Purple Book (Guide for Controlling ACM in Buildings) Part 7 PDF

Table 2. Assessment Table for Surfacing Materials Current Condition of ACM Potential for Future Damage, Disturbance, or Erosion Good* Low No Further Action Now Beyond Special O & M Program High † Removal, Enclosure, Encapsulation Integrated with Other Building Activities Minor Damage or Deter...

Table 2. Assessment Table for Surfacing Materials Current Condition of ACM Potential for Future Damage, Disturbance, or Erosion Good* Low No Further Action Now Beyond Special O & M Program High † Removal, Enclosure, Encapsulation Integrated with Other Building Activities Minor Damage or Deterioration Poor Selective or Complete Removal as Soon as Possible Removal as Soon as Possible * Good condition means no water damage, physical damage, or deterioration. † High potential means that ACM is exposed or accessible, in an air plenum or airstream, or subject to vibration Table 3. Comparison of Asbestos Abatement Methods for Surfacing Materials Method Removal Advantages Eliminates asbestos source Eliminates need for special operations and maintenance program Disadvantages Replacement with substitute material may be necessary Appropriate applications Inappropriate applications General comments Containment barriers needed Can be used in most situations Worker protection required Porous surfaces also may require encapsulation Wet removal is required for all types of asbestos, (amosite will not absorb water or water with traditional wetting agents) Improper removal may raise fiber levels Disposal may be a problem in some areas Unusual circumstances, complex surfaces, and the presence of utilities may require special removal techniques Enclosure Reduces exposure in area outside enclosure Asbestos source remains and must be removed eventually Initial costs may be lower than for removal unless utilities need relocating or major changes Fiber release continues behind enclosure Usually does not require replacement of material Special operations program required to control access to enclosure for maintenance and renovation Periodic reinspection required to check for damage Repair of damaged enclosure necessary Fibers released in dry form during construction of enclosure Long-term coats could be higher than for removal ACM is located in a small area (e. g., a column) Disturbance or entry into enclosed area unlikely Damaged or deteriorating materials causing rapid fiber release Water damage evident Damage or entry into enclosure likely Ceiling to be enclosed IS low Containment barriers needed Use of tools with HEPAfiltered vacuum attachments advisable Worker protection needed Table 3. (continued) Method Encapsulation Advantages Reduces asbestos fiber release from material Initial costs may be lower than for removal Does not require replacement of material Disadvantages Asbestos source remains and must be removed later If material is not in good condition, sealant may cause material to delaminate Appropriate applications Material still retains bonding Integrity Material does not adhere well to substrate Damage to material not likely Material is deteriorating or damaged, or damage is likely Material not highly accessible Periodic reinspection required to check for damage or deterioration Material granular, cementitious Repair of damaged or deteriorating encapsulated surface required After removal of ACM, if the substrate is porous Encapsulated surface is difficult to remove and may require dry techniques for eventual removal Long-term costs may be higher than removal Inappropriate applications General comments Containment barriers needed Worker protection needed Airless sprayers should be used Water damage is evident Material is fibrous, fluffy Previously encapsulated materials may have to be re-encapsulated 4.2.1.3 Method The choice of abatement method is determined mainly by the condition of the ACM. Surfacing materials can be removed, encapsulated with sealant, or enclosed within an airtight structure. The three methods are summarized in Table 3 and described in more detail in Section 5.1. Worker protection and the construction of sealed containment barriers around the work site are required for all three methods. Removal has the widest applicability. It also is the only truly permanent solution, since no building containing asbestos can be demolished without first removing the ACM. If ACM has only minor, isolated damage, removal of selected areas may be sufficient. Enclosure and encapsulation have limited application. Enclosure is restricted to situations where ACM can be isolated in small localized areas. Encapsulation can be used only for acoustical plaster in good condition. In addition, the special O&M program must be continued and the enclosed or encapsulated materials reinspected periodically (at least monthly) until the ACM is removed or the building is demolished. Encapsulation may make eventual removal more difficult and costly, since encapsulated ACM may have to be removed in dry form. Initial cost of removal may be higher than for other abatement methods. However, removal may be less expensive over the long term, since the continued presence of ACM requires special O&M practices, periodic reinspection, and repairs. Enclosure and encapsulation are options only when the ACM is in good condition. These are primarily temporary measures to reduce the potential for future disturbance or erosion until the ACM is eventually removed. 4.2.2 Pipe and Boiler Insulation 4.2.2.1 Need Pipe and boiler insulation typically presents a more localized fiber release problem than surfacing material. The insulated pipes, boilers, ducts, and other equipment are frequently confined to equipment rooms or placed within walls or behind ceilings. Even accessible insulation is localized to the piece of insulated equipment. Thus, the potential for disturbance, damage, or erosion is lower than for surfacing material; frequent inspection can spot any new disturbance and the damage can be repaired quickly. The condition of the ACM determines the need for further action (see Table 4). If the insulation is intact, no further action is needed. 4.2.2.2 Timing Damaged insulation should be repaired or replaced as soon as possible. Major renovation, such as installation of a new boiler, is a good time to consider replacing pipe and boiler insulation with non-asbestos material. This will eliminate the need for a continuing special O&M program. 4.2,2.3 Method Removal is appropriate where the insulation is extensively damaged or deteriorated. It involves cutting and stripping the insulation from pipes (or other equipment) and substituting non-asbestos material. Plaster around elbows, valves, and flanges should also be replaced with non-asbestos materials. Removal of pipe and boiler insulation requires many of the same precautions and worker protection measures for removal of surfacing materials. 4-10 Table 4. Assessment Table for Pipe and Boiler Insulation Current Condition of ACM Potential for Future Damage, Disturbance, or Erosion Low High † Good* No Further Action Beyond a Special O&M Program Removal Integrated With Other Building Activities Minor Damage or Deterioration Patching or a New Jacket as Soon as Possible Patching or a New Jacket as Soon as Possible. Removal Integrated with Other Building Activities Poor Removal and Replacement as Soon as Possible * Good condition means that the wrapping is intact and there is no water damage, physical damage, or deterioration. † High potential means the ACM is exposed or accessible, or in an air plenum.