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Respirator User with Breathing Air from Independent Sources of the Ambient Atmosphere

Yuan S

The Maximum Use Concentrations for respirators is calculated by multiplying the Assigned Protection Factors for the respirator by the permissible exposure limit. The Maximum Use Concentrations is the upper limit at which the class of respirator is expected to provide protection. Whenever the exposures approach the Maximum Use Concentrations, then the employer should select the next higher class of respirators for the employees. Employers must not apply Maximum Use Concentrations to conditions that are immediately dangerous to life or health, instead, they must
use respirators listed for immediately dangerous to life or health conditions of this standard. When the calculated Maximum Use Concentrations exceeds the immediately dangerous to life or health level for hazardous substances or the performance limits of the cartridge or canister, then employers must set the maximum Use Concentrations at that lower limit