Personal Protective Equipment

Assigned Protection Factor, or APF, means the workplace level of respiratory protection that a respirator or class of respirators is expected to provide to employees when the employer implements a continuing effective respiratory protection program. Maximum Use Concentration, or (MUC), means the maximum atmospheric concentration of a hazardous substance from which an employee can be expected to be protected when wearing a respirator, and is determined by the assigned protection factor (APF) of the respirator or class of respirators and the exposure limit of the hazardous substance. The Maximum Use Concentration is usually determined mathematically. The formula requires you to multiply the assigned protection factor signed protection factor specified for a respirator by the permissible exposure limit, short-term exposure limit, ceiling limit, peak limit, or any other exposure limit.

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Penetration is the movement of chemicals through materials on a larger scale. This happens frequently in the workforce through holes created and tears in workers Personal Protective Equipment (or PPE).

Permeation is the process where a chemical dissolves in or is able to move through a barrier, this is done on a molecular scale. This often happens at such a small scale there is often no visible evidence of the chemicals permeating PPE and workers are completely unaware until they are harmed. Degradation is when the presence of a chemical has the ability to physically deteriorate the material of the PPE and its physical properties are changed due to the exposure.

There are two main types of respirators, Air Purifying Respirators, or APR, and Supplied Air Respirators, (SAR). 

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Air Purifying Respirators are where the air the w

orkers breathe is purified using cartridges or canisters. This group of respirators are further divided into three categories: particulate, gas & vapor, and combination. Particulate respirators are intended to catch particulates in the air such as dusts, fumes, mists, and other vapors. Combination respirators normally are used in areas that contain risks of both particulates and gases and vapors. Supplied Air Respirators are respirators where the air workers breathe is supplied from another source that is uncontaminated. There are separated into three categories. The categories are airline, combination, or self-contained breathing apparatus, or SBCA. Airline Respirators use a lightweight airline hose to deliver clean, breathable air from an uncontaminated source. Combination respirators have an auxiliary self-contained air supply that can be used if the primary supply fails. Self-Contained Air Breathable Air respirators consist of a wearable, clean air supply pack and normally used when there is a short time need to enter and escape from spaces that are or may be immediately dangerous to life.

Qualitative fit tests are based on the human senses smell, taste, or overall reaction to the chemical in order to determine if there is any contamination into the respirator piece. Quantitative fit tests measure the actual concentration of the contamination. A Written hazard assessment is used to identify a hazard in a workplace. For example, to assess the need for masks needed for workers who work in coal mines.

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