1 Va. Admin. Code § 30-20-120:1
The 20-variable algorithm is an expansion on the old EPA or Sawyer algorithm. Where the primary variables are identical to the Sawyer algorithm, the first six variables have two sub-variable used to adjust the subjective or general score. The subjective or general score can be adjusted to represent a more accurate reflection of the true value of that general variable.
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 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.
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 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, graffitti, pieces dislodged or missing, scrape marks from movable equipment or furniture, or accumulation of the friable material of 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 exposed the substrate. Inspectors should touch the asbestos-containing material and determine if dust is released when the material is lightly brushed or rubbed. 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.
FACTOR ONE: MATERIAL CONDITION:
This factor is comprised of three levels:
NUMERICAL VALUE: 0
NUMERICAL VALUE: 2
NUMERICAL VALUE: 5
After the subjective score is determined for material condition based on the standard EPA guidelines for determining such, the score should be adjusted up one point or down one point depending on the building area age. If the age of the material or building in question is greater than 30 years, the objective variable is increased by one. If the area age is less than 15 years, it is subtracted by one. If the age is between 15 and 30 years, the score does not change. Then if the type of material, in particular pipe coverings, is a magnesium or calcium silicate preformed pipe which has a tendency to deteriorate more rapidly, the score is up by one; and if the material type is corrugated air cell or paper product, it is reduced by one. For ceiling plasters or fireproofing, if the material type is a more cementitious Monokote Type it is reduced by one. If it is a cotton candy Cafco type blaze shield or sound shield, it is up by one. For standard acoustical plaster materials, there is no change in the subvariable.
FACTOR TWO: WATER DAMAGE:
Water damage is usually caused by roof leaks, particularly in buildings 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 lavatories.
Water can dislodge, delaminate, or disturb asbestos-containing materials that are otherwise in satisfactory 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 resuspended 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.
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.
FACTOR TWO: WATER DAMAGE:
This factor is comprised of three levels:
NUMERICAL VALUE: 0
NUMERICAL VALUE: 1
NUMERICAL VALUE: 2
After the general subjective determination has been made, if the roof above the material is a sloped or hipped roof, the subjective is reduced by 1/2. If it is a flat roof and built- up it is increased by 1/2. If the substrate type is is metal or concrete, it is reduced by 1/2.
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. This factor is comprised of three levels:
FACTOR THREE: EXPOSED SURFACE AREA:
NUMERICAL VALUE: 0
NUMERICAL VALUE: 1
NUMERICAL VALUE: 4
After the general determination is made, if there is an HVAC system that is part of the plenum area, the general determination is increased by one. If there is no plenum but only an enclosed dead space, it is reduced by one. If there is a semi- or permanent enclosure under the fireproofing or acoustical plaster isolating the mechanical system, the general determination is reduced by 1/2.
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 intention 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. This factor is comprised of three levels:
ACCESSIBILITY
NUMERICAL VALUE: 0
NUMERICAL VALUE: 1
NUMERICAL VALUE: 4
If the ceiling height or material height is greater than 9 1/2 feet, the subjective score is reduced by one. If it is under 9 1/2 feet it is increased by one. Since the building occupancy and use status tells us a great deal about how often the material is going to be accessed, we adjust the subjective determination by 1 1/2+ depending on the amount of occupancy.
Pipe chases, crawl spaces, attics and mechanical air handling rooms are reduced by 1 1/2, whereas major boiler rooms, classrooms, secretarial pools, or offices are increased by 1 1/2.
FACTOR FIVE: ACTIVITY AND MOVEMENT
The level of activity and movement in the vicinity of the asbestos-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, et cetera.
Another source of vibration is sound, such as music and noise. Sound sets airwaves in motion in 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 extend in a band room, music practice room, or auditorium than in the remainder of the building. Aircraft noise also has the ability to vibrate buildings; therefore, the inspector should determine if the building is in a direct flight path. It has been reported 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.
ACTIVITY AND MOVEMENT
NUMERICAL VALUE: 0
NUMERICAL VALUE: 1
NUMERICAL VALUE: 2
After the subjective determination is made, we must determine whether there is sedentary or nonsedentary movement. If the room in question is a library or other sedentary work environments, the subjective variable is reduced by 1/2. However, if the area in question has a great deal of activity such as in a hallway, a boiler room, a maintenance shed, etc. the variable will be increased by 1/2. If the room in question in subject to sound or mechanical vibration such as in an auditorium or a band hall or in an air handling or boiler room where there are constant vibrations, the variable is up by 1/2. If the area in question contains no recognizable sound or mechanical vibrations, or if no air handling systems are on the roof of the area, the subjective variable is reduced by 1/2.
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. 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.
AIR PLENUM OR DIRECT AIR STREAM
NUMERICAL VALUE: 0
NUMERICAL VALUE: 1
After the general determination is made, we look at the velocity of the air flow if in fact there is an air flow. If the air flow is recognizable by human feeling rather than subtle, the variable is increased by 1/4. If it nonrecognizable it is reduced by 1/4. If the air flow is a constant, steady stream it, again, is reduced by 1/4; whereas if the air flow is an impact air flow such as through thermastatic action where large gusts of air impact the material from time to time it is increased by 1/4.
FACTOR SEVEN. FRIABILITY
The term "friable" is applied to dry material that can be crumbled, pulverized, or reduced to powder by hand pressure or which under normal use or maintenance emits or can be expected to emit asbestos fibers into the air. In order to evaluate the friability of the material it should 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. A material that contains asbestos can be expected to emit fibers during use or maintenance if the original integrity of the material has been disturbed.
FRIABILITY
NUMERICAL VALUE: 0
NUMERICAL VALUE: 1
NUMERICAL VALUE: 2
NUMERICAL VALUE: 3
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.
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
NUMERICAL VALUE: 0
NUMERICAL VALUE: 2
NUMERICAL VALUE: 3
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.
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.
Step 3: Comparison of Exposure Number to Corrective Action Scale
Appendix B, Corrective Action Scale, presents five Priority Levels, and a range of Exposure Numbers for which that Priority Level is appropriate. Compare the Exposure Number derived in Step 2 to the Priority Levels in Appendix B. For example, an Exposure Number of 65 indicates that a Priority Level of I should be assigned. An Exposure Number of 10, however, indicates that a Priority Level of IV should be assigned. The proper response action for each Priority Level is found in Section IX of these standards.
1 Va. Admin. Code § 30-20-120:1