A negative pressure fit test for a protective mask is conducted by which method?

The method for conducting a negative pressure fit test for a protective mask involves placing both palms against the intake filters. This technique creates a seal around the mask, allowing the individual to take a breath in. If the mask has a proper fit, the wearer should feel a slight inward pull, indicating that air is being drawn in exclusively through the filter and not leaking from the sides. This test is essential to ensure that the mask provides adequate protection by preventing the inhalation of airborne contaminants.

The rationale behind this method is that it assesses the integrity of the mask's seal, ensuring that it fits securely against the face. A poor seal will allow unfiltered air to enter, which defeats the purpose of the protective mask.

Using other methods mentioned, such as placing hands over the exhalation points or conducting the test weekly, do not specifically assess the negative pressure needed to evaluate the mask's effectiveness in filtering and sealing. Repeating the test until an air leak is detected does not establish a standard fit but rather indicates failure in achieving a proper seal. Thus, the selected method effectively confirms the mask’s suitability for use in environments requiring respiratory protection.