# Regulations
1 - 1910.134(d)(3)(i)(A) - Respiratory protection.
# Standard Interpretations
1 - 1910.134(d)(3)(i)(A) - Use of powered-air purifying respirators (PAPR) for welding operations and assigned protection factor
2 - 1910.134(d)(3)(i)(A) - APF for the combination pressure-demand, full-facepiece SAR with auxiliary SCBA
3 - 1910.134(d)(3)(i)(A) - Protection factors for respirators used in pharmaceutical industry: policy change.