Home page of Andrew F. Oberta, MPH, CIH -- The Environmental Consultancy

European Conference on Asbestos Risks and Management
Rome, Italy -- December 4-6, 2006


RISK ASSESSMENT AND REMEDIATION PRIORITIZATION FOR ASBESTOS-CONTAINING MATERIALS

Andrew F. Oberta 1 , Vincent J. Brennan 2

1 The Environmental Consultancy , Austin, Texas, United States (Part One)
2 University of Vermont, Burlington, Vermont, United States (Part Two)

PART ONE (by Mr. Oberta)

The health effects of breathing asbestos fibers are so well known that they need not be documented in this paper. Historically, the affected individuals have mostly included workers in the mines, mills and factories where the fiber and numerous products were produced, as well as those who installed the products in buildings and facilities. More recently, attention has been focused on those who work around asbestos-containing materials (ACM) as part of construction or maintenance activities.

The management of ACM in buildings and facilities consists of an on-going Operations and Maintenance (O&M) program and abatement when necessary, usually by removal. Assessing the risk of exposure to airborne asbestos fibers involves several factors, as does estimating the costs associated with managing the installed materials and their eventual removal.

This paper describes an approach to assessing the risk posed by ACM on the basis of its Current Condition and Potential for Disturbance. A graphical presentation of the assessments for all ACM in a building or facility allows one to visually prioritize remediation activities and decide which materials to remove and which to continue managing in place. The Customized Compliance Program for Asbestos software applies unit costs for removal to calculate the cost of the risk-based decisions for abatement and displays these costs in tabular and graphical formats.

Assessing asbestos-containing materials

The protocol for assessing the Current Condition and Potential for Disturbance of ACM appears in ASTM E2356 Standard Practice for Comprehensive Building Asbestos Surveys. [ASTM 2004; Oberta, 2005] Those who are familiar with inspection and assessment protocols developed for compliance with the U.S. Environmental Protection Agency (AHERA) regulations issued under the Asbestos Hazards Emergency Response Act [EPA, 1987] will find that the methodology in E2356 yields a greater amount of more usable information. The Customized Compliance Program for Asbestos software [Environment-i-media, Inc., 2004] further improves on the E2356 protocol.

Asbestos-containing materials in a building or facility are assessed during the activity described in E2356 as a Baseline Survey. In addition to taking bulk samples of materials that may contain asbestos for analysis in a laboratory, the inspector assesses the Current Condition and Potential for Disturbance of different types of ACM in various locations. The basis for this assessment is explained next.

Based on visual observation by the inspector, the Current Condition (CC) of each material is categorized as shown below: A rating of "1" represents the low end of "Poor" and "10" represents the high end of "Good," i.e. completely intact material.

Qualitative Ranking

Numerical Ratings

Description of ACM

Poor

1, 2 or 3

Extensive damage and/or visible debris

Fair

4, 5, 6 or 7

Moderate amounts of damage and/or visible debris

Good

8, 9 or 10

Little or no damage or visible debris

Anticipating what might happen to suspect ACM in the future – its Potential for Disturbance (PFD) -- is more complex. A regulatory definition of "Disturbance" is "...activities that disrupt the matrix of ACM or PACM, crumble or pulverize ACM or PACM, or generate visible debris from ACM or PACM." [OSHA 1994] The inspector assesses each material based on one or more of the factors shown below:

Qualitative Ranking
Numerical Ratings
Assessment factors
Physical disturbance
Environmental disturbance
Low
1, 2 or 3
accessibility activities vibration
air currents
airborne dust
water damage
corrosive
Medium
4, 5, 6 or 7
High
8, 9 or 10

Physical disturbance considers the accessibility of the material by workers during normal facility operations, including maintenance and repair, and the activities performed near the material - what people do and how often they do it. Environmental disturbance considers sources of vibration , such as operating machinery, HVAC equipment, whether air currents are strong enough to dislodge loose ACM or if airborne dust (Figure 1) can erode the material.  Water from a leaking roof (Figure 2) or pipe can damage the material. The material may be subjected to a corrosive atmosphere or liquids that can erode the matrix and expose asbestos fibers.

Figure 1 . Erosion by airborne dust
Figure 2 . Damage from leaking roof

NOTE: This is not an algorithm! The ratings are not added, multiplied or arithmetically combined in any manner. They are plotted as shown in Figure 3, which illustrates two extremes of prioritization on an Abatement vs O&M Decision Chart. The tank insulation on the upper left is in very poor condition, with a Current Condition (CC) of 2, and it is in an easily-accessible mechanical room, giving it a Potential for Disturbance (PFD) of 9. This places it in the upper left corner of the chart, indicating a high priority for abatement. The pipe insulation, on the other hand, is nearly intact for a CC=9 and seldom accessed in a pipe chase for a PFD=2. These ratings put it in the lower right corner as evidence that it can be managed in place.

 

Figure 3 . Abatement vs O&M Decision Chart

Assessment tables and charts  

Figure 4 shows pipe and steam drum insulation and breeching insulation in a small boiler plant. Table 1 contains the survey and assessment data for this insulation. The table has been sorted to place the materials in the worst condition (lowest CC rating) at the top, and if there are two or more materials with the same PFD rating for the same CC rating, a second sort was performed to rank these materials according to the highest PFD rating (most accessible). A glance at the table shows which materials in what locations are the most in need of attention. This is the first step in deciding which ones to remove and which to keep managing in place.

Figure 4 . Boiler plant insulation


Location
Area
Asbestos-Containing Materials
Quantity
Assessment
Current Condition
Potential for Disturbance
Rating
Based on
Rating
Based on

G

Boilers #1 &2

Insulation covering top of boilers #1 & 2

500 ft²

1

Damage & debris

7

Frequent access

D

Southwest corner

Tank & fittings insulation

120 ft²

2

Damage & debris

9

Frequent access

C

Southwest corner

Pipe insulation

150 ft

3

Damage & debris

8

Frequent access

E

Boilers #1 &2

Steam drum insulation

250 ft²

3

Missing covering

7

Elevated location

F

Boiler #3

Steam drum insulation

100 ft²

7

No visible damage

5

Elevated location

B

East aisle and southeast corner

Pipe insulation

440 ft

9

No visible damage

5

Elevated location

A

East aisle and northeast corner

Breeching insulation

1500 ft²

9

No visible damage

4

Elevated location

Table 1. Assessment ratings and quantities of asbestos-containing materials in boiler plant

E2356 includes a two-dimensional chart called the Abatement vs O&M Decision Chart on which these ratings are plotted. Figure 5 shows such a chart for the boiler plant example in Table 3. The closer to the upper left corner the rating for a particular ACM is plotted, the greater the risk of exposure to asbestos fibers and consequently the higher the priority is for removing the ACM. The area above the curved line is called the Abatement region. Below the line is the O&M region, and the closer to the bottom right corner the rating for a particular ACM is plotted, the lower the risk of exposure and managing it in place is more feasible.

Figure 5 . Two -dimensional Abatement vs O&M Decision Chart for boiler plant

The position and shape of the line in Figure 5 biases decisions toward abatement, which occupies more area of the chart than O&M. One reason is that O&M tasks for remaining ACM in this boiler plant would be of more-than-average complexity and frequency. Complexity takes into account the difficulty of access to the ACM, the difficulty of preparation such as de-energizing and cooling pressurized lines, disruption of operations, type of personal protective equipment required and other factors in addition to the difficulty of the work itself. Frequency is simply to expectation of how often the O&M work will need to be done. In this example, the i nsulation covering the top of boilers #1, #2 & #3 and the steam drum insulation on these boilers are clear candidates for removal, as is the thermal system insulation in the southwest corner. The remaining ACM is close to the line and whether to remove it or leave it in place is a matter deserving consideration of other factors. These might include the proficiency of the O&M crew (in-house or contractor) and whether including these items in an abatement project for other ACM is cost-effective.

Making decisions about removing ACM or managing it in place is not a simple matter of drawing a line on a chart. The benefit of doing so is to encourage an honest evaluation of the overall asbestos management program as part of the decision-making process. The risks associated with ACM should be viewed as a continuum of severity that can be more realistically represented by using color and a three-dimensional chart. The Customized Compliance Program for Asbestos software [Environment-i-media, Inc., 2004] displays the Current Condition and Potential for Disturbance ratings on the “floor” of a three-dimensional chart, with the vertical axis representing the amount of each ACM. The three-dimensional chart for theboiler plant is shown in Figure 6.



Figure 6 . Three -dimensional Abatement vs O&M Decision Chart for boiler plant

The horizontal axes have been arranged so that the ACM in the poorest Current Condition and the highest Potential for Disturbance are in the right front corner of the “floor.” Also, the color of the “floor” goes from green in the left rear corner to red in the right front corner. The further into the green area the ACM is located, the more amenable it is to being managed in place. The further the ACM is into the red area, the higher the priority for abatement. The three-dimensional chart visually separates the ACM in the boiler plant into two items in the green area that are clearly amenable to O&M, four clear candidates for removal in the red area and one in between for which either option may be acceptable. The vertical axis shows the quantities of each of these items of ACM. Even though the breeching and some pipe insulation (aqua-colored bars) constitute the largest amounts of ACM, they are also the most amenable to being managed in place.

The Abatement vs O&M Decision Chart supports the process of making asbestos management decisions on the basis of the exposure risk associated with the ACM, and the three-dimensional representation introduces the quantities of the ACM into the process. The Customized Compliance Program for Asbestos software also determines the costs of implementing the decisions.

Potential and probable costs

Many asbestos survey reports include an estimate of cost for removing ACM based on unit costs for each type of material found. If not, typical values can be used in preparing Table 4, using data from the same boiler plant as in Table 1. The column titled "Potential Cost" is the amount that would be spent if the material was removed. It is the cost of abatement, for example, that would be incurred in event that renovation or demolition required prior removal of ACM that might be disturbed by construction activities. (EPA, 1990) However, the probability that the material would be removed based solely on its Current Condition and Potential for Disturbance ratings is almost certainly less than one, and is actually a function of those ratings.

The Customized Compliance Program for Asbestos software contains a "probability matrix" for all combinations of Current Condition and Potential for Disturbance. At one extreme, material in perfect condition with almost no chance of disturbance (mastic under intact non-asbestos floor tile is a good example) is found at CC=10 and PFD=1; therefore the probability of removal equals 0.01. On the other hand, it is quite certain that heavily-damaged pipe insulation close to the floor in a high-traffic area with ratings of CC=1 and PFD=10 would be removed; hence a probability of removal of 1.0. In between are 98 other combinations of ratings and their associated probabilities of removal based solely on the Current Condition and Potential for Disturbance of the ACM.

Location
Area
Asbestos-Containing Materials
Quantity
Ratings
Removal costs
CC
PFD
Unit cost
Potential cost

Probable
Cost

G

Boilers #1 & #2

Insulation covering top of boilers #1 & 2

500 ft²

1

7

$15

$7,500

$5,250

D

Southwest corner

Tank & fittings insulation

120 ft²

2

9

$10

$1,200

$972

C

Southwest corner

Pipe insulation

150 ft

3

8

$10

$1,500

$960

E

Boilers #1 & #2

Steam drum insulation

250 ft²

3

7

$15

$3,750

$2,100

F

Boiler #3

Steam drum insulation

100 ft²

7

5

$15

$1,500

$300

B

East aisle and southeast corner

Pipe insulation

440 ft

9

5

$15

$6,600

$660

A

East aisle and northeast corner

Breeching insulation

1500 ft²

9

4

$20

$30,000

$2,400

Total

$52,050

$12,642

Table 2. Potential and probable removal costs for asbestos-containing materials in boiler plant


The last column in Table 2 applies these probabilities to the Potential Costs for each material to create a set of values called the Probable Costs. By summing the Potential Cost and Probable Cost columns, Table 2 shows that the expected abatement costs for the facility are reduced significantly by taking into account the fact that relatively intact, inaccessible asbestos-containing materials will continue to be managed in place as long as they stay that way. Consequently, the amount that must be budgeted for removal under these circumstances (absent any planned renovation or demolition) is a fraction of what could (and eventually will) be spent.

Figure 7. Potential Removal Cost (left) and Probable Removal Cost (right) for ACM in boiler plant

Figure 7 shows three-dimensional representations of the Potential Cost and Probable Cost that were created for the above example by the Customized Compliance Program for Asbestos software. Both figures show the cost of removing the ACM in the context of its assessment ratings, and the vertical bars are in the same positions on the “floor” as in Figure 6. Notice the difference in the relative heights of the bars, however, and the different scale of the vertical (cost) axes in the figures.

This example is of necessity a simplified illustration. A large building or facility would have several sets of tables and charts, each depicting the conditions in a location within the building or facility, such as a floor of a multi-story building, a mechanical room or a separate building. The Customized Compliance Program for Asbestos software also has the capability to sort these tables and charts according to different types of ACM and to combine the data from two or more tables and charts into an ensemble representing part or all of a building or facility. Other features of the program may be reviewed at http://www.environment-i-media.com/ccpa.html .

Conclusion – Part One

The assessment protocol for asbestos-containing materials in ASTM E2356 provides risk-based information with which to prioritize decisions as to whether the ACM should be removed or managed in place. The Customized Compliance Program for Asbestos software allows the user to visualize these priorities in color and three dimensions, and also estimates the costs associated with the decisions.

REFERENCES

ASTM 2004, E2356-04 Standard Practice for Comprehensive Building Asbestos Surveys. ASTM International, 100 Barr Harbor Drive, West Conshohocken , PA 19428 . www.astm.org

Oberta, 2005. Manual on Asbestos Control: Surveys, Removal and Management – Second Edition. Andrew F. Oberta. A STM International, 100 Barr Harbor Drive, West Conshohocken , PA 19428 . www.astm.org

EPA 1987, Asbestos-Containing Materials in Schools, 40CFR Part 763, Subpart E. U.S. Environmental Protection Agency , Washington , D.C. Federal Register, October 30, 1987 .

Environment-i-media, Inc. 2004, Customized Compliance Program for Asbestos , 900 Route 620 South, Suite C101, MS 101, Austin, TX 78734.

OSHA 1994, Occupational Exposure to Asbestos: Final Rule. 29 CFR Parts 1001, 1915 and 1926. U. S. Department of Labor, Occupational Safety and Health Administration.59 FR 40964 - 41162, Federal Register, August 10, 1994

EPA 1990, National Emission Standards for Hazardous Air Pollutants: Subpart M - Asbestos. 40 CFR Part 61. U. S. Environmental Protection Agency, Federal Register, November 20, 1990.


Contact information:

Andrew F. Oberta, MPH, CIH, The Environmental Consultancy, 107 Route 620 South, Suite 102 , MS 35E, Austin , TX 78734 . (512) 266-1368 andyobe@aol.com

Vincent J Brennan, CIE, Physical Plant Department, University of Vermont , 284 East Avenue , Burlington , VT 05405 . (802) 764-6613 vincent.brennan@uvm.edu


ASTM E2356 is copyrighted by ASTM International, 100 Barr Harbor Drive, West Conshohocken , PA 19428.

The Customized Compliance Program for Asbestos is copyrighted by Environment-i-media, Inc., 900 Route 620 South, Suite C101, MS 101, Austin, TX 78734.