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Corrosive Materials

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  1. US Department of Transportation Regulation Corrosive Materials • Materials that evoke a chemical process which converts minerals and metals into unwanted products • Acidity (HCl, H2SO4, ClSO3H, HF, HCOOH, CHCOOH) Oxidizing agent (HClO4, H2SO4 , HNO3) Hygroscopic (H2SO4), Alkalis (KOH, NaOH) Occupational Safety and Health

  2. Corrosive Materials • Chemical substances that, by direct chemical action, are injurious to living tissues or corrosive to metal surfaces • The degree of hazard associated with a corrosive material is greatly dependent upon its physical state (solid, liquid, gas) • Minor corrosive injury = irritation Occupational Safety and Health

  3. Corrosive Liquids • Most common cause of corrosive injury • Corrosive liquids will destroy any living tissue but the most frequently injured organs are the skin and eyes. Corrosive vapors can also escape from some solutions (check out the interior of any acid cabinet). Fuming acids are particularly hazardous Occupational Safety and Health

  4. Corrosive Liquids: Bases • Concentrated alkalies are more damaging to tissues than most strong inorganic acids • Alkaline solutions gelatinize and saponify tissues, producing deeply penetrating, painful burns • Even weak alkaline solutions can dissolve skin fats and weaken the epidermis, making the skin more permeable to other agents • Initial contact may not be painful – poor warning property! Occupational Safety and Health

  5. Corrosive Liquids: Acids • Chemical action of acids is different from that of bases. Acids burn largely due to thermal action with moisture in tissues. When acids come into contact with skin, the acid reacts to form a (very slightly) protective barrier, whereas bases dissolve proteins. Occupational Safety and Health

  6. Corrosive Liquids: organic solvents • A corrosive liquid need not have a very high or low pH to be capable of causing corrosive injury. Many organic solvents can cause severe irritation of skin and mucus membranes by defatting tissues, which paves the way for secondary infections. Occupational Safety and Health

  7. Corrosive Liquids: hydrofluoric acid • HF and gaseous hydrogen fluoride merit special discussion. These are easily the most hazardous corrosive materials encountered in the laboratory • HF is extremely dangerous not only because it is an acid but because the fluoride ion is capable of traveling through layers of tissue on its way to the bone, producing severe, slow healing burns • Always store/use HF solutions and hydrogen fluoride gas in a chemical fume hood – never on the lab bench! Occupational Safety and Health

  8. Corrosive Gases • Most seriously hazardous of all corrosive materials! Readily absorbed into the body by dissolution in tissue moisture (e.g. in skin and/or respiratory tract and/or eyes). • Severity of the corrosive effect and the region o the respiratory tract affected by exposure is greatly dependent upon the aqueous solubility of the chemical (see table on next slide). • Always use/store corrosive gases in a chemical fume hood – never ever on the bench! Occupational Safety and Health

  9. Corrosive Gases Occupational Safety and Health

  10. Improper Acid Storage • Flammables and acids must be segregated • Oxidizing acids must be stored separate from all other chemicals, including other acids • Must be stored to prevent contact with bare metal/wood • Must be stored on a plastic liner/tray to minimize potential contamination/spills Occupational Safety and Health

  11. HIGHLY TOXIC A chemical which has the median lethal dose of: • 50 mg per kg when administered orally • 200 mg per kg by continuous contact for 24 hrs A chemical which has the median lethal concentration of: • 200 parts per mil of gas or vapor or 2 mg per L of mist, fume or dust when continuously inhaled for one hour IN THE ABOVE DESCRIPTIONS DEATH OCCURS WITHIN THE TIME FRAME DESCRIBED IN LABORATORY ANIMALS Occupational Safety and Health

  12. IRRITANT An irritant chemical is one which is not corrosive but which causes a REVERSIBLE inflammatory effect on living tissue by chemical action at the site of contact Occupational Safety and Health

  13. SENSITIZER A chemical which causes a substantial portion of exposed people to develop an allergic reaction in normal tissue after repeated exposure to the chemical Occupational Safety and Health


  15. FLAMMABLE MATERIALS Occupational Safety and Health

  16. Flammable and Combustible Liquids • Flammable and combustible liquids are potential fuel sources for fires and are present in almost every workplace. • It is actually the vapor created by flammable and combustible liquids that ignites and burns. • It is important to understand what materials in your work area are flammable and combustible so that you may properly store and isolate them from ignition sources. Occupational Safety and Health

  17. Flammable and Combustible Liquids Lacquer thinner Gasoline Toluene Isopropyl alcohol Acetone Methyl formate Kerosene Ethyl ether MEK Diethyl ether Occupational Safety and Health

  18. How do I tell what’s flammable? • NFPA classification system • The NFPA diamond is an easy way to determine the safety risks associated with hazardous materials. To determine a materials flammability refer to the red section of the diamond. A number in this section will indicate the flammability rating of the material. • The following numbering system is used to indicate flammability 0- will not burn 1- must be preheated to burn 2-ignites when moderately heated 3-ignites at normal temperature 4-extremely flammable For example, An NFPA diamond on a can of gasoline would have a 3 in the red section indicating that gasoline could ignite at normal working temperatures. NFPA Diamond Occupational Safety and Health

  19. FlammableLiquids • Flammable liquids can cause a fire or explosion, and like many other substances, they can also cause serious health effects from overexposure. 3 Note: On the NFPA diamond label, a fire hazard rating of 3 or 4 denotes a flammable liquid. Occupational Safety and Health

  20. Flammable Liquids • The vapors of flammable liquids often present the most serious hazard. • The vapors can easily ignite or explode. • Flammable liquid vapors are heavier than air and may settle in low spots, or move a significant distance from the liquid itself. Occupational Safety and Health

  21. ExplosiveLimits • The explosive concentration of vapors in air has a lower and upper limit. • The Lower Explosive Limit (LEL) is the lowest concentration that will ignite. • The Upper Explosive Limit (UEL) is the highest concentration that will ignite. • If the vapor concentration is between the LEL and UEL, there is serious risk of fire or explosion. Occupational Safety and Health

  22. Explosive Limits Above the Upper Explosive Limit, the mixture is too rich to burn UPPER EXPLOSIVE LIMIT Explosive Range LOWER EXPLOSIVE LIMIT Below the Lower Explosive Limit, the mixture is too lean to burn Occupational Safety and Health

  23. Flammability Relationships Vapor Pressure Curve UFL UFL Liquid Vapor pressure / concentration Auto-ignition zone Gas LFL LFL Flash Point AIT Ambient Temperature Temperature Occupational Safety and Health

  24. NFPA Classification System Continued... • Where can I find NFPA diamonds? • Product labels • Material Safety Data Sheets (ask your supervisor for them) • How do I determine the flammability of chemicals that don’t use the NFPA classification system? • The flashpoint of a chemical may be used to determine its flammability. Flashpoint information may be found on product labels or MSDS sheets. The flashpoint of a liquid is the lowest temperature at which the liquid gives off enough vapor to be ignited. The lower the flashpoint, the greater the risk for ignition. What’s a Flashpoint? Occupational Safety and Health

  25. Flammable and Combustible Liquids Continued... • Flammable liquids are considered flammable because their flashpoints are < 100ºF. This means that flammable liquids burn easily at normal working temperatures. • Combustible liquids have a flashpoint at or above 100ºF. These liquids are less hazardous than flammable liquids but still pose a risk. • The volatility of flammable and combustible liquids requires special storage and handling requirements. Occupational Safety and Health

  26. Classification • Flammable and combustible liquids are classified according to their flashpoints. This is important to know because the quantity of flammable/combustible liquids that can be stored in any one location is determined by the class of the liquid. Occupational Safety and Health

  27. FlammableLiquids Occupational Safety and Health

  28. Combustible Liquids • A combustible liquid is any liquid having a flashpoint at or above 100°F. Note: Check your Material Safety Data Sheet (MSDS) sheet for the characteristics or classification of a particular liquid. Occupational Safety and Health

  29. CombustibleLiquids Occupational Safety and Health

  30. Area Exempt Amounts • There are certain amounts of flammable and combustible liquids stored in each control area that are considered exempt. • If these amounts are exceeded, then the area or building may have to be reclassified as a Hazardous Use Group under the building code. Occupational Safety and Health

  31. Storing Flammable and Combustible Liquids • Flammable liquids must be stored away from ignition sources in cool, well ventilated areas away from incompatible materials • Limit the amount of flammable and combustible liquids to the minimum amount necessary. • As a general rule, No more than 10 gallons of flammable materials should be outside of approved flammable liquid storage cabinets or approved storage rooms. • Room storage limits of flammable and combustible materials depend on various factors such as sprinklers, and storage cabinets. Refer to the table on the following slide for storage guidelines. Occupational Safety and Health

  32. Storage Areas • Flammables should be stored in an approved cabinet in a cool, well ventilated area to avoid pressure buildup and vaporization. Occupational Safety and Health

  33. Storage Areas • There should be at least one fire extinguisher in the area. • Large storage areas should have a fire protection system installed and must be approved for this use. Occupational Safety and Health

  34. Storage Cabinets • Use flammable liquid storage cabinets where greater quantities of liquids are needed. Contrary to popular belief, these cabinets are not designed to contain a fire, but to prevent an outside fire from reaching the contents for a period of 10 minutes – enough time to evacuate the area. Occupational Safety and Health

  35. Flammable Liquid Exempt Amounts (in gallons) Occupational Safety and Health

  36. Combustible Liquid Exempt Amounts (in gallons) Occupational Safety and Health

  37. Limitations on Storage The maximum storage of flammables and combustibles in any one area under the Virginia Fire Prevention Code is 60 gallons of flammables and 120 gallons of combustibles. These quantities must be in an approved storage area, i.e. a flammables cabinet or other acceptable means. Occupational Safety and Health

  38. There are also limitations on quantities stored in individual containers. Occupational Safety and Health

  39. Containers should be tightly sealed when not in use. Approved safety cans are recommended for smaller quantities. The spring-loaded safety cap prevents spillage, prevents vapors from escaping, acts as a pressure vent if engulfed in fire, prevents explosions and rocketing of the can! Storage Containers Occupational Safety and Health

  40. Flammable Liquid Limitations(in gallons) Occupational Safety and Health

  41. Combustible Liquid Limitations(in gallons) Occupational Safety and Health

  42. Precautions • The unsafe use, storage, dispensing, or disposal of flammable materials can be a prime source of fires and explosions. • Read labels of all spray cans to identify those with flammable gas-propellants. Ex. Butane and Propane Occupational Safety and Health

  43. Precautions • Some flammable liquids have a tendency to accumulate a static electric charge, which can release a spark that ignites the liquid. • Always bond metal dispensing and receiving containers together before pouring. benzene toluene gasoline xylene Occupational Safety and Health

  44. Precautions • To bond containers, each container is wired together and one container is connected to a good ground point to allow any charge to drain away safely. • Because there is no easy way to bond plastic containers, their use should be limited to smaller sizes (no more than 4L). Occupational Safety and Health

  45. Precautions • Overexposure to flammable liquids may present health hazards. • Consult the Material Safety Data Sheet (MSDS) on the material you will be using to identify health hazards and protective measures to be taken. Occupational Safety and Health

  46. Precautions • Effects of overexposure to flammable liquids includes: • Inhalation: Irritation to respiratory passages, nausea, headaches, muscle weakness, drowsiness, loss of coordination, disorientation, confusion, unconsciousness, and death. Occupational Safety and Health

  47. Precautions • Skin Contact: irritated, dry, cracked skin, rashes, dermatitis. • Eye Contact: burning, irritation, eye damage. • Ingestion: irritated digestive tract, poisoning, death. Occupational Safety and Health

  48. I.S.U. Flammable Liquid Storage Limits Occupational Safety and Health

  49. FIRE BEHAVIOR Occupational Safety and Health

  50. Law of Conservation of Mass • Mass and Energy are neither created nor destroyed, only changed in state • Why Fire Load is a crucial part of scene size up Occupational Safety and Health