Remove and dispose of particulate filters after ___ hours of cumulative use if there is no specific instruction from the manufacturer.

• A. 4
• B. 16
• C. 100
• D. 8

Answer: (D)

Filters in respirators lose efficiency as they load with particles during use, so replacing them at the right time is crucial to maintain protection. If there isn’t a specific instruction from the manufacturer, the recommended point to remove and dispose of the particulate filter is after eight hours of cumulative use. This means the total time the filter has been worn across all work sessions since it was installed, not just a single continuous shift. If the filter becomes damaged, wet, or clogged, you should replace it sooner, regardless of the eight-hour guideline. If the manufacturer does provide a replacement schedule, follow that instead. The other time frames don’t fit this guidance because they either risk disposing of a still-serviceable filter earlier than necessary or allowing the filter’s performance to decline beyond a safe point.