This document establishes the procedures for ensuring the level of respiratory protection provided by Chemical, Biological, Radiological, and Nuclear (CBRN) Protection requirements for Powered Air-Purifying Respirator (PAPR) submitted for Approval, Extension of Approval, or examined during Certification Product Audits, meet the minimum certification standards set forth in Title 42 CFR, Part 84, Subpart G, Section 84.63(a)(c)(d); Federal Register Volume 60, Number 110, June 8, 1995 and the Statement of Standard for Chemical, Biological, Radiological, and Nuclear (CBRN) Powered Air- Purifying Respirator (PAPR). The purpose of this Standard Test Procedure (STP) is to describe the test conditions and procedures necessary to test and certify manufacturer submitted CBRN PAPR applications. A CBRN PAPR being a complete tight fitting or loose fitting facepiece or hood, properly outfitted with manufacturer unique components and a powered air purifying unit that can draw air from a filter to enter the respiratory system to remove particulates, gases, vapors and other contaminants.