Laboratory Safety Rules

Transcription

1 While working in the science laboratory, you will have certain important responsibilities that do not apply to other classrooms. You will be working with materials and apparatus which, if handled carelessly or improperly, have the potential to cause injury or discomfort to someone else as well as yourself. Laboratory Safety Rules Basic Safety Rules # Rule: Use common sense. Others: No horseplay. No unauthorized experiments. Handle chemicals/glassware with respect. Safety Features of the Lab safety shower fire blanket fire extinguisher eye wash fume hood circuit breaker switch Obey ALL Signs CAUTION HAZARDOUS MATERIALS SATELLITE ACCUMULATION POINT UNAUTHORIZED PERSONNEL MUST KEEP OUT

2 Basic Safety Rules # Rule: Others: Use common sense. No horseplay. No unauthorized experiments. Handle chemicals/glassware with respect. Safety Features of the Lab safety shower fire blanket fire extinguisher eye wash fume hood circuit breaker switch -- Material Safety Data Sheet (MSDS) gives information about a chemical -- lists Dos and Don ts; emergency procedures acute exposure a one-time exposure causes damage e.g., reaction to drugs or medication Chemical Exposure chronic exposure damage occurs after repeated exposure e.g., smoking, asbestos LD 5 the lethal dosage for 5% of the animals on which the chemical is tested There are various ways an LD 5 can be expressed. For example, acetone has the following LD 5 s: ORL-RAT LD 5 : 5,8 mg/kg IHL-RAT LD 5 : 5, mg/m -h SKN-RBT LD 5 : g/kg

3 Example Chemical A: LD 5 =. mg/kg Chemical B: LD 5 = 8 mg/kg Which is more toxic? Chemical A is more toxic because less of it proves fatal to half of a given population. LABORATORY SAFETY Chemical Hazard Label MSDS Safety Quiz Courtesy Christy Johannesson Safety Symbols HEALTH FLAMMABILITY SPECIAL REACTIVITY (STABILITY) Least Serious Most Serious Flammable vapor which burns readily Diborane Severe health risk. Burns readily. W May detonate with heat or ignition. Substance is stable Avoid water.

4 NFPA Label Chem. name Health (blue) deadly extreme danger hazardous slightly hazardous normal material Specific Hazard OXY oxidizer ACID acid ALK alkali COR corrosive W use no water RAD radiation hazard Fire Hazard (red) Flash Point Temp. below 7 o F Temp. 7 to o F v. flam. to o F flam. over o F - slightly combustible will not burn Reactivity (yellow) may detonate shock or heat may detonate violent chem. reaction unstable if heated stable Complete Label for Acetone Complete Label for Phosphine MSDS Material Safety Data Sheet On file for all purchased chemicals. Includes all information shown on a chemical label and more. Different formats are used by different chemical companies. MSDS Health Hazard Very short exposure could cause death or serious residual injury even though prompt medical attention was given. Short exposure could cause serious temporary or residual injury even though prompt medical attention was given. Intense or continued exposure could cause temporary incapacitation or possible residual injury unless prompt medical attention is given. Exposure could cause irritation but only minor residual injury even if no treatment is given. Exposure under fire conditions would offer no hazard beyond that of ordinary combustible materials.

5 Prior to 996, this section was titled "Reactivity". The name was changed because many people did not understand the distinction between a "reactive hazard" and the "chemical reactivity" of the material. The numeric ratings and their meanings remain unchanged. INSTABILITY FLAMMABILITY Will rapidly or completely vaporize at normal pressure and temperature, or is readily dispersed in air and will burn readily. Liquids and solids that can be ignited under almost all ambient conditions. Must be moderately heated or exposed to relatively high temperature before ignition can occur. Must be preheated before ignition can occur. Materials that will not burn. Readily capable of detonation or of explosive decomposition or reaction at normal temperatures and pressures. Capable of detonation or explosive reaction, but requires a strong initiating source or must be heated under confinement before initiation, or reacts explosively with water. Normally unstable and readily undergo violent decomposition but do not detonate. Also: may react violently with water or may form potentially explosive mixtures with water. Normally stable, but can become unstable at elevated temperatures and pressures or may react with water with some release of energy, but not violently. Normally stable, even under fire exposure conditions, and are not reactive with water. ACID ALK This indicates that the material is an acid, a corrosive material that has a ph lower than 7. This denotes an alkaline material, also called a base. These caustic materials have a ph greater than 7. OX This denotes an oxidizer, a chemical which can greatly increase the rate of combustion/fire. This denotes a material that is corrosive (it could be either an acid or a base). Unusual reactivity with water. This indicates a potential hazard using water to fight a fire involving this material. The skull and crossbones is used to denote a poison or highly toxic material. See also: CHIP Danger symbols. The international symbol for radioactivity is used to denote radioactive hazards; radioactive materials are extremely hazardous when inhaled. This section is used to denote special hazards. There are only two NFPA 7 approved symbols I di t l i t i l Thi b l i h t 5