As we become accustomed to a world with Coronavirus, clients have increasingly asked us for guidance on how long to wear surgical masks and N95 respirators for best performance. While we are not medical professionals, here’s some information that may help you.
How long surgical masks and N95 respirators can be worn depends on the mask type
The decision on how long to wear surgical masks and N95 respirators for must also take into account the manufacturer’s guidance, environment, and conditions that the mask is subject to.
How long can you wear a surgical mask?
Surgical masks can typically be worn for up to 8 hours, or until they become soiled or too moist.
How long does an N95 mask last?
Manufacturer guidance typically suggests that N95 respirators can be worn for 3-4 hours at a time.
How to make sure what the time duration is?
At the time of testing in a laboratory, the manufacturer will have suggested the appropriate length of time. It may be written in the detailed lab test report for the mask.
Can surgical masks and N95 respirators be reused?
Manufacturer’s advice is that single-use products like medical surgical masks and respirators should not be reused after being worn on one occasion. To define ‘re-use,’ this is where the face mask or respirator is removed and put on again later.
Respirator masks are in particularly short supply during the pandemic and some hospitals have chosen to reuse them in limited amounts. The CDC says the following about respirator reuse:
If no manufacturer guidance is available, preliminary data suggests limiting the number of reuses to no more than five uses per device to ensure an adequate safety margin.
Due to the shortage of PPE in the USA, some healthcare providers implemented sterilization machines for used N95 respirator masks, effectively allowing them to be reused on different occasions. It is said that the technology:
…had 99.9% efficiency in killing bacterial spores and sterilization could be performed up to 20 times before damaging a respirator.
Reusing single-use PPE in a hospital environment is not recommended by manufacturers, and while the FDA cleared the sterilization machines for use, they warned the manufacturer not to endorse the technology as being ‘safe or effective for the prevention or treatment of COVID-19.’
Can these masks be worn for longer than recommended (extended use)?
During the coronavirus pandemic, many healthcare professionals have worn face masks for longer which otherwise may have been discarded between patient encounters, as long as they are dealing with patients suffering from the same condition (i.e. COVID-19) because of shortages in such equipment.
The FDA says this about surgical mask extended wear:
During times of limited access to surgical masks, facilities could consider having health care providers continue to wear the same surgical mask (i.e., extended use), remove only used gloves and gowns , and perform hand hygiene between treating patients with the same infectious disease diagnosis or exposure who are maintained in a confined area. If the mask, gloves, or gowns become contaminated, replace them.
The CDC states that respirators may also be used for an extended period if necessary:
A key consideration for safe extended use is that the respirator must maintain its fit and function. Workers in other industries routinely use N95 respirators for several hours uninterrupted. Experience in these settings indicates that respirators can function within their design specifications for 8 hours of continuous or intermittent use.
They go on to make the point that: ‘Extended use is favored over reuse because it is expected to involve less touching of the respirator and therefore less risk of contact transmission.’
The problem with wearing N95 respirators for extended periods
N95 respirators filter the air that the wearer breathes, removing airborne particulates, such as virus particles, and protecting the user. The need to breathe through the materials puts a strain on the user, and so while extended use may be possible, it is not easy or recommended:
When worn properly, these respirator masks get very hot inside and are very difficult to breathe in due to the pressure change between the air inside and the outside atmosphere. It is like breathing through a blanket and can become distressing to the user. A user’s blood-oxygen saturation can drop and carbon dioxide increases significantly with correct and prolonged use. Even a healthy and fit adult could find wearing an N95, if put on correctly, difficult after an hour or so of use. An older person or an immunocompromised individual likely would have a very hard time using an N95 mask even for a short time. Wearers may take it off for a break which would reduce its protection. Children and infants are also generally not appropriate candidates for wearing N95s as the risk of suffocation is higher.
Be aware of moisture’s effect on mask life
The Nursing Times makes the point that:
A mask wet with exhaled moisture has increased resistance to airflow, is less efficient at filtering bacteria and has increased venting. Current recommendations are that a new surgical mask is used for each surgical case and that they should be changed when wet.
This point is echoed by the WHO as well, therefore, if a mask has become wet (or soiled, of course), it should be disposed of regardless of the length of time that it has been worn.
We’ve previously made the link between moisture and increased risk of infection in this blog post, too: Is It Safe To Receive Packages From China? [Coronavirus FAQs]
How about when the general public wears masks?
Some European countries have now also mandated that people wear face masks when outside in public, such as in Austria when shopping. Therefore the question of how long face masks should be worn in public must also be addressed.
In some Asian countries, the general population are provided with a ready source of surgical masks to wear to slow infection rates. For example, in Taiwan, citizens are guaranteed to able to purchase 3 surgical masks per week from chemists.
While it is recommended to dispose of surgical masks after a day of wear, this would seem to suggest an expectation for the general public in Taiwan to practice ‘extended use’ of face masks, and, anecdotally, we have also seen people in China who have worn a single mask for a couple of days before changing to a new one.
Given that the risk of viral transmission is far greater in a COVID-19 hospital ward then, say, an office or supermarket where social-distancing rules are being applied, the question of how to long to wear face masks for is different, and it is probably fair to say that, for the public, limited extended use of face masks is still better than not wearing them at all.
Learn more about importing face masks during the pandemic
If you’re interested in purchasing face masks, read this general blog post: Face Mask Regulations and China Export Challenges For Buyers During The Coronavirus Pandemic
Then you may like these pages specific to your region:
Or, reach out to our team if you need help with purchasing: