NPPTL COVID-19 Response: International Respirator Assessment

Manufacturer: Shenzhen Dingwei Optical Technology Co.

Model Tested: KN95

Date Tested: May 18, 2021

These findings pertain to the Shenzhen Dingwei Optical Technology Co., model KN95. The information 

submitted with this product does not indicate what standard this product meets.

Ten respirators were submitted for evaluation. The samples were tested using a modified version of 

NIOSH Standard Test Procedure (STP) TEB-APR-STP-0059. This modified assessment plan can be found 

here.

No certificate of approval was provided with the samples received; therefore, the authenticity of the 

claims cannot be validated.

The maximum and minimum filter efficiency was 83.69% and 75.56%, respectively. All ten respirators

measured less than 95%. It is noted that respirator number six had extra straps attached in the 

breathing area (see photos at end of report). 

NIOSH does not have knowledge about the sustained manufacturer quality system and product quality 

control for this product. NIOSH also does not have knowledge about the product’s handling and 

exposures after leaving its manufacturer’s control.

In addition, this product is an ear loop design. Currently, there are no NIOSH-approved products with 

ear loops; NIOSH-approved N95s have head bands. Furthermore, limited assessment of ear loop 

designs, indicate difficulty achieving a proper fit. While filter efficiency shows how well the filter media 

performs, users must ensure a proper fit is achieved.

This assessment is not a part of the NIOSH respirator approval process and will in no way lead to or 

preclude NIOSH approval through the official approval process. This assessment was developed as an 

assessment of the filter efficiency for those respirators represented as certified by an international

certification authority, other than NIOSH, to support the availability of respiratory protection to US 

healthcare workers due to the respirator shortage associated with COVID-19. Only particulate filter 

efficiency was assessed.

The results provided in this letter are specific to the subset of samples that were provided to NPPTL for 

evaluation.

These results will be used to update the CDC guidance for Crisis Capacity Strategies (during known 

shortages).
NPPTL COVID-19 Response: International Respirator Assessment

Evaluation of International Respirators

Test: Modified TEB-APR-STP-0059

Date Tested: May 18, 2021

Report Prepared: May 18, 2021

Manufacturer: Shenzhen Dingwei Optical Technology Co.

Item Tested: KN95

Country of Certification: UNKNOWN

Filter Flow Rate

(LPM)

Initial Filter 

Resistance 

(mmH2O)

Initial Percent 

Leakage

(%)

Maximum 

Percent Leakage

(%)

Filter Efficiency

(%)

1 85 6.7 17.21 17.21 82.79

2 85 7.4 16.31 16.31 83.69

3 85 7.5 18.16 18.16 81.84

4 85 7.1 19.08 19.08 80.92

5 85 7.8 24.44 24.44 75.56

6 85 6.3 20.75 20.75 79.25

7 85 7.1 18.31 18.31 81.69

8 85 7.0 18.39 18.39 81.61

9 85 7.8 20.11 20.11 79.89

10 85 7.2 23.61 23.61 76.39

Minimum Filter Efficiency: 75.56% Maximum Filter Efficiency: 83.69%

• The test method utilized in this assessment is not the NIOSH standard test procedure that is used for certification of 

respirators. Respirators assessed to this modified test plan do not meet the requirements of STP-0059, and 

therefore cannot be considered equivalent to N95 respirators that were tested to STP-0059. 

• Respirators tested may not be representative of all respirators with the same certification mark. NIOSH has no 

control over suppliers and distributors of respirators certified by other national or international parties.

• This assessment is not a confirmation that it conforms with any or all of its specifications in accordance with its 

certification mark. 

• This assessment was not a part of the NIOSH approval program. These results do not imply nor preclude a future 

approval through the NIOSH respirator approval program.

Pictures have been added to the 

end of this report.
NPPTL COVID-19 Response: International Respirator Assessment
NPPTL COVID-19 Response: International Respirator Assessment
NPPTL COVID-19 Response: International Respirator Assessment

 
NPPTL COVID-19 Response: International Respirator Assessment