Threshold Limit Value–Time-Weighted Average (TLV–TWA)

2016 ◽  
Author(s):  
John H. Duffus ◽  
Monica Nordberg ◽  
Douglas M. Templeton
Keyword(s):  
Weighted Average ◽  
Threshold Limit Value ◽  
Limit Value ◽  
Threshold Limit ◽  
Time Weighted Average

scholarly journals Medición de concentraciones de formaldehído en un laboratorio de anatomía humana, comparándolas con estándares internacionales

2017 ◽  
Vol 11 (1-2) ◽  
pp. 7-13 ◽  
Author(s):  
Ernesto Hurtado ◽  
Andrea Vallecampo ◽  
Karen De Liévano ◽  
Beatriz De Artiga ◽  
Guadalupe Vásquez
Keyword(s):  
Weighted Average ◽  
Threshold Limit Value ◽  
International Agency ◽  
Limit Value ◽  
Threshold Limit ◽  
Time Weighted Average

Introducción. El Laboratorio de Anatomía Humana dispone de cadáveres que han sido sometidos al proceso de fijación y conservación de tejidos mediante la aplicación de formaldehído (al 10%), sustancia tóxica y cancerígena para el ser humano, según lo estipulado por la International Agency for Research on Cancer (iarc), a la que están expuestos estudiantes, profesores y técnicos. La presente investigación tuvo como propósito medir las concentraciones de formaldehído en el ambiente dentro de las instalaciones de un laboratorio de Anatomía Humana y compararlas con estándares laborales internacionales. Metodología. El diseño del estudio fue transversal con enfoque descriptivo. La muestra del estudio fue de 640 mediciones realizadas con el aparato digital hal-hfx105 HalTech y aplicando la norma técnica de prevención ntp 587, validada para la determinación de gases y vapores orgánicos en el aire dentro del laboratorio. Resultado. La concentración de formaldehído promedio estimada en general dentro de las instalaciones del Laboratorio de Anatomía fue de 0.24 ppm. ConclusIón. El promedio de concentración de formaldehído encontrado en el presente estudio es inferior al límite de exposición profesional estimado por la American Conference of Industrial Hygienists (acgih), cuyo valor tlv-twa (Threshold Limit Value-Time Weighted Average) para un día laboral de 8 horas y una semana de 40 horas, y como límite máximo a las concentraciones que cualquier trabajador puede ser expuesto día tras día sin efectos adversos, es de 0.3 ppm.CREA CIENCIA Vol. 11 No 1-2 ISSN 1818-202X enero-diciembre 2017, p. 7-13

Tropospheric Ozone: The Dynamics of Human Exposure

1989 ◽  
Vol 5 (3) ◽  
pp. 493-504 ◽  
Author(s):  
Paul J., Lioy ◽  
Raymond V., Dyba
Keyword(s):  
Human Exposure ◽  
Weighted Average ◽  
Ambient Air ◽  
Quality Standard ◽  
Threshold Limit Value ◽  
Ozone Exposure ◽  
Ambient Atmosphere ◽  
Limit Value ◽  
Time Weighted Average ◽  
Ambient Air Quality Standard

The conditions in the ambient atmosphere conducive to ozone exposure are examined, and placed into a context of the time arid locations where individuals would be expected to be affected by high ozone. This is done for both 1 h and 8 h averaging times. Concentrations of ozone in the ambient atmosphere can violate the National Ambient Air Quality Standard (NAAQS) and also the Time Weighted Average-Threshold Limit Value (TWA-TLV) for workers. Exposures that occurred in a 1982 episode associated with a health effects study are described in detail. The effective dose received by a camper at a children's summer camp appeared to be similar to that delivered to volunteers during a controlled human exposure study in which effects on pulmonary function were observed.

Use of Methanol as a Coolant During Machining of Aluminum in a Shipbuilding Environment: A Failure to Assess and Manage Risk

2014 ◽  
Vol 955-959 ◽  
pp. 1061-1064 ◽  
Author(s):  
Thomas Neil McManus ◽  
Assed N. Haddad
Keyword(s):  
Weighted Average ◽  
Threshold Limit Value ◽  
Breathing Zone ◽  
Short Term ◽  
Limit Value ◽  
Diffusion Tubes ◽  
Exposure Limit ◽  
Long Duration ◽  
Short Term Exposure ◽  
Time Weighted Average

Minimization of harm during the conduct of work is one of the most important tenets of industrial hygiene. Organizations make changes to solve perceived problems. What appears to be expedient for solving a problem can create serious risks totally unrecognized by the proponent. This investigation reports on such a situation involving the use of methanol as a lubricant during machining of aluminium panels using a router. Spot samples for methanol were measured using colorimetric detector tubes and samples of long duration by colorimetric diffusion tubes utilizing similar chemistry. Both were positioned in the breathing zone. Most of the spot samples exceeded the 8-hour TLV-TWA (Threshold Limit Value-Time-Weighted Average) of 200 ppm and the TLV-STEL (Short-Term Exposure Limit) of 250 ppm. The two long duration samples also exceeded the TLV-TWA. A change in the operation prevented collection of additional long duration samples. By these measures, workers were overexposed to methanol during this activity. An additional serious consequence from use of methanol in this manner was risk of fire. This situation illustrates the complexity of decisions affecting workplace operations. What appears to be expedient for solving a problem may be totally inappropriate.

EXPERIMENTAL SUBSTANTIATION OF THE MAXIMUM ALLOWABLE CONCENTRATION OF DIOCTYL TEREPHTHALATE IN THE AIR OF THE WORKING AREA

2020 ◽  
pp. 34-38
Author(s):  
A. S. Radilov ◽  
S. A. Solntseva ◽  
I. E. Shkaeva ◽  
S. A. Dulov ◽  
E. V. Vivulanets ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Functional State ◽  
Hematological Parameters ◽  
Inhalation Exposure ◽  
Threshold Limit Value ◽  
Maximum Allowable Concentration ◽  
Limit Value ◽  
Threshold Limit ◽  
The Central Nervous System

Toxicity and hazard assessment of dioctyl terephthalate (DOTP) was performed in acute, subacute, and chronic experiments, and its principal toxicometry parameters were determined.It was found that on single exposure DOTP exhibits low toxicity and hazard. No resorptive and irritant effects on skin and mucous membrane of eyes were detected in animal experiments. The single inhalation exposure threshold limit value was set at 300 mg/m3, based on the results of monitoring of the functional state of the central nervous system and myocardium and hematological parameters.Thirty-day subacute experiments (oral administration, inhalation exposure, and skin applications) revealed no accumulation of the compound.Four-month chronic exposure to DOTP aerosols (concentration 96,8 mg/m3) caused disorder of the functional state of the central nervous system and myocardium, changes in the hematological and biochemical parameters, gas and acid-base status of the blood, and morphological changes in the lungs and heart. Embryotoxic, genotoxic and gonadotoxic effects were not detected.The chronic inhalation exposure threshold limit value for DOTP (Limch) was set at 18,6 mg/m3, and the concentration of 3,4 mg/m3 was found to be ineffective.The maximum allowable concentration of DOTP in the air of the working area was set at 3,0 mg/m3, hazard class 3.

Metallic Mercury Contamination of the Dental Operatory

1975 ◽  
Vol 17 (4) ◽  
pp. 346-355 ◽  
Author(s):  
Richard G. Domey
Keyword(s):  
San Antonio ◽  
Threshold Limit Value ◽  
Mercury Contamination ◽  
Metallic Mercury ◽  
General Lack ◽  
Limit Value ◽  
Threshold Limit ◽  
Routine Monitoring ◽  
Cleaning Methods

The American Conference of Governmental Industrial Hygienists 1971 standard threshold limit value (TLV) of 0.55 mgHg/m of air was found to be exceeded frequently in a sample of 60 dental operatories in San Antonio, Texas. Significant differences in contamination among laboratories were found, among sites within operatories, and among times of day, correlated with kilograms of mercury used, average number of amalgams inserted per day, age of operatories, height of carpeting pile, cleaning methods, frequency of cleaning, and general lack of routine monitoring and use of bioassays. Recommendations for control of metallic mercury contamination in dental operatories are offered.

scholarly journals Modeling the Effect of the 2018 Revised ACGIH® Hand Activity Threshold Limit Value® (TLV) at Reducing Risk for Carpal Tunnel Syndrome

2019 ◽  
Vol 16 (9) ◽  
pp. 628-633 ◽  
Author(s):  
Marcus Yung ◽  
Ann Marie Dale ◽  
Jay Kapellusch ◽  
Stephen Bao ◽  
Carisa Harris-Adamson ◽  
...  
Keyword(s):  
Carpal Tunnel Syndrome ◽  
Carpal Tunnel ◽  
Threshold Limit Value ◽  
Limit Value ◽  
Threshold Limit ◽  
Tunnel Syndrome
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