The use of a mask with ties, often a filtering facepiece respirator like an N95, is a protective measure that depends entirely on a correct fit. These devices are designed to create a seal against the face, ensuring that inhaled air is filtered through the mask material rather than leaking in through gaps around the edges. Respirators must adhere to strict sequential steps for donning to achieve the necessary seal for particle filtration. Following the proper sequence is the only way to realize the device’s certified protection level against airborne hazards.
Initial Preparation
Thorough hand hygiene is the first and most fundamental step before attempting to put on any personal protective equipment, including a respirator. Contaminants on the hands can easily be transferred to the inside surface of the mask during the donning process, which would negate the device’s purpose. Hands should be washed with soap and water or sanitized with an alcohol-based rub immediately before handling the mask.
Once hands are clean, the mask requires a quick inspection to confirm its integrity. The wearer should visually check the device for any tears, punctures, or holes that could compromise the filtration barrier. It is also important to inspect the metal nosepiece and the elastic straps or ties, ensuring they are not damaged, stretched out, or broken. Any structural damage means the mask cannot form a proper seal and should be discarded for a new one.
The Specific Donning Order
The correct sequence for positioning the mask and its straps is essential for seal formation and begins by holding the respirator in a cupped position. The mask should be held in the palm of one hand with the nosepiece facing upward, allowing the elastic straps to hang freely. This prevents the straps from twisting, which could cause pressure points or break the seal. The mask is then positioned under the chin, covering the mouth and nose completely.
The upper strap is always positioned first and should be pulled over the head, resting high on the crown, above the ears. This strap pulls the top of the mask firmly against the bridge of the nose and upper face. Next, the bottom strap is pulled over the head and settled around the neck, positioned below the ears. This specific order ensures the tension is distributed correctly across the sealing surface of the mask.
With the mask securely on the face, the final adjustment before a seal check involves the metal nosepiece. Using the index fingers of both hands, the wearer molds the metal strip to the exact contour of the nose bridge. Using two hands simultaneously to shape the nosepiece is important because pinching with a single hand can create a sharp crease, which is less effective than a smooth, uniform curve for sealing the area. This precise molding prevents air leakage where the mask meets the face.
Verifying the Seal
After the mask is fully donned and the nosepiece is molded, a user seal check must be performed to confirm the tight fit before entering any area requiring respiratory protection. The seal check determines if the mask is seated correctly on the face, a procedure distinct from the annual fit test. The wearer can perform two types of checks: the positive pressure and the negative pressure check.
The positive pressure check is conducted by placing both hands over the mask and gently exhaling. If the mask is sealed correctly, a slight positive pressure will build up inside, and no air will be felt leaking out around the edges of the mask. For the negative pressure check, the hands are placed over the mask, and the wearer inhales sharply. A successful negative check will cause the mask to slightly collapse toward the face without any air leaking inward.
If air leakage is detected during either check, the wearer must adjust the nosepiece or the position of the straps and repeat the seal check. If adjustments fail to eliminate leaks, the mask must be discarded, and a different size or model must be tried to ensure the wearer is protected.