Unit 3: Classification of Hazardous Materials

Transcription

1 Unit 3: Classification of Hazardous Materials Terminal Objective Upon completion of this unit, participants will be able to classify hazardous materials that were identified during the fire inspection of an occupancy into the physical, health and reactive code classifications. Enabling Objective Upon completion of this unit, you should be able to: Describe the Department of Transportation and the Occupational Safety and Health Administration hazardous materials classification systems. Research hazardous materials chemical and physical property definitions. Given MSDS/SDS and chemical and physical property definitions, identify primary hazards which are physical, health and reactive and material properties which include, but are not limited to: flammable liquid, combustible liquid, flammable solid, corrosive and toxic. Classification Process Hazardous materials are classified by the hazard or hazards that they present. Classification systems exist in the building and fire codes but are also utilized by DOT, OSHA and other federal agencies. These classifications provide the foundation not only for identification but also for code application and enforcement. If the material is improperly identified or classified, then the code enforcement process and public safety is impaired. Classification is generally regulated by the most prevalent hazard. Some materials may possess a single hazard while others represent multiple hazards. Consideration should always be given to the possibility of a material having multiple hazards. If there is ever a question or doubt about how to classify or what the hazards are, then technical assistance should be obtained. Resources for classification include, but are not limited to: MSDS/SDS NFPA 400 Hazardous Materials Code Chemical dictionaries OSHA regulations List of lists Wiser International Fire Code Appendix E: Hazard Categories Appendix F: Hazard Ranking NFPA 1 Fire Prevention Code Annex B Hazardous Materials Classifications 1

2 OSHA Classification OSHA has classified hazards as either physical or health hazards. Physical Hazard - A chemical that presents a fire or explosion hazard to a structure, such as a: Combustible liquid. Cryogenic fluid. Explosive. Flammable (solid, liquid, or gas). Organic peroxide (solid or liquid). Oxidizer (solid or liquid). Oxidizing gas. Pyrophoric (solid, liquid, or gas). Unstable (reactive) material (solid, liquid, or gas). Water-reactive material (solid or liquid). A Health Hazard is a classification of a chemical for which there is statistically significant evidence that acute or chronic health effects are capable of occurring in exposed persons. The term health hazard includes chemicals that are: Toxic. Highly toxic. Corrosive. DOT Classification System The United States Department of Transportation has established a classification system for hazardous materials. Nine broad classes, some of which are broken down into divisions. Divisions are used to delineate the degree or type of reactive hazard. The DOT classifications are used in certain parts of the fire codes. Example - explosives Class 1 Explosive (Six Divisions). Class 2 Gases (3 Divisions). Class 3 Flammable and Combustible Liquids. Class 4 Flammable Solids, Spontaneously Combustible and Water Reactive Materials. Class 5 Oxidizing Substances and Organic Peroxides. Class 6 Toxic and Infectious Materials. Class 7 Radioactive Materials. Class 8 Corrosive Substances. Class 9 Miscellaneous hazardous materials. Example of Divisions Division 1.1. Explosives that have a mass explosion hazard. A mass explosion is one which affects almost the entire load instantaneously. Division 1.2. Explosives that have a projection hazard but not a mass explosion hazard. Division 1.3. Explosives that have a fire hazard and either a minor blast hazard or a minor projection hazard or both, but not a mass explosion hazard. Division 1.4. Explosives that pose a minor explosion hazard. The explosive effects are largely confined to the package. 2

3 Division 1.5. Very insensitive explosives. This division is comprised of substances that have a mass explosion hazard but are insensitive. Division 1.6. Extremely insensitive articles which do not have a mass explosion hazard. Chemical and Physical Properties In order to understand and apply the classification systems, a review of some basic definitions is essential. The number of definitions is quite extensive and it is impossible to accurately memorize all of them. A listing of all of the critical definitions is contained in the glossary as part of the course. These definitions were sourced from the fire codes and applicable DOT regulations. Flashpoint Flammable range Vapor pressure Vapor density Boiling Point Specific Gravity Water miscible or water soluble Definitions are contained under the Glossary tab at the top of the page. Combustible Liquids Compressed Gas Corrosive Cryogenic Explosive Flammable Liquids Flammable Solid Liquefied Compressed Gas Pyrophoric Toxic Highly Toxic Oxidizers Organic Peroxide Reactive (Unstable) Water Reactive Exceptions Hazard classifications are assigned to the material in normal usage and conditions. Hazards may change or intensify with: Presence of oxidizers or contaminants. Presence of incompatible materials. Environmental conditions such as humidity, moisture and temperature. For example, a material with no hazard classification, such as an inert gas at normal temperature and pressure, is capable of reacting with other materials under abnormal conditions such as high temperatures, pressures and similar extrinsic physical forces. Anhydrous ammonia is classified as non-flammable but will indeed burn under the right conditions. Some products don t meet 3

4 the definition of toxic but indeed are harmful if inhaled, ingested or absorbed. Just because a product or material is not classified as a particular hazard does not mean it is not hazardous. Common Mistakes Common mistakes that can be made during the classification of materials: Not using the MSDS/SDS or reading the MSDS/SDS incorrectly. Incorrectly classifying a flammable or combustible liquid. Classifying mixtures incorrectly (classify with worst hazard(s) of mixture). Using the primary hazard but ignoring secondary hazards. Using only one classification for materials with multiple classifications. Spelling errors. Correct spelling, including numbers is critical. A simple spelling error or missed number can mean the difference between life and death. Trichloroethyene C 2 HCl 3 Colorless liquid with sweet odor Slight fire hazard Flash Point: No data available Auto-ignition at 770 F Range 7.8% to 52% May undergo polymerization 1,1,1 Trichloroethane CH 3 CCl 3 Liquid no data on odor May combust at high temperatures Auto-ignition at F Range 7.5% to 12.5% No polymerization 1,1,2 Trichloroethane C 2 H 3 CI 3 Colorless liquid with sweet chloroform like odor May combust at high temperatures Auto-ignition at Range 6% t0 15.5% No polymerization Global Harmonization Globally Harmonized System of Classification and Labeling of Chemicals is an internationally agreed-upon system, created by the United Nations. It is designed to replace the various 4

5 classification and labeling standards used in different countries by using consistent criteria for classification and labeling on a global level. At this time there is no international schedule for implementation but global harmonization will ultimately effect definitions, regulation, labeling and placarding. Global Harmonization System definitions are included in the glossary. Summary Hazardous materials are classified by the hazard or hazards that they present. Classification systems exist in the building and fire codes but are also utilized by DOT, OSHA and other federal agencies. These classifications provide the foundation not only for identification but also for code application and enforcement. If the material is improperly identified or classified, then the code enforcement process and public safety is impaired. 5