Environmental Engineering Reference
In-Depth Information
Table 2.1
Asbestos Minerals Used Commercially or Found in
Asbestos Products Used in Buildings
Commercial
name
Building
occurrence
Mineral
Chemical formula
Chrysotile
Chrysotile
(Mg)
(OH)
S
O
(±Fe)
*
6
8
14
10
Grunerite
Amosite
Fe
(OH)
S
O
(±Mg, Mn)
**
7
2
18
22
Rubeckite
Crocidolite
Na
(Fe
3+
)
(Fe
2+
)
(OH)
S
O
(±Mg)
X
2
2
3
2
18
22
Anthophyllite
Anthophyllite
(Mg, Fe)
(OH)
OS
O
***
7
2
18
22
Actinolite
Actinolite
Ca
Fe
(OH)
S
O
(±Mg)
***
2
5
2
18
22
Tremolite
Tremolite
Ca
Mg
(OH)
S
O
(±Fe)
***
2
5
2
18
22
* Very commonly found in ACM products.
** Commonly found.
*** Uncommonly found.
X
Typically not used in ACM in North America.
Source:
Asbestos in Public and Commercial
Buildings: A Literature Review and Synthesis of Current Knowledge,
From Health Effects Institute-Asbestos Research,
Cambridge, MA, 1991. With
permission.
asbestos fibers have the following characteristics when viewed by light
microscopy: (1) particles typically having aspect ratios from 20 to 100:1 or
higher, and (2) very thin fibers (typically <0.5
m in width). The parallel
fibers often occur in bundles. The very fine individual fibers are best seen
using transmission electron microscopy. Chrysotile asbestos fiber diameters
have been reported to range from 0.02 to 0.08
µ
µ
m, amosite between 0.06 and
0.35
µ
m, and crocidolite between 0.04 and 0.15
µ
m. The smaller the diameter,
the higher the tensile strength.
B.
Asbestos-containing building materials
Commercial and industrial use of asbestos has a relatively long history.
Asbestos fibers have been used extensively, with well over 3000 applications.
Generic uses have included fireproofing, thermal and acoustical insulation,
friction products such as brake shoes, and reinforcing material.
Materials made of asbestos, or having asbestos within them, are
described as asbestos-containing materials (ACM). When used in building
construction, they are identified as asbestos-containing building materials
(ACBM). Types of ACBM, their characteristics, asbestos content, and time
1.
ACM in nonresidential buildings
For regulatory purposes, asbestos-containing building materials are classi-
fied as surfacing materials (SM), thermal system insulation (TSI), and mis-
cellaneous materials (MM). Surfacing materials include spray-applied fire-
proofing (
Figure 2.2
)
and spray-applied or troweled-on acoustical plaster.
Asbestos-containing fireproofing was sprayed on steel I beams in multistory
buildings to keep buildings from collapsing due to structural fires. Acoustical
