Material Safety Data Sheet definition

TLV The TLV or Threshold Limit Value refers to a safe level of exposure by inhalation. The definition was established by the American Conference of Governmental Hygienists. There are several variations or criteria levels for the TLV. As an example, hydrogen sulfide has a TLV for short-term exposure limits (STEL) of 15 minutes of only 5 ppm. Comparing this to the TLV-STEL of 400 ppm for carbon monoxide provides an indication of the need to be extremely careful when H2S is suspected. Under OSHA Standards, and particularly on MSDS (Material Safety Data Sheets) compounds are associated with a time weighted average (TWA) TLV, which is the allowable concentration for an 8-hour continuous exposure period. For firefighting purposes, the short-term exposure is likely more realistic. 

Often safety data or material safety data sheets mention the thermal stability as an intrinsic property of a substance or mixture. In fact, this is an oversimplification of a concept that must be defined in a more comprehensive way. Basically, a substance or a mixture is thermally stable in a situation where the heat released can be removed in such a way that no temperature increase occurs. This definition... 

While there a commonly accepted definition of the term label, the concept itself is surrounded by a considerable degree of ambiguity. In the chemical industry the term label or labeling incorporates the printed device(s) affixed directly or indirectly to a container surface, inserts found within the container, associated Material Safety Data Sheets, product descriptions, overpacks and wrappers, workshop signs and placards, most forms of advertising and the like. From this perspective, labeling of chemicals is a system involving a veiriety of elements. 

For some chemicals, the material safety data sheet Material Safety Data Sheet (MSDS) show a short-term exposure limit (STEL) value. STEL is defined as the 15-minute average that should not be exceeded even if the average value for an eight-hour day is below the PEL. STEL values are related to short term effects while PEL values apply to chronic exposures. The following are some definitions used by OSHA ... 

Material Safety Data Sheets, which are now required to be provided by distributors and manufacturers of commercial chemicals, give detailed information on the characteristics of all commonly sold laboratory chemicals. The definitions of explosive, flammable, combustible, and various healthhazards are consistent with those provided by OSHA in CFR 29, Parts Table 3.2 Exemption Limits for a Few Critical Classes of Materials Representing Health Hazards For a Class 4, Hazardous Use Occupancy... 

Hazardous and toxic substances can be defined as those chemicals present in the workplace that are capable of causing harm (see Figure 23.6). In this definition, the term chemicals includes dusts, mixtures, and common materials such as paints, fuels, and solvents. OSHA currently regulates exposure to approximately 400 substances. The OSHA Chemical Sampling Information file contains a listing for approximately 1,500 substances. The EPA s Toxic Substance Chemical Act Chemical Substances Inventory lists information on more than 62,000 chemicals or chemical substances. Some libraries maintain files of Material Safety Data Sheets (MSDSs) for more than 100,000 substances. It is not possible at this time to address or regulate the hazards associated with each of these chemicals that can potentially be found in the workplace. 

Aldehydes can be named as the longest hydrocarbon chain (includes the carbonyl carbon atom) and affixing the suffix al to the hydrocarbon name. No number is assigned to the aldehyde functional group since by definition it is attached to the terminal carbon atom. However, numbers are assigned to any alkyl or other group attached to the main hydrocarbon chain. Formaldehyde is methanal, acetaldehyde is ethanal, propionaldehyde is propanal, n-bu-tyraldehyde is -butanal, and isobutyraldehyde is 2-methyl propanal. The common names of formaldehyde, acetaldehyde, propionaldehyde, n-butyral-dehyde, and isobutyraldehyde are most often encountered in the chemical industry. The CAS numbers (Chemical Abstract Service, American Chemical Society) for the aldehydes are listed in Table 9.1 along with the physical properties. The CAS numbers refer to the major aldehyde component. Refer to the Material Safety Data Sheet (MSDS) for CAS numbers of any minor impurities in the solvent. 

It is important that the adhesive manufacturer should be assessed for the quality and consistency of his products. Quality control test data should be available for each batch of adhesive, which requires the prior definition of the necessary characteristics and the means of assessing them. Adhesive materials should be packed in suitable containers ready for mixing, and each container should be durably and legibly marked with appropriate information. An instruction sheet should also accompany any delivery of adhesive, detailing information which includes product chemical type, storage conditions, mixing and application instructions, advice on compatible primers, curing profiles, safety instructions, and so on (e.g. see Appendix),... 

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