Koken 1121 Series Dust Mask

Manufacturer: KOKEN LTD.
Model: 1121 Series

Important points when wearing a mask

Dust masks utilize high-efficiency filters to effectively prevent the inhalation of hazardous particles. To protect yourself while wearing a dust mask, both the performance of the filter and the “tight seal” (fit) between the mask and your face are critical.

1. Filter Technology with High Particle Collection Efficiency

Mighty (Uni) Micron Filter
Using unique technology, wool fibers are electrostatically charged, allowing electrostatic force to draw particles to the fiber surface. This is the primary mechanism for capturing particles. A high-density fiber structure is unnecessary, successfully integrating the two contrasting features: “high collection efficiency” and “low inhalation resistance.” It consistently maintains the highest standard of performance and quality, making it an excellent long-term filter solution.

Applied products are on P.4 ~ 6, P.11

Alpha Ring Filter

Increasing the fiber density of the filter enhances collection efficiency. To meet airflow resistance standards, paper filters traditionally require an expanded surface area.

For the first time in Japan, ultra-fine fibers were formed into pristine circular shapes in a single process, creating the Alpha Ring filter. Today, this filter continues to succeed in expanding the surface area while maintaining a compact shape, significantly reducing airflow resistance.

Applied products are from page P.8 to P.11

Dust Respirator Standards

In addition to JIS standards, dust respirators are tested according to assay standards based on national regulations. These standards are comprehensive, ensuring that products meeting strict safety requirements are manufactured.

Dust Respirator Standards	In addition to JIS standards, dust respirators are tested according to assay standards based on national regulations. These standards are comprehensive, ensuring that products meeting strict safety requirements are manufactured.

Note: The table below is excerpted from the “Dust Respirator Standards”.

Disposable Dust Respirator
Replaceable Dust Respirator	Isolation Type Dust Respirator
Replaceable Dust Respirator	Direct-Connection Type Dust Respirator

Inhalation Resistance (Test flow rate 40 ℓ /min)	Replaceable Type			Disposable Type
Test Particles	Type	NaCl (Sodium Chloride)		DOP (Dioctyl Phthalate)
	Particle Size	0.06 μm to 0.1 μm		0.15 μm to 0.25 μm
	Concentration	50mg/m³ or less		100mg/m³ or less
Test Flow Rate		85 ℓ /min		85 ℓ /min
Particle Collection Efficiency (Continuous measurement; must meet values in the right column)		For NaCl particles Load up to 100mg		For DOP particles Load up to 200mg
	Replaceable Type	RS1	80.0% or higher	RL1	80.0% or higher
		RS2	95.0% or higher	RL2	95.0% or higher
		RS3	99.9% or higher	RL3	99.9% or higher
	Disposable Type	DS1	80.0% or higher	DL1	80.0% or higher
		DS2	95.0% or higher	DL2	95.0% or higher
		DS3	99.9% or higher	DL3	99.9% or higher
	RS1　RL1		70Pa or less	DS1　DL1	60Pa or less (45Pa or less)
	RS2　RL2		80Pa or less	DS2　DL2	70Pa or less (50Pa or less)
	RS3　RL3		160Pa or less	DS3　DL3	150Pa or less (100Pa or less)
Exhalation Resistance (Test flow rate 40 ℓ /min)	Replaceable Type			Disposable Type
	RS1　RL1		70Pa or less	DS1　DL1	60Pa or less (45Pa or less)
	RS2　RL2		70Pa or less	DS2　DL2	70Pa or less (50Pa or less)
	RS3　RL3		80Pa or less	DS3　DL3	80Pa or less (100Pa or less)

Values in ( ) are for products without an exhalation valve.

Exhalation Valve Airtightness	Exhalation valve leak test	– Internal pressure must drop immediately during suction. – Time for internal pressure to return to normal must be 15 seconds or more.
CO2 Concentration Increase	Measured using a test headform and artificial lung. The difference in CO2 concentration in inhaled air with and without the mask must be 1.0% or less.
Dead Space	Value calculated from the CO2 Concentration Increase Test.

Inhalation Resistance Increase	Test Particles	NaCl (Sodium Chloride)
	Test Flow Rate	After dust accumulation at 85 ℓ/min, measurement is taken at 40 ℓ/min.
	Dust Accumulation Amount	100mg

Test Particles & Efficiency Disposable / Replaceable		S	L	Classification (Efficiency)
Test Particles & Efficiency Disposable / Replaceable		Test particle: Solid NaCl	Test particle: Liquid DOP	Classification (Efficiency)
R	Replaceable Dust Respirator	RS1	RL1	Class 1 (≥ 80.0%)
		RS2	RL2	Class 2 (≥ 95.0%)
		RS3	RL3	Class 3 (≥ 99.9%)
D	Disposable Dust Respirator	DS1	DL1	Class 1 (≥ 80.0%)
		DS2	DL2	Class 2 (≥ 95.0%)
		DS3	DL3	Class 3 (≥ 99.9%)

High Efficiency Filter + Face-Friendly Surface

2. Surface Engineering for a Better Facial Fit

Even if a dust mask has a high collection efficiency filter, it is useless if dust leaks in through the facepiece seal. The primary cause of leakage is the “gap at the contact area when wearing the mask.” We consider the fit of the mask to be as important as the filter performance. Therefore, our company has developed technology to enhance the airtightness of the facial contact area.
Silicone Facepiece
Silicone is a hypoallergenic material that is gentle on the skin. Its surface is flexible and easily adapts to body movements, ensuring wearing comfort and stability during use.

HAWC Harness
The harness design ensures high tension and maximizes the “suction” effect when wearing the mask, guaranteeing an airtight seal on the face.

Freeposition Underchin
The special shape of the facial contact area prevents dust entry. The nose section is adjustable for different sizes, ensuring a perfect fit for a wide range of facial dimensions (see image below).

Fit Status of the Freeposition Underchin Facepiece
(Cross-sectional simulation to show the contact position between the mask and the chin).

For large faces:
Uses the outer section of the mask to adjust the fit around the chin.

For small faces:
Uses the inner section of the mask to adjust the fit around the chin.

FF Lip		Wearing Safety		Internal Fit Checker
	Designed for various face shapes; the cushion naturally fits your face.		Utilizes a 3D poly-band harness that matches head shapes to enhance the feeling of fit and seal.		Built-in fit checker allows for seal checks at any time (for models 1005, 1010A, 1015, 1180 series).

Head Strap Types
Please replace the head straps periodically.

Sakai – Model 1121R-08

RL2 – Dual filter mask, easy to breathe

Type Certification: TM231
Assigned Protection Factor: 10
Compatible with KBC filter

Under Chin Design
Silicone Facepiece
Size S available

Particle Collection Efficiency	95.0% or higher (Average 98.8%)
Inhalation Resistance	64Pa or less (Average 44Pa)
Exhalation Resistance	52Pa or less (Average 29Pa)
Inhalation Resistance Increase	― (Average 71Pa)
Weight	167g or less (Average 144g)
Head Harness	RB Type

Replacement Parts: Exhalation valve: T-6K type

Sakai – Model 1121RX-04

RL2 – Stable fit with 4-point head strap

Type Certification: TM311
Assigned Protection Factor: 10
Compatible with KBC filter

Under Chin Design
Silicone Facepiece
Size S available

Particle Collection Efficiency	95.0% or higher (Average 99.0%)
Inhalation Resistance	64Pa or less (Average 48Pa)
Exhalation Resistance	47Pa or less (Average 29Pa)
Inhalation Resistance Increase	― (Average 68Pa)
Weight	172g or less (Average 150g)
Head Harness	XRB Type

Replacement Parts: Exhalation valve: T-6K type

▲ Shared Replacement Parts for 6 Models (1181R-03, 1121R-08, 1191SD-03, etc.)

Inhalation valve: Circular type
Moisture sponge: Oval type

Replacement Filters · Optional Accessories

LAS-52 (for 1181R)	LAS-52C (for 1181RC)	LAS-1 (for 1121R, 1121RX, 1191SD, 1191D)	LAS-51 (for 1180)	LAS-51C (for 1180C)	KBC Filter for 1121 / 1191 (Ozone & organic odor removal – pack of 5) For: 1121R / 1121RX / 1191SD / 1191D / 1122R (Optional)	Fit Test Device – Type F For: 1181R, 1181RC, 1121R, 1121RX, 1191SD, 1191D (Optional)

Screw-in connection – Pack of 2	Screw-in connection – Pack of 2	Pack of 2	Screw-in connection – Pack of 2	Screw-in connection – Pack of 2

Underchin: Specialized curve improves facial seal.
Silicone: Soft, skin-friendly material provides a comfortable wearing experience. Facepiece uses a silicone seal.
Size S available: Smaller facial dimensions are catered for with Size S.
Low Resistance: Uses Alpha Ring filter for low breathing effort, suitable for long-duration work.
Speaking Diaphragm: Enables clear communication and commands while wearing the mask.
Activated Carbon: Simultaneously removes low-concentration ozone using carbon-treated filters.
Micron Filter: High-efficiency electrostatic filter compliant with RL classification.
Fit Checker: Simple lever mechanism to perform fit tests at any time.

Double-Layer Bonnet Structure

The exhalation valve is shielded inside the bonnet, protecting it from external factors like wind. Exhaled air within the upper bonnet acts as a barrier, preventing direct external impact and protecting the valve. This significantly improves exhalation valve performance and stability under real usage conditions.