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.
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