Chemistry

General Guidelines

1. Do not store excessive quantities of chemicals in research laboratory. Purchase the minimum amount required and dispose of unneeded chemicals in a timely fashion.
2. Date bottles of chemicals when they are opened. Peroxidizable chemicals such as isopropyl ether should be tested periodically or discarded according to the time limits. Discard any chemical of dubious purity (by the usual waste disposal procedures) if it cannot be purified safely.
3. Store reagents on shelves or in cabinets. Store large bottles of chemicals on the lowest shelves of any chemical storage area. Do not allow bottles to extend over the edge of a shelf.
4. Do not store chemicals on benchtops. They are more readily knocked over and are unprotected from potential exposure to fire.
5. Hoods should not be used for chemical storage. Hood storage interferes with air flow in the hood, causes clutter, and increases the fuel load in the event of a hood fire. If small quantities of chemicals are stored in the hood, they should be placed on an elevated shelf.
6. No chemicals (either reagents or waste chemicals) should be stored on the floor. Floor storage presents a major safety hazard because bottles can break if knocked over or struck together.
7. Chemicals requiring refrigerated storage should be properly labeled and sealed to prevent escape of any vapors. Use only refrigerators designated for chemical storage. Flammable liquids MUST be stored only in explosion-safe refrigerators. Do not refrigerate chemicals unnecessarily.
8. Seal caps of open bottles of volatile chemicals using Parafilm. This will prevent odor problems and deterioration of air/moisture sensitive reagents.
9. Inspect storage areas periodically for damaged containers such as cracked bottles or caps or rusted cans. Replace loose or deteriorating labels.

Storage of Specific Classes of Chemicals

1. Provide separate storage areas for corrosive chemicals, solvents, oxidizing agents, pyrophoric materials, and air- or water-reactive materials.
2. Store acids separate from bases. Store ammonium hydroxide in a separate cabinet, preferably ventilated.
3. Store oxidizers, including oxidizing acids such as nitric and perchloric acids separate from oxidizable compounds such as acetic acid. Perchloric acid MUST be stored where it cannot contact organic material.
4. Store highly toxic chemicals in unbreakable secondary containers labeled with a description of the contents. Cyanides and sulfides MUST be kept safe from any contact with acids. Store cyanides in a closed cabinet, not in a location visible to passersby. Dispose of cyanides for which you have no current use.
5. Store pyrophoric materials separate from flammable materials, in a dry, inert atmosphere such as a nitrogen-filled desiccator or a glove box.

Solvent Storage

1. Solvents are classified by the National Fire Protection Association (NFPA) by flash point (Fp) and boiling point (bp) as illustrated in table above. Flash point is defined as the minimum temperature at which a liquid gives off vapor in sufficient concentration to form an ignitable mixture with air near the surface of the liquid. Many common solvents such as acetone, ethanol, and hexane are Class IB liquids. Ethyl ether and low-boiling petroleum ether are class IA liquids. Storage of flammable and combustible liquids is regulated by fire codes. The following storage procedures and regulations are taken largely from NFPA codes 45 and 30.
2. Store flammable and combustible liquids in approved flammable liquid storage cabinets. Such cabinets may be vented, but this is not required. If the cabinet is not vented, the vent openings should be sealed with the bungs supplied with the cabinet. The total volume of flammable and combustible liquids stored in the cabinet should not exceed the maximum quantities recommended by the manufacturer of the cabinet. No more than 3 cabinets may be located in a single fire area (laboratory).
3. Quantities of flammable liquids greater than one liter should be stored in approved safety cans. Glass containers no larger than 1 gallon (4 L) are acceptable if purity would be adversely affected by storage in metal.
4. The largest allowable laboratory container for a Class IA solvent is 1 gallon (4 L) for glass, plastic, or metal, or 2 gallon ( 8L) for approved safety cans. Five gallon (20 L) cans may not be stored or used anywhere in the department except in the stockroom solvent storage rooms. It is recommended that the Class IA solvents such as ethyl ether be purchased only in 1 gallon (4 L) or smaller containers. If you require a larger quantity, you should order more than one bottle of the 1 gallon size.
5. Solvents such as acetone and ethanol that are stored in plastic carboys for dispensing purposes should be positioned with the spigot over a sink, or over a tray large enough to contain the entire contents in the event of leakage from the spigot.