Abatement Step 2: Conduct Removal and Abatement Activities
Table of Contents
The removal and abatement procedures for building materials such as masonry, wood, and bricks that were contaminated with or contain PCBs should be determined based on the building material classification, described in the section on the building characterization and sampling plan. When caulk with PCB concentrations equal to or greater than 50 ppm is removed along with any attached PCB containing building materials, it must all be disposed in accordance with the methods provided in 40 CFR 761.62 and described in Abatement Step 3.
- Factors to Consider when Selecting Appropriate Tools and Methods
- Typical Tools and Methods for Removal Activities
- Protective Measures
- Suggested Work Area Decontamination Methods
The following subsections provide an overview of various tools and methods available for removal and abatement of caulk and related building materials. Generally tools should be selected that minimize dust and heat.
Factors to Consider when Selecting Appropriate Tools and Methods
To select the most appropriate tools, it is important to evaluate the location and accessibility of the caulk. Material properties are an important consideration for choosing the right tool to remove old caulk. Check whether the caulk is hard and brittle (aged and weather-exposed caulks, frequently seen in exterior areas) or elastic and soft (primarily in areas protected from sunlight and weather, and located indoors). Furthermore, the material and condition of the adjoining structures (smooth or rough joint faces) play a role in the selection of tools. The most frequently encountered materials of adjoining structures include concrete, sandstone, bricks, polystyrene (with plaster layer), wood, and metals (e.g., window frames).
More comprehensive protective measures are necessary for methods that generate moderate to heavy amounts of dust or heat.
The anticipated dust and heat generation plays an important role in selecting the right tools and methods for removal. If your tools or work methods generate high heat (temperatures exceeding 212° F.), there is the risk that the PCBs may be released into the air, and workers or building occupants may breathe in PCB gases. More comprehensive protective measures are necessary for methods that generate moderate to heavy amounts of dust or heat.
Typical Tools and Methods for Removal Activities
Manual tools are primarily used for smaller joint lengths or when the joints are difficult to access for structural reasons. The summary of suggested tools and methods page provides a summary of the typical manual tools and methods used for removal activities. Advantages of manual processes compared to electromechanical methods include a lower volume of fine dust, the absence of heat development, and consequently, lower expenditures for personal and environmental protection. Utility knives are particularly suitable for manual processes, provided the caulk is not too hard or brittle. Soft caulk, especially indoors and in external areas without weather or sun exposure, can be quickly and efficiently removed with a utility knife. Hard or brittle caulk is mainly found in exterior areas, especially in places with sun exposure. Hard or brittle caulk may have to be broken or chiseled out with ripping chisels, crowbars, hammers, and chisels. Depending on the condition of the caulk and the surrounding materials, the joint faces can be reworked by shaving and scraping with a putty knife, scraper, or wire brush.
Electromechanical tools have ergonomic advantages over most manual methods. Electromechanical tools are better suited for projects with many joints and semi-soft to hard and brittle caulk. Electrical joint cutters with rotating blades (also known as oscillating knives) have proven especially useful in these situations. Generally, electromechanical procedures generate higher volumes of dust and more heat, which requires more complex protective measures (personal and environmental protection) than manual methods. Some electromechanical tools may have limited applications (e.g., jigsaw) or are unsuitable because they produce significant amounts of dust or high heat. The summary of suggested tools and methods page provides a summary of the typical electromechanical tools and methods used for removal activities.
Typically, joint faces have to be cleaned after the removal of the old caulk to install the new, high-quality caulking. The removal of the caulk containing PCBs should be as complete as possible, with no visible residue remaining. The selection of tools and methods for cleaning/reworking joint faces is primarily based on structural requirements and consideration of protective measures. Additionally, the material properties of the adjoining structures must be taken into account to ensure that the joint faces are not damaged. Tools with beating, striking, or pronounced abrasive effects are not suitable for working on sensitive adjoining structures, such as limestone, plaster-covered insulation, wood, or metal parts.
An effective method to treat joint faces is dry ice blasting, which is primarily reserved for major restoration projects because of the complex protective measures it requires. In the case of smooth, non-porous surfaces such as metal (e.g., unpainted window frames), glass, ceramic materials, or tiles, that are not to be removed and disposed of, the surface should first be cleaned with a rag dipped in solvent (e.g., acetone). When working with solvents, you should observe protective measures such as, the use of solvent-resistant gloves, increased air exchange with sufficient fresh air supply, compliance with workplace limit values, and measures to prevent fire and explosion. In addition, used solvent and/or cleaning rags may be subject to regulation under federal or authorized state hazardous waste regulations.
Data from individual restoration projects have shown that PCBs spread from the caulk into adjoining structures (e.g., brick, wood, or concrete) over time. Consequently, it is highly likely that the material adjoining the PCB-containing caulk at the joint face is contaminated. In many cases of caulk contaminated with PCBs at > 1,000 ppm, several millimeters of the adjoining concrete contained PCB contamination in a concentration range of several hundred to several thousand parts per million. As previously discussed, the adjoining materials contaminated with PCBs are typically characterized as PCB remediation wastes. PCB bulk product waste must be handled in accordance with 40 CFR part 761.62 while PCB remediation waste must be handled in accordance with 40 CFR part 761.61 while PCB remediation waste must be handled in accordance with 40 CFR part 761.61. Refer to Abatement Step 3 for more information.
Under certain situations, it may be more practical to separate PCB-contaminated parts of the building materials from adjacent PCB-free materials in the area of the joint faces. This can be done with electromechanical tools such as circular saws or slot mills with diamond blades or with maximum pressure blasting methods. In such cases, the material separation should include sufficient safety spacing from the non-contaminated building parts, and suitable measures to contain the dust volume and retain the blasting materials.
Take note that PCB contaminated building materials are considered PCB bulk product waste when the PCB caulk is still attached, while PCB contaminated building materials are considered PCB remediation waste when the PCB caulk has been separated from the building materials and disposed of separately. If your abatement plan states that you intend to dispose of the PCB caulk and any contaminated building materials together and the PCB caulk becomes separated from the adjacent contaminated building materials during remediation, you may still dispose of all the materials as a PCB bulk product waste.
- Occupational Protective Measures
- Protective Measures for Third Parties and the Environment
- Heating, Ventilating and Air Conditioning (HVAC)
- Communications about the Job and Site Security
The need for protective measures primarily depends on the volume of dust generated by the particular work method. To limit protective measures needed, it is best to select tools and methods that generate the lowest possible dust volume. Protective measures should provide for direct personal protection (workers), protection of building users and third parties (e.g. passers-by), and safeguard the potential for spreading PCB contamination (cross-contamination) to surrounding areas of the abatement project.
An integral step in implementing protective measures is to assign a containment area for each distinct abatement area.
An integral step in implementing protective measures is to assign a containment area for each distinct abatement area. The containment area size and construction should be proportionate to the activities that will be conducted (i.e., amount of dust generation expected). Containment structures should be constructed within the containment area at each location where abatement is performed and in a manner that prevents airborne dust from spreading outside the abatement area. For example, a containment structure can be constructed of poly sheeting draped over existing building features and/or support frames built specifically for the containment area. The containment area should be maintained under negative air pressure by installing an induced draft fan equipped with High Efficiency Particulate Air (HEPA) filters to prevent dust particles from being carried out of the containment area. The filtered exhaust from the fan should be routed outside the containment area and vented outside of the building. When significant dust may be produced by the abatement activities, dust monitoring outside the containment structures may be warranted.
Dust aspiration techniques can be used to reduce the amount of dust created from tools/methods that can generate higher dust volumes, such as grinders, cutters, saws, and slot mills as identified on the summary of suggested tools and methods page. These techniques are efficient methods for reducing the amount of dust that can spread through the containment area, and can significantly reduce the amount of dust in the breathing zone of the worker using the tool. Affixing a dust collector nozzle (connected to an industrial vacuum with HEPA filters) to the working end of the electromechanical tool is an example of a dust aspiration technique. The figure below illustrates examples of dust aspiration techniques.
Source: Rex, G.B., www.pcbinschools.org, accessed July 2009.
Occupational Protective Measures -- his section discusses measures for protecting workers from exposure to PCB gases and dust. Depending on the selection of tools, PCB gases and dust are likely to be released to air when working on an abatement project. Therefore, workers should use suitable protective measures (personal protection gear) when working with dust-generating methods or tools. These protection measures should prevent PCBs from getting into the body through inhalation, ingestion, and/or by absorption through exposed skin.
The following protective measures are generally applicable, and should be considered when handling materials containing PCBs:
Gloves and skin protection -- Chemical-resistant gloves and Tyvec coveralls are the standard personal protective equipment (PPE). Chemical-resistant gloves made of nitrile butadiene rubber (NBR) are particularly protective. Pay particular attention to the type of gloves and how long gloves can be used when working with solvents (e.g. for cleaning non-porous surfaces). Only certain gloves are suitable for working with particular solvents, and how long gloves can be used with that solvent (breakthrough time) differs.
Eye protection -- All workers should wear safety glasses or protective goggles for all removal, abatement, and sampling activities.
Respiratory protection -- Consider using an air-purifying respirator (OSHA/NIOSH approved) with combination organic vapor and HEPA cartridges when working with dust generating activities or solvents.
- Worker hygiene -- Eating, drinking, and smoking should be prohibited in the work site. For work involving dust generation, showers and separate changing cabins for work clothing and everyday clothing should be provided.
To protect third parties and the environment during abatement projects, it is important to prevent PCB-contaminated dust from contaminating the immediate surroundings.
Protective Measures for Third Parties and the Environment -- To protect third parties and the environment during abatement projects, it is important to prevent PCB-contaminated dust from contaminating the immediate surroundings (i.e. adjoining rooms for interior projects and directly adjoining areas of exterior projects). PCBs can stay in the environment for long periods of time, and can be a source of exposure to building occupants. Consider the following protective measures for third parties and the environment when handling materials containing PCBs:
- Adequately construct a containment area to minimize the spread of PCB dust to other surrounding areas and to make sure proper control requirements are followed (i.e., removal of used PPE prior to exiting the control area).
- Properly store removed PCB-contaminated materials, directly at the place of removal. Materials should be placed in tightly-locking, stable containers, for example fiber drums or polyethylene buckets with polyethylene lining.
- Regularly clean the work area, including tools and machinery, with an industrial vacuum and HEPA filter and/or mopping to remove particles.
- Properly dispose of contaminated protective clothing (gloves and protective suits), filters of aspiration devices, and cleaning aids in the containment area.
In addition to these generally applicable protective measures, consider conducting air sampling in the vicinity of the containment area to assess whether PCB-contaminated dust is escaping the containment area and impacting nearby clean areas. The air sampling should be conducted the procedures discussed in the section on testing and characterizing suspect materials. When determining if air sampling should be conducted during abatement activities, consider the following:
- amount of dust generated by the activities
- location of abatement activities
- duration of dust-generating activities
- size of the area being remediated
- concentration of PCBs in the material being remediated
- effectiveness of the containment area structure
Heating, Ventilating and Air Conditioning (HVAC) -- The HVAC system should be shut down and remain off until PCB abatement is complete. If this is not possible, isolation of the abatement area from the HVAC system should be implemented. During the preliminary assessment of the extent of PCB contamination, sampling should be conducted in all areas/rooms/units serviced by the HVAC system to determine the spread of contamination, and sampling results should be noted in the cleanup plan.
Hire contractors who specialize in cleaning ventilation systems to clean HVAC systems. These contractors have specialized tools and training to ensure thorough cleanup. It is important to remember that not all ventilation system ducts can be cleaned. For example, some ducts are lined with fiberglass or other insulation (which, if damaged during cleaning, can release fiberglass into living areas). Also, flexible ductwork frequently has a porous inner surface and, in most cases, cannot be economically cleaned. For this reason, the ductwork should be discarded and replaced after the ventilation system is cleaned.
If it is determined that the HVAC system can be cleaned, it should be cleaned early in the abatement process. Once cleaned, the HVAC system should be sealed at all openings to prevent potential recontamination. At a minimum, when approaching a ventilation system constructed of non-porous materials, ventilation contractors should:
- Perform a walk-through of the structure to establish a specific plan for decontamination of the ventilation system.
- Follow safety and health procedures, in accordance with OSHA regulations and guidelines and other applicable state or local worker safety and health regulations, to protect workers and others in the vicinity of the structure during the decontamination process.
Communications About the Job and Site Security -- Clear communication with all affected groups (e.g., building occupants, workers, building owners, and community members) is necessary to create a safe working environment. Site security measures should also be implemented to prevent unauthorized access to the containment areas. Read about specific security measures and suggested notification.
Suggested Work Area Decontamination Methods
Following the abatement activity and break down of the containment area, the entire area should be vacuumed with an industrial HEPA vacuum and wiped with wet rags to remove any dust from surfaces within the area. All wastes collected or created (e.g., used rags) should be placed in a container or wrapped in plastic, and transported to the disposal storage area. Then, conduct a visual inspection of the decontaminated area to determine if additional decontamination is warranted (i.e., if the area is still dusty). The HEPA vacuum should also be decontaminated or disposed of.
After the decontamination is considered complete, collect wipe samples from surfaces within the subject area. Collect a sufficient number of wipe samples within the subject area to ensure that the area was fully decontaminated. The number and location of samples should be determined in accordance with 40 CFR 761 Subpart O (bulk wastes and porous surfaces) or Subpart P (non-porous surfaces), with a minimum of three samples collected from each type of Bulk PCB Remediation Wastes. You should collect samples from horizontal surfaces where dust is most likely to accumulate.
The subject area is considered sufficiently decontaminated if conducted in accordance with 40 CFR 761.79. If the standard of 10µg/100 cm2 is not met for all of the wipe samples, additional decontamination procedures must be performed within the entire subject area and additional wipe samples must be collected. These procedures will be repeated until the 10µg/100 cm2 standard has been achieved.
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