CDPH Lead Inspector/Assessor California State Practice Exam 2026 - Free Lead Inspector Practice Questions and Study Guide

Supplied Air Respirators (SARs) are specifically designed to provide breathable air to the user from a source that is independent of the ambient atmosphere. For SARs, the air supplied must meet certain purity standards to ensure safety for the person using the respirator. Grade D Air is the standard that indicates the air quality must meet certain minimum requirements, including limits on contaminants such as nitrogen, oxygen, carbon monoxide, and other harmful substances.

Grade D Air is defined by the Compressed Gas Association (CGA) as having no more than 10 parts per million (ppm) of carbon monoxide, a minimum of 19.5% oxygen, and less than 100 ppm of total hydrocarbon contamination, among other specifications. This ensures that the air is suitable and safe for workers who may be exposed to hazardous conditions.

In comparison, other grades like Grade A or Grade B Air have different specifications that do not meet the safety requirements necessary for breathing air supplied to SARs. Therefore, the use of Grade D Air in Supplied Air Respirators is crucial for ensuring that the users have access to clean and safe breathing air necessary for their health and safety while working in potentially hazardous environments.