Standards and Rating of Masks
NIOSH stands for National Institute for Occupational Safety and Health. A division of the CDC, this agency is responsible for conducting research and making recommendations for the prevention of work-related injury and illness.
ASTM refers to the American Society of Testing and Materials. ASTM is an international standards organization that develops and publishes voluntary consensus technical standards for a wide range of materials, products, systems, and services.
N, R and P Ratings
The first part of the rating can either be an N, R, or a P. It may help to understand that the filters used in respirators trap particles by 2 means; first is how tightly the material is woven, which regulates the size of openings for air to pass through. Second is a static electric charge. This static electric charge is literally woven in during manufacturing.This charge may be reduced or dissipated by the presence of oil. So the letter designations are meant to convey the relative ability of the filter media to resist that oil.
N-rated respirator masks are not resistant to oil-based substances. They should only be used in environments without oil aerosols. They protect against solid and liquid airborne particles, except those that contain oil.
R-rated respirator masks are somewhat resistant to oil-based substances. They protect against solid and liquid airborne particles, including those that contain oil. When using R-rated filters in oil-filled environments, you should only use the respirator for 8 hours at a time. Dispose of the filter or mask at the end of your shift. You should also replace these filters as they become clogged over time.
P-rated respirators are considered oil-proof. They go above and beyond R-rated respirators when it comes to oil resistance. They protect against all types of solid and liquid airborne particles. Just like R-rated respirators, P-rated respirators tend to degrade more quickly when used in atmospheres with oil-based particles.
Types of masks
Procedure mask- traditionally characterized by an ear loop attachment. Intended for use on hospital floors, isolation units, and labor and delivery units, among other areas of the hospital. Additionally, these masks may be used in the emergency department and the intensive care unit for bedside procedures. However, they are not suitable for use in the operating room
Surgical masks- traditionally characterized by surgical ties and closeness of fit. Recommended for use in the Operating Room. Intended to protect against a high risk of fluid exposure
Surgical N95 respirator- which is used to filter surgical smoke created by energy-generating devices such as electrosurgical units, lasers and ultrasonic scalpels or dissectors during invasive procedures. The N95 is recommended whenever there is a need to wear respiratory protective equipment as secondary protection against residual surgical smoke. It should also be worn during higher-risk aerosol-generating procedures on patients with known or suspected aerosol-transmittable diseases such as tuberculosis, varicella and rubella. Standard surgical masks with ties should not be used during these procedures.
Particulate respirators- also known as “air-purifying respirators” because they protect by filtering particles out of the air as you breathe. These respirators protect only against particles—not gases or vapors.
When choosing the right mask, always look to the level of protection that is recommended by ASTM
Level 1: low barrier protection for general use for low-risk, nonsurgical procedures and exams that do not involve aerosols, sprays and fluids. An ear loop mask is a level 1 mask. ASTM level 1 masks are the general standard for both surgical and procedural use.
Level 2: moderate barrier protection for low-to-moderate levels of aerosols, sprays and fluids.
Level 3: maximum barrier protection for any situation that has the potential for exposure to heavy levels of aerosols, sprays and fluids. Includes 4 layers of construction. Recommended as a best practice for supporting OR safety initiatives.
Some masks are rated as follows (European standard)
Type I: bacteria filtering effectiveness > 95%.
Type II: bacteria filtering effectiveness > 98%.
Type IIR: bacteria filtering effectiveness > 98% and splash-resistant.
The "4 Fs" of mask selection
- Filtration: When smoke is present or when interacting with a tuberculosis-infected patient, use a high filtration mask (N95 respirator).
- Fluid resistance: Choose a fluid-resistant mask when there is any chance of blood or other bodily fluid splatter. ASTM level 3 surgical masks are recommended.
- Features: Always use a level 3 surgical mask with ties in surgical settings. Anti-fog film, foam and tapes reduce fogging issue distractions, and shields and protective eyewear keep eyes clear of blood and splash.
- Fit: Even the correct mask could put you at risk if it is not worn correctly. The nose and mouth must be completely covered and create a seal around the face to prevent gaps that increase the risk of inhalation exposure.
How to wear a mask
- Before putting on your mask, wash your hands with soap and water for at least 15 seconds or use alcohol-based hand sanitizer.
- Secure the elastic loops of the mask around your ears. If your mask has strings, tie them securely behind your head.
- Cover your mouth and nose with the mask and make sure there are no gaps between your face and the mask.
- Do not touch the front of the mask while you wear it. Wash your hands with soap and water for at least 15 seconds or use alcohol-based hand sanitizer if you accidentally touch your mask.
Taking off your face mask
- Wash your hands or use alcohol-based hand sanitizer containing at least 60% alcohol.
- Don’t touch the front of the mask or your face.
- Carefully remove your mask by grasping the ear loops or untying the ties. For masks with a pair of ties, unfasten the bottom ones first, then the top ones.
- If your mask has filters, remove them and throw them away. Fold the mask and put it directly into the laundry or into a disposable or washable bag for laundering.
- Clean your hands again.
Cleaning your face mask
You should clean your mask after every wearing. This reduces the risk of spreading the coronavirus or other germs.
- Bandannas, face scarves and masks made of fabric, such as cotton, can be washed in your regular laundry using hot water.
- Disposable, blue surgical masks cannot be laundered or cleaned and should be thrown away when it is visibly soiled or damaged.
- You can also hand wash your mask, using hot, soapy water. Scrub the mask for at least 20 seconds, and dry them on high heat in the dryer.
Link to mask manufacturers approved by CDC (Centre for Disease Control)