KOKEN LTD.
Koken 1021 Series And 1091D-04 Dust Mask
Manufacturer: KOKEN LTD.
Model: 1021 Series and 1091D-04
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.
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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. |
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Note: The table below is excerpted from the “Dust Respirator Standards”.
| Replaceable Dust Respirator | Isolation Type Dust Respirator |
|---|---|
| Direct-Connection Type Dust Respirator | |
| Disposable Dust Respirator | |
| Test Particles | Type | NaCl (Sodium Chloride) particles | DOP (Dioctyl Phthalate) particles | ||
|---|---|---|---|---|---|
| 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 test aerosol Loaded up to 100mg | For DOP test aerosol Loaded 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 | ||
| Inhalation 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 | 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) | ||
( ) indicates products without an exhalation valve.
| Exhalation Valve Airtightness | Exhalation valve operation leak test | – When air is drawn, the internal pressure must decrease immediately – The time for internal pressure to return to normal atmospheric pressure must be 15 seconds or more |
|---|---|---|
| Carbon Dioxide (CO2) Concentration Increase | Using a test headform and an artificial lung to inhale/exhale air containing CO2. The difference in CO2 concentration in the inhaled air between wearing and not wearing the mask must be 1.0% or less. | |
| Dead Space Volume | Value calculated from the (Carbon Dioxide Concentration Increase Test) | |
| Inhalation Resistance Increase | Test Particles | NaCl (Sodium Chloride) |
|---|---|---|
| Test Flow Rate | Measured at 40 ℓ/min after loading test dust at 85 ℓ/min | |
| Amount loaded onto dust respirator | 100mg |
Test aerosol and collection efficiency Disposable Type | S | L | Classification (Collection efficiency) | |
|---|---|---|---|---|
| Test aerosol is Solid Sodium Chloride (NaCl) | Test aerosol is Liquid Dioctyl Phthalate (DOP) | |||
| R | Replaceable Dust Respirator | RS1 | RL1 | Class 1 (Above 80.0%) |
| RS2 | RL2 | Class 2 (Above 95.0%) | ||
| RS3 | RL3 | Class 3 (Above 99.9%) | ||
| D | Disposable Dust Respirator | DS1 | DL1 | Class 1 (Above 80.0%) |
| DS2 | DL2 | Class 2 (Above 95.0%) | ||
| DS3 | DL3 | Class 3 (Above 99.9%) | ||
High Efficiency Filter + Ergonomic Face Seal
2. Facepiece Fit Technology
Even if a dust mask has a high collection efficiency filter, it is ineffective if dust leaks through the facepiece seal during use. This is primarily caused by a “gap at the facial contact area.” We consider mask fit to be as important as filter performance. Therefore, our company has long 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 effortlessly adapts to facial movements, ensuring a comfortable fit. The material is also stable during use.
HAWC harness strap
The strap design ensures a high level of fit, maximizing the “suction” effect when wearing the mask to ensure an airtight facial seal. 
Freeposition Underchin
The unique curve of the facial contact area prevents dust entry. The nose section is aligned first, allowing it to accommodate various facial dimensions and providing a secure fit for a wide range of face sizes (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 Stability | 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 fit and seal. |  | Fit checker is integrated inside, allowing for seal checks at any time (available for models 1005, 1010A, 1015, 1180 series). |
Replaceable Dust Mask
Mighty Micron Filter
（Head Harness Types）
Please replace the head straps periodically.
Koken’s Unique Facial Seal – Extreme Focus on Fit
Shape (Freeposition Underchin Mask)
The “Freeposition Underchin Mask” allows the user, when donning, to first set the nose portion in the correct position. The underchin support then automatically settles into place, achieving an optimal wrap-around fit. Regardless of face size, almost anyone can achieve a secure seal and soft wearing feel with just one mask size.
Material (Silicone – Flexible and Stable)
Silicone material is hypoallergenic and unlikely to cause skin dryness. It remains flexible according to facial expressions, ensuring stable and comfortable wear. Additionally, it is highly resistant to skin oils and easy to clean, making it suitable for long-term use in professional environments.
Features
- Under-chin design: Enhanced seal at the facial contact points due to specialized curvature.
- Silicone: Soft, skin-friendly material for a comfortable wearing experience.
- Size S available: Size options for individuals with smaller facial dimensions.
- Speaking Diaphragm: Enables clear verbal communication and commands while wearing the mask.
- Micron: Employs high-performance electrostatic filters compliant with RL classifications.
Sakai Model 1021R-07
RL2 Rating
Low-profile filter design ensures a clear downward field of vision.
Type Certification: TM545
Assigned Protection Factor: 10
Compatible with KBC filters
- Under-chin Seal
- Silicone Facepiece
- Size S Available
- Micron Filter
| Particle Collection Efficiency | 95.0% or higher (Average 98.0%) |
|---|---|
| Inhalation Resistance | 80Pa or less (Average 51Pa) |
| Exhalation Resistance | 52Pa or less (Average 29Pa) |
| Resistance Increase | ― (Average 87Pa) |
| Weight | 160g or less (Average 149g) |
| Head Harness | RB Type |
Replacement Parts: Exhalation Valve – T-6K type
Sakai Model 1021RX-05
RL2 Rating
4-point head harness prevents mask shifting
Type Certification: TM546
Assigned Protection Factor: 10
Compatible with KBC filters
- Under-chin Seal
- Silicone Facepiece
- Size S Available
- Micron Filter
| Particle Collection Efficiency | 95.0% or higher (Average 98.0%) |
|---|---|
| Inhalation Resistance | 80Pa or less (Average 53Pa) |
| Exhalation Resistance | 52Pa or less (Average 29Pa) |
| Resistance Increase | ― (Average 86Pa) |
| Weight | 163g or less (Average 154g) |
| Head Harness | XRB Type |
Replacement Parts: Exhalation Valve – T-6K type
Sakai Model 1091D-04
RL2 Rating
4-point harness with integrated speaking diaphragm
Facilitates verbal communication and instructions while wearing the mask.
Type Certification: TM548
Assigned Protection Factor: 10
Compatible with KBC filters
- Under-chin Seal
- Silicone Facepiece
- Speaking Diaphragm
- Micron Filter
| Particle Collection Efficiency | 95.0% or higher (Average 98.1%) |
|---|---|
| Inhalation Resistance | 80Pa or less (Average 55Pa) |
| Exhalation Resistance | 35Pa or less (Average 17Pa) |
| Resistance Increase | ― (Average 85Pa) |
| Weight | 178g or less (Average 173g) |
| Head Harness | XRB Type |
*The Model 1091SD-03 is also available with an RB-type head harness.
Replacement Parts: Exhalation Valve T-1 (T-1 type)
4-Point Support
XRB Type Head Harness (1021RX / 1091D)
The 4-point harness secures the mask at four locations (top, bottom, left, and right) to contour firmly to the face. Even during work involving heavy head movement, the mask remains stable and maintains a tight seal.
▲ Common Replacement Parts for All 3 Models
- Inhalation Valve (Circular)
- Moisture Sponge (Oval type)
Replacement Filters · Optional Accessories
 |  |  |
| Mighty Micron Filter for Model 1021-02 | KBC Filter for 1021 / 1091 (Optional) Ozone and organic odor removal (5 sets per pack) Applicable models: 1021R / 1021RX / 1091D | Fit Tester Type F (Optional) Left & Right Set |
Related Protective Equipment
Dust Safety Goggles
Prevent eye injury caused by particulates.
Sakai Model KR-11
These are goggle-style safety glasses designed for easy combination with our half-face dust masks. Equipped with high-performance ventilators and dual-sided anti-fog treated lenses. They can be worn over prescription glasses, ensuring safer operations. (Note: Large glasses may not be compatible.)
High-Performance Ventilators
- Lens: Cellulose-based plastic (dual-sided anti-fog treatment)
- Frame: Soft vinyl
- Headband: Nylon
Dust Protective Hood
Prevents dust accumulation on the head and shoulders.
Sakai – Type A
| Compatible Masks | Hi-Luck, 1010A, etc. |
|---|---|
| Vision Window | Cellulose Plastic |
| Fabric | Canvas |
Sakai – Type C 
| Features inhalation port, front button style | |
|---|---|
| Compatible Masks | Hi-Luck, 1010A, 1021R, 1121R, 1005R, etc. |
| Vision Window | Cellulose Plastic |
| Fabric | Canvas |
※ Masks shown in illustrations are not included with the hood.
Note: Product is not water-resistant.
Associated Testing Equipment
Filter Replacement Indicator – Type 7M / 7S
Type 7M (For Medium facepieces):
1005, 1021, 1091, 1121, 1191, 1122, 1181, 7191, 7121, 6061
Type 7S (For Small facepieces):
1005, 1021, 1121, 1122, 1181, 7121
This tester is compatible with masks using Mighty Micron or Alpha Ring filters. Dust accumulation status on the filter is displayed via color-coded indicators, allowing clear confirmation and precise determination of the filter replacement schedule.
Options
- For Model 1010
- For Model 1111 / 1180 (Compatible with 1015)
- Medium Facepiece Connector
- Small Facepiece Connector
※ Not compatible with Model 1180 size S.
- Power Consumption: 50 W
- Power Supply: AC 100 V
- Weight: 6.5 kg
Qualitative Fit Test Kit FIT-Ⅱ
This kit is used for performing qualitative fit testing to assess whether the mask fits the user’s face securely with an airtight seal. (Complies with JIS T 8150)
- Uses Sodium Saccharin solution (sweet taste component).
- Includes 10 hoods, convenient for testing multiple personnel.
- Distinct color-coded labels for easy identification of screening (sensitivity) and fit test solutions.
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