ABC of Safety in the Biological Sciences

 

 

Chemical Storage

General Guidelines

  • Do not store excessive quantities of chemicals in any laboratory.
  • Purchase the minimum amount required for immediate local requirements.
  • Regularly review the disposal of unneeded chemicals.
  • Date bottles of chemicals when they are opened.
  • Chemicals which produce peroxides such as diethyl ether should be tested periodically or discarded according to set time limits.
  • Discard any chemical of dubious purity (by the usual waste disposal procedures) if it cannot be purified safely.
  • Store reagents on shelves or in cabinets. Store large bottles of chemicals on the lowest shelves of any chemical storage area. Ensure that bottles sit safely on a shelf and do not overhang the edge.
  • Do not store chemicals on benchtops where thay might be knocked over increasing a risk of potential exposure to hazards and to an exposed naked flame.
  • 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.
  • Bottles containing chemicals (either reagents or waste chemicals) should not be stored on the floor. Floor storage presents a major safety hazard because bottles can break if knocked over or struck together.
  • Chemicals requiring refrigerated storage should be properly labelled and sealed to prevent escape of any vapors. Use only refrigerators designated for chemical storage, with spark free fitments. Flammable liquids MUST be stored only in explosion-safe refrigerators. Do not refrigerate chemicals unnecessarily.
  • Seal caps of open bottles of volatile chemicals using Parafilm. This will prevent odor problems and deterioration of air/moisture sensitive reagents.
  • Periodically inspect chemicals in storage areas for damaged containers such as cracked bottles or caps or rusted cans. Replace loose or deteriorating labels.
Storage of Specific Classes of Chemicals
  • Provide separate storage areas for corrosive chemicals, solvents, oxidizing agents, pyrophoric materials, and air- or water-reactive materials.
  • Store acids separate from bases. Store ammonium hydroxide in a separate cabinet, preferably ventilated.
  • 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.
  • Store highly toxic chemicals in unbreakable secondary containers labelled 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.
  • Store pyrophoric materials separate from flammable materials, in a dry, inert atmosphere such as a nitrogen-filled desiccator or a glove box.
Solvent Storage
  • Solvents are classified by flash point (Fp) and boiling point (bp) as follows: 
    	Flammable Liquids (Class I): Flash point < 100o F (37.8o C)

		Class IA:	Fp < (23oC) bp < (38oC)
		Class IB:	Fp < (23oC) bp > (38oC)
		Class IC	Fp > (23oC) bp < (38oC)
		Class IIA	Fp > (38oC) bp < (60oC)	
		Class IIIA	Fp > (60oC) bp < (93oC)
		Class IIIB	Fp > (93oC)
    Flash point is defined as the minimum temperature at which a liquid gives off vapor in sufficient concentration to form an ignitible mixture with air near the surface of the liquid. Many commonly used solvents such as acetone, ethanol, and hexane are Class IB liquids. Diethyl ether and low-boiling petroleum ether are Class IA liquids. Storage of flammable and combustible liquids is regulated by fire codes. Check local regulations in your state.
  • Store flammable and combustible liquids in approved solvent storage cabinets. Such cabinets may be vented, but this is not usually required. If the cabinet is not vented, the vent openings should be sealed with bungs usually 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.
  • 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.
  • 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.

 

 

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