Workplace limit value

Biologische Arbeiisstoffioleranzwerte (Biological Tolerance Value for 0( pa mal e sutes). Arbeitspla gmtzwerte (workplace limit values). 

The workplace limit value Arheitsplatzgrenzwert or AGW) is a substance related limit value. If this value is respected, a risk to health is in general not to be expected. 

In these adhesives, the polymers and resins are dissolved in organic solvents. The hazard potential is determined by the nature of the solvent (e.g., flammability, irritation potential). Due to the high volatility of the solvents, exposure by inhalation of the vapors is the bi est problem. For most solvents, the maximum concentration at the workplace and limiting factors are laid down (workplace limit value). Due to the small amounts of adhesive used by private users, these limit values are generally not reached or are only exceeded for a very short time. 

The limits for prolonged exposure are expressed as the threshold limit values. These are essentially acceptable concentrations in the workplace. There are three categories of threshold limit values ... 

The mean exposure limit value for 3-methyl-1-butanol in the air of workplaces was set at 100 ppm in 1984 by the ACGIH (135). Standards have not been set for the other alcohols (135). 

Because pulp bleaching agents are, for the most part, reactive oxidising agents, appropriate precautions must be taken in their handling and use. For example, it is important to ensure that the threshold limit values (TLV) (20) in Table 2 are not exceeded in the workplace air. These are airborne concentrations in either parts per million by volume under standard ambient conditions or mg per cubic meter of air. They "represent conditions under which it is beUeved that nearly all workers may be repeatedly exposed, day after day, without adverse effect" (20). TWA refers to a time-weighted average for an 8-h workday STEL is a short-term exposure limit or maximum allowable concentration to which workers can be continuously exposed for 15 minutes. 

CFN (1992). Workplace atmospheres — Guidance for the assessment of exposure by inhalation to chemical agents for comparison with limit values and measurement strategy. EN 689. 

The limit value for suspended matter is given in mg/m or multiples thereof for actual environmental conditions (temperature and pressure) at the workplace. The limit values for fibers are given in fibers/m or fibers/cm for actual operating conditions of temperature and pressure. It is possible to con vert one expression to the other using the formula... 

The first step is to identify the substances present at the workplace. As a starting point, knowledge of the process is needed in order to formulate a list of all chemical agents used in the establishment. The list should include not only primary products but also intermediate and final products, as well as reaction products and by-products. For the chemical agents in the list, it is necessary to know their chemical properties, especially hazardous ones their OEL values, including biological limit values and, where these are not available, other technical criteria that can be used to evaluate the risk. It is also helpful to include any information on the safety and health risks of those substances provided by the supplier or other readily available sources. This information on dangerous substances and preparations, in the form of safety data sheets, is intended primarily for industrial users, to enable them to take the measures necessary to ensure the safety and health of workers. 

The initial appraisal allows consideration of the likelihood of exposure due to the presence of chemical agents. When the conclusions of the initial appraisal show a possible risk exposure for the worker, more data are gathered taking special account of tasks with high exposures. If necessary, workplace measurements are taken if the input data are not sufficient to enable valid comparison with the limit values. 

Finally, for situations in which it is not clear that exposure is and will continue to be below the limit values, a detailed survey with a measurement strategy is required. The methods used are based mostly on instruments for sampling the environment in order to obtain reliable measurements of workplace air concentrations. In general, the measurement strategy must consider the most efficient use of resources for the purpose of obtaining quantitative data on exposures by having a clear idea of what the data will be used for or whether it meets the specified need. For example, if the data pertain to peak exposures, these peaks have to be assessed according to the STEL requirements, if any. 

Threshold limit value (TLV) The limits of airborne concentration of chemical substances that are allowed in workplaces published by the American Conference of Governmental and Industrial Hygienists (ACGIH). Also known as MAC. 

ACGIH maintains annual editions of the TLVs and BEIs which are used worldwide as a guide for evaluation and control of workplace exposures to chemical substances and physical agents. Threshold Limit Value (TLV ) occupational exposure guidelines are recommended for more than 700 chemical substances and physical agents. There are more than 50 Biological Exposure Indices (BEIs ) that cover more than 80 chemical substances. 

Filter samples can be prepared to airborne workplace concentrations by spiking each filter with aqueous solution containing elements with concentrations gravimetrically traceable to ultrapure metals or stoidiiometricaUy well defined oxides. The amormts correspond for some of the materials to current threshold limit values of contaminants in workroom atmospheres provided that the simulated filter has been exposed to one cubic meter of air. The certified values are based on a gravimetric procedure, i.e. weight per volume composition of the primary reference material dissolved in high purity sub-dis-tiUed acids. The National Institute of Occupational Health in Oslo, Norway, has produced several batches of such materials certified for 20 elements. Additionally, information values are reported for four other elements see Table 6.2. 

OSHA has set a Permissible Exposure Limit (PEL) of 500 ppm for //-hexane in workplace air. A court decision struck down a proposed PEL of 50 ppm. Damage to nerves has been found in people at 500 ppm. The American Conference of Governmental Industrial Hygienists (ACGIH) recommends a Threshold Limit Value (TLV) of 50 ppm. 

This situation does not apply only to Germany. The Health and Safety Executive quotes specific figures for the UK, which give an idea of application of occupational health and safety legislation there In approximately 1.3 nullion British compaiues chemicals are handled. When questioned, only 16% of these compaiues were able to state the applicable law for handling chenucals or the limit values for these substances at the workplace. With regard to the need for protective measures, these 16% also rely almost entirely on the details contained in the safety data sheets. 

ACGIH) also recommends a Threshold Limit Value (TLV-TWA) of 75 ppm (450 mg/m ) (ACGIH 1996). Current control technologies should limit workplace concentrations to this level. 

Industrial workers make up the segment of the population that is most vulnerable to chemical injury. To protect them from occupation-related harm, the American Conference of Governmental and Indnstrial Hygienists publishes annually revised threshold limit values (TLVs), guidelines for permissible chemical exposure at the workplace. http //www.acgih.org/Resources/press/HAL.htm... 

TWA, time-weighted average SUiL, short-term exposure limit MAK, maximum workplace concentration TLV, threshold limit value REL, recommended exposure hmit PEL, permissible exposure limit Ca, potential occupational carcinogen sk, skin notation... 

The American Conference of Governmental Industrial Hygienists (ACGIH) (1997) has recommended 5 iiig/m as the 8-h time-weighted average threshold limit value for occupational exposures to benzoyl peroxide in workplace air. Similar values have been used as standards or guidelines in many countries (International Labour Office, 1991). 

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