同: TLV

WordNet

fix or determine the value of; assign a value to; "value the jewelry and art work in the estate"
the amount (of money or goods or services) that is considered to be a fair equivalent for something else; "he tried to estimate the value of the produce at normal prices" (同)economic value
(music) the relative duration of a musical note (同)time value, note value
relative darkness or lightness of a color; "I establish the colors and principal values by organizing the painting into three values--dark, medium...and light"-Joe Hing Lowe
the quality (positive or negative) that renders something desirable or valuable; "the Shakespearean Shylock is of dubious value in the modern world"
a numerical quantity measured or assigned or computed; "the value assigned was 16 milliseconds"
an ideal accepted by some individual or group; "he has old-fashioned values"
restrict or confine, "I limit you to two visits to the pub a day" (同)circumscribe, confine
the mathematical value toward which a function goes as the independent variable approaches infinity (同)limit_point, point of accumulation
the greatest amount of something that is possible or allowed; "there are limits on the amount you can bet"; "it is growing rapidly with no limitation in sight" (同)limitation
the greatest possible degree of something; "what he did was beyond the bounds of acceptable behavior"; "to the limit of his ability" (同)bound, boundary
the boundary of a specific area (同)demarcation, demarcation line
as far as something can go
small in range or scope; "limited war"; "a limited success"; "a limited circle of friends"
mediocre (同)modified
having a specific function or scope; "a special (or specific) role in the mission" (同)special
including only a part
not excessive
not unlimited; "a limited list of choices"
the starting point for a new state or experience; "on the threshold of manhood"
the smallest detectable sensation (同)limen
strictly limiting the reference of a modified word or phrase; "the restrictive clause in `Each made a list of the books that had influenced him limits the books on the list to only those particular ones defined by the clause"

PrepTutorEJDIC

〈U〉(…の)『価値』,値打ち,有用性,重要性《+of+名》 / 〈U〉〈C〉(…の)『価格』,値段《+of+名》 / 〈U〉〈C〉《米》《修飾語句を伴って》(払った金銭に対する)正当な値打ち / 〈C〉(単語の)意味,意義 / 〈C〉値,数値 / 〈C〉音の長短 / 〈C〉色価,(色の)明暗の度 / 〈C〉《複数形で》(道義・倫理などの)価値基準,価値観 / (ある金額に)…‘を'『評価する』,見積もる《+名+at+名〈金額〉》 / …‘を'『高く評価する』,尊重する,重んじる
(空間・行為などの)『限界』,《+『of』+『名』》 / 《しばしば複数形で;単数扱い》『境界』,境界線範囲,区域 / (数量などの)許容量,制限 / 適度に / …‘を'『制限する』
限られた,狭い / 《米》(鉄道・バスなどが)特別の,特急の / 《英》(会社が)有限の(《米》incorporated) / 特急列車(バスなど)
『敷居』 / 《単数形で》(…の)『始め』,出発点,発端《+of+名》 / 閾(心理学で刺激に対して反応を示し始める点)
制限する,限定する

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/02/09 19:11:50」(JST)

wiki en

The threshold limit value (TLV) of a chemical substance is a level to which it is believed a worker can be exposed day after day for a working lifetime without adverse health effects. Strictly speaking, TLV is a reserved term of the American Conference of Governmental Industrial Hygienists (ACGIH). However, it is sometimes loosely used to refer to other similar concepts used in occupational health and toxicology. TLVs, along with biological exposure indices (BEIs), are published annually by the ACGIH.

The TLV is an estimate based on the known toxicity in humans or animals of a given chemical substance, and the reliability and accuracy of the latest sampling and analytical methods. It is not a static definition since new research can often modify the risk assessment of substances and new laboratory or instrumental analysis methods can improve analytical detection limits. The TLV is a recommendation by ACGIH, with only a guideline status. As such, it should not be confused with exposure limits having a regulatory status, like those published and enforced by the Occupational Safety and Health Administration (OSHA). The OSHA regulatory exposure limits permissible exposure limits (PELs) published in 29CFR 1910.1000 Table Z1 are based on recommendations made by the ACGIH in 1968, although other exposure limits were adopted more recently. Many OSHA exposure limits are not considered by the industrial hygiene community to be sufficiently protective levels since the toxicological basis for most limits have not been updated since the 1960s. The National Institute of Occupational Safety and Health (NIOSH) publishes recommended exposure limits (RELs) which OSHA takes into consideration when promulgating new regulatory exposure limits.

Definitions[edit]

The TLV for chemical substances is defined as a concentration in air, typically for inhalation or skin exposure. Its units are in parts per million (ppm) for gases and in milligrams per cubic meter (mg/m³) for particulates such as dust, smoke and mist. The basic formula for converting between ppm and mg/m³ for gases is ppm = (mg/m^3) * 24.45 / molecular weight. This formula is not applicable to airborne particles.

Three types of TLVs for chemical substances are defined:

Threshold limit value - Time weighted average (TLV-TWA): average exposure on the basis of a 8h/day, 40h/week work schedule
Threshold limit value - Short-term exposure limit (TLV-STEL): spot exposure for a duration of 15 minutes, that cannot be repeated more than 4 times per day with at least 60 minutes between exposure periods
Threshold limit value - Ceiling limit (TLV-C): absolute exposure limit that should not be exceeded at any time

There are TLVs for physical agents as well as chemical substances. TLVs for physical agents include those for noise exposure, vibration, ionizing and non-ionizing radiation exposure and heat and cold stress.

Defining Acceptable Exposure[edit]

The TLVs and most other occupational exposure limits are based on available toxicology and epidemiology data to protect nearly all workers over a working lifetime. Exposure assessments in occupational settings are most often performed by Occupational / Industrial Hygiene (OH/IH) professionals who gather "Basic Characterization" consisting of all relevant information and data related to workers, agents of concern, materials, equipment and available exposure controls. The exposure assessment is initiated by selecting the appropriate exposure limit averaging time and "decision statistic" for the agent. Typically the statistic for deciding acceptable exposure is chosen to be the majority (90%, 95% or 99%) of all exposures to be below the selected occupational exposure limit. For retrospective exposure assessments performed in occupational environments, the "decision statistic" is typically a central tendancy such as the mean or geometric mean or median for each worker or group of workers. Methods for performing occupational exposure assessments can be found in "A Strategy for Assessing and Managing Occupational Exposures, Third Edition Edited by Joselito S. Ignacio and William H. Bullock". ^[1]

Simple representation of exposure risk assessment and management hierarchy based on available information

Similar concepts[edit]

The TLV is equivalent in spirit to various occupational exposure limits developed by organizations around the world; however, the materials covered, values recommended, and definitions used can differ amongst organizations. These occupational exposure limits include:

United States[edit]

WEEL (Workplace Environmental Exposure Level), formerly created by a committee of the American Industrial Hygiene Association; as of January 1, 2012, new WEELs are created by a committee of volunteers that is supported by the Occupational Alliance for Risk Science.^[2]

Other countries[edit]

Australia
- OES Occupational exposure standard [1]
France
- VME (Valeur Moyenne d'Exposition)
- VLE (Valeur Limite d'Exposition)
Germany
- AGW (Arbeitsplatzgrenzwert trans. Workplace Limit Value)
- MAK (Maximale Arbeitsplatz-Konzentration trans. Maximum Workplace Concentration)
Malaysia
- PEL (Permissible exposure limit)
Netherlands
- MAC (Maximaal Aanvaarde Concentratie trans. Maximum Accepted Concentration)
New Zealand
- WES (Workplace Exposure Standards)
Poland
- NDN (Najwyższe Dopuszczalne Natężenie)
Russia
- ПДК (предельно допустимая концентрация)

References[edit]

Exposure Assessment

^ "A Strategy for Assessing and Managing Occupational Exposures, Third Edition Edited by Joselito S. Ignacio and William H. Bullock AIHA Press" http://iweb.aiha.org/iweb/Purchase/ProductDetail.aspx?Product_code=AEAK06-327/
^ "WEEL Development Finds a New Home". American Industrial Hygiene Association. February 22, 2012. Retrieved 2013-04-26.

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Detection of mandarin in orange juice by single-nucleotide polymorphism qPCR assay.

Aldeguer M, López-Andreo M, A Gabaldón J, Puyet A.SourceCentro Tecnológico Nacional de la Conserva, Molina de Segura, Murcia, Spain; Departamento de Ciencia y Tecnología de Alimentos, Universidad Católica San Antonio de Murcia (UCAM), Murcia, Spain.
Food chemistry.Food Chem.2014 Feb 15;145:1086-91. doi: 10.1016/j.foodchem.2013.09.002. Epub 2013 Sep 13.
A dual-probe real time PCR (qPCR) DNA-based analysis was devised for the identification of mandarin in orange juice. A single nucleotide polymorphism at the trnL-trnF intergenic region of the chloroplast chromosome was confirmed in nine orange (Citrus sinensis) and thirteen commercial varieties of m
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Migration of odorous compounds from adhesives used in market samples of food packaging materials by chromatography olfactometry and mass spectrometry (GC-O-MS).

Vera P, Canellas E, Nerín C.SourceAnalytical Chemistry Department, GUIA Group, I3A, CPS, University of Zaragoza, Mª de Luna 3, 50018 Zaragoza, Spain. Electronic address: pvera@unizar.es.
Food chemistry.Food Chem.2014 Feb 15;145:237-44. doi: 10.1016/j.foodchem.2013.06.087. Epub 2013 Jun 28.
Adhesives are commonly used in the manufacture of multilayer food packaging materials. Although they are not in direct contact with the packed food, their compounds may migrate from the adhesive through the substrates to the food. The aim of this work is to determine the migrant concentration in ord
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Hydroxylation of silica nanoclusters (SiO2)M(H2O)N, M = 4, 8, 16, 24: stability and structural trends.

Jelfs KE, Flikkema E, Bromley ST.SourceDepartment of Chemistry, Imperial College London, London, SW7 2AZ, UK.
Physical chemistry chemical physics : PCCP.Phys Chem Chem Phys.2013 Dec 21;15(47):20438-43. doi: 10.1039/c3cp53347f. Epub 2013 Nov 5.
Employing global optimisation and ab initio calculations, we follow the step-wise molecular hydroxylation of (SiO2)M(H2O)N, M = 4, 8, 16, 24, cluster species from their anhydrous state up to a N : M ratio (RN/M) of ≥0.5. Increasing N from zero for low RN/M values, significantly and progressive
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