Case Study 4: Classifying Mixed ACM in a 1954 Hospital Renovation
A 1954 hospital is being renovated. The accredited inspector reports 5,000 ft² of sprayed-on fireproofing on structural steel at 15% amosite, 300 linear feet of pipe elbow insulation at 20% chrysotile, 10,000 ft² of 12-inch by 12-inch corridor floor tile at 2% chrysotile, and 1,200 ft² of transite cement wall panels in a mechanical room. The general contractor says the amosite was banned, so the fireproofing is not regulated; the floor tile is only 2%, so it is not ACM; and the transite is nonfriable, so the crew can break it up and throw it in the dumpster. The owner wants to keep the corridors open during tile removal because patients use them. The lab reports are in the project file and are not part of this question.
1. Classify each material as friable or nonfriable and, where applicable, as Category I or Category II, and determine which materials are ACM.
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All four materials are ACM because each exceeds the greater-than-1-percent asbestos threshold by weight. The sprayed-on fireproofing is friable: it can be crumbled or reduced to powder by hand pressure when dry. The pipe elbow insulation is also friable. The 12-inch by 12-inch floor tile is a Category I nonfriable material while intact; floor tile and its associated mastic are commonly grouped there because they cannot be crumbled by hand pressure when dry. The transite cement wall panels are Category II nonfriable material because they are not otherwise listed as Category I. Nonfriable status does not remove the material from regulation; it affects the work practices and whether the material becomes regulated as friable when cut, broken, sanded, or otherwise abraded. The mineral type, amosite or chrysotile, does not change the ACM determination.
2. Evaluate the general contractor's three statements about amosite, the 2% floor tile, and the transite.
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All three statements are wrong. Amosite is an amphibole asbestos mineral whose uses were phased out or banned in some products, but there is no general rule that existing amosite-containing material is unregulated; the fireproofing is ACM and must be handled as such. The floor tile at 2% chrysotile is ACM because the threshold is greater than 1%; the contractor appears to be confusing the threshold with a zero-tolerance or 1% cutoff. The transite is nonfriable only while it remains intact. Breaking, cutting, or dumping it will crumble or abrade the material and can make it regulated as friable, and disposal in an ordinary dumpster is not acceptable. The contractor should not rely on these claims to avoid containment, notification, or licensed abatement. The owner should require a written work plan that reflects the actual ACM determinations.
3. What work-practice and notification differences follow for removing the fireproofing versus the floor tile, especially with corridors open?
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Removal of sprayed-on fireproofing is a high-fiber-release operation requiring full containment, negative pressure, critical barriers, wet methods where feasible, HEPA vacuuming, worker PPE, air monitoring, and a Nebraska notification with the required advance notice. The corridor tile removal is lower-fiber-release and may use low-fiber-release methods such as wetting, scoring, and careful prying, but it still requires a notification, licensed workers and supervisor, isolation of the work area, and proper waste handling. Because patients use the corridors, the contractor cannot simply leave the area open; it should schedule the work off-hours, install critical barriers and negative pressure, seal HVAC openings, and maintain egress. The notification should describe the corridor phasing and any changes in start dates or quantities. The transite should be removed before demolition or handled as regulated ACM if it will be broken.