in the Chemical laboratory Edited by NORMAN V. STEERE, 1 4 0 Melbourne Ave., S.E. Minneapolis, Minn. 5 5 4 1 4
XC. Identification of Hazardous Materials-Part
II
NORMAN V. STEERE FLAMMABLE MATERIALS Flammable Gases Anhydrous ammonia is a. flammable gas, according to "Hazardous Chemicals Data, NFPA No. 49-1971." The reported flammable limits are 16 to 25%, for horizontal propagation of flame, and the ignition temperature is 1204OF (651DC). The NFPA degree of flammability hazard for most flammable gases is four (for extreme hazard), hut mhydrous ammonia. is rated a t one, probably because spills do not usually become ignited. Anhydrous ammonia. is NOT rs A m mable gas according t o MCA definitions and DOT regulation, DOT classifies anhydrous ammonia as a nonflammable compressed gas. DOT Hazardous Materials Regulations, in CFR 49 Sec. 173.300. define compressed gases and classify them as flammable compressed gas if any one of the following occurs: "(1) Either a mixture of 137' or less (by volume) with air forms B flammable mixture or the flammahle range with sir is wider than 127, regardless of the lower limit. These limits shall be determined a t atmospheric temperature and pressure. The method of sampling and test procedure shall be acceptable to the Bureau of Explosives. "(2) Using the Bureau of Explosives' Flame Projection Apparatus (see Note I), the flame projects more than 18 in. beyond the ignition source with valve opened fully, or, the flame flashes back and bums a t the valve with any degree of valve opening. "(3) Using the Bureau of Explosives' Open Drum Apparatus (see Note I), there is anv . significant wrowaestion of flame away from the ignition source. "(4) Using the Bureau of Explosives' Closed Drum Apparat,us (see Note I), there is any explosion of the vapor-air mixture in the drum. "Note 1: A description of the Buresu of Explosives' Flame Projection Apparatus, Open Drum Apparatus, Closed Drum Apparatus, and method of tests may be procured from the Bureau of Explosives," 2 Pennsylvania Plaza, New Yark, N. Y. 10001. The DOT classification of flammable compressed gas derives from their specification that "compressed gas" shall be designated as: ". . . any material or mixture hrwing in the container an absolute pressure exceeding 40 psi a t 70°F or, regardless of the pressure a t 7OSF, having an absolute pressure exceeding 104 psi a t 130°F; or any liquid Rammable material having a. vapor pressure
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exceeding 40 psi shsolute a t 100°F as determined by the Reid method covered by the American Society for Testing Materials 'Method of Test for Vapor Pressure of PetroleumProduets' (D-323)." Some of the chemicals classified as Flammable Compressed Gas under DOT regulations are: aeet,ylene, carbon monoxide, cyclopropane, ethane, ethylene, hydrogen, hydrogen sulfide, and methyl mercaptan. Fluorine is also classified as a flammable compressed gas under DOT Hazardous Materials Regulations; the obvious misclsssification is probably attributable to the fires which occur when this powerful oxidizing material contacts almost any material. (Chlorine is classified by DOT as a. nonflammable compressed gas, not as an oxidising material or a poison gas.) DOT-required markings for flammable gases are the diamond-shaped Danger placard on railroad cars, the rectangularshaped Flammable Gas placard on trucks, and a diamond-shaped red lahel for packages. The label required for packages shipped by rail, truck, or water is similar to the red lahel described earlier, with omission of" Leaking packages must be removed to a safe place" and addition of "Keep cool," "Flammable-Compressed Gas," and a space to insert the name of the contents. The red lahel for packages of flammable gases for air shipment is the same as the label for air shipment of flammable liquids: "Dnmnged paokages must he removed to a safe place-FLA.MMABLE-Keep away from fire, heat, and open-flame lighls" and space far the name of contenbs. MCA in the "Guide to Precautionary Labeling of Haaarduus Chemicals" gives the definition "A Flammable Gas is s. gas with either of the following properties: (a) a t atmospheric temperatwe and pressure forms a flammable mixture with air when present, s t a. concentration of 13% or less (by volume) or which forms a, range of flammable mixtures with air wider than 12% regardless of the lower limit, or (b) projects a flame more than 18 in. beyond the ignition source wit.h valve opened fully, or the flame flashes back and bums at. the valve with any degree of valve opening, when tested in t,he Bureao of Explosives' Flame Proiectian Aooaratrls." No definillom are given by tho other organiaxtions listed earlier.
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and gives data on two materials which have flash points while they are in the solid state. Camphor has a flash point temperature of 150°F (66"C), with a melting point of 3 5 4 T (179°C). Naphthalene has a flash point of 174°F (79"C), and a.melbing paint of 176OF (80°C). MCA defines a flammable solid as one ot,her than an explosive that is "liable to cause fire through friction, absorpt,ion of moisture, spontaneous chemical change, or retained heat from manufacturing or processing, or which can be ignited readily and when ignited burns so vigorously and persistently as to create a. serious hazard." The MCA Guide does not give . anv examules of flammable solids. DOT regulations define flammable solids as: "any solid material, other than an explosive, which is liable to cause fires through friction, absorption of moisture, spontaneous chemical changes, retained heat from manufacturing or processing, or which can be ignited readily and when ignited burns so vigorously and persistently ss to create 8. serious transportation hazard." Some of the materials classified as flammable solids by DOT regulations are: ammonium bichromate, calcium, calcium phosphide, charcoal, cobalt resinate, decahorane, hafnium, isopropyl percarbonate, lithium aluminum hydride, lithium amide (powdered), magnesium scrap, phosphorus, phosphorus pentachloride, phosphorus sesquisulfide, and phosphoric mhydride. Others are picric acid wet with not less than lOYo water, potassium, sodium, thorium (powdered), titanium (powdered), and zirconium powder and scrap. DOT-required labels for packages of flammable solids are diamond-shaped, 4 in. long on each side, and bright yellow with black printing. The label for packages shipped by mil, truck, or water have wording which is ambiguous and almost exactly the same sa on the red label for flammable liquids. The yellow
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Flammable Solids NFPA does not define flammable solids, but "Fire-Harard Properties of Flammable Liquids, Gases and Volatile Solids, NFPA N o . 32?M," refers to ,
Required on packages containing flammable liquids for oir shipment,. (Red label with black printing.)
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Volume 48, Number I I, November 1971
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labels for identification of flammable solids for surface shipments read: "Keep away from fire, heat, and open-flame lights-CAUTION-remove carefully the contents of broken packages-do not drop-this is to certify Chat the contents of this package are properly described by name and are packed and marked and are in proper condition far transportation according to the Regulations prescribed by the Department of Transportation-hipper's name required hereon for shipments by express." Yellow labels for air shipment of flsmmable solids show 8. stylized pictograph of s. radiating flame in the upper half of the diamond, and with the wording: "damaged psckages must be removed to a safe place-FLAMMABLE-keep away from fire, heat, and open-flame lights-do not load with articles bearing white labels."
OXIDIZING MATERIALS Adding to the confusion of labels for flammable solids which are almost completely ditrerent far sir and for surface shipment,, and which look almost the same as the labels for flammable liquids except far color, me the DOT-1,equired labels far oxidizing materials. Consider the desirabilitv of identifvine osidiaine
leaking or broken packages.
I t may be
Required on pockoger containing Rommable solidr or oxidizing moteriol$ for roil, truck or voter shipment. IYellow label with black printing.)
hard to believe, but the DOT-required labels for flammable solids and for oxidiaing materials a t r e IDENTICAL. The yellow label for surface shipment of packages of oxidizing materials is identical to the one described for surface shipment of packages of flammable solids, and except for color and a few words is almost identical to the red label for surface shipment of packages of flammable liquids. Yellow labels for air shipment of oxidizing materials and flammable solids are identical, and are very similar to the labels for air shipment of flammable liquids and gases. Oxidizine materials are defined bv IIOT regilations as substances such (Continuedon page A715)
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as chlorates, permanganstes, peroxides, nitrocarbonitrates, or nitrates that yield oxygen readily to stimulate the combustion of organic matter. This definition includes ammonium nitrate even though ammonium nitrate is commonly used as an explosive. Some of the other materials which are classified as oxidizing material by DOT are: ammonium perchlorete, benzoyl peroxide, tertiary butylisopropyl benzene hydroperoxide, cumene hydroperoxide, magnesium perchlorate, and tetranitrometh~e. (As an i h s t r s tion of the limits of the present DOT Hazardous Materials Rkgulatians, tetra: nitromethane is described in the "Condensed Chemical Dictionary," 7th Ed., as a. very toxic liquid which is poison, a fire hazard, and used as a rocket fuel, either as an oxidant or as a manopropellant. Some of the other examples listed above are explosive, heat or shack sensitive, or capable of detonation.) The "MCA Guide to Precautionary Labeling of Hilsitrdous Chemicals" does not give any examples hut defines the term "strong oxidizer" as: "a substance that yields oxygen readily to stimulate the combustion of organic matter." "NFPA No. 49, Hazardous Chemicals Data," has an explanatory paragraph on oxidizing materials which lists a number including chlorates, bromates, nitrates, and bromine, chlorine, fluorine, and iodine. "NFPA No. 49" mentions that most oxidiaing materials will readily yield oxygen when heated so that the hazard is greatly increased a t elevated temperatures, that violent reactions may occur when oxidizing materials are mixed or contaminated with combustible materials, and such mixtures are ordinarily very sensitive to heat, friction and impact. (Although such facts may seem obvious, laboratory accident, experience shows that the facts are not always taught or learned witboutinjury.)
UNSTABLE, REACTIVE, AND EXPLOSIVE MATERIALS
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The 1967 Federal Hazardous Substances Act defines the term hitzwdous substrtnce to include any substance or mixture which generates pressure through decomposition, heat, or other means, if such "may cause substantial personal injury or substantial illness during or as a proximate result of any customary or reasonably foreseeable handling or use . . . ." No forther definition or example is given. MCA defines hazardous substance to include any substance or mixture that is dangerously reactive or pressure-generating," provided such substance or mixture of substances may cause substantial personal injury or substantial illness during or as a. direct result of any customary or reilsonably foreseeable handling or use." MCA does not define dangerously reactive, but does define pressuregenerating substance as one falling within any of these three categories: "1. A substance that must be protected from spontaneous polymerization
by the addition of an inhibitor, or by refrigeration or other thermal control. "2. A substance that may decompose to release gas in its container. "3. A substance that comprises the contents of a self-pressurized container." The Material Safety Data Sheet, Form LSB 0 0 s - 4 , required by the DOD MIL-STD-1341A and by DOL under other regulations, defines hazardous material to include any which is subject to spontaneous heating, or to polymerization with the release of large amounts of energy. No further definition or example is given. Instn~ctions for completing the section on reactivity data call for the contractor furnishing the material to provide certain information on stability, incompatibility, hazardous decomposition products, and hasardous polymerization, Far example, is the material "stable or unstable under reasonably foreseeable conditions of storage, use, or misuse?" Another request which could be difficult to answer on one line is to: "Provide information on such common materials and contaminants with which the product may reasonably come into contact, to produce ra reaction which would release large amounts of energy." "NFPA No. 49" briefly notes the limitations of the Self-Accelerating Decomposition Temperature (SADT) reported for some organic peroxides, lists some reported SADT, and notes some materials which may undergo hazardous polymerization, "NFPA No. 49, Hamrdous Chemicals Data," does not list sobsbsnces classified as explosives by DOT, but does list a number of chemicals which may detonate (high explosives) or deflagrate (low explosives). Both NFPA and DOT limit their regulation of explosive materials by definition of the term "explosive." "NFPA No. 40h1967, Code for the Manufacture, Transportation, Storage and Use of Explosives and Blasting Agents," defines the term "explosive" or "explosives" to mean "any chemical compound, mixture or device, the primary or common purpose of which is to function by explosion, i.e., with substantially instantaneous release of gas and heat, unless such compound, mixtnre, or device otherwise specifically classified by the U. S. Department of Transportation.'' The DOT definition is practically identical. The foreword of the NFPA Code on explosives and blasting agents states that the code is also "intended to cover the storage and use of explosives and blasting agents in industrial laboratories and laboratories of technical instit,otions, colleges and universities." The NFPA Code notes that oertain chemicals and fuel n~aterialsmay have explosive char-, acteristies not classified by 1)OT or the NFPA Code, and recommends that "Authoritative information should be obtained for such unclassified materials and action commensurate with their hazards, location, isolation and safeguards, should be taken." Part 111will discuss definitions of terms used for describing heslth hazards of chemicals.
