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APPENDIX E <br />2015 MINNESOTA STATE FIRE CODE 483 <br />SECTION E103 <br />EVALUATION OF HAZARDS <br />E103.1 Degree of hazard. The degree of hazard present <br />depends on many variables which should be considered indi- <br />vidually and in combination. Some of these variables are as <br />shown in Sections E103.1.1 through E103.1.5. <br />E103.1.1 Chemical properties of the material. Chemical <br />properties of the material determine self reactions and <br />reactions which may occur with other materials. Gener- <br />ally, materials within subdivisions of hazard categories <br />will exhibit similar chemical properties. However, materi- <br />als with similar chemical properties may pose very differ- <br />ent hazards. Each individual material should be researched <br />to determine its hazardous properties and then considered <br />in relation to other materials that it might contact and the <br />surrounding environment. <br />E103.1.2 Physical properties of the material. Physical <br />properties, such as whether a material is a solid, liquid or <br />gas at ordinary temperatures and pressures, considered <br />along with chemical properties will determine require- <br />ments for containment of the material. Specific gravity <br />(weight of a liquid compared to water) and vapor density <br />(weight of a gas compared to air) are both physical proper- <br />ties which are important in evaluating the hazards of a <br />material. <br />E103.1.3 Amount and concentration of the material. <br />The amount of material present and its concentration must <br />be considered along with physical and chemical properties <br />to determine the magnitude of the hazard. Hydrogen per- <br />oxide, for example, is used as an antiseptic and a hair <br />bleach in low concentrations (approximately 8 percent in <br />water solution). Over 8 percent, hydrogen peroxide is <br />classed as an oxidizer and is toxic. Above 90 percent, it is <br />a Class 4 oxidizer “that can undergo an explosive reaction <br />when catalyzed or exposed to heat, shock or friction,” a <br />definition which incidentally also places hydrogen perox- <br />ide over 90-percent concentration in the unstable (reac- <br />tive) category. Small amounts at high concentrations may <br />present a greater hazard than large amounts at low concen- <br />trations. <br />E103.1.3.1 Mixtures. Gases—toxic and highly toxic <br />gases include those gases that have an LC50 of 2,000 <br />parts per million (ppm) or less when rats are exposed <br />for a period of 1 hour or less. To maintain consistency <br />with the definitions for these materials, exposure data <br />for periods other than 1 hour must be normalized to 1 <br />hour. To classify mixtures of compressed gases that <br />contain one or more toxic or highly toxic components, <br />the LC50 of the mixture must be determined. Mixtures <br />that contain only two components are binary mixtures. <br />Those that contain more than two components are mul- <br />ticomponent mixtures. When two or more hazardous <br />substances (components) having an LC50 below 2,000 <br />ppm are present in a mixture, their combined effect, <br />rather than that of the individual substance components, <br />must be considered. In the absence of information to <br />the contrary, the effects of the hazards present must be <br />considered as additive. Exceptions to the above rule <br />may be made when there is a good reason to believe <br />that the principal effects of the different harmful sub- <br />stances (components) are not additive. <br />For binary mixtures where the hazardous compo- <br />nent is diluted with a nontoxic gas such as an inert gas, <br />the LC50 of the mixture is estimated by use of the meth- <br />odology contained in CGA P-20. The hazard zones <br />specified in CGA P-20 are applicable for DOTn pur- <br />poses and shall not be used for hazard classification. <br />E103.1.4 Actual use, activity or process involving the <br />material. The definition of handling, storage and use in <br />closed systems refers to materials in packages or contain- <br />ers. Dispensing and use in open containers or systems <br />describes situations where a material is exposed to ambi- <br />ent conditions or vapors are liberated to the atmosphere. <br />Dispensing and use in open systems, then, are generally <br />more hazardous situations than handling, storage or use in <br />closed systems. The actual use or process may include <br />heating, electric or other sparks, catalytic or reactive mate- <br />rials and many other factors which could affect the hazard <br />and must therefore be thoroughly analyzed. <br />E103.1.5 Surrounding conditions. Conditions such as <br />other materials or processes in the area, type of construc- <br />tion of the structure, fire protection features (e.g., fire <br />walls, sprinkler systems, alarms, etc.), occupancy (use) of <br />adjoining areas, normal temperatures, exposure to <br />weather, etc., must be taken into account in evaluating the <br />hazard. <br />E103.2 Evaluation questions. The following are sample <br />evaluation questions: <br />1. What is the material? Correct identification is import- <br />ant; exact spelling is vital. Check labels, MSDS, ask <br />responsible persons, etc. <br />2. What are the concentration and strength? <br />3. What is the physical form of the material? Liquids, <br />gases and finely divided solids have differing require- <br />ments for spill and leak control and containment. <br />4. How much material is present? Consider in relation to <br />permit amounts, maximum allowable quantity per <br />control area (from Group H occupancy require- <br />ments), amounts which require detached storage and <br />overall magnitude of the hazard. <br />5. What other materials (including furniture, equipment <br />and building components) are close enough to interact <br />with the material? <br />6. What are the likely reactions? <br />7. What is the activity involving the material? <br />8. How does the activity impact the hazardous character- <br />istics of the material? Consider vapors released or <br />hazards otherwise exposed. <br />9. What must the material be protected from? Consider <br />other materials, temperature, shock, pressure, etc. <br />10. What effects of the material must people and the envi- <br />ronment be protected from? <br />11. How can protection be accomplished? Consider: <br />11.1. Proper containers and equipment. <br />Copyright © 2016 ICC. ALL RIGHTS RESERVED. 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