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Packages. Packages means the complete product of the packing operation, consisting of the packaging and its contents prepared for transport. For packages for radioactive material, see 2.7.2 of IMDG Code.

Packer. Any enterprise which puts dangerous goods into packagings, including large packagings and intermediate bulk containers (IBCs) and, where necessary, prepares packages for carriage.

Packaging. Packaging means receptacles and any other components or materials necessary for the receptacle to perform its containment function. For packagings for radioactive material, see 2.7.2 of IMDG Code.

Packing group. A group to which, for packing purposes, certain substances may be
assigned in accordance with their degree of danger. The packing groups have the following
meanings which are explained more fully in Part 2:
Packing group I: Substances presenting high danger;
Packing group II: Substances presenting medium danger; and
Packing group III: Substances presenting low danger;

NOTE: Certain articles containing dangerous goods are assigned to a packing group.

Particulate matter. A suspension of fine solid or liquid particles in air, such as dust, fog, fume, mist, smoke or sprays. Particulate matter suspended in air is commonly known as an aerosol.

PEL. Permissible exposure limit. An exposure limit that is published and enforced by OSHA as a legal standard.

Personal protective equipment (PPE). Devices worn by the worker to protect against hazards in the environment. Respirators, gloves, and hearing protectors are examples.

pH. Means used to express the degree of acidity or alkalinity of a solution with neutrality indicated as seven.

Polymerization. A chemical reaction in which two or more small molecules (monomers) combine to form larger molecules (polymers) that contain repeating structural units of the original molecules. A hazardous polymerization is the above reaction, with an uncontrolled release of energy.

ppm. Parts per million parts of air by volume of vapor or gas or other contaminant. Used to measure air concentrations of vapors and gases.

psi. Pounds per square inch (for MSDS purposes) is the pressure a material exerts on the walls of a confining vessel or enclosure. For technical accuracy, pressure must be expressed as psig (pounds per square inch gauge) or psia (pounds per square absolute; that is, gauge pressure plus sea level atmospheric pressure, or psig plus approximately 14.7 pounds per square inch).