although some removal or disturbance may occur.
Examples of Class III work include repairing broken pipes that have asbestos wrapping, installing floor anchors in an area with asbestos floor tile, or installing electrical conduit through walls with asbestos insulation.
Class IV operations include maintenance and custodial activities in which employees contact but do not disturb ACM. These activities must be related to the construction project or to Class I, II, or III activities. Custodial work that is not related to a construction project or Class I, II, or III work is covered by the asbestos general industry standard.
The use of safe work practices is another category of administrative controls to make sure employees are not exposed airborne asbestos fibers. Below is a list of safe work practices:
Respiratory Protection: The employer should implement a respiratory protection program. Under this program, the employer should do the following:
|Airborne Concentration or Condition of Use||Required Respirator|
|< or = 1 f/cm3 (fibers per cubic centimeter) (10 X PEL)||Half-mask air-purifying respirator other than a disposable respirator, equipped with high-efficiency filters*.|
|< or = 5 f/cm3 (50 X PEL)||Full-facepiece air-purifying respirator equipped with high-efficiency filters*.|
|< or = 10 f/cm3 (100 X PEL)||Any powered air-purifying respirator equipped with high-efficiency filters* or any supplied-air respirator operated in continuous-flow mode.|
|< or = 100 f/cm3 (1,000 X PEL)||Full-facepiece supplied air respirator operated in pressure-demand mode.|
|> 100 f/cm3 (1,000 X PEL), or unknown concentrations||Full-facepiece supplied-air respirator operated in pressure-demand mode, equipped with an auxiliary positive-pressure self-contained breathing apparatus.|
* A high-efficiency filter means a filter that is at least 99.97% efficient against mono-dispersed particles of 0.3 µm (micrometers) in diameter or higher.
Protective Equipment: The employer should provide personal protective equipment including coveralls, gloves, head and foot covering, face shields, and vented goggles.
Do not use the following work practices and engineering controls for work related to asbestos or for work that disturbs ACM or PACM, regardless of measured levels of asbestos exposure or the results of initial exposure assessments:
For more information on general respiratory protection requirements, see OSHAcademy Course 756, Respiratory Protection.
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