Document oDEMR70VYze2wj34er0DNZYXo

floors; or areas where pieces of the asbestos-containing material iibvc separated into layers or fallen down, thereby exposing the substrate. .. ... Close inspection is required. In many areas, staining may occur only in a limited area while water damage causing delamination may have occurred in a much larger area. In addition, the water damage may have occurred since the original inspection for friable material, causing new areas to become friable and require a reinspqction. Delamination is particularly a problem in areas where the substrate is a very smooth concrete slab. Check to see if the material "gives" when pressure is applied from underneath. D.2 Potential for Disturbance or Erosion _,p:: .i-.nr-Xic D.2.1 Factor 4; Air Plenum or Direct Airstream : > , ' ;-!...> : : ,>r-; . :i r. ';c; ,;u.,- ... vr.f< v;. , K ; ' : An air plenum exists when the return (or, in rare cases, conditioned) air leaves a room or hall through vents in a suspended ceiling and travels at low speed and pressure through the space between the actual ceiling and the suspended ceiling or ducts. The moving air may erode any asbestos-containing material in the plenum, In evaluating whether an air plenum or direct airstream is present, the inspector must look for evidence of ducts or cavities used to convey air to and from heating or cooling equipment or the presence of air vents or outlets which blow air directly onto friable material. ,:ri . :;c A typical construction technique is to use the space between a suspended ceiling and the actual ceiling as a return air plenum. In many cases, the tiles in the suspended ceiling must be lifted to check if this is the case. Inspection of the air handling or HVAC equipment rooms may also provide evidence (such as accumulated fibers) of the presence of this material in the plenums. Special attention should be paid to whether frequent activities (such as maintenance) disturb the material in the plenum. It is also important to check for evidence that the material is being released or eroded (i.e., has it deteriorated or been damaged so that the material is free to circulate in the airstream?). ... . ,J.,.. ..... i:" D.2.2 Factor 5: Exposure, Accessibility, and Activity . J r:i. iV. : .> 'T:" ' 1 m V.: ::: These three considerations are highly interrelated and have been combined into a single factor. In generalrfdr a site to show a high potential for disturbance, it must be exposed (visible) and accessible, and be located near movement corridors or subject to vibration. The amount of asbestos-containing material exposed to the area occupied by people will contribute to the likelihood that the material may be disturbed and determines whether the fibers can freely move through the area. An asbestos-containing material is considered exposed if it can be seen. For a material not to be exposed, a physical barrier must be complete, undamaged, and unlikely to be removed or dislodged. An asbestos-containing material should be considered exposed if it is visible, regardless of the height of the material. If the asbestos-containing material is located behind a suspended ceiling with movable tiles, a close inspection must be made of the condition of the suspended ceiling; the likelihood and frequency of access into the suspended ceiling, and whether the suspended ceiling forms a complete.barrier or is only partially concealing the material. D-2 GLEASON-001121