What does NIOSH method 7400 measure?

NIOSH Method 7400 is specifically designed to measure the airborne concentration of asbestos fibers in the environment, utilizing phase contrast microscopy (PCM). This method is essential for assessing occupational exposure to airborne asbestos, as it allows trained professionals to analyze samples collected from air monitoring devices.

Through NIOSH Method 7400, fibers are counted and evaluated based on their characteristics, which helps in determining whether the levels of asbestos in the air exceed the permissible exposure limits established by regulatory agencies. Accurate measurement of asbestos fiber concentrations is critical for ensuring the safety of workers who may be exposed to this hazardous material, thus highlighting the importance of this method in occupational health and safety.

The other options do not relate accurately to NIOSH Method 7400. For instance, water contamination levels, bulk asbestos content in materials, and thermal insulation effectiveness pertain to other aspects of asbestos management and testing but are not the focus of this specific method. Each of those areas requires different testing methodologies to obtain accurate results.