1in the Chemical Laboratory ( Edited by N O R M A N V. STEERE,
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140 Melbourne Ave., S.E. Minneapolis, Minn. 55414
XLVI. Hazardous Chemicals Data*
The 1!167 edit,ion of Hazardous Chernicals Data incorporates changes prepared hy the Sectional Committee on Properties of IIssardow Chemicals and adopted by the National Fi1.e Protection Association a t the 1967 Annual Meet,ing on recommendat,ion of the Correlating Committee of the Commit.tee on Chemicals and Explosives. I t supersedes the 1966 edition. Amendments adopted in 1967 are summarized irr n pnmgraph aftel. the next section.
Origin and Development The compilaI.ion of information on hnnxrdow chemicals was originated by the XFPA Committee an lIasardous Chemienls and Explosives in cooperation wit,li the American Chemical Society. A Table of Common Haaardous Chemicals (NFPA No. 49) u-ns adopted in 1928. Revisions were adopted in 1929, 1931, 1!135, 1948, 1W9, 1!141, 1942, 1944, 1946, and 1!150. A complete revision, prepared hy the S e c t i o d Commit,tee ou Properties of IIazardaus Chemicals, was adopted in 11161 under the new title, 1-Iaaa1.dous Chemicals Data (NFPA No. 49M).
* From H ~ z s r d o u s Chemicals Data, NFPA No. 411, copyrighted by Nat,ional Fi1.e Protection Assoeiat,ion. Reminted by permission
Amendments were adopted in 1962, 1063, 1964, 196.5, 1966, and 1967. Starting with the 1964 edition, the identifying number of Hazardous Chemicals Data has been NFPA No. 49. The data presented are subject to additions and revisions and are not allinclosive, hut are presented as the most authoritative information available to date. The purpose in lisbing a. substance is not to diseollrage its pmper use, hut rather to make available information relative to its hazardous properties and fire fighting phases in order to promote and improve methods of fire protection and prevention. This is not a regulatory standard and does not include all possible detailed information with regard to hazards, storage, safeguards, fire fighting, or unnsnal eonditions which may he ellcotmtered.
ComrniWee on Chemicals and Explosives Dr. Robert W. Van Dolah, Chaivn~an,Explosives Research Center, Bureau of Mines, U. S. Ikpartment of the Int,erior, 4800 Forbes Ave., Pit,tsborgh, Pa. 15213 Chester I. Babcock,? S e c ~ e t a q ,Nat,ional Fire Pmtection Assn., 60 Bst,terymareh St., Boston, IMaiis. O2ll0 W. H. Doyle, Fact,ory Insurance Assn. Thomas E. Duke, Fire Protectiun & Engineering Bureau of Texas. Dr. Richard Y. Le Vine, Olin Mathiesun Chemical Corp. Henry T. Rittman, Institute of Makers of Explosives. Russell H. Scott, Bat,t,elle-Northwest. SCOPE: This committee serves as a policy-making and correlating group to administer and process report,s of the various sectional committees dealing with c h e m i d s and eq,lusives.
Sectional Committee on Properties of Hazardous Chemicols Thomas E. Duke, Chairman, Fire Prevention & Etrgiueering Bnrenu of Texas, ,520 Mercantile Securi1,ies Bldg., Ilallas, Texas 75201 Chester I. Babcock,t Sec~eta~.!q,National Fire Protect,ion Association, GO Batterymarch St,reet, Boston, Mass. 02110 Douglas R. Abbey, Uon Mills, Ont,., Canada.
t Kou-vot,ing member.
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Arthur G. Baker, Mutual Fire 4 a w . of Sew Enelnnd. Mathew Braidech, American Chemiral Society. R. E. Dufour, Underwriters' Lahornt.r,ries, Inc. William E. Grubert, Conference of Special Riik Underwriters. Paul D. Hallev. .. American Petndeurn Institute. Joseph A. Haughtou, Liberty Mutual Ins.
C,, ~ o b e rW. t Kiefer, Union Carbide Carp. Dr. Richard Y. L e Vine, Manufacturing chemist,^' Assn., Inc. Rudolph Schmidt, Jr., American 111mranee Assn. Russell H. Scott, BattelleNorthsest. Charles J. Shukes, Illinois Ii~ipect,ion& Rilt,ing B I I I . ~ ~ . Charles B. Smith, U. S. Coast. G~rard. William H. Van Amurn, )Yestern Elertvic Company, Ine. Dr. Robert W. Van Dolah, V. 8. Depart, ment uf t,he Interior. SCOPE: To compile information on hazardous chemicals and develop recommended fire hazard ratings of chemicals.
Amendments Adopted in 1967
Correloting Committee
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NATIONAL FIRE PROTECTION ASSOCIATION, 6 0 Bdierymorch Street, Boston, Moss. 02110
I n ICY28 the Committee on Hannrdous Chemicals and Explosives of the Amec ioan Chemical Societ,yand t,heNational Fire Protection Association prepared "A Table of Common Hazardous Chemicals," with a listing of 61 chemicals, their fire and life hazard, and recummendat~ions on storage of usoal shipping cont,ainers. Since 1928 the pnhliextion ha.? grown from only 11 pages t,o 192, and now gives rather complete information on 205 chemicals in s. pghlioatior~ eutitled "Hasardons Chemicals I)at,a." Because we believe "Hszsrdous Chemicals Data" is one of the better r e fwences available for low cost (81.50) and that copies should be widely available for common use in the laboratory, we have obtained special permission from the Nntionnl Fire Protection ASSOciation to reprint the explan~torysection of the copyl.ighled p,~hlicationand mme examples of t,he data present,ed.
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Data were added on 18 chemicals; "Explanatory" was expanded to include's paragraph, "Special Protective Clothing"; and a sentence was added to "Heallh" definition4 to recommend the use of special p1,otective clothing. Throughout the standard, special protective clothing is now recommended instead of in11 protective clothing for clremieals with Health Hazard Ratings of 4. Reactivity definitions in "Explanatory" were clarified hy addition of "iu themselves" in each irrst,ance. The second paragraph of "EleeIrical Equipment" in "Explanatory" xvas added in 1967.
Explanatory Chemicals Included. Dnt,a w e inchded on tilose chemicals used and shipped rommereially 2 n d nhirh meet one or m w e of the following criteria: A henlt,h hazard rat,ing of 2 or higher; a r e a h v i t y rating of 1 cx higher; or which present um~snalstorage or fire fighting prublems or can become hazardous on being contaminated or mixed wi1.h other chemicals. There are nmny el~emicalsmeeting these criteria that, are not included became the Sectional Cummittee on Properties of Hazardous Chemicals has nut completed compilation of data on them. The committee's present schedule calls for the addition of data on approximately 20 chemicals per year. Thus, the reader shrluld not. asmme that because a chemical is not included it does (Continued on pago A 116)
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and may call for special engineering judgment, particularly in largescale applications. The use of standard approved equipment is also of major importance. The chemical and physical properties not possess any unusual hazards. No of a flammable substance will also affect materials are included whose only sigthe choice of s n extinguishing method. nificant hsesrd is flammability (see NFPA Ordinary-type foam, for example, would No. 325M for these materials), nor are not be suitable on a fire involving a explosives included unless they 8.180 are water-soluble flammable liquid. These commercially used for other purposes. special properties affecting extinguishSuggestions of chemicals meeting the ment were taken into consideration when above criteria that should he added to preparing the statements in FIREFIGHTHazardous Chemicals Data will he apm a PHASES. preciated. Please send your suggestion to Water may be ineffective in fighting the Chairman of the Sectional Committee fires in liquids with low flash points. This on Properties of Haesrdous Chemicals precautionary wording is used for m a t e or to the National Fire Protection Asriah having a, flash point below 100' F. sociation. Obviously, the lower the flash point, the Description. When given for a listed less effective water will he. However, mat,erial, the information under this headwater can he used on low flash point liquids ing is intended to be a guide to assist in when applied in the form of a spray to identifying the material in the form in absarh much of the heat and to keep exwhich i t is ordinarily eneoontered. posed material from being damaged by the Usual Shipping Containers. The confire. tainers listed are those in which the m a t e Much of the effectiveness of using water rids are usually shipped or stored in comspray, particularly from hose lines, will mercial practice. depend on the method of application. Storage. The Storage recommendations With proper noeales, even gasoline spill areintended to supplement but not replace fires of some types have been extinguished those contained in pertinent NFPA stanwhen coordinated hose lines were used to dards. For example, storage of flammable sweep the Aames off the surface of the liquids in containers or tanks should comliquid. ply with the requirements of the FlamWater also has been used to extinguish mable and Combustible Liquids Code fires in water-soluble flammable liquids (NFPA No. 30). The pertinent NFPA standards are listed under the REMARKS by cooling, diluting and mixing the flammableliquid with water. paragraphs. Isolate and separate are terms used to The inclusion of the phrase "water may describe recommended storage practices be ineffective" is to indicate that alfor certain hazardous chemicals. Isolated though water ean be used to cool and storage means storage away from inprotect exposed material, water may not compatible materials in a different storage extinguish the fire unless used under favormom or in a separate and detached buildable conditions by experienced fire fighters ing located s t a safe distance. Separated trained in fighting all types of flammable storage refers to storage in the same fire liquid fires, area but separated by as much space as Water or foam may cause frothing practicable or by intervening storage from when applied on viscous flammable liquids incompatible materials. heated above 212' F., the boiling point of Protection against moisture during water. This remark is included only s s a Btorage is recommended for those chemprecaution and does not indicate that i d s that react with water. When conwater or foam should not or could not be tainers of water-reactive chemicals are used in fighting fires in such liquids. The to be opened, they should first be allowed frothing may be quite violent and could to warm to the temperature of the apenendanger the life of the fire fighter, paring area. If this procedure is not followed, ticularly when solid streams are directed moisture in the air is likely to condense into the hot, burning liquid. On the on the cool surface of the contents of the other hand, water spray carefully applied open container. bas frequently been used with success in F i e Fighting Phases. This information extinguishing such fires by causing the indicates the best extineuishinn media for frothing to occur only on the surface; fires involving the ma&rials l h d . The this foaming action blankets, cools, and recommendations pertain to manual fire extinguishes the fire. fighting. Do not use water is advised where the Water usually is the hest extinguishing chemical properties of the flammable subor controlling agent due to its cooling stances are such that a more or less violent effect and because i t is usually available reaction would occur if water came in conin large quantities. However, the selection tact with the material. The statement "do of the extinguishing method should be not use water" does not imply that made with caution as there are factors to sprinkler protection should not be probe considered in any individual problem vided where needed. of extinguishment which may affect the Water may be used to blanket fire and choice of extinguishing agent and the accomplish extinguishment when the method of application. Flawing fires, such flammahle liquid has a specific gravity of as might be caused by a leaking overhead 1.1 or heavier, and is not water soluble. pipe, with the liquid on the ground also Here again, however, the method of applyburning, are always difficult to extinguish. ing water is significant since the water The amount and rate and method of must be applied gently to the surface of application of the extinguishing material the liquid. in relation to the size and type of fire "Alcohol" foam is recommended for all anticipated must he carefully considered water-soluble flammable liquids except for
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those that are only "very slightly" soluble, and is recommended for those liquids that for some other reason break down ordinary foam. Certain judgment factors are again introduced since far some liquids ordinary foam might he used successfully to extinguish fires for liquids only "slightly" soluble in water, particularly if regular foam was applied a t increased rates over those normslly recommended. Application of "almhol" joam in all cases should he gradual and gentle. Stop flow of gas rather than extinguish the fire is usually the best procedure to follow when escaping gas is burning. I t may be dangerans to extinguish the flame and allow thegas to continue to flow, as an explosive mixture may be formed with air which, if ignited, may cause far greater damage than if the original fire had been allowed to burn. Extinguishing the flame by carbon dioxide or dry chemical may be desirable where necessary to permit immediate access to valves t o shut off the supply. I n many cases, however, it is preferable to allow the flame to continue, keeping the surroundings cool with water spray to prevent ignition of other combustible materials. The term dry chemical is used to designate those pulverized dry materials suitable for use on fires involving flammable liquids and gases. Dry powder refers to those powdered extinguishing agents mi& able for use on combustible metal fires. Flammable (Explosive) Limits and Range. I n the case of gases or vapors which form flammable mixtures with air or oxygen, there is a minimum concentration of vapor in air or oxygen below which propagation of flame does not occur on contact with a source of ignition. There is also a maximum proportion of vapor or gas in air above which propagation of flame does not occur. These boundary-line mixtures of vapor or gas with air, which, if ignited, will just propagate flame, are known as the "lower and upper flammable or explosive limits," and are usually expressed in terms of percentage by volume of gas or vapor in air. The range of flammable vapor or gasa u mixtures between the upper and lower flammable limits is known as the "flaw mahle range," also often referred to as the "explosive range." For example, the lower limit of flammability of acrolein a t ordinary ambient temperatures is approximately 2.8 per cent vapor in air by volume, whiie the upper limit of flammability is shout 31.0 per cent. All concentrations by volume of acrolein vapor in air falling between 2.8 per cent and 31.0 per cent are in the flammable or explosive range. The flsmmable limits are not appreciably changed by normal variations in atmospheric pressure and temperature. Changes in humidity result in the upper limit being changed to B small extent (due to oxygen displacement by water vapor) and the lowerlimit isonly slightly changed. However, a t high temperatures the upper limit is raised and the lower limit lowered, resulting in a greater flammable, or explosive, range. Hence in processes involving high tempemtures, the limits given for ordinary (ambient) temperatures no longer indicate the danger lines. The effect of high pressures on the limits is dif-
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ferent for each gas or vapor, depending upon its nature. I n general, the upper limit is higher and the lower limit lower (i.e., the range is increased) far upward, than for downward or horizontal flame propagation. The limits far upward proptlgation are considered the most important from a safety standpoint, and therefore the flammable limits and ranges given will be for upward propagation unless otherwise noted.
liquid, or gaseous, is the minimum temperature required to initiate or cause selfsustained combustion independently of the heating or heated element. Ignition temperatures observed under one set of conditions may be changed substantially by a change of conditions. For this reason, ignition temperatures should be looked upon only as approximstions. Some of the variables known to affect ignition temperatures are percentage composition of the vapor or g a s 4 1 mixture, shape and size of the space where the ignition occurs, rate and duration of heating, kind and temperature of the ignition source, catalytic or other effect of materials that may be present, and oxygen concentration. As there are many differences in ignition temperature test methods, such as sise and shape of containers, method of heating and ignition source, i t is not surprising that varying ignition temperatures are obtained. The ignition temperature of a combustible sohd is influenced by the rate of air flow, rate of heating, and sise of the solid. Small sample tests have shown that as the rate of air flow or the rate of heating is increased, the ignition temperature of a solid drops to a minimum and then increases. The same appears to be the case as the sise of the sample increases. Propagation of Flame. By "propagsr tion of flame" is meant the spread of flame from the source of ignition through a combustible mixture. A gas or vapor mixed with air in proportions below the lower Limit of flammability may burn a t the source of ignition, that is, in the zone immediately surrounding the source of ignition, without propagating (spreading) away from the source of ignition. However, if the mixture is within the flammable limits, the flame will spread through it when a source of ignition is supplied. The use of the termflame propagation is therefare convenient to distinguish between combustion which takes place only a t the source of ignition and that which travels (propagates) through the mixture. Flash Point. Flash point of a liquid is the minimum temperature of the liquid a t whieh it gives off vapor sufficient to form an ignitible mixture with the air near the surface of the liquid or within the vessel used. By i p i t i h k mizture is meant a mixture within the flammable range (between upper and lower limits) that is capable of the propagation of flame away from the source of ignition when ignited. Some
evaporation takes place below the flash point but not in sufficient quantities to form an ignitible mixture. This term applies mostly to flammable liquids, although there are certain solids, such as camphor and naphthalene, that evaporate slowly or volatilize a t ordinary room temperature and therefore have flash points while still in the solid state. The flash point figures represent closed cup tests except where the open cup flash point is designated by the initials "oc" following the figure. Open cup flash points, determined in a different type of testing appaarstus, are usually somewhat higher than the closed cup flash point figures for the same substances. Closed cup flash point figures are commonly used in determining the classification of liquids which flash in the ordinary temperature range, but for certain materials which have relatively high flash points, the open cup flash point testing is often preferred. Self-Accelerating Decomposition Temperature (SADT). The rate of decomposition of certain organic peroxides accelerates when stored a t moderate ambient temperatures. To prevent deteriorar tian of the peroxides during storage, some manufacturers report "self-accelerating decomposition temperature" of their products. This temperature is defined as the minimum temperature a t whieh decomposition starts when the peroxide is stored in its shipping container. The nominal SADT test period is 7 days and the test is conducted on the largest container in which t,he oeroxide is oaekaeed. Self-
conditions. Breathing Equipment for Toxic or Oxygen-Deficient Atmospheres. Respiratory protective devices are of two general types: (1) supplied or self-contained air or oxygen breathing apparatus, and (2) air-purifying respirators. Self-contained breathing apparatus provides the wearer with respirable air from s. source of supply independent of the atmosphere where the wearer is located. Air-purifying respirat,ors remove contaminants fromair surrounding the wearer. Air-purifying respirat,ors are approved for use in different kinds of harmful atmospheres and usually will not offer satisfactory protection against other harmful atmospheres. Air-purifying respirators should not be relied upon when the concentration of contamination is ahove 2 per cent (24000 parts per million). I n emergency situations, where concentration of contaminants may be high or is unknown, supplied or self-contained b d i n g apparatus should he worn. The Bureau of Mines classifies, tests and approves both types of breathing equipment. Reference should he made to Information Circular 7886, "Respiratory Protection Devices Approved by the Bureau of Mines," for information on suitable protection for specific atmospheres. Information Circular 788.5 is available from the Superintendent of Documents, Washington25, D. C. Full Protective Clothing. As used in this standard, full protective clothing (Continued on page A1191
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means lnoiecliou 11, prevent gases, vapors, liquids, and solids from comiug in contact. with the skim Fkdl pwteetive clothing includes the helmet,, self-contained hrenthing apparat,la, m a t aud pants ewbomarily worn by fire fighlers (turn-ant or bunker coat and psnt,s), rubber boots, gloves, bands arotind legs, arms and waist, and face mask, as well as covering for neck, ears and other parts of the head not protected hy the helmet, hreathing apparatus or face mask. Special Protective Clothing. As used in this standard, special proteclive rlotl~ir~g refers 11, clothing specially designed to protect ngail~sta. specific hazard. Special protective rlolhing is recommended for those ehemicsls wit,h a health hnzard rating of 4. Clothing Contamination. Under fire fightiug and other emergeuc,v condit,ions, contaminntian of clothing may occur. A numher of rhemieals are capable of being absorbed t,hrough t,he skin and of causing severe poisoning and, in some instances, dent,h. For t,his reason any contaminated clot,hilcg, such as 1est.her shoes, t,rousers, shirts, etc., which ret,ains the rhemicrtl for any length of time, permits absorplion t,hrr,ugh the skin by contact or t,hlaugh high vapor concentration. Therefore it is mandatory that d l contaminated clothing be promptly removed rtnd not worn again trnt,il thoroughly decontaminated. As a gnide to the degree of hazard of tlrose chemicals, a health hazard rating of 3 or more indicates that. contaminated clothing could cause injury through skin xbswption. A thorough washing with soap and copious quanlities of water is most important. Chemicals which can be absorbed thmngh the skin inclnde but are not limited to: aniline, eresol, nitroaniline, nitrobensene, phenol, tetraethyl lead, tetramethyl lead, toloidine, and other liquid aromatic nitm and amino compounds. Threshold Limit Value. In place of the term "maximum aecept,able concent,ration," "bhreshald limit value" is now used t,o indicate the average 8-hour-per-day c~maentrationin air of a vapor, gas, dust, or fume, 11, which persons may be exposed without injury to health. These values s h o ~ l dbe applied rtnd iut,erpreted by persons undcrstmding their meaning and limitations and should not be miswnstrued as having similar relative physiological effects in higher concentrations for shorter periods oi time, such as could be eoeountered in nceident,alor fire conditions. However, the inclusion of "threshold limit values" under the Lrm H ~ Z A R D paragraphs has these uses: For fire protection authorit,ies u well ss commercial handlers of chemivds, the "threshold limit value," considered along with the listed torir effects, warns of the nature of the hazard t,o life in t,he event of fire and/or accidents; for fire fighting personnel during tlre overhaul work after a fire, t,hese values may be applied usefully for their prot,eetion and to facilitate their work. IJnleqs otherwise noted, the "threshold limit values" have been obt,ained fram t,he list, reviewed and updated annually
Poison Control Centers A list of facilities which provide medical information on a 24-hour daily basis, concerning the prevention and treatment of accidents involving ingestiou of poisonous and potentially poisonow sobstances, titled "Direct,ory of Poison Conlrol Ceuters," has been compiled by the N a t i o d Clearinghouse for Poison Control Centers, Division of Accident. Prevention, U. S. Public Health Service. Single copies available from Poison Control Branch, Diviaion of Accident Prevention, U. S. Public Health Service, Washington, D. C. 20201. Pamphlet intmber 611113OR-A11gost,,l9G2. No charge. Vapor Density. Vapor densit* is the weight of a volume of pure gas compared to the weight of au eqi~alvolume of dry air a t the same temperature and pressure. I t is calculated as the ratio of the molecular weight of tlre gas lo the average molecular weight of air, 29. A vapor density figure less than 1 indicates that the gas is lighter than air and will tend to rise in a, relalively calm atmosphere. A figure grestor than 1 indicates that the ga? is heavier than air and may t,ravel a t low level for a considerable distance to a source of ignition and R a ~ hhack (if thegas is flammable). Vaoor densitv fieurm are reoorted in
Vapor-Air Density (saturated vaporair density). Vapor-air density is the weight of a vapor-air mixture resulting from the vaporization of a flammable liquid a t equilibrium temperature and pressure conditions a s compared with the weight of a n equal volume of air under the same conditions. The density of a. vapor-air mixture thus depends upon the ambient temperature, the vapor pressure of the liquid a t that temperature, and upon the molecular weight of the liquid. At temperatures well below the boiling point of a liquid, the vapor pressure of the liquid may be so low that the vaporair mixture consists mostly of air and ha.. a density of approximately the density of pure air. As the temperature of the liquid approaches its boiling point (bhe temperature at which its vapor pressure equals atmospheric pressure), the rate of vaporization inc.reases t,o the point that, vapar is displacing the surrounding air. A vapor-air mixture with a density significantly above that of air a t the ambient kmperature will seek lower levels. On the other band, diffusion, and mixing by convection, will limit the distance of travel of flammable mixtures havingdensities near 1. Vapor-air density figures are reparbed in this standard for those flammable liquids with hoiling points above 100DF. and flash points below 100°F. The (Continued a page A120)
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ambient temperature (and pressure if significantly different from sea-level pressure) can he used to adjust the density value. Thevapor-air density (v.a.d.1 of a liquid that is at ambient temperature may he calculated as follows: Let P equal the ambient pressure, p the vapor pressure of the material at ambient temperature, and d its vapor density. Then v.a.d. = pd/P ( P - p ) P . The first term (pd/P) is the contribution of the vapor to the density of the mixture; the second term ( P - p ) P u the contribution of air. EXAMPLE: find the vapor-air density at 100' F. and atmospheric pressure for a flammable liquid whose vapor density is 2 and whose vapor pressure at 100" F. is 76 mm.
+
Electrical Equipment. At present, there are chemicals (such as carbon disulfide) far which there is no electrical equip ment listed by any nationally recognized
6). When such a situation exists, precautions should be taken so that the location in question will meet the stipulations in paragraph 500Wb) of the Code. Installrstion of electrical equipment suib able for Class I, Division 2 locations will satisfy the Code requirements. Specific reference to the National Electrical Code requirements for special electrical equipment is made for those liquids having flash points below 140" F. I t should be remembered that if a liquid with a flash point at or above 140' F. is heated above its flash point, there may be isolated instances of locations containing flsmmable atmospheres. Electrical installations in such locations should be in accordance with M i c l e 501 of the National Electrical Code, and electrical equipment should be suitable for use in atmospheres containing flammable mixtures of thevapor. Oxidizing Materials. Most oxidizing materials will decompose readily to yield oxygen when heated and may react readily with other chemicals. Because of their ability to furnish oxygen when heated, the hazmd of oxidizing materials is greatly increased a t elevated temperatures. Violent reactions may occur when they are mixed with or contaminated by combustible materials, such as wood, paper, metal powders and sulfur. Under ordinary circumstances such mixtures are very sensitive to heat, friction and impact. Oxidizing materials include chlorates, perchlorates, bromates, peroxides, nitric acid, nitrates, nitrites and permanganatea. Bromine, chlorine, fluorine and iodine react similarly to oxy-
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gen under some conditions and are therefore also classified as oxidizing materials. Polymerization. Certain of the materials covered are noted as presenting a haaard due to their ability to undergo polymerkation. This reaction is usually prevented by inhibitors hut inhibition may be nullified by heat or certain chemicals, as noted in individual cases. In addition, once initiated, this exothermic polymerization reaction is accelerated by its own heat. Also, the increased temperature may cause an increase in pressure which requires provision of adequate venting to prevent destructive explosive failure of wntainers. Explosives. Substances classified by the Interstate Commerce Commission as explosives are not included in this standard unless they have uses other than as explosives. Safe handling and storage requirements for explosives will be found in the Code for the Manufacture, Transportation, Storage, and Use of Explosives and Blasting Agents, NFPA No. 495. Explosive substances in dilute form as components of manufactured articles of commerce are not included. Commercial and military explosives on which information is available in other publications are not included except for reference or compasison. By explosives resl~ictions is meant established safety requirements and regulations relating to the transportation, handling and storage of explosives, information on which is included in publications by the Bureau of Mines (mining explosives), Bureau of Explosives of the Association of American Railroads, Department of Transportation (transportation of explosives), the Department of Defense (military explosives and ammunition). See AMC Regulation 385-224, and the Code for the~Manufacture,Transportation, Storage and Use of Explosives and Blasb ing Agents (NFPA No. 498). Laws for the enforcement of such regulations have been enacted in many states. The primary class of explosives does not burn under ordinary conditions without exploding or detonating. The safe course in the case of fire is to retreat to a safe shelter or to get away a safe distance as fast as possible (see American Table of Distances for Storage of Explosives, published in NFPA No. 495). High ezplosives are substances which detonate, releasing energy very rapidly and creating very high pressures. Low explosives (also called deflagrating explosives) burn a t much lower rates, creating lower pressures. High explosives m e divided into primary and secondary classes. Prlma~y high explosives (also called initisting explosives) are comparatively sensitive to friction, impact (blows), shock, snd heat. Primary high explosives differ widely in properties, and it is not to be inferred that those listed are equally hazardous. Semndary high ezplosioes generdly require initiation by a primary explosive. Hazard Identification System. The diamond-shaped diagram shown for each chemical gives a t a glance a general idea of the inherent ha~ardsof the chemical and (Cmtinued on page A122)
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tho order of severity of these hazards. Based an the hazard ideutificatian system in "Recommended Syslem far the Iden& ficnt.ion of t.he Fire Hazards of Materials, NFPA Yo. i04M," the diagram provides planning guidance to fire departments for safe taclical procedures in emergency operatiow, gives otl-the-spot information to safegnxrd the lives of fire fighbing persormel nod the others who may he exposed, and provides plant d ~ i g n engineers, plant proleclioa and safety personnel with n means of identifying hasatdoos mnterials nlld areas ill whieh they are stored. The diagram ide~~tifiesthe "healt,h," "flammability" and "reactivit,y" (instability nud water reactivity) of a chemical nud indicates the order of rieverity of each hazard by use of one of five numeral gradings, from four (4), indioat,ing the severe hazard or extreme danger, to zero (O), indicating no special hazard. In the diamond-shaped diagram "health" hazard is identified at the left, "flammahility" a t Lhe top, and "react,ivity" s t the right. The bottom space is primarily used to identify u n m d reactivity with water. A W with a line thmogh ils center W slert,n fire fighting personnel to the possible hazard in use of water. This bottom space may be also used to in-
Diborclns
dicate that the chemical i3 s~lbject to polymerization under some emergency conditkm (P), or to idenlify a radiation hazard by showing t,heradiation symhnl. To supplement the spatial arrangement, NFPA No. 704M recommends the use of colored backgrounds or colored nnmbers to identify the hazard categories-blue for "healt,h." red for "flrtmmsbilitv." vellow for "r&ctivity." Examples "of spatial arrmgement and color schemes are shown in the illustration. For a detailed desoript,ion of the haoard identification system used here, see "Recommended System for the Identification of the Fire Hazards of Materials, NFPA No. 704M, 1966 Edit,h,n." The following paragraphs summarize the meanings of the numbers in each hasard category and explain what a number should lell fire fighting personnel ahout protecting t h e m ~ e l v eand ~ how to fight fires where the h a a d exists.
Vlnylidine Chloride
Heallh. 4 A few whiffs of the vapor cm~ldcause death or the vapor or liquid rordd he fats1 on penetrating the fire fighler's normal full protective clothing which is designed for resistance to heat. The normal full protective clothing available to the average fire department will not provide adequate proteethm against skin contact with these materials. Only special protective clothing designed to protect against the specific hazard should be worn. 3 Materials extremely hazardous to health, but areas may be ent,ered with extreme care. Full protective clothing, inchding self-contained breathing appamtus, rubber gloves, boots and bands around legs, arms and waist should he provided. No skin surface should he exposed. 2 Materials hazardous to health, but areas may be entered freely with selfcontained breathing apparatus. 1 Materials only slightly hazardous to health. I t may be desirable to wear self-contained breathing apparatus. 0 Materials which on exposure under fire conditions would offer no health hazard beyond that of ordinary combust~ible material.
Flammability 4 Very flammable gases, very volatile flammable liquids, and materials that in the form of dusts or mists readily form explosive mixtures when dispersed in air. Shut off flow of gas or liquid and keep cooling water streams on exposed tank3 or containers. Use water spray carefully in the vicinity of dusts so as not to create dust clouds. 3 Liquids which can be ignited under almost all normal temperature conditions. Water may he ineffective on these liquids because of their low flash points. Solids which form coarse dusts, solids in shredded or fibrons form that create flash fires, d i d s that burn rapidly, usually because they contain their own oxygen, and any material that ignites spontaneously at normal temperatures in air. 2 Liquids which must he moderately heated before ignition will occur and solids that readily give off flammable vapors. Water spray may be used to exbinguish the fire because the material can be cooled to below its flash point. 1 Materials that must be preheated before ignition can occur. Water may cause frothing of liquids with this flammability rating number if it gets below the surface of the liquid and turm to steam.
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Circle NO.136 0s Readers' Service Card
Journal of Chemical Education
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Safety
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However, water spray gently applied to the surface will cause a frothing which will extinguish the fire. Most eombustible solids have a flammability rating of
1 -. 0 Materials that will not burn.
Reactivity 4 Materials whieh in themselves are readily capable of detonation or of explosive decomposition or explosive reaction a t normal temperatures and pressures. Includes materials which are sensitive to mechanical or localized thermal stock. If a chemical with this hazard rating is in an advanced or ma?sive fire, the area should be evacuated. 3 lMaterials whieh in themselves are capable of detonation or of explosive decomposition or of explosive reaction but whieh require a strong initiating source or which must be heated under confinement, before initistiuu. Includes materials which are sensilive to dhermal or mechanical shock at elevat,ed temperatures and pressures or which react explosively with water without requiring heat or confinement. Fire fighting should be done from a protected loco, tion. 2 Msterials which in themslves are normally unst,able and readily undergo violent change but do not detonate. Includes mat,erials which can undergo
chemical change with rapid release of energy a t normal temperatures and pressures or whieh can undergo violent chemical change at elevated temper* tures and pressures. Also includes those materials which may react violently with water or which may form potentially explosive mixtures with water. In advanced or massive fires, fire fighting should be done from a protected loco, tion. 1 Materials which in themselves are normally stable but whieh may become umtable at elevated temperatures and pressures or which may react with water with some release of energy but not violently. Caution must be used in approaching the fire and applying water. 0 Materials which are normally stable even under fire expusme conditions and which are not reactive with water. Normal fire fighbing procedures may be used.
Hazardous Chemicals Data NOTE: This publication presents data on certain hazardous chemicals and omission of a chemical does not signify that it is nonhazardous.
DESCRIPTION:Colorless liquid a t temperatures below 69' F. but rapidly volatilizes a t this temperature; suffocating, fruity odor. FIRE AND EXPLOSIONHAZARDS:R e active and flammable liquid which rapidly
volatilizes a t 69'F. Vapor fwms explosive mixtures with air over a wide range. Flammable limits, 4% and 53%. Flash point, minus 36' F. Ignition temperature, 36.5" F. Liquid is lighter than water (specific gravity 0.8). Vapors are heavier than air (vapor density, 1.5), and may travel a. considerable distance to a source of ignition end flash back. Very reactive and can he oxidized or reduced readily. Combines with halogens and amines, and forms a great number of condensation products with alcohols, ketones, acid anhydrides, phenols and similar compounds. Hydrogen oyanide, hydrogen sulfide and anhydrous ammonia react with acetaldehyde readily. Easily undergoes polyme~ization which is accompanied by evolution of heat. All of these reactions csn be violent. Vapor oxidizes readily with air and may form highly explosive and unst~hleperoxides. LIFE HAZARD: Eye, skin and respiratory irritant. Capable of producing serious eye burns. Prolonged inhalation may have a narcotic effect, resulting in drowsiness. Threshold limit value, 200 parts per million. Wear goggles and use selfcontained breathing apparatus. FIREFIGHTINGPHASES:Acetaldehyde is soluble in water in all proportions. Flooding with water can dilute to point where combustion will not he supported. Weter spray, carbon dioxide, dry chemical, and "alcohol" foam can be used to extinguish acetaldehyde fires. Wear goggles and self-contained breathing appo, ratus. USUALSHIPPING CONTAINERS:Onequart glass pressure bottles, 5- to 55gallon metal drums, insulated tank cars and insulated tank trucks, tank barges. STORAGE: Protect against physical dsmage. Store bulk quantities outside in detached tanks provided with refrigeration and inert gas blanket, such as nitrogen, in void space above liquid level. Smaller container storage should be in a detached noncombustible building, provided with cooling facilities, adequate ventilation and free of sources of ignition; no alkaline materials (such as caustics, ammonia, amines), halogens, alcohols, ketones, acid anhydrides, phenols, nor oxidizing materials, permitted in storage room. Inside storage should be in a standard flammable liquids storage room or cabinet. Isolate from other storage. REMARKS: Electrical installations in Class I hazardous locations, as defined in Article 500 of the National Electrical Code, should be in accordance with Article 501 of the Code; and electrical equipment should be suitable for use in atmospheres containing acetaldehyde vapors. See Flammable and Combustible Liquids Code (NFPA No. 30), National Electrical Code (NFPA No. 70), Static Electricity (NFPA No. 77), Lightning Protection Code (NFPA No. 781, FireHazard Properties of Flammable Liquids, Gases and Volatile Solids (NFPA No. 325M), and Chemical Safety Data Sheet SD-43 (Manufacturing Chemists' Association, Inc.).
Additional ezamplm will be published in this column in the March issue.
