&EPA
United States
Environmental Protection
A g e n c y
October, 1982
(Revised!
Toxic Substances
Asbestos Exposure
Assessment In Buildings
Inspection Manual
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ASBESTOS EXPOSURE ASSESSMENT IN BUILDINGS
INSPECTION MANUAL
Revised: October 1982
Prepared By
Wolfgang Brandner
Regional Asbestos Coordinator
Air and Waste Compliance Branch
Air and Hazardous Materials Division
U. S. Environmental Protection Agency - Region VII
324 East llth Street
Kansas City, Missouri 64106
(816) 374-6538
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TABLE OF CONTENTS
Section Page
Introduction and Background 1
Asbestos Exposure Assessment 6
Air Monitoring 7
Fiber Release Mechanisms 10
Building Inspection 14
Evaluation Form #1 14
Evaluation Form #2 23
Exposure Assessment - A Numerical System 28
Step 1: Factor Score Selection 29
Step 2: Exposure Number Calculation 64
Step 3: Comparison of Exposure Number to 65
Corrective Action Scale
Use of Algorithm Scores to Determine Potential 68
for Fiber Release
Ceiling Tiles and Pipe and Boiler Wrapping 72
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FIGURES AND TABLES
Page
Figure 1 Description of Spray-Applied Asbestos- 3
Containing Material
Figure 2 Types of Ceiling Construction 19
Figure 3 Thickness of Coating 20
Table 1 Asbestos Exposure Assessment Factor 30
Scores
Table 2 Corrective Action Scale 66
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INTRODUCTION
Once friable asbestos-containing material has been identified in a
building, the potential that the material will release asbestos fibers
and contaminate the building should be evaluated. This manual will
introduce you to the different types of materials found in buildings,
explain some of the difficulties of ascertaining the potential of
these materials to release asbestos fibers, and describe the methods
for scoring the conditions you observe in buildings. This inspection
manual is designed to be used in conjunction with the Environmental
Protection Agency's (EPA) Guidance Documents, "Asbestos-Containing
Materials in School Buildings: Part 1 and Part II". The Part I Guidance
Document describes how to conduct visual building inspections and how
to collect samples of ceiling or wall material suspected of containing
asbestos. A more detailed description is presented herein on how to inspect
buildings, particularly schools, for asbestos-containing material and
how to evaluate the potential hazard of exposure to asbestos fibers.
BACKGROUND
During the past four years, members of the EPA Region VII office evaluated
over 600 buildings in Iowa, Missouri, Kansas and Nebraska, identified as
containing asbestos. Inspection of these buildings revealed basically three
types of sprayed-on asbestos-containing material (See Figure 1). One was
very fibrous (composed almost entirely of fibers), spongy, fluffy, loosely
bonded, highly friable (easily crushed by hand pressure), and one to four
inches thick. The asbestos content was usually greater than 10% with a
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raaximum asbestos concentration of 98%. It had the appearance of cotton
candy or Spanish moss hanging from the celling and/or walls. This material
was usually a mixture of asbestos plus cellulose, rock wool, or fibrous
glass which had been spray-applied and in many instances had been tamped
(compressed). Several instances were found in which latex or enamel paints
had been applied over the asbestos-containing material.
A second type of asbestos-containing material was an essentially non-fibrous,
cementitious material commonly referred to as acoustical plaster. The major
component of the cementitious, acoustical plaster was usually a dense,
non-fibrous mixture of granular materials such as perlite, calcite, calcium
carbonate and vermiculite. The only fibrous component was the asbestos,
usually at a concentration of less than 10%. This acoustical plaster had most
frequently been spray-applied; although, in a few instances it had been
troweled on. This material had a coarse sand, textured appearance and was
most often 1/8 inch to 1/2 inch thick, with a maximum thickness of 3/4 inch.
Such materials were soft and could easily be indented by hand pressure
and if rubbed, a powder residue remained on the hand. It was light tan in
color If unpainted, but was frequently observed coated with latex paint.
The third type of spray-applied coating was a very hard, concrete-like asbestos-
containing material. It also had a coarse sand, textured appearance and was
approximately 1/8 to 3/4 inch thick. It was most often used to fireproof
structural steel members and was therefore commonly referred to as fireproofing
concrete. It did not leave a powder residue on the hand when rubbed and required
a mechanical device to penetrate the material.
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FIGURE 1.
thick
DESCRIPTION OF SPRAY-APPLIED
ASBESTOS-CONTAINING MATERIAL
FIBROUS
ASBESTOS IS:
1. Highly Friable
2. Very soft
3. Fluffy & Spongy
4. Loosely bonded
together
5. Composed almost
entirely of fibers
6. Cotton candy/Spanish
Moss appearance
7. Usually contains more
than 10% asbestos
GRANULAR
CEMENTITIOUS
ASBESTOS IS:
1. Friable
2. Soft, easily indented
by hand pressure
3. Easily rubbed off as
powder by hand
pressure
4.. Non-fibrous mixture
of granular material,
(only fibrous components
are the few asbestos
fibers)
5. Densely packed
6. Coarse sand, textured
appearance
7. Usually contains less
than 10% asbestos
8. Commonly referred to as
- acoustical plaster
CONCRETE LIKE
thick
ASBESTOS IS:
1. Hard
2. Not friable; can not
be damaged by
hand pressure
3. Requires mechanical
device to penetrate
surface
4. Non-fibrous mixture
of granular material,
(only fibrous components
are the asbestos
fibers]
5. Densely packed
6. Coarse sand, textured
appearance
concrete slab
or steel deck
asbestos
insulation
UJ
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Other types of asbestos-containing material have been observed in other parts
of the United States. An asbestos-containing material having the consistency
and appearance of mud is an example of a type of material observed in a
Maryland school but, to date, not encountered in mid-western schools and
buildings. It is therefore possible that the user of this manual may
encounter an asbestos-containing material not described herein. Evaluation
of such materials should be the same as illustrated in this text.
Asbestos-containing materials were most frequently encountered in the following
areas: air handling room(s), boiler room, gymnasium, auditorium, stage and
backstage, cafeteria, bandroom and music practice rooms, library, bathrooms,
swimming pool, corridors, and above suspended ceilings. Each of these areas
should be inspected and samples collected of suspect material. The highly
friable, spongy, asbestos-containing material was rarely observed throughout
an entire building. In most cases it was observed only in isolated rooms.
For this reason, it is extremely important that each and every air handling
room or music practice room, etc. be inspected. We have inspected schools
with bare concrete in two air handling rooms only to find the ceiling and walls
in the third air handling room coated with two-inch thick asbestos-containing
material. Such air handling rooms are of particular concern because the fan
can pull asbestos fibers off the ceiling and walls and blow the fibers throughout
the building.
Of all the asbestos-containing buildings examined in the Midwest, approximately
80% of the coatings were acoustical plaster having the appearance of textured
ceilings and having the consistency of the second type of asbestos-containing
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material described above. Whenever cementitious, acoustical plaster was
found, it had usually been spray-applied on ceilings throughout the entire
building. The predominant celling construction in mid-western schools
was found to be a 3 coat plaster system on suspended metal lath. The
final coat, or finish coat, of this 3 coat plaster system was the acoustical
treatment containing asbestos fibers.
The concrete like coating was rarely located and usually did not represent
an asbestos fiber exposure hazard because the material was not friable.
In one instance though, this fire proofing concrete had been applied to
structural steel columns which were frequently bumped by fork lifts. Pieces
of fire proofing concrete were knocked to the floor and pulverized by the
tires of the fork lifts thereby releasing asbestos fibers.
The use of asbestos as pipe and boiler wrapping is widespread. Damaged
asbestos wrapping can easily be rewrapped in canvas or with duct tape. Since
such wrapping usually has a high asbestos content, it is important to note
damaged or split canvas jackets and to determine what activity caused the
damage so preventive measures can be instituted.
Many other products in buildings contain asbestos. Just because asbestos is
present in a product or on a ceiling or a wall does not automatically represent a
hazardous situation. Only if these asbestos-containing products or coatings
release asbestos fibers is there a potential for harm. To evaluate whether a
potentially hazardous condition exists, a technique to assess and predict exposure
to asbestos fibers had to be developed.
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ASBESTOS EXPOSURE ASSESSMENT
Since early 1979 EPA has been investigating the development of an assessment
inspection technique which could be used not just to measure the level of
fibers in the air at any one time but rather to predict the potential for
fiber release from material and subsequent contamination of the area. EPA
identified eight factors which describe the condition of the material in
the building, the characteristics of the activities in the vicinity of
the material, and the results of analysis of the material contents. The
information collected through an inspection of an area for these factors
could be combined through a formula to provide a measure of the exposure
potential. This information could also be used to compare different
sites to one another to determine which problems are most severe and to
decide the best corrective action.
All exposure assessment systems now under consideration have a similar
basic format; the inspector visually inspects the area, assesses a value
for each of the factors according to the severity of conditions found in
each inspection area, and combines these values using the formula provided
by the exposure evaluation system. By computing the weighted values In
the formula, the exposure evaluation system gives an "exposure score" or
indication of the appropriate corrective action. The score for each area
can then be compared to other scores; the higher the score, the greater
potential for fiber release and building contamination.
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AIR MONITORING
When EPA first began to address the problem of evaluating asbestos exposure
In buildings, one of the first techniques to be investigated was to take
air samples in the area around the asbestos-containing materials and
determine the concentrations of asbestos fibers* The levels found in
these early examinations could then be compared with the Occupational
Safety and Health Administration's (OSHA) workplace standard for asbestos.
This standard was established to reduce the worker exposure in asbestos
mining and processing industries. This technique has subsequently proven
to be inappropriate in school buildings because of problems in both
attempting to monitor the highly variable levels of fiber release found
in nonindustrial situations and problems in the sampling technique.
The National Institute for Occupational Safety and Health (NIOSH) developed
the method for use in measuring airborne asbestos in industry. NIOSH's
air monitoring method involves drawing a measured amount of air through a
filter and counting the fibers on the filter using a technique called
Phase Contrast Microscopy.
Early researchers looking at asbestos exposure in buildings with friable
asbestos-containing material attempted to use air monitoring with the
NIOSH technique. However, several considerations made the NIOSH method
unsuitable for assessing potential exposure to asbestos in schools and
other buildings.
First, it is impossible for the microscoplst, using phase contrast
microscopy as required by the technique, to distinguish between asbestos
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and other fibers, so that any other fibers found in the area, such as
fibers from carpets and clothing, animal hairs, or wood fiber, could be
mistaken for asbestos. This is not a problem in industry where the fibers
are known to be asbestos but could lead to misidentifications in other
buildings where the type of fiber is not known.
Second, an analyst using the NIOSH Phase Contrast Microscopy Method cannot
identify thin fibers (fiber diameter less than 0.5 micrometers) no matter
the length of the fiber. The method also does not count fibers shorter than
5 micrometers. Therefore, use of the NIOSH method will not detect short/thick
fibers nor long/thin fibers both of which are frequently found in buildings.
Last, and most important, is the fact that the NIOSH method uses short-
term, high volume samples which are (1) inadequate to record the occasional,
high-level fiber releases which occur when the material is disturbed because
it is impossible to predict the location or frequency of these disturbances,
and (2) inadequate to record the low levels typically found in schools
during those times when disturbances of the material are not occurring in
the vicinity of the sampling device.
The NIOSH technique was developed for use in industrial settings where
the level of asbestos could be assumed to be constant and within the
range of detectability of the technique. However, in schools, unpredictable
"peak exposures" from occasional impacts are a significant source of
fiber release which could result in building users' exposure to asbestos
and which cannot, in most cases, be recorded by short term sampling
techniques. Further research has Indicated that very long term sampling
(such as one to three weeks) and analysis using electron microscopy rather
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than phase contrast microscopy could be used to measure the low and
variable concentrations of fibers in schools. This technique is, however,
extremely expensive and time consuming and has therefore not proven useful
in evaluating the thousands of school buildings where exposure problems
are thought to exist.
Because of the highly unpredictable frequency of fiber release in schools
and the limitations of the N10SH analytical technique to identify different
types and sizes of fibers, air monitoring using the NIOSH technique has
proven to be an inappropriate method for evaluating asbestos exposure
problems in schools and similar buildings.
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FIBER RELEASE MECHANISMS
The asbestos-containing materials most likely to release asbestos fibers
are those which were sprayed or troweled onto ceilings and walls or
other structural elements for fireproofing, acoustic or thermal insulation,
or decoration. Because of the type of mixtures used by the construction
industry, these materials are commonly friable, that is easily crushed
or crumbled to a powder when dry, and easily disturbed. The common
application technique of pumping a dry mixture of asbestos and binder
through a ring of water at the nozzle of the applicator tended to create
a very friable mixture. The more friable the material, the poorer the
cohesive strength of the material and the easier it is for the fibers
to come loose.
The type of building also plays a part in predicting whether the material
will be disturbed and fibers released. This is particularly true in
schools built in the periods from World War II up until the late 1970's
when the use of spray-applied asbestos was banned. Schools were usually
constructed with low ceilings and the level of user activity is high;
large numbers of students use the hallways, classrooms, and other areas
of the school for six to eight hours a day. The materials are often
located within reach of the students and the frequent movement of the
population, as well as regular cleaning and rnalntenance, can stir up the
fallen fibers and resuspend them in the air where they can be inhaled by
occupants of the building.
From this discussion, three mechanisms which describe how fibers
are released and dispersed within the building can be identified:
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FALLOUT and IMPACT, which cause the fibers to be released from the
material, and RESUSPENSION of the fibers, which promotes the dispersal
of the fibers throughout the building. These three mechanisms provided
the basis for the development of the eight assessment factors.
FALLOUT
Fallout is the constant release of fibers which occurs as a result of the
weak bonds in the material as it was installed or which have developed
over time due to the deterioration of the bonding materials. Fallout can
be caused by building vibrations and movements of people or machines in
the vicinity of the material. These relatively constant disturbances can
break the weak bond between the asbestos fibers and the rest of the
material and release the fibers into the air. In many cases the material
was not properly applied, for example the components may have been poorly
mixed or not allowed to cure properly, and the material is prematurely
losing its cohesive strength. In other cases the material, which may
have been in place for up to 35 years, has simply outlived its useful
life and deteriorated. Conditions in the area where the material was
applied, such as a particularly high humidity or long exposure to the
sun, can speed up the deterioration process.
The type of substrate (the material to which the friable asbestos-
containing material was applied) may also contribute to the fallout.
Very smooth substrates, such as concrete slabs or steel, or soft material
such as wallboard, tend to offer a poor surface for bonding which may
lead to a premature failure of the adhesive bond between the friable
asbestos-containing material and the substrate. The entire coating of
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material may then pull away from the substrate and be more susceptible
to failure if disturbed.
Usually, fallout is a slow, imperceptible process, but the rate of fiber
release may increase with the age of the structure as the material
deteriorates. The rate of fallout varies primarily due to the level of
background vibration and movement and to the integrity of the material.
Background vibration may be caused by heating and ventilation equipment,
by structural vibration, and by human activity.
IMPACT
Impact is any direct contact with the material that knocks fibers loose.
Such contact may be intentional, as when material is disturbed to install
electrical systems, or when the material is damaged by vandalism. It may
also be unavoidable and accidental, as in the case of maintenance activity.
The frequency of the impact depends on both the location of the material
and the type of activities which occur in the area. If the material is
accessible to building users, the chances of impact are obviously greater.
The use of the structure where the material is located and the activities
of the building users also increase or decrease the chance of impact*
The amount of fibers released during impact will vary according to both
the intensity of the impact as well as the quality of the installation,
especially the degree of friability, the cohesive and adhesive strength
of the material, and the degree of deterioration which has occurred.
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Generally speaking, impact is responsible for a large release of airborne
fibers in a short amount of time. Fallout is low level and relatively
constant, and occurs over a long period of time.
RESUSPENSION
Resuspenslon is the secondary dispersal or reentrainment of fibers which
have previously been released by impact or fallout. The released fibers
will accumulate in the area and be easily stirred up during the course
of routine activities such as maintenance and general foot traffic.
Once resuspended the fibers will remain in the air for long periods of
time. Because the asbestos fibers are extremely aerodynamic, that is
they tend to float in the air for long periods of time, resuspension can
lead to high concentrations of airborne fibers in areas where there is a
source of fibers from fallout and impact.
Resuspension is caused by activities such as sweeping, dusting, and
pedestrian traffic and by air current from circulation systems. As an
example of the level of fibers in the air which can be caused by
resuspension, in a university library where custodians continuously dusted
over a mile of shelving, concentrations of airborne asbestos in the
vicinity of the custodian's breathing zone reached over twice the current
industrial standard for asbestos factory workers. Measurable levels
were also found in the vicinity of other library users at some distance
from the dusting. Generally, resuspension is proportional to the level
of activity within the area.
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BUILDING INSPECTION
Two evaluation forms have been developed to assist you in performing a complete
building inspection and to help you assess the risk of exposure to asbestos
fibers. The data you record will provide the basis for advice on asbestos
control measures given to building owners. An explanation of the importance
of this data and how it will be used follows.
EVALUATION FORM #1
All blanks on Evaluation Form #1 should be filled in. Some questions listing
multiple answers require you to circle the appropriate term(s). This form must
be completed for each building or school inspected and will require interviewing
the maintenance supervisor and/or the school principal. Evaluation Form #2
should be completed only if friable material is found.
The first part of Form #1 is self-explanatory. Many state and local agencies
are cooperating with EPA in this program and you should be aware of who
these contacts are. In most states, the asbestos contact is in the State
Health Department. Be sure to include the mailing address of the school so
that suggested abatement procedures can be sent to the school officials. Line
seven requests the school district number and the total number of schools in
that particular district. This information is needed to assure that all
public and private schools in each district in the state have been inspected.
Line eight requires you to circle which type of building is being inspected.
Circle which type of construction material was used.
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The type of roof in schools Is usually flat with a gravel/asphalt coating.
The reason for asking about the type of roof Is that often water damage to
asbestos-containing ceilings can only be corrected by first repairing the
roof. The date constructed and/or renovated Is of concern because asbestos
was sprayed In buildings mainly from 1945 to 1978. Buildings constructed
and/or renovated during this period deserve special attention. The reason
for requesting the number of floors is to alert you to the possibility that
air-handling rooms could be on several floors. The presence of a basement
usually indicates the location of the boiler room. The attic may have been
sprayed with asbestos-containing insulation and sometimes air-handling rooms
are located here.
Number of faculty, students, maintenance personnel and other building occupants
indicates number of people being exposed. Number of other building occupants
should include such individuals as secretaries, lunch-room workers, volunteer
aides, etc. Frequency of building evening use, and for what purpose, provides
information on the degree of activity in the building and may indicate an
area receiving more damage than other areas.
The persons contacted and their telephone number should be listed. This
identifies the persons familiar with the conditions in the building from whom
additional information can be obtained at a later date, If needed. The section
for comments Is provided to record such information as the names of other
schools or buildings built by the same contractor In the same time period.
It is highly probable that these other buildings also contain asbestos material.
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BUILDING EVALUATION FORM #1
U. S. ENVIRONMENTAL PROTECTION AGENCY
REGION VII - TOXICS AND PESTICIDES BRANCH
324 EAST 11TH STREET
KANSAS CITY, MISSOURI 64106 Date:
Evaluator:
Address:
Phone #
State or Local Asbestos Contact:
EPA Asbestos Coordinator: Wolfgang Brandner, Kansas City, Missouri (816) 374-6538
Building Visited:
Address:
District No.
Number of Schools in District:
Type of Building: Elementary Jr. High Sr. High Other:
Type of Construction: Pre-Cast Concrete Steel Frame Wood
Cast in Place Concrete Other:
Type of Roof:
Masonry
Date Constructed:
Areas Renovated:
Date Renovated:
Number of Floors:
Number of Faculty:
Basement: Yes No Attic: Yes No
Number of Students:
No. of Maintenance Personnel:
No. of other Building Occupants:
Number of Evenings Building Used Per Week:
Parts of Building Used in Evening:
Purpose of Evening Use:
Persons Contacted and Telephone Numbers:
Comments:
Friable Material Found: Yes No
Total Amount of Friable Material in Building:
Evaluator's Signature:
If yes, complete Form #2
sq. ft.
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BUILDING EVALUATION FORM #1 *
U. S. ENVIRONMENTAL PROTECTION AGENCY
REGION VII - TOXICS AND PESTICIDES BRANCH
324 EAST 11TH STREET
KANSAS CITY, MISSOURI 64106 Date:
Evaluator: Roy Jotf£S Address: £"PA K.c. . Mo. Phone #
State or Local Asbestos Contact:
EPA Asbestos Coordinator; Wolfgang Brandner, Kansas City. Missouri (816) 374-6538
Building Visited: WORTHV/EST HIGH SCHOOL _
Address; 3?*J/ Go*y _ Number of Students: /.
No. of Maintenance Personnel : 7 No. of other Building Occupants:
Number of Evenings Building Used Per Week: _ S_ _
Parts of Building Used in Evening: a /
Purpose of Evening Use; sports , ^e.e+i^»s }
Persons Contacted and Telephone Numbers : ^ &. r ry f4 «.r t . S<*.* t. of- R /(*.
r^"^ / T / r- -c.- - ^
Comments; An
Friable Material Found: (Jep No If yes, complete Form #2
Total Amount of Friable Material in Building; 3.? So sq. ft.
Evaluator 's Signature:
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Indicate whether material was found that could be crushed and pulverized
by hand pressure. If such friable material was discovered, Evaluation
Form #2 should be completed for each unique situation in the building.
It may be necessary to consult the school's architect or review the
school's floor plan in order to determine the total number of square
feet of friable material in a building. The total amount of friable
material provides some measure of the magnitude of the suspected problem.
Be sure to sign the evaluation form.
EVALUATION FORM #2 - Front Side
Evaluation Form #2 is to be filled out only if friable material is present.
This form is used to describe the conditions in a separate room or in a
part of a room; therefore, it is very likely that more than one of these
forms will be filled out in a single building. This form contains a few
blanks which need to be filled in. Most of the remainder of the form
requires circling the appropriate description of the conditions observed.
The observations made will provide the following data: 1) What area is
coated with asbestos? 2) What is the type of ceiling construction and
its shape? Figure 2 presents the type of ceiling construction most
frequently encountered in our inspections. Undoubtedly other types of
ceiling construction will be found. 3) Height of ceiling. 4) What is
the type of wall construction if the wall is coated with asbestos-containing
material? 5) What is the thickness of the asbestos-containing material?
6) Is the thickness uniform over the entire sprayed surface (See Figure
3)? 7) Is it spongy and fluffy (See Figure 1)? 8) Are pieces of the
coating lying on the floor or on other horizontal surfaces?
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FIGURE 2.
TYPES OF CEILING CONSTRUCTION
CONCRETE JOIST
AND BEAM CONSTRUCTION
* * m^f** '
.''&'.;
I
>.*.;. ...
*:#::&;
" **"*«
^^^^^J
'''' '\5%?
:**:-: 3°^
OFTEN ASBESTOS APPLIED
ONLY ON UNDERSIDE OF DECK
NOT ON JOISTS OR BEAMS
CONCRETE WAFFLE SLAB CONSTRUCTION
ASBESTOS USUALLY
UNIFORM THICKNESS
STEEL BEAM CONSTRUCTION
CONCRETE OR STEEL.' DECK ^^^^^IjS^i^S^^-'^
SUSPENDED CEILING CONSTRUCTION
^
BAR JOISTS
OR CONCRETE
JOISTS
STEEL
BEAMS
WIRES
AND ~"
CHANNELS
:«s-s»i-:-:-.--MiS^>»Hg:
SPRAYED-ON
ASBESTOS
ASBESTOS USUALLY SPRAYED ON EXPANDED METAL LATH
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FIGURE 3.
THICKNESS OF COATING
UNIFORM COATING
NON-UNIFORM COATING
Concrete joist and beam construction
Asbestos:
uniform thickness
of coating
itJrte&H '..-.. t.*ii>yL!4l*/wSWftl':.-''\.i^i*w
Asbestos:
thickness of coating
varies
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9) Has it been painted? If painted then an attempt should be made to identify
the paint used. 10) Has material been tamped (compressed)? 11) Does the
coating cover the entire ceiling and/or wall or only the beams and joists, or
only the spaces between the beams (See Figure 2)? 12) Is the coating a
granular, cementitious surface having a textured appearance (See Figure 1)?
13) If cementitious material, does it leave a powder on the hands when
rubbed or is powder on furniture and the floor? 14) Are curtains, drapes,
expandable partitions, etc., being pulled across the asbestos-containing
surface. 15) What type of floor and air circulation is present? 16) How
are the lights mounted and how many lights are present? The space for
comments is provided to record any of these findings in more detail.
The information collected on Evaluation Form #2 provides the detailed data
upon which suggestions for corrective action can be made to a school or
building owner. Ceiling construction and height may determine whether a
suspended ceiling can be installed or whether removal is the best option.
The texture of the surface upon which an asbestos coating has been
applied will determine if the cleaned wall or ceiling has to be sealed
with an encapsulant after the asbestos has been removed.
The type of heating/cooling system needs to be Identified as to whether it
is central air or unit ventilators or some other kind. We have observed
some schools with no asbestos in any of the classrooms, corridors or gymnasium,
but found severely damaged asbestos-containing material on the ceiling and
walls of the fan room. A central air duct system connected to the fan served
as the conduit for spreading asbestos fibers throughout the entire building.
Whether the lights are surface mounted to the asbestos-containing material,
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suspended (hang below the asbestos) or recessed (submerged into the asbestos-
containing material) may affect the choice of abatement methods. If an
enclosure system were chosen, recessed and surface mounted lights would
have to be lowered and rewired.
The type of floor is important to note because instructions must be provided
on how to remove asbestos fibers from carpet if any is present. Tile and
wood floors can easily be damaged if water containing a wetting agent is
allowed to contact such floors during asbestos removal. The building
owners need to be alerted to this potential problem so that they can
make certain the contractor takes appropriate steps to protect these
types of floors.
The question about what is above the room being evaluated is significant
when the possibility of ceiling vibration exists. Some schools have
been evaluated in which classrooms were in the basement and the gymnasium
was directly above these rooms. The floor of the gymnasium vibrated
frequently from ball impacts and other sports activities, causing asbestos
fibers to shake loose from the coating on the basement classroom ceilings.
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EVALUATION FORM #2 - Reverse Side
On the reverse stde of Form #2 is a numerical system (algorithm) for
evaluating the asbestos exposure hazard in a room. This algorithm was
developed for EPA and evaluated in several large urban and statewide
school systems. It has been used in both the Iowa and Kansas school
inspection efforts by state inspectors. The remainder of this manual
describes this evaluation system and how to determine which numerical
values to assign to each of the factors being evaluated.
Recent comparisons of this algorithm with long-term air sampling data
revealed that the algorithm did not provide accurate and reliable exposure
information. For example, some instances were observed in which low
numerical scores were recorded indicating no need for abatement actions
yet air samplings revealed significant levels of asbestos fibers in the
air. Research is continuing in an effort to develop more reliable hazard
evaluation systems. In the meantime, this algorithm along with the
other information collected on Evaluation Forms #1 and 92 is the best
available tool for measuring potential risk.
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BUILDINGS EVALUATION FORM #2
U. S. ENVIRONMENTAL PROTECTION AGENCY
REGION VII - TOXICS AND PESTICIDES SECTION Date:
324 EAST 11TH STREET
KANSAS CITY, MISSOURI 64106 Dist. No.:_
Room: Sample Number(s):_
Building: Address:
Evaluator: Phone No*:
Coated Area: Celling Wall(s) Structural Members Above Suspended Celling
Pipe Lagging Boiler Insul. Other:
Type of
Celling: Concrete 3 Coat Plaster System Suspended Metal Lath
Concrete Joists and Beams Tile Suspended Lay-In Panels
Metal Deck Corrugated Steel Steel Beam or Bar Joists
Celling Height: _ ft.
Ceiling Shape: Flat Dome Other
(draw):
W/V/S/V /-VV>
Folded Plate Barrel
Type of Wall (If Coated): Smooth Concrete Rough Concrete Masonry
Plasterboard Other: _
Amount of Friable Material in Area being Evaluated: _ sq. ft.
Description Fibrous Granular/Cementltious Concrete Like
of Coating: (highly friable) (soft) (hard)
Thickness: _ Inch(s) Is thickness uniform: Yes No
Coating debris on Floor/Furniture/Work Surfaces: Yes No
Curtains, expandable partitions, etc. being pulled across coating: Yes No
Coatng is Painted: Yes No Coating Is tamped: Yes No
Type of Lighting: Surface Mounted Suspended Recessed
No. of Lights: _ Type of Heating/Cooling System: _
Type of Floor: Concrete Tile Wood Carpet Other:
What is above the room being evaluated?
Comments;
Evaluator's signature:
(continue on back)
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-25-
BUILDINGS EVALUATION FORM #2
U. 8. ENVIRONMENTAL PROTECTION AGENCY
REGION VII - TOXICS AND PESTICIDES SECTION
324 EAST 1 1TH STREET
KANSAS CITY, MISSOURI 64106 Dlst. No. \
Date:/*-
Room ;
srA .
LMetal Deck) Corrugated Steel
Celling Height; jgo- 3o ft.
Celling Shape: Flat
Suspended Metal Lath
Suspended Lay-In Panels
Beam or Bar Joists^
Other
(draw):
Folded Plate Barrel
Type of Wall (If Coated): Smooth Concrete Rough Concrete
Plasterboard Other:
sonry
Amount of Friable Material in Area being Evaluated; /*>, pop sq. ft.
Description /" Fibrous " \ Granular/Cementltious Concrete Like
of Coating: ((highly friable)) (soft) (hard)
Thickness; «7-3 inch(s) Is thickness uniform: Yes
Coating debris on Floor/Furniture/Work Surfaces: \^£) No
Curtains, expandable partitions, etc. being pulled across coating: Yes
Coatng is Painted: Yes (N$) Coating Is tamped: Yes (No^>
Type of Lighting: Surface Mounted ("Suspended^ Recessed
No. of Lights: /»2 Type of Heating/Cooling System:
CWood
Carpet Other:
Type of Floor: Concrete Tile
What is above the room being evaluated?
Comments: A*L**tat. #* IIe** +/»j j*M£tAl>*<**4* »rt»p* *t»r*4 *jml«jf ** II.
Evaluator's signature;
(continue on back)
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- 26 -
NUMERICAL EXPOSURE ASSESSMENT
FACTORS
1. CONDITION
2. WATER DAMAGE
3. EXPOSED SURFACE
+
4. ACCESSIBILITY
5. ACTIVITY/MOVEMENT
6. AIR PLENUM/AIR STREAM
7. FRIABILITY
X
8. % CONTENT
SCORES
(0,2.5)
(0,1,2)
(0,1,4)
(0,1,4)
(0,1,2)
(0,1)
(0,1,2,3)
(0,2,3)
SUM
PRODUCT X
EXPOSURE NUMBER
Additional Comments and/or Illustrations:
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-27 -
NUMERICAL EXPOSURE ASSESSMENT
FACTORS
1. CONDITION
2. MATER DAMAGE
3. EXPOSED SURFACE
f
4. ACCESSIBILITY
5. ACTIVITY/MOVEMENT
6. AIR PLENUM/AIR STREAM
7. FRIABILITY
X
8. % CONTENT ft%A~o*ite
SCORES
(0,2,5) S
(0,1,2) *
(0,1,4) H
(0,1,4) V
(0,1,2) *
(0,1) '
(0,1,2,3) 3
(0.2.3) 3
^**>/
SUM , ,
PRODUCT X -
EXPOSURE NUMBER / k X
Additional Comments and/or Illustrations:
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-28-
EXPOSURE ASSESSMENT - A NUMERICAL SYSTEM
An asbestos exposure assessment system is a decision tool which can be
used to determine the level of exposure to asbestos which exists in a
building and which can also indicate what, if any, corrective action is
required to control the problem. Chapter 7 "Exposure Assessment" of EPA's
manual "Asbestos-Containing Materials in School Buildings: A Guidance
Document-Part I" presents eight factors which must be considered by the
building inspector when determining whether a hazardous condition exists
due to the presence of asbestos. Presented is a method for numerically
combining these factors to obtain an "Exposure Number" which, when compared
to a "Corrective Action Scale" will indicate whether (and in some cases
which) abatement action is necessary.^ The actual characteristics of
the asbestos-containing material and the activities in the vicinity of
the material provided the basis for the selection of the eight assessment
factors.
The numerical system has been prepared taking into consideration fiber
characteristics, asbestos risk factors, and experience with school
exposure situations. It is intended as a guide by which officials can
determine the appropriate level of concern for an exposure problem. It
will also aid in the selection of appropriate corrective methods.
Chapter 7 points out limitations of exposure assessment, which apply to
numerical as well as unquantified methods.
1 A true exposure assessment must consider factors such as duration of
exposure and population characteristics. This numerical method does not
Include such factors.
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The numerical system has three steps: (1) the eight factors are assigned a
numerical value by the inspector of the building; (2) the numerical values are
combined by SL mathematical formula to produce the Exposure Number; and (3) the
Exposure Number is compared to the Corrective Action Scale. These three steps
should be performed for each area of the building in which asbestos has either
been found or is believed to be present. The three steps of the exposure
assessment are described below.
Step 1; Factor Score Selection
Table 1 presents a list of the eight factors, a brief description of the
range or extent to which a particular condition applies, and a numerical
"Factor Score" corresponding to that description. The building inspector
must first select the description best fitting the situation in that area.
Only the scores Indicated can be assigned to a factor. For example, "1",
"3", and "4" are not acceptable scores for material condition. The selected
score must then be written in the appropriate box (1 through 8) of Form 92
which initiates Step 2.
The area to be evaluated may be any part of the building where the factors
remain uniform. For example, an auditorium with both an inaccessible ceiling
surface in the stage area and a very accessible and damaged surface in the
audience area constitutes two different areas. The scores for the two
areas may exhibit a wide variation in exposure numbers, a different exposure
assessment, and possibly different corrective actions.
A detailed description of the eight factors and photographs representing
each of the numerical values has been assembled from actual building
-------
Factor
1. Material Condition
(Deterioration/
Damage)
-30-
TABLE I
ASBESTOS EXPOSURE ASSESSMENT
FACTOR SCORES
Range or Extent
None
Moderate; small areas
Score
0
Widespread; severe; pieces dislodged
2. Water Damage
None
Minor
Moderate to major
3. Exposed Surface
Area
Not exposed. Located above suspended
ceiling. None visible without removing
panels or ceiling sections
10% or less of the material is exposed
10% to 100% of the material is exposed
4. Accessibility
Not accessible
Low; Rarely accessible
Moderate to high; Access may be frequent
5. Activity and
Movement
None or low; Libraries, most classrooms
Moderate; Some classrooms, corridors
High: Some corridors and cafeterias, all
gymnasiums
6. Air Plenum or
Direct Air Streams
None
Present
7. Friability
Not Friable
Low friability. Difficult but possible
to damage by hand.
Moderate friability. Fairly easy to
dislodge and crush.
Highly friable. Fluffy, spongy, flaking,
pieces hanging. Falls apart when touched.
8. Asbestos Content
(total % present)
Trace to 1%
1% to 50%
50% to 100%
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-31-
inspections conducted in the four state area. The photographs have been
included to provide graphic images of the type of conditions described by
each of the numerical values and to provide some uniformity to the
assigning of these values when different inspectors rate suspected
asbestos-containing material.
ASSESS EACH OF THE FACTORS
Carefully consider each of the following seven factors (the eighth factor,
asbestos content, must be determined from laboratory reports) and record
your observations:
FACTOR ONE. MATERIAL CONDITION;
The condition of the asbestos-containing material is the most important
indicator of whether fibers have been released in the past or may be
released in the future.
An assessment of the condition should evaluate: the quality of the
installation, the adhesion of the friable material to the underlying
substrate, deterioration, destruction of the material by water, vandalism
which has damaged the material, and any other damage. Evidence of debris
on horizontal surfaces, material hanging, dislodged chunks, scrapings,
indentations, or cracking are indicators of poor material condition.
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-32-
Condition is closely related to other factors considered in the assessment
inspection: if the asbestos-containing material is accessible, it is
likely to be damaged; if the activity level is high in the area, the level
of damage may be high; and materials which are exposed may be more likely
to sustain damage.
Accidental or deliberate physical contact with the friable material can
result in damage to the asbestos-containing material. Inspectors should
look for any evidence that the asbestos-containing material has been
disturbed such as finger marks in the material, graffltti, pieces dislodged
or missing, scrape marks from movable equipment or furniture, or accumulation
of the friable material on floors, shelves, or other horizontal surfaces.
Asbestos-containing material may deteriorate as a result of the quality
of the installation as well as environmental factors which affect the
cohesive strength of the asbestos-containing material or the strength of
the adhesion to the substrate. Deterioration can result in dusting of
the surface of the asbestos-containing material, delamination of the
material (i.e. separating into layers), or an adhesive failure of the
material where it pulls away from the substrate and either hangs loosely
or falls to the floor and exposes the substrate. Inspectors should
touch the asbestos-containing material and determine if dust is released
when the material is lightly brushed or rubbed.
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-33-
If the coated surface "gives" when slight hand pressure is applied or the
material moves up and down with light pushing, the asbestos-containing
material is no longer tightly bonded to its substrate.
This factor is comprised of three levels:
A. NO DAMAGE: Material is intact and shows no sign of deterioration,
No pieces larger than a half-dollar have been dislodged.
NUMERICAL VALUE: 0
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-34-
FACTOR ONE: MATERIAL CONDITION:
B. MODERATE DAMAGE - SMALL AREAS: Through visual inspection and
physical contact there are indications that 10% or less of the
material is breaking up into layers or beginning to fall. There
may be small areas where the material is deteriorating. There
may be signs of accidental or intentional damage.
NUMERICAL VALUE: 2
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-35-
FACTOR ONE. MATERIAL CONDITION:
C. WIDESPREAD SEVERE DAMAGE: Greater than 10% of the material is
damaged. Large pieces are dislodged and/or debris in the area
is evident. Parts of the material may be suspended from the
ceilings or may have fallen to the floor. Evidence of severe
accidental or intentional damage.
NUMERICAL VALUE: 5
Severely deteriorated
and damaged asbestos-
containing ceiling
insulation. -Note the
material is composed
entirely of fibers.
Asbestos-containing
wall insulation
deteriorated and
falling to the floor,
-------
-36-
FACTOR ONE. MATERIAL CONDITION:
C. WIDESPREAD SEVERE DAMAGE: (continued)
Large pieces of granular/cementitious, asbestos-containing
acoustical plaster have seperated from the ceiling and
fallen to the floor.
Pieces of asbestos-containing, acoustical plaster lying on
the floor and being pulverized by foot traffic.
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-37-
FACTOR TWO. WATER DAMAGE;
Water damage is usually caused by roof leaks, particularly in schools with
flat roofs or a concrete slab and steel beam construction. Skylights can
also be significant sources of leaks. Water damage can also result from
plumbing leaks and water in the vicinity of pools, locker rooms, and lava-
tories .
Water can dislodge, delaminate, or disturb friable asbestos-containing materials
that are otherwise in good condition and can increase the potential for fiber
release by dissolving and washing out the binders in the material. Materials
which were not considered friable may become friable after water has dissolved
and leached out the binders. Water can also carry fibers as a slurry to other
areas where evaporation will leave a collection of fibers that can become resus-
pended in the air.
Inspect the area for visible signs of water damage such as discoloration of the
asbestos-containing material, stains on the asbestos-containing material,
adjacent walls, or floor, buckling of the walls or floor, or areas where pieces
of the asbestos-containing material have separated into layers (delaminated) or
come loose and fallen down thereby exposing the substrate.
Close inspection is required. In many areas staining may only occur 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 was conducted causing new areas to
become friable and require an assessment inspection.
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-38-
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.
This factor is comprised of three levels:
A. NO WATER DAMAGE: No water stains or evidence of the material being
disturbed by water. No stains on the floor or walls to indicate
past water damage.
NUMERICAL VALUE: 0
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-39-
FACTOR TWO. WATER DAMAGE:
B. MINOR WATER DAMAGE: Small areas of the material or adjacent floor
and/or walls show water stains and ceiling material may be slightly
buckled. However, pieces have not fallen from the ceiling and the
damage affects 10 percent or less of the material.
NUMERICAL VALUE: 1
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-40-
FACTOR TWO. WATER DAMAGE:
C. MODERATE TO MAJOR WATER DAMAGE: Water has dislodged some of the
material and caused the material to break away, or has become
saturated and has the potential to fall, and/or greater than 10
percent of the material has been affected. Asbestos fibers have
been carried from the asbestos-containing material by water,
evaporation has occurred, and the fibers have been deposited on
other surfaces.
NUMERICAL VALUE: 2
Water has destroyed the bond between the acoustical plaster
and the substrate. Note delamination of ceiling coating.
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-41-
FACTOR TWO. WATER DAMAGE:
C. MODERATE TO MAJOR WATER DAMAGE: (continued)
Water damage particularly severe around sky lights.
*
Water has leached asbestos fibers from the acoustical plaster ceiling,
carried these fibers down the wall and evaporated leaving a deposit
of asbestos fibers on the wall.
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-42-
FACTOR THREE. EXPOSED SURFACE AREA;
The amount of asbestos-containing material exposed to the area occupied by
people can increase 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, i.e. if there
are no physical barriers which must be moved in order to get to the material,
For a material not to be exposed, the barrier must be complete, undamaged,
and not likely 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 ceilings, 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.
Asbestos-containing material above a suspended ceiling is considered
exposed if the space above the suspended ceiling comprises an air plenum.
Suspended ceilings with numerous louvers, grids or other open spaces
should be considered exposed.
-------
-43-
This factor is comprised of three levels:
A. MATERIAL NOT EXPOSED: Located above suspended ceiling. None
visible without removing panels or ceiling sections. Suspended
ceiling is not damaged.
NUMERICAL VALUE: 0
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-44-
FACTOR THREE. EXPOSED SURFACE AREA:
B. TEN PERCENT OR LESS OF THE MATERIAL IS EXPOSED: A few panels of
a suspended celling have been removed. Spaces between ceiling
tiles exist which would allow fibers to pass through the barrier.
NUMERICAL VALUE: 1
i
Space between
suspended ceiling
Danels and wall.
Asbestos-containing
Insulation above
suspended celling.
Light difuser panel
missing from sus-
pended ceiling.
Light recessed into
as bestos-containing
insulation.
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-45-
FACTOR THREE. EXPOSED SURFACE AREA:
C. GREATER THAN 10 PERCENT OF THE MATERIAL IS EXPOSED.
NUMERICAL VALUE: 4
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-46-
FACTOR FOUR. ACCESSIBILITY;
If the friable asbestos-containing material can be reached by building users
or maintenance people either directly or by impact from objects used in the
area, it is accessible and subject to accidental or intentional contact and
damage. Material which is accessible is most likely to be disturbed in the
future.
Evidence of degree of accessibility can also be determined by examining
asbestos-containing surfaces for impact marks, gouges, scrapes, finger marks,
items thrown into the material, etc. Even coated ceilings 25 feet high have
been observed with pencils, pens, forks and other items stuck in the material.
Also note such practices as stacking boxes from floor to ceiling. The top
box may scrape the asbestos-containing coating off the ceiling when it is
moved.
The proximity of the friable asbestos-containing material to heating,
ventilation, lighting and plumbing systems requiring maintenance or repair
may increase its accessibility.
In addition, the activities and behavior of persons using the building
should be included in the assessment of whether the material is accessible.
For example, persons involved in athletic activities may accidentally cause
damage to the material on the walls and ceilings of gymnasiums through contact
by balls or athletic equipment. To become fully aware of the uses of the
building by its occupants, the inspector should consult with building staff
or personnel familiar with routine building activities.
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-47-
This factor is comprised of three levels:
A. NOT ACCESSIBLE: The material is located above a tight suspended
ceiling or is concealed by ducts or piping. The building occupants
cannot contact the material.
NUMERICAL VALUE: 0
Asbestos-containing insulation on ceiling behind a suspended,
splined-tile ceiling.
-------
KACTOK KOUK. ACCKSSIIIII.ITY:
H. KAKKI.Y ACCKSSIHI.K: Tin- inatnlal In rontai'ti-d only din Ing abnormal
activity mull MM I 111 i ci| in-ill ma I ill rnancc or i |-.i I i ol nearby In'iilni;
- ni i 1.11 11 HI . Mi'liiini' 01 |i I mill, i n;' . ,". i i-iM'. . tin i I il I ii)'. 01 i iijiani .'i rarely
t < null t lie mat t-1 I a I 01 t Ii i ow ol» |i-r t n i,'. i I n-. I I I .
NIIMI'KICAI. VAI.IIK: I
»,.-jJ*-*^"«»
l.lf.lit MxtiiM' i ...-.I Into II.IH--II on ( onl ,t I nl UK I nmi I at 1 on ,
liji.n i- .iliovi- MIIII|IIMII|I-I| « i-ll hi)-, lan-ly <-iit < t c
-------
KACTOK KOIIK. ACCI'.SSIIII I.ITY:
C. IIICHI.Y ACCK.SSIHI.K: M/it.-il.il In cmintr t ril I r ci| ncnt I y ', ncr ii|i i n I '. .111 i i in I n I t lie
in.iii-il.il liming iK.iinil .irtlvlly .it which I I mi- I licy r out I in-I y
I micll Mild (I I u I ixlf'c I In- in.il i-i I .1 I ; MI Iliiuw iili|i-rln ,i^.,ilii'il It
NIIMKKICAI. VAI.IIK: /t
-------
-50-
FACTOR FOUR. ACCESSIBILITY:
C. HIGHLY ACCESSIBLE: (continued)
Look, for evidence of contact and damage such as finger marks in
acoustical plaster ceilings.
Although some ceilings may be more than 18 feet high, evidence
of ball impact damage is observable on the ceiling.
-------
FACTOR FOUR. ACCESSIBILITY:
C. HIGHLY ACCESSIBLE: (continued)
Although some asbestos-
containing ceiling
insulation may be out
of the reach of
building occupants,
a ceiling is still
considered highly
accessible if items
have been thrown at
it. In many cases
such items remain
embedded in the
insulation, as
the paper airplanes
in the photograph.
Another example of highly
accessible, asbestos-
containing insluation is
wall coatings. Normal
activities such as flip-
ping a light switch can
result in knocking pieces
of the wall insulation to
the floor.
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-52-
FACTOR FIVE. ACTIVITY AND MOVEMENT;
The level of activity and movement in the vicinity of the astestos-containing
material can affect both the potential for disturbance of the material as well
as the level of resuspension of the fibers which have come loose from the
material. Consider not only the movement caused by the activities of people
in the area but also movement from other sources such as high vibration from
adjacent rooms, highways, etc.
Another source of vibration is sound, such as music and noise. Sound sets air-
waves in motion at certain frequencies. As these sound waves impact on asbestos-
containing material, they may vibrate this material and contribute to fiber
release. Therefore fibers may be released to a greater extent in a band room,
music practice room, or auditorium than in the remainder of the building. Air-
craft noise also has the ability to vibrate buildings; therefore, the inspector
should determine if the building is in a direct flight path. Although 1 am
not aware of any research data which would substantiate my hypothesis that
sound vibrations could contribute to fiber release, common sense would indicate
that this theory has merit. During our inspections we have learned that in
several schools whose ceilings were coated with asbestos-containing acoustical
plaster, the band rooms were dustier than any other room in the school and
granular material was deposited on floors and desks after music practice sessions.
The level of activity can best be described by identifying the purpose of the area
as well as estimating the number of persons who enter the area on a typical day.
This factor is comprised of three levels:
A. NONE OR LOW ACTIVITY: This level would normally include areas
such as administrative offices, libraries, and those classrooms
where the population is quiet and non-destructive.
NUMERICAL VALUE: 0
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-53-
FACTOR FIVE. ACTIVITY AND MOVEMENT:
B. MODERATE ACTIVITY: This level describes corridors, classrooms or
other areas where activities exist that could create undue vibration.
This vibration could result in fibers being released from the
material into the immediate area.
NUMERICAL VALUE: 1
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-54-
FACTOR FIVE. ACTIVITY AND MOVEMENT:
C. HIGH ACTIVITY LEVEL: This level may be found in cafeterias and
corridors whose occupants are vandalous or disruptive in their
activities. This also includes all gymnasiums, swimming pools
and rooms containing machinery.
NUMERICAL VALUE: 2
Although the activity
level of the room
occupants may be low,
sound waves generated
by the musical instru-
ments may vibrate the
asbestos-containing
insulation and result
in fiber release.
Gymnasiums are high activity level
areas and ceiling damage is usually
evident.
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-55-
FACTOR SIX. AIR PLENUM OR DIRECT AIR STREAM;
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. In evaluating whether an air plenum or
direct air stream 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.
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 you
will have to lift the tiles in the suspended ceiling to check if this is the
case. Inspection of the air handling or HVAC equipment rooms may also provide
evidence of the presence of this material in the plenums.
Special attention should be paid to whether activities such as maintenance
frequently occur which would disturb the material in the plenum. Also any
evidence that the material is being released or eroded (i.e. is it damaged
or deteriorated so that the material is free to circulate in the airstream)
such as accumulations of the material in the plenum should be noted.
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-56-
The presence of a direct air stream is indicated by discoloration of the
asbestos coating in the vicinity of a vent or erosion patterns may be
evident in the asbestos-containing material.
This factor is comprised of two levels:
A. NO AIR PLENUM OR DIRECT AIR STREAM PRESENT:
NUMERICAL VALUE: 0
An Anemostat - air diffuser designed to direct the
air stream downward in a circular pattern, usually
directing no air passage across ceiling surface.
No dust patterns are evident either on the ceiling
or on nearby walls.
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-57-
FACTOR SIX. AIR PLENUM OR DIRECT AIR STREAM:
B. AIR PLENUM OR DIRECT AIR STREAM PRESENT: Look for dust patterns
deposited by an air stream on surfaces next to air supply diffusers,
Fan rooms coated with asbestos-containing material may be con-
tributing asbestos fibers to the building air if the circulation
system draws air from such a coated room. Look for debris from
the asbestos-containing material being deposited on dampers and
filters of the air intake.
NUMERICAL VALUE: 1
Look for air erosion patterns in the ceiling or wall coating.
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-58-
FACTOR SIX. AIR PLENUM OR DIRECT AIR STREAM:
B. AIR PLENUM OR DIRECT AIR STREAM PRESENT:
(continued)
Insulation debris
on ceiling tiles
Erosion Pattern in
Asbestos Ceiling
Insulation.
<-Open End Air Duct
Suspended Ceiling
Tiles
Air Plenum Space Above Suspended Tile Ceiling
As bestos-Containing
insulation debris
Close-up of lower portion of photo above,
Perforated Metal
Ceiling Tiles (Note
numerous 1/8 inch
holes in tiles)
-------
-59-
FACTOR SEVEN. FRIABILITY:
The term "friable" is applied to material that can be crumbled, pulverized,
or reduced to powder by hand pressure. In order to evaluate the friability
of the material it must be touched. The asbestos-containing material can
vary in degree of friability. The more friable the material, the greater
the potential for asbestos fiber release and contamination. Spray applied
asbestos-containing material is generally more friable than trowel applied
material.
This factor is comprised of four levels:
A. NOT FRIABLE: Material that is hard and crusty. Cannot be
damaged by hand. Sharp tools required to penetrate material.
NUMERICAL VALUE: _0
B. LOW FRIABILITY: Material that is difficult yet possible to damage
by hand. Material can be indented by forceful impact. If the
granular, cementitious asbestos-containing material is rubbed,
it leaves granules on the hand but no powder.
NUMERICAL VALUE: 1
v*r/- N^BT
-------
-60-
KACTOK SKVKN. KK1AH1UTY:
C. MODKKATK KKIAHll.lTY: Kairly eany to dislod^i- ami nush or
pulverize. Material may bt> removed In small or lai^i- |ilecea.
Material In soft and can eaully be Indented by hand |>re«sure.
Tin- granular, ceraentttloua aabeBtos-contal ul nf, inaiftlal leaves a
powiltT residue on the hands when ruhb«'d.
NUMKKICAL VA1.UK: 2
-------
I-1
FACTOR SKVKN. KK1 ABILITY:
L). IIK;H KKIABIUTY: The material In tlutfy, spongy, or flaking and may
huve pieces hau^lu^ ciown. Kaully crushed or pulverized by minimal
hand pressure. Material may disintegrate or fall apart when touched,
NUMKK1CA1. VAI.IIK: 3
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-62-
FACTOR EIGHT. ASBESTOS CONTENT:
The percentage for all types of asbestos present should be added for the total
asbestos content. The numerical value is assigned based upon the report of
analysis, not on appearance of the material. The photographs are included only
to demonstrate the appearance of coatings most frequently observed that contain
asbestos at the concentrations describing this factor. Many coatings look
just like those represented in the pictures, but do not contain any asbestos.
With a high percentage of asbestos, there are more fibers that can be released
and contaminate the building environment. Therefore, if certain areas are
identical in their assessment using the other seven factors, this factor will
be helpful in establishing priorities and indicating which area needs to be
addressed first. This factor is comprised of three levels:
A. TRACE AMOUNTS TO ONE PERCENT.
NUMERICAL VALUE: 0_
B. ONE PERCENT TO FIFTY PERCENT. Ceiling and wall coatings most
frequently encountered in this category were the granular, cementitious
acoustical plasters.
NUMERICAL VALUE: 2
- V
' .
'- >:' ' J**l
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FACTOR EIGHT. ASBESTOS CONTENT:
C. FIFTY PERCENT TO ONE HUNDRED PERCENT. Most frequently materials
containing over 50% asbestos were pipe and boiler wrapping or the
fibrous, cotton candy, type sprayed-on insulation.
NUMERICAL VALUE: 3
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Step 2: Exposure Number Calculation
The Exposure Number is derived from the Factor Scores by a formula. After
entering the chosen Factor Scores on lines 1 through 8 of Form #2:
a) Sum factors 1 through 6 and enter opposite SUM;
b) Multiply factor 7 times factor 8, and enter opposite PRODUCT;
c) Multiply SUM times PRODUCT and enter opposite EXPOSURE NUMBER.
This number represents the result of your assessment for each area of the
building. The values can range from 0 to 162. The higher the numerical
value, the greater the potential for fiber release and therefore the more
hazardous the situation. The Exposure Number must now be compared to the
Corrective Action Scale, which is Step 3.
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Step 3: Comparison of Exposure Number to Corrective Action Scale
Table II, Corrective Action Scale, presents four types of corrective action,
a brief description of each, and a range of Exposure Numbers for which that
Corrective Action is appropriate. Compare the Exposure Number derived in
Step 2 to the ranges in Table II to determine whether action is needed.
For example, an Exposure Number of 60 clearly Indicates that the asbestos
should be removed. An Exposure Number of 10, however, might suggest
encapsulation or deferral of action. In this case it is necessary to
further analyze the situation, perhaps to consider factors such as length
of time that action could be deferred.
The Exposure Number can be used:
(1) To determine whether corrective action can be deferred or
initiated. With a score of zero to twelve, corrective action
can usually be deferred. This is assuming that a continuing
inspection program will be Implemented and that Inadvertent
damage to the material will be avoided.
(2) To set priorities for decision making. The higher the exposure
number, the higher the priority.
(3) To select a corrective action. The exposure number Indicates
methods found to be appropriate in school exposure situations.
The corrective action scale is to be considered as a guideline for
decision making. Local conditions will have significant
Influence on corrective action selection.
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TABLE 2
CORRECTIVE ACTION SCALE
CORRECTIVE ACTION
Deferred Action
EXPOSURE NUMBER RANGE
0-12
Encapsulation
There appears to be a wide range of
numbers and conditions where use of
a sealant has provided a satisfactory
solution. Encapsulation seems to be appro-
priate especially for conditions where
there is a large area exposed
(Factor 3) and there is a low score
for the other factors. It is
inappropriate to use encapsulation
where severe water damage or the
potential for water damage is evident
(Factor 2). A high accessibility
factor (Factor 4) also indicates that
encapsulation is inappropriate.
Enclosure
Enclosure has been used over virtually
the entire range from below 10 to above
10-50
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100. It is also, by far, the least used
corrective method. It is an Inappropriate
corrective method in the same situations
where encapsulation is inappropriate
(Factors 3, 2, and 4).
Removal 40 and over
Removal is the only complete solution.
It is usually appropriate where the
exposure number indicates a high exposure
problem. Removal can be inappropriate
if the asbestos material must be removed
from a complex surface (such as pipes,
lines, and ducts) which is relatively
inaccessible.
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USE OP ALGORITHM SCORES TO DETERMINE POTENTIAL FOR FIBER RELEASE
In the previous publication of this manual examples were provided demonstrating
the use of algorithm scores to determine appropriate corrective actions.
During four years of use by EPA Regional Office inspectors as well as by
state inspectors, the algorithm was found to be more useful as an indicator
of the degree of hazard than as a justification method for a particular
corrective action. Experience has shown that the corrective action chosen by
a building owner often is determined by none of the algorithm factors; instead,
it is determined by available financial resources and by employee as well as
public pressure. The algorithm proved to be a useful tool in setting
priorities. The assumption was made that the higher the algorithm exposure
number, the more hazardous the situation and the more likely for asbestos
fibers to be released Into the building air. In this manner school districts
as well as building owners could be advised of which buildings or areas within
buildings needed correction on a priority basis and which ones could be postponed.
The use of an algorithm or any other assessment system for determining the need
to take corrective actions relies on estimating the likelihood of fiber
release from asbestos-containing materials. Factors are evaluated which are
assumed to represent a relationship between the asbestos-containing materials
and airborne, asbestos fiber levels. Such an assessment tool has the advantage
of being practical by allowing an inspector the use of the powers of observation
to reveal the potential for future fiber release even when actual levels of
airborne asbestos fibers are relatively low. An Inspector trained In the use
of the algorithm can evaluate the asbestos-containing materials in various
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locatlons within a single building or in different buildings and compare
results. This type of comparative rating system can then be used for setting
asbestos control priorities.
To determine the validity of the assumed relationships between the eight
algorithm factors and actual concentrations of airborne asbestos fiber levels,
EPA sponsored a comprehensive study in an urban school district comparing
algorithm scores with air monitoring. Of the eight algorithm factors assumed
to be positively correlated to measured levels of airborne asbestos fibers,
only two were confirmed: the presence of water damage and proximity of the
asbestos-containing material to an airstream created by the ventilation
system. Results for the degree of friability, percent asbestos content and
degree of activity did not confirm prior expectations of a direct relationship
with airborne asbestos fiber levels. The factors of accessibility, degree of
exposed surface area, and condition of the material did not receive a fair
evaluation because little or no variation in algorithm scores was observed in
the schools. These and other findings indicate that ratings derived from
subjective assessments of fiber release potential are not reliable indicators
of measured airborne asbestos levels* This conclusion Illustrates that air
monitoring only provides information on current airborne fiber levels and
cannot be used as a tool to predict potential fiber release. The algorithm
was intended as a device to measure the potential for fiber release and as
such is a useful evaluation mechanism in the hands of a trained Inspector.
By recognizing the limits of the algorithm, as demonstrated by the recent
EPA study, It can still be a useful hazard evaluation tool.
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In our experience, we recognized that the algorithm was not sufficient within
itself to allow us to make asbestos abatement suggestions to school officials
and building owners. Therefore, Evaluation Form #1 and the front of Evaluation
Form #2 were developed. By combining the algorithm scores with information
from these forms abatement decisions could be reached. For example, if the
algorithm score was high, over 60, and there was asbestos debris on the floor
and almost every square inch of ceiling was covered by ball impact marks, the
prudent decision was made to close and seal the gymnasium until asbestos
removal could be undertaken. Conversely, if the algorithm score was low,
below 15, and there was no asbestos debris on horizontal surfaces, the
asbestos-containing ceiling coating was out of the reach of the building
occupants, objects had not been thrown into the ceiling coating, and neither
curtains nor expandable partitions were brushing across the asbestos-containing
material, no abatement actions were needed but periodic re-inspections and
wet cleaning methods were instituted.
An algorithm score of between 10 and 40 indicated an asbestos-containing
material that was still in relatively good condition but was likely to be
releasing asbestos fibers. Such material could be considered for encapsulation.
In addition to the algorithm score, the appropriateness of encapsulation was
in part determined by the thickness of the asbestos-containing material and
whether this thickness was uniform throughout the spray-applied material.
Based on previous encapsulation studies by Battelle Laboratories under contract
to EPA, most penetrating encapsulants could only penetrate through 3/4 inch
of fibrous material. Only two encapsulants were capable of penetrating to
1 1/4 inch. Therefore, fibrous coatings thicker than 3/4 inch were considered
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for encapsulation only after testing to determine if the encapsulant could
penetrate through the coating and re-attach it to the substrate. Such other
factors as adherence of the asbestos-containing material to the substrate
and cohesive strength within the material itself also had to be evaluated
before a decision on encapsulation could be reached, especially if an encap-
sulant was to be used which formed a membrane over the material rather than
penetrate through it. In many instances encapsulation was found to be a
useful abatement technique for use on granular/cementitious acoustical plaster.
Before encapsulation is selected as the abatement choice, the encapsulant
should be applied to test patches of the asbestos-containing material and a
determination made that asbestos fibers are not released from the treated
material even when subjected to inadvertent abuse. The decision to encapsulate
must be made with the understanding that periodic re-application of the
encapsulant will be required during the remaining useful life of the building
and before demolition of the structure can occur, the encapsulated asbestos
must be removed as required by EPA regulation.
Perhaps the most important lesson learned form recent evaluations of the
algorithm factors is that decisions to undertake corrective action to control
asbestos exposures must rely on informed judgement. The algorithm is only
one of several tools which can be used to collect information upon which a
judgement to conduct asbestos abatement can be based. Until new and more
accurate evaluation techniques are developed, the algorithm and the associated
forms described in this document represent one practical approach to detecting
and evaluating existing asbestos exposure hazards and determining the potential
for future asbestos fiber release.
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CEILING TILES AND PIPE AND BOILER WRAPPING
Although this manual concetrates more on inspecting and evaluating asbestos-
containing ceiling and wall coatings, suspended ceiling tiles as well as pipe
and boiler wrapping should not be overlooked as potential sources of asbestos
fibers. The familiar suspended ceiling panels, approximately 1/2" thick, have
in almost all cases been found to be composed of non-asbestos materials.
However some thin, 1/8" thick, suspended ceiling tiles have been found to be
composed of as much as 30% asbestos. These thin tiles are a hard, non-friable
material and under normal use conditions are not expected to release asbestos
fibers. If these thin tiles are broken as a result of being dropped or some
other activity, they will shatter and release fibers. The inspection program
should note the existence of such tiles so that care can be taken not to
damage the tiles.
Asbestos-containing,
1/8 inch thick, sus-
pended ceiling tile.
(End view of broken
tile, note fibers.)
Non-asbestos, 1/2 inch thick,
suspended ceiling panel.
(End view)
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Asbestos-containing pipe and boiler wrapping has been manufactured in various
forms, the most common having the appearance of a white, chalky material.
Often this material has been preformed to accoraodate a certain diameter pipe
or molded into bricks for attachment around boilers. Other types of pipe and
boiler wrapping have the appearance of mud or an insulating blanket. Some
pipe wrapping has been made from corrugated, asbestos-containing paper. Pipe
and boiler wrapping is covered on the outside with a protective jacket con-
structed of such materials as cloth, canvas or metal. Undamaged and intact
protective jackets should prevent spontaneous asbestos fiber release. Care
must be exercised to prevent the tearing of the fabric jackets and the release
of asbestos fibers. Such common practices as laying ladders against pipes
and boilers or storing boxes against wrapped pipes may have to be eliminated
to prevent destruction of the asbestos-containing insulation and fiber release.
Correcting minor damage to pipe and boiler wrapping can often be accomplished
with duct tape or re-wrapping torn protective jackets. Replastering of the
pipe and boiler wrapping may be required for larger damaged areas. If damage
to the protective jacket and wrapping is so extensive that removal is the only
option, the same containment and worker protection measures must be implemented
as required for safe asbestos removal from ceilings or walls.
Asbestos-containing, corrugated
paper, pipe wrapping covered by
a protective jacket.
Preformed, asbestos/magnesia,
pipe wrapping covered by a
protective jacket.
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NOTES
U.S. GOVERNMENT PRINTING OFFICE: !983-666-113/252
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