Q: What is an N95 disposable dust mask?
A: N95 is one of the nine types of dust masks certified by NIOSH (National Institute for Occupational Safety and Health) in the U.S. The letter “N” indicates that the material is only suitable for filtering non-oil-based particles, while “95” means that under test conditions, its filtration efficiency reaches at least 95%.
Q: Is it true that the smaller the dust particles, the harder they are to filter?
A: No. The most challenging particles to filter are typically 0.3 microns (μm) in size. Standards such as the European EN149, the U.S. NIOSH, and the Australian AS1716 use 0.3-micron particles as the test medium for masks. Only masks that are certified by authoritative organizations can effectively filter 0.3-micron particles as well as other particle sizes, protecting the human respiratory system from harm.
Q: Can a mask be reused after washing?
A: No. The mask’s filtration mainly relies on ultrafine electrostatically charged fibers, which are about 1-5 microns (μm) in diameter. Washing destroys the electrostatic adsorption capability, rendering the mask ineffective. Therefore, masks should not be washed. Please dispose of used masks as per regulations. This is why they are called disposable masks.
Q: Some mask models have an exhalation valve. What is its function?
A: In hot, humid, or poorly ventilated workplaces, or in physically demanding work environments, masks with exhalation valves enhance wearer comfort. The exhalation valve works by opening due to the positive pressure of exhaled air, quickly expelling exhaled gases, moisture, and heat, reducing stuffiness inside the mask. When inhaling, the negative pressure automatically closes the valve, preventing external contaminants from entering.
Q: Can activated carbon masks protect against toxic and hazardous gases or vapors?
A: No. Activated carbon masks are only effective for filtering particulate matter and absorbing irritating odors. They do not provide protection against toxic or hazardous gases or vapors. In non-IDLH (Immediately Dangerous to Life or Health) environments, protection against toxic gases or vapors requires a higher Assigned Protection Factor (APF) product, such as a half-face or full-face mask with appropriate filter cartridges or canisters based on the specific toxic substance. In IDLH environments, supplied-air respiratory protection, such as positive-pressure self-contained breathing apparatus (SCBA) or mobile air supply systems with emergency escape options, must be used.
Q: What is the lifespan of filter cartridges and canisters?
A:
- Storage lifespan: Unopened filter cartridges last 3 years, while canisters last 5 years.
- Usage lifespan:
- Opened but unused filter cartridges or canisters have a shelf life of six months because activated carbon absorbs moisture, particles, and other impurities from the air, leading to eventual saturation and failure.
- The lifespan of opened and used filter cartridges or canisters depends on actual usage conditions, environmental factors, and duration of use. Consult a safety product specialist for precise recommendations.
Q: Can the activated carbon inside filter cartridges or canisters be reused by exposing it to sunlight, like household activated carbon?
A: No. The activated carbon inside filter cartridges or canisters is specially treated with designated adsorption sites designed for specific toxic gases. These sites cannot be restored by sun exposure. In contrast, household activated carbon only relies on physical adsorption and lacks special treatment, so it can be reused after sun exposure.
Q: Why can’t the SCBA (Self-Contained Breathing Apparatus) completely deplete the air inside the cylinder?
A: If the air inside the cylinder is completely used up, the internal pressure will equal the external pressure, allowing moisture from the surroundings to enter. This can lead to cylinder corrosion, air leakage, or other failures. Therefore, whether in use or in storage, SCBA cylinders should always maintain at least 0.5 MPa of internal pressure. Otherwise, the cylinder must be professionally dried before reuse.
Q: What does “positive pressure” mean in a positive-pressure SCBA?
A: “Positive pressure” means that when the SCBA is in use, the pressure inside the mask is maintained at approximately 300 Pa, slightly higher than the external atmospheric pressure. This prevents external toxic or hazardous gases from entering the mask, ensuring better respiratory protection.
Q: How should an SCBA cylinder be refilled?
A: SCBA cylinders must be refilled by a professional organization with nationally recognized qualifications. For detailed procedures, consult a safety product specialist.
Q: What is a PAPR?
A: PAPR (Powered Air-Purifying Respirator) is a type of respiratory protection device that uses mechanical or electrical power to overcome the resistance of filter elements, forcing airflow into the mask. This reduces breathing effort, enhances comfort, and improves protective reliability, making it suitable for high-intensity work environments. PAPR systems are commonly used in welding, grinding, painting, and sandblasting applications.
Q: How do you choose an emergency escape respirator?
A: The selection of emergency escape respirators follows similar principles to general respiratory protection selection:
- Determine the nature and severity of the hazardous environment.
- Select the appropriate type of protective product based on the hazard.
- Unlike general respiratory protection, emergency escape respirators do not have an Assigned Protection Factor (APF). Instead, they are chosen based on the type of hazardous gas they must protect against and whether facial or eye protection is required.
