TLV-TWA. The Threshold Limit Value-Time Weighted Average is the time-weighted average concentration for a normal 8-hour workday and a 40-hour workweek, to which it is believed nearly all workers may be repeatedly exposed without adverse effects.
TLV-STEL. Threshold Limit Value-Short Term Exposure Limit is the concentration to which it is believed workers can be exposed continuously for a short period of time without suffering from irritation, chronic or irreversible tissue damage, or narcosis of sufficient degree to increase the likelihood of accidental injury, impaired self-rescue, or reduced work efficiency, and provided that the daily TLV-TWA is not exceeded. It is not a separate independent exposure limit; rather it supplements the time-weighted average (TWA) limit where there are recognized acute affects from a substance whose toxic effects are primarily of a chronic nature. STELs are recommended only where toxic effects have been reported from high short-term exposures in either humans or animals.
TLV-C. Threshold Limit Value - Ceiling Limit is the concentration that should not be exceeded during any part of the working exposure.
REQUIRED PROGRAM ELEMENTS
1. General:
a. Employee exposure to airborne contaminants shall not exceed the OEL.
b. A written program incorporating both QEA and QM aspects.
c. A Certified Industrial Hygienist (CIH) must oversee the QEA and QM process.
d. Quantitative Measurement is required when the results of a QEA indicates that an exposure above 25% of the OEL is likely. To help make this determination, the CIH may use previous air sampling data; conduct limited air sampling using direct-reading instruments or worst-case sampling, etc.
2. Qualitative Exposure Assessment (QEA):
a. The QEA must adequately describe the operation. This typically will include the following items:
i) Department or other unique identifiers (i.e., exposure zone)
ii) Description of task, equipment, process, operation, etc.
iii) Chemical use and byproducts
iv) Employee information
v) Controls (i.e., engineering controls)
vi) Work practices and personal protective equipment
vii) Maintenance/service activities
viii) Exposure evaluation (e.g., duration of task, amount of chemical used, any dermal contact, etc.)
ix) Date(s) of the assessment
x) Assessor name(s) and signature (or equivalent)
b. After the initial QEA has been completed, a formal written review is required at least every three years (36 months).
c. A new or updated QEA must be performed whenever a change in the workplace occurs which is deemed significant enough by the CIH to potentially increase personal exposure.
d. Only those tasks that potentially result in significant exposure require a QEA (example: a task involving a swab of isopropyl alcohol for cleaning in an electronics laboratory will likely not require a QEA).
3. Comprehensive QEA:
In addition to QEA process described above, a comprehensive process that assess all involved hazards and risks including hazardous chemicals, noise, physical agents, such as ionizing and non-ionizing radiation, extreme temperatures, etc, and ergonomic hazards should be implemented in major production lines.
4 Quantitative Measurement (QM):
TLV-TWA. The Threshold Limit Value-Time Weighted Average is the time-weighted average concentration for a normal 8-hour workday and a 40-hour workweek, to which it is believed nearly all workers may be repeatedly exposed without adverse effects. TLV-STEL. Threshold Limit Value-Short Term Exposure Limit is the concentration to which it is believed workers can be exposed continuously for a short period of time without suffering from irritation, chronic or irreversible tissue damage, or narcosis of sufficient degree to increase the likelihood of accidental injury, impaired self-rescue, or reduced work efficiency, and provided that the daily TLV-TWA is not exceeded. It is not a separate independent exposure limit; rather it supplements the time-weighted average (TWA) limit where there are recognized acute affects from a substance whose toxic effects are primarily of a chronic nature. STELs are recommended only where toxic effects have been reported from high short-term exposures in either humans or animals. TLV-C. Threshold Limit Value - Ceiling Limit is the concentration that should not be exceeded during any part of the working exposure. REQUIRED PROGRAM ELEMENTS 1. General:a. Employee exposure to airborne contaminants shall not exceed the OEL. b. A written program incorporating both QEA and QM aspects. c. A Certified Industrial Hygienist (CIH) must oversee the QEA and QM process. d. Quantitative Measurement is required when the results of a QEA indicates that an exposure above 25% of the OEL is likely. To help make this determination, the CIH may use previous air sampling data; conduct limited air sampling using direct-reading instruments or worst-case sampling, etc. 2. Qualitative Exposure Assessment (QEA): a. The QEA must adequately describe the operation. This typically will include the following items: i) Department or other unique identifiers (i.e., exposure zone) ii) Description of task, equipment, process, operation, etc. iii) Chemical use and byproducts iv) Employee information v) Controls (i.e., engineering controls) vi) Work practices and personal protective equipment vii) Maintenance/service activities viii) Exposure evaluation (e.g., duration of task, amount of chemical used, any dermal contact, etc.) ix) Date(s) of the assessment x) Assessor name(s) and signature (or equivalent) b. After the initial QEA has been completed, a formal written review is required at least every three years (36 months). c. A new or updated QEA must be performed whenever a change in the workplace occurs which is deemed significant enough by the CIH to potentially increase personal exposure. d. Only those tasks that potentially result in significant exposure require a QEA (example: a task involving a swab of isopropyl alcohol for cleaning in an electronics laboratory will likely not require a QEA).3. Comprehensive QEA: In addition to QEA process described above, a comprehensive process that assess all involved hazards and risks including hazardous chemicals, noise, physical agents, such as ionizing and non-ionizing radiation, extreme temperatures, etc, and ergonomic hazards should be implemented in major production lines. 4 Quantitative Measurement (QM):
การแปล กรุณารอสักครู่..