Evaluation of Decontaminated N95 Respirators 

Date Tested: 4/30/2020 – 5/1/2020 

Respirator Model: Halyard Fluidshield 46727 Reg 

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

Integrity with Tensile Testing 

Decontamination Method: Sterrad NX100 Hydrogen Peroxide Vapor/Low Temp plasma; Tyvek Pouch with Sterrad Chemical 

Indicator (Advanced Sterilization Products, Part #12340)

Decontamination Cycles: 2 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). 

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

evaluation. This included 15 respirators that were subjected to 2 cycles of the hydrogen peroxide vapor/low 

temp plasma decontamination process and an additional 5 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: The minimum and maximum filter efficiencies were 98.29% and 98.82%, 

respectively. All respirators measured more than 95%. See Table 1. 

Manikin Fit Factor Results: The manikin fit factor showed passing fit factors (greater than 100) for four out of 

five treated respirators evaluated. Small changes in fit factors may be attributed to manufacturing variation, 

variation in donning on the manikin, the decontamination method, or a combination of these factors. Larger 

variations may require further research to understand the cause. See Table 2. 

Strap Integrity Results: No visual degradation of the straps was observed. Decreases in strap forces were found 

for the top (5.61%) and bottom (5.58%) straps. While the exact correlation between the force exerted by straps 

and fit is not well understood, higher force values may be associated with a tighter fit of the respirator to the 

face. Significant reductions in this force would be associated with a loss of elasticity of the straps, thereby 

reducing their ability to create a tight fit. See Table 3. 

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 – Halyard Fluidshield 46727 Reg – VHP/low temp plasma, 2 cycles

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 Fluidshield 

46727 Reg, VHP/low 

temp plasma, 2 cycles

Min Fil Eff: 98.29%

Max Fil Eff: 98.82%

1

85 11.0 1.17 1.18 98.82

2

85 11.4 1.45 1.45 98.55

3

85 10.7 1.29 1.30 98.70

4

85 10.6 1.47 1.47 98.53

5

85 11.0 1.65 1.70 98.30

6

85 10.8 1.54 1.56 98.44

7

85 11.0 1.45 1.45 98.55

8

85 10.8 1.56 1.56 98.44

9

85 11.5 1.35 1.35 98.65

10 85 11.6 1.71 1.71 98.29

Control 1 85 12.7 0.729 0.729 99.27

Control 2 85 11.4 1.32 1.32 98.68

Control 3 85 10.6 1.08 1.44 98.56
Table 2. Manikin Fit Evaluation - Halyard Fluidshield 46727 Reg – VHP/low temp plasma, 2 cycles

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 

Fluidshield 46727 

Reg, VHP/low 

temp plasma, 2 

cycles

Static Advanced 

Large Headform 

(Lunar Studio)

11 200+ 200+ 200+ 200+

12 200+ 200+ 200+ 200+

13 200+ 200+ 184 195

14 200+ 142 200+ 176

15 127 79 90 95

Control 4 200+ 200+ 192 198

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.

• BOLD overall manikin fit factors < 100

Table 3. Strap Integrity Evaluation - Halyard Fluidshield 46727 Reg – VHP/low temp plasma, 2 cycles

Tensile Force in Respirator Straps of Decontaminated N95s

(recorded force values are at 150% strain)

Straps from Treated Sample # Force in Top Strap (N) Force in Bottom Strap (N)

1 2.468 2.360

2 2.339 2.317

3 2.425 2.464

Decontaminated Strap Average 2.411 2.380

Control 1 2.515 2.530

Control 2 2.592 2.513

Control Strap Average 2.554 2.522

% Change

((Deconned - Controls) / Controls) -5.61% -5.58%