Evaluation of Decontaminated N95 Respirators 

Date Tested: 6/19/2020 – 6/23/2020 

Respirator Model(s): 3M 8511, 3M 1860, Halyard 62126 

Tests: Filtration with NaCl (modified version of STP-0059), Manikin Fit Factor with Static Advanced Headform, and Strap 

Integrity with Tensile Testing

Decontamination Method: Heat-based decontamination method using commercial laundry dryers. Each FFR is placed in a 

Ziploc bag, which are put in a box in a tumble dryer. Each cycle is performed at a setting to achieve temperatures > 80°C for

> 70 minutes.

Decontamination Cycles: 3 cycles 

While decontamination and reuse of FFRs are not consistent with standard and approved usage, these options 

may need to be considered when FFR shortages exist. This assessment was developed to quantify the filtration 

efficiency and manikin fit factor1 of an N95 respirator that has been decontaminated. This assessment is not to 

determine the effectiveness of the decontamination procedure at killing pathogenic microorganisms. The results 

provided in this report are specific to the subset of samples that were provided to NPPTL for evaluation. These 

results may be used to update the CDC guidance for Crisis Capacity Strategies (during known shortages). 

60 respirators that were unworn and not subjected to any pathogenic microorganisms were submitted for 

evaluation. This included 45 respirators that were subjected to 3 cycles of the dry heat decontamination process 

and an additional 15 respirators that served as controls. Figure 1 photos document the procedures used. The 

samples were tested using a modified version of the NIOSH Standard Test Procedure (STP) TEB-APR-STP-0059 to 

determine particulate filtration efficiency. The TSI, Inc. model 8130 using sodium chloride aerosol was used for 

the filtration evaluation. For the laboratory fit evaluation, a static manikin headform was used to quantify 

changes in manikin fit factor. The TSI, Inc. PortaCount® PRO+ 8038 in “N95 Enabled” mode was used for this 

evaluation. Additionally, tensile strength testing of the straps was performed to determine changes in strap 

integrity. The Instron® 5943 Tensile Tester was used for this evaluation. The full assessment plan can be found 

here. 

Filtration Efficiency Results: All respirators measured more than 95%. See Tables 1, 4, and 7. 

Manikin Fit Factor Results: The manikin fit factor showed passing fit factors (greater than 100) for all respirators 

evaluated. See Tables 2, 5, and 8. 

Strap Integrity Results: No visual degradation of the straps was observed. Inconsistent changes were shown 

between the 3M 8511 top and bottom straps, with the top strap showing a decrease in recorded force and the 

bottom strap showing an increase in force. Both the 3M 1860 and Halyard 62126 top and bottom straps showed 

decreases in recorded force. See Tables 3, 6, and 9. 

Other notes: Respirator information on the outer surface of the 3M 1860 was blurred/illegible. Respirator name 

on front of Halyard 62126 was blurred/illegible. 

1The American Industrial Hygiene Association defines the Manikin Fit Factor as “An expression related to the amount of leakage measured through the 

face or neck seal of a respirator mounted to a manikin under specified airflow and environmental conditions. If the challenge to the seal is an airborne 

substance, it is the ratio of its airborne concentration outside the respirator divided by the concentration that enters the respirator through the seal. If the 

challenge is airflow or air pressure, conditions and assumptions for quantifying leakage must be specified. Leakage from other sources (e.g., air purifying 

elements) must be essentially zero. The respirator may be mounted to the manikin without sealants; be partially sealed to the manikin; or be sealed to the 

manikin with artificially induced leaks.” 
Figure 1. Laboratory Test Photos
Table 1. Filter Efficiency Evaluation – 3M 1860

Notes:

• 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 necessarily meet the requirements of STP0059, and therefore cannot be considered equivalent to N95 respirators that were tested to STP-0059. 

Respirator Model, 

Decon Method, # 

of cycles

Treated 

Sample #

Flow Rate

(Lpm)

Initial Filter 

Resistance

(mmH2O)

Initial Percent 

Leakage (%)

Maximum 

Percent 

Leakage (%)

Filter 

Efficiency 

(%)

3M 1860, Dry 

Heat, 3 cycles

Min Fil Eff: 95.08%

Max Fil Eff: 98.89%

1

85 8.7 0.425 0.938 99.06

2

85 7.7 0.619 1.25 98.75

3

85 7.6 2.73 2.88 97.12

4

85 8.9 0.649 2.00 98.00

5

85 8.0 2.70 2.70 97.30

6

85 7.9 0.537 1.11 98.89

7

85 8.1 0.579 1.13 98.87

8

85 8.9 4.91 4.92 95.08

9

85 8.3 0.692 1.43 98.57

10 85 8.3 0.578 1.11 98.89

Control 1 85 8.6 0.531 1.04 98.96

Control 2 85 8.5 0.466 1.08 98.92

Control 3 85 8.8 0.424 0.874 99.13
Table 2. Manikin Fit Evaluation – 3M 1860

Manikin Fit Factor of Decontaminated N95s

Respirator 

Model, Decon 

Method, # of 

cycles

Treated

Sample #

mFF Normal 

Breathing 1

mFF Deep 

Breathing

mFF Normal 

Breathing 2

Overall 

Manikin Fit 

Factor

3M 1860, Dry 

Heat, 3 cycles

Static Advanced 

Medium 

Headform 

(Hanson Robotics)

11 200+ 200+ 200+ 200+

12 200+ 200+ 200+ 200+

13 200+ 200+ 200+ 200+

14 200+ 200+ 200+ 200+

15 200+ 200+ 200+ 200+

Control 4 200+ 192 200+ 198

Control 5 200+ 200+ 200+ 200+

Notes:

• Per OSHA 1910.134(f)(7), if the fit factor as determined through an OSHA-accepted quantitative fit testing protocol 

is equal to or greater than 100 for tight-fitting half facepieces, then the fit test has been passed for that respirator.

• This assessment does not include fit testing of people and only uses two exercises (normal and deep breathing) on 

a manikin headform. 

• This assessment is a laboratory evaluation using a manikin headform and varies greatly from the OSHA individual 

fit test. This headform testing only includes normal breathing and deep breathing on a stationary (non-moving) 

headform; therefore, fit results from this assessment cannot be directly translated to using the standard OSHAaccepted test. Instead, this testing provides an indication of the change in fit performance (if any) associated with 

the decontamination of respirators. 

Table 3. Strap Integrity Evaluation – 3M 1860

Tensile Force in Respirator Straps of Decontaminated N95s

(recorded force values are at 150% strain)

Respirator Model, Decon 

Method, # of cycles Straps from Treated Sample # Force in Top Strap (N)

Force in Bottom 

Strap (N)

3M 1860, Dry Heat, 3 cycles

1 2.711 2.458

2 2.802 2.528

3 2.667 2.517

Decontaminated Strap 

Average 2.727 2.501

Control 1 2.928 2.591

Control 2 2.907 2.540

Control Strap Average 2.918 2.566

% Change

((Deconned - Controls) / 

Controls)

-6.55% -2.53%
Table 4. Filter Efficiency Evaluation - Halyard 62126

Notes:

• 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 necessarily meet the requirements of STP0059, and therefore cannot be considered equivalent to N95 respirators that were tested to STP-0059. 

Respirator Model, 

Decon Method, # 

of cycles

Treated 

Sample #

Flow Rate

(Lpm)

Initial Filter 

Resistance

(mmH2O)

Initial Percent 

Leakage (%)

Maximum 

Percent 

Leakage (%)

Filter 

Efficiency 

(%)

Halyard 62126, Dry 

Heat, 3 cycles

Min Fil Eff: 97.31%

Max Fil Eff: 99.32%

1

85 10.8 1.88 1.92 98.08

2

85 10.7 1.66 1.73 98.27

3

85 10.1 1.66 1.67 98.33

4

85 10.5 1.17 1.32 98.68

5

85 10.8 2.51 2.69 97.31

6

85 10.7 1.34 1.37 98.63

7

85 10.5 2.09 2.14 97.86

8

85 10.9 1.681 0.681 99.32

9

85 10.5 1.66 1.66 98.34

10 85 10.5 0.768 0.768 99.23

Control 1 85 11.7 1.04 1.06 98.94

Control 2 85 11.5 0.348 0.352 99.65

Control 3 85 11.4 0.968 0.971 99.03
Table 5. Manikin Fit Evaluation - Halyard 62126

Manikin Fit Factor of Decontaminated N95s

Respirator 

Model, Decon 

Method, # of 

cycles

Treated

Sample #

mFF Normal 

Breathing 1

mFF Deep 

Breathing

mFF Normal 

Breathing 2

Overall 

Manikin Fit 

Factor

Halyard 62126, 

Dry Heat, 3 cycles 

Static Advanced 

Large Headform 

(Lunar Studios)

11 189 150 200+ 177

12 200+ 200+ 200+ 200+

13 160 105 142 131

14 200+ 148 197 178

15 128 80 180 116

Control 4 200+ 181 200+ 194

Control 5 120 159 85 114

Notes:

• Per OSHA 1910.134(f)(7), if the fit factor as determined through an OSHA-accepted quantitative fit testing protocol 

is equal to or greater than 100 for tight-fitting half facepieces, then the fit test has been passed for that respirator.

• This assessment does not include fit testing of people and only uses two exercises (normal and deep breathing) on 

a manikin headform. 

• This assessment is a laboratory evaluation using a manikin headform and varies greatly from the OSHA individual 

fit test. This headform testing only includes normal breathing and deep breathing on a stationary (non-moving) 

headform; therefore, fit results from this assessment cannot be directly translated to using the standard OSHAaccepted test. Instead, this testing provides an indication of the change in fit performance (if any) associated with 

the decontamination of respirators. 

Table 6. Strap Integrity Evaluation - Halyard 62126

Tensile Force in Respirator Straps of Decontaminated N95s

(recorded force values are at 150% strain)

Respirator Model, Decon 

Method, # of cycles Straps from Treated Sample # Force in Top Strap (N)

Force in Bottom 

Strap (N)

Halyard 62126, Dry Heat, 3 

cycles

1 2.144 2.187

2 2.132 2.209

3 2.181 2.268

Decontaminated Strap 

Average 2.152 2.221

Control 1 2.283 2.343

Control 2 2.228 2.345

Control Strap Average 2.256 2.344

% Change

((Deconned - Controls) / 

Controls)

-4.61% -5.25%
Table 7. Filter Efficiency Evaluation – 3M 8511

Notes:

• 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 necessarily meet the requirements of STP0059, and therefore cannot be considered equivalent to N95 respirators that were tested to STP-0059. 

Respirator Model, 

Decon Method, # 

of cycles

Treated 

Sample #

Flow Rate

(Lpm)

Initial Filter 

Resistance

(mmH2O)

Initial Percent 

Leakage (%)

Maximum 

Percent 

Leakage (%)

Filter 

Efficiency 

(%)

3M 8511, Dry 

Heat, 3 cycles 

Min Fil Eff: 98.14%

Max Fil Eff: 99.12%

1

85 7.6 0.355 1.07 98.93

2

85 6.9 0.496 1.35 98.65

3

85 6.9 0.577 1.16 98.84

4

85 6.1 0.348 1.06 98.94

5

85 7.6 0.385 1.04 98.96

6

85 7.4 1.37 1.86 98.14

7

85 7.4 0.328 0.959 99.04

8

85 8.7 0.616 1.61 98.39

9

85 8.3 0.483 1.16 98.84

10 85 6.6 0.277 0.876 99.12

Control 1 85 7.4 1.03 1.27 98.73

Control 2 85 7.6 0.251 0.544 99.46

Control 3 85 7.3 0.356 0.954 99.05
Table 8. Manikin Fit Evaluation – 3M 8511

Manikin Fit Factor of Decontaminated N95s

Respirator 

Model, Decon 

Method, # of 

cycles

Treated

Sample #

mFF Normal 

Breathing 1

mFF Deep 

Breathing

mFF Normal 

Breathing 2

Overall 

Manikin Fit 

Factor

3M 8511, Dry 

Heat, 3 cycles 

Static Advanced 

Medium 

Headform 

(Hanson Robotics)

11 200+ 199 200+ 200

12 200+ 200+ 200+ 200+

13 200+ 200+ 200+ 200+

14 200+ 200+ 200+ 200+

15 200+ 88 195 140

Control 4 200+ 200+ 200+ 200+

Control 5 200+ 200+ 200+ 200+

Notes:

• Per OSHA 1910.134(f)(7), if the fit factor as determined through an OSHA-accepted quantitative fit testing protocol 

is equal to or greater than 100 for tight-fitting half facepieces, then the fit test has been passed for that respirator.

• This assessment does not include fit testing of people and only uses two exercises (normal and deep breathing) on 

a manikin headform. 

• This assessment is a laboratory evaluation using a manikin headform and varies greatly from the OSHA individual 

fit test. This headform testing only includes normal breathing and deep breathing on a stationary (non-moving) 

headform; therefore, fit results from this assessment cannot be directly translated to using the standard OSHAaccepted test. Instead, this testing provides an indication of the change in fit performance (if any) associated with 

the decontamination of respirators. 

Table 9. Strap Integrity Evaluation – 3M 8511

Tensile Force in Respirator Straps of Decontaminated N95s

(recorded force values are at 150% strain)

Respirator Model, Decon 

Method, # of cycles Straps from Treated Sample # Force in Top Strap (N)

Force in Bottom 

Strap (N)

3M 8511, Dry Heat, 3 cycles 

1 2.782 2.837

2 2.767 2.864

3 2.677 2.855

Decontaminated Strap 

Average 2.742 2.852

Control 1 3.072 2.576

Control 2 3.166 2.622

Control Strap Average 3.119 2.599

% Change

((Deconned - Controls) / 

Controls)

-12.09% 9.73%