Flammability laboratory chemicals

Waste generated in the laboratory can often be characterized from knowledge of the starting materials (e.g., hydrocarbon mixture, flammable laboratory solvents, chlorobenzene still bottoms). Professional expertise, common sense, judgment, and safety awareness of trained professionals performing chemical operations in the laboratory usually put them in a position to judge the type and degree of chemical hazard. 

Hazards Wear gloves when handling 60% nitric acid, and 98% sulfuric acid. Extinguish all flames before using cotton, which is highly flammable, and a fire hazard, especially when laboratory chemicals are present. Caution Nitrocellulose if highly flammable. 

Awareness of very reactive chemicals is essential. Advice on handling highly flammable and/or potentially explosive reagents is provided in the lUPAC-IPCS book Chemical Safety Matters, and the properties of many common but hazardous laboratory chemicals are succinctly summarised in the yellow pages section of Hazards in the Chemical Laboratory, 5th edn., ed. S.G. Luxon, Royal Society of Chemistry, Cambridge, 1992. One particular explosive hazard, peroxide-forming chemicals, is described in more detail in Section 11.8. 

As a good general rule, all low boiling (<100°) organic liquids should be treated as highly flammable and toxic (because they can be inhaled in large quantities) and the necessary precautions should be taken (see Safety precautions associated with the purification of laboratory chemicals in Chapter 1, p 4). 

Flammable Limits—The lower flammable limit is the minimum concentration (percent by volume) of a vapor in air below which a flame is not propagated when an ignition source is present. Below this concentration the mixture is too lean to bum. The upper flammable limit is the maximum concentration (percent by volume) of the vapor in air above which a flame is not propagated. Above this concentration the mixture is too rich to bum. The flammable range comprises all concentrations between these two limits. This range becomes wider with increasing temperature and in oxygen-rich atmospheres. Table 13 lists these properties for a few common laboratory chemicals. 

Flash Points, Boiling Points, Ignition Temperatures, and Flammable Limits of Some Common Laboratory Chemicals... 

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... 

The NFPA fire hazard ratings, flash points, boiling points, ignition temperatures, and flammability limits of a number of common laboratory chemicals are given... 

All laboratory personnel should know the properties of chemicals they are handling as well as have a basic understanding of how these properties might be affected by the variety of conditions found in the laboratory. As stated in section 5.B, Laboratory Chemical Safety Summaries (LCSSs) or other sources of information should be consulted for further information such as vapor pressure, flash point, and explosive limit in air. The use of flammable substances is common, and their properties are also discussed in Chapter 3, section 3.D. 

FIGURE 3.1.2.1 Ether Structure and Laboratory Chemical Container. Ethyl ether is a common laboratory chemical, also called diethyl ether and ether. It is very flammable and tends to form dangerous peroxides if stored over extended periods of time. 

FIGURE 3.1.2.6 Laboratory Chemical Bottle with NFPA Diamond. It is important to know the meaning of the ratings (0-4) in the fire diamond to properly assess the various hazard levels of health, flammability, and reactivity. 

Handling and Disposal of Chemicals in Laboratories Flammability of Chemical Substances Threshold Limits for Airborne Contaminants Octanol-Water Partition Coefficients Protection Against Ionizing Radiation Annual Limits on Intakes of Radionuclides Chemical Carcinogens... 

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