Dwell time, also known as contact time, is the amount of time that a surface should remain wet to achieve a sanitization product’s desired result. For example, some products advertise that they kill 99.9% of germs; however, to kill those 99.9% of germs there is usually a dwell time where the surface area must remain wet with that sanitizing product.
A dwell time on average can last between 30 seconds to 10 minutes or more. Sanitizing is less effective when proper dwell times are not observed. Dwell times also require a proper amount of sanitizing product to be applied, which is just as important as the dwell time itself. Here are some examples where dwell times should be practiced and adhered with sanitizing products:
Disinfectant Wipes: Some of the most popular household wipes (including Lysol and Clorox) recommend that the surface being sanitized must remain wet for 4 minutes after being wiped.
Disinfectant Sprays: In addition to dwell time, sprays may have further directions such as distance to spray a surface to sanitize it. Lysol recommends spraying for 3-4 seconds within 6” to 8” of the surface being sanitized with a dwell time of 3 minutes where the surface must remain wet.
Bleach Solution Soak: When 1/3 cup household bleach is mixed with 1-gallon water, objects should usually be immersed for not less than 60 seconds and not more than 10 minutes, depending on what is being sanitized.
Hand Sanitizer: Hands should remain wet with a hand sanitizer for at least 20 seconds after application. Dwell time language is usually not used with hand sanitizer, but we felt it’s appropriate because many will not wet their entire hands with hand sanitizer, nevermind keep them wet for at least 20 seconds with plentiful product. Our sparing use of sanitizing agents today is mostly born from the appalling shortage of sanitizing agents available during this pandemic, which has not been helpful in preventing the spread of germs.
The four sanitizing products and practices listed above have dwell times that range from 20 seconds and up to 10 minutes, where the surface areas or objects being sanitized must remain wet. Proper sanitation is regularly not achieved if a product’s dwell time is not provided.
Some people will spray or wipe a surface area with a sanitation product, and then wipe it dry without allowing for dwell time. This is one of today's most popular and improper uses of a sanitizing product. It is important to not rush the sanitization process by adhering to proper dwell times, or else the entire effort could be an expensive waste of time and leave you exposed to a dirty or infected workspace.
Hard surfaces versus porous objects can have different dwell times. Different kinds of sanitary agents, as well as different sanitation manufacturers could have contrasting instructions. It is extremely important to follow each product’s individual instructions to keep yourself safe, and your clients happy and healthy during this viral age. It only takes a few seconds to read and practice these various uses, but those few seconds could make the difference of properly sanitizing your business, or leaving it exposed to germs.