Prudent Practices in the Laboratory: Handling and Disposal of Chemicals

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TABLE 4.3 Container Size for Storage of Flammable and Combustible Liquids

	Flammable Liquids^a						Combustible Liquids^b
	Class IA		Class IB		Class IC		Class II		Class IIIA
Container	Liters	Gallons	Liters	Gallons	Liters	Gallons	Liters	Gallons	Liters	Gallons
Glass^c	0.5	0.12	1	0.25	4	1	4	1	4	1
Metal or approved plastic	4	1	20	5	20	5	20	5	20	5
Safety cans	7.5	2	20	5	20	5	20	5	20	5
NOTE: Label safety cans with contents and hazard warning information. Safety cans containing flammable or combustible liquid waste must have appropriate waste labels. Place 20-L (5-gallon) and smaller containers of flammable liquids that are not in safety cans into storage cabinets for flammable liquids. Do not vent these cabinets unless they also contain volatile toxics or odoriferous chemicals. Aerosol cans that contain 21% (by volume), or greater, alcohol or petroleum base liquids are considered Class IA flammables. When space allows, store combustible liquids in storage cabinets for flammable liquids. Otherwise, store combustible liquids in their original (or other Department of Transportation-approved) containers according to Table 4.2. Store 55-gallon drums of flammable and combustible liquids in special storage rooms for flammable liquids. Keep flammable and combustible liquids away from strong oxidizing agents, such as nitric or chromic acid, permanganates, chlorates, perchlorates, and peroxides. Keep flammable and combustible liquids away from an ignition source. Remember that most flammable vapors are heavier than air and can travel to ignition sources. ^a Class IA includes those flammable liquids having flashpoints below 73 °F and having a boiling point below 100 °F, Class IB includes those having flashpoints below 73 °F and having a boiling point at or above 100 °F, and Class IC includes those having flashpoints at or above 73 °F and below 100 °F. ^b Class II includes those combustible liquids having flashpoints at or above 100 °F and below 140 °F, Class IIIA includes those having flashpoints at or above 140 °F and below 200 °F, and Class IIIB includes those having flashpoints at or above 200 °F. ^c Glass containers as large as 1 gallon can be used if needed and if the required purity would be adversely affected by storage in a metal or approved plastic container, or if the liquid would cause excessive corrosion or degradation of a metal or approved plastic container. SOURCE: NFPA (1991c), Chapter 7-2.3, "Storage."

areas. Return them to the supplier when you are finished with them.

For commonly used laboratory gases, it is prudent to consider the installation of in-house gas systems. Such systems remove the need for transport and in-laboratory handling of compressed gas cylinders. Chapter 5, section H, provides additional information on working with compressed gases in the laboratory.

4.E.5 Storing Highly Reactive Substances

The following guidelines should be followed when storing highly reactive substances:

Consider the storage requirements of each highly reactive chemical prior to bringing it into the laboratory.
Consult the MSDSs or other literature in making decisions about storage of highly reactive chemicals.
Bring into the laboratory only the quantities of material you will need for your immediate purposes (less than a 3- to 6-month supply, the length depending on the nature and sensitivity of the materials).
Label, date, and inventory all highly reactive materials as soon as received. Make sure the label states,

DANGER! HIGHLY REACTIVE MATERIAL!
Do not open a container of highly reactive material that is past its expiration date. Call your institution's hazardous waste coordinator for special instructions.
Do not open a liquid organic peroxide or peroxide former if crystals or a precipitate are present. Call your institution's hazardous waste coordinator for special instructions.
Dispose of (or recycle) highly reactive material prior to expiration date.
Segregate the following materials:
- oxidizing agents from reducing agents and combustibles,
- powerful reducing agents from readily reducible substrates,
- pyrophoric compounds from flammables, and
- perchloric acid from reducing agents.

Store highly reactive liquids in trays large enough to hold the contents of the bottles.
Store perchloric acid bottles in glass or ceramic trays.
Store peroxidizable materials away from heat and light.
Store materials that react vigorously with water away from possible contact with water.
Store thermally unstable materials in a refrigerator. Use a refrigerator with these safety features:
- all spark-producing controls on the outside,
- a magnetic locked door, and
- an alarm to warn when the temperature is too high.

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