Respirator Fit:What is “Fit”?｜An essential factor when choosing a respirator│KOKEN LTD.

Relationship between Respirator Performance and Respirator Fit

The respirator with high-performance filter is now commonplace,
but if it does not fit on your face, it does not fulfill its intended purpose.

When you wear a respirator and breathes in, the pressure inside the respirator becomes negative. If there is a gap between the face and the respirator, the air outside the respirator will always leak in directly through the gap.The larger the gap, the more leakage will occur, and even though the respirator is worn, a large amount of air that does not pass through the filter will be inhaled.
Wearing a respirator has the effect of preventing inhalation of the outside air containing bacteria and viruses by filtering it through a filter. No matter how high-performance the filter is, it does not make sense to wear a respirator if it allows a large amount of air to leak in.

Gap between Respirator and Face

Places where gaps between the respirator and the face are likely to occur are the sides of the nose, cheeks, chin, etc., but the fit differs depending on the respirator.
Then, how much particulates are leaked into the respirator when a respirator is worn?
The leakage rate (%) of particulates into the respirator can be obtained from the results of measuring the particulate concentrations on the outside and inside of the respirator.

For example, if there are 1,000 particulates in air outside the respirator,
the leakage rate is 1% when 10 particulates in air inside the respirator are measured.
Similarly, the leakage rate is 10% if 100 particulates are measured in air inside the respirator.
You can see that the lower the leakage rate, the less particulates leak into the respirator and the respirator fits snugly on the face.

Function that Makes a Respirator Fit Easier

Advanced facepiece technology to easily ensure a snug fit on face

Ensuring “a snug fit” plays an important role in the performance of a respirator. Even if the respirator has a high particulate filtering function, it is meaningless if particulates leak in from the face contact part of a facepiece when worn.
Many causes of harmful particulates leaking into the respirator are the gaps in the face contact part that occur when the respirator is worn. Considering that a respirator fit is as important as the performance, we have commercialized the technology to enhance the tight-fit of the face contact part from early on.

	*Silicone Facepeice 1**
	Silicone is a skin-friendly material with less irritating properties. It is flexible enough to follow facial movements so that it can be worn stably. It exhibits excellent stability of properties.
	*Free-Position Under-Chin Structure 2**
	This special shape of the face contact part is designed to provide a tight-fitness of the facepiece. Positioning the top of the facepiece aligned with the bridge of the nose (where leakage is likely to occur) and then placing the bottom of the facepiece under the chin, it can fit a wide variety of face sizes and shapes.
	Stability throughout Wear
	3-dementional plastic-molded cradle harness designed to fit on the shape of head is constructed with a headband. It fits the crown of the head snugly and a good fitting feeling and a tight seal are enhanced.
	Built-in Fit Checker
	With a built-in fit checker, anyone can easily check a respirator fit at any time.
	*FF (Free Fit) Lip 3**
	The surface of the uniquely curbed facepiece lip expands the contact area with the face to give a respirator fit. The design makes it easy to follow the facial movements so that it also reduces the occurrence of gaps due to changes in facial expressions.
	*Adjustable Straps 4**
	The strap can be adjusted to proper length. If the strap is loose on your face, the respirator may slip out of place or a gap may be created during the work. If the strap is too tight, the respirator may deform and create gaps, or it may cause pain in the face or head.

It is important to have a respirator fit in order to obtain the expected particulate filtering efficiency or protection against harmful gasses.

Hazardous substances generated in the work environment vary depending on the work content, so it is necessary to select an appropriate respirator for the type and concentration of the hazardous substances being generated.
In order to deal with toxic gases, vapors, harmful particulates, etc. being generated in the work environment, it is necessary to know the work environment such as the type and concentration, etc. of harmful substances.
Make sure that you understand the dangers of the target substances and choose the right type of respirator that fits your face snugly. Here are some tips for choosing the right respirator for your face that suits your particular work environment.

・Choose a respirator that matches the shape of your face.
・Wear a respirator that fits snugly on your face.
・Choose a respirator that has the function of preventing the inward leakage of particulates, gasses, etc.