Department of Health and Human Services 

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health

Self-Contained Self-Rescuer 

Long Term Field Evaluation 

Tenth Phase Results 

RI 9675 

REPORT OF INVESTIGATIONS /2008 
This page intentionally left blank 
Report of Investigations 

Self-Contained Self-Rescuer Long Term Field 

Evaluation: Tenth Phase Results 

DEPARTMENT OF HEALTH AND HUMAN SERVICES
 

Centers for Disease Control and Prevention
 

National Institute for Occupational Safety and Health
 

June 2008
 
 

 

This Document is in the public domain and may be freely copied or reprinted 

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 www.cdc.gov/niosh/eNews 

DHHS (NIOSH) Publication Number 2008-138 

June 2008 

SAFER • HEALTHIER • PEOPLE TM 

iii 
 

Contents 

Abstract........................................................................................................................................... 1 

Results and Discussion ................................................................................................................... 7 

Draeger OXY K-Plus.................................................................................................................... 19 

MSA Life-Saver 60....................................................................................................................... 20 

OCENCO EBA 6.5 ....................................................................................................................... 20 

OCENCO M-20 ............................................................................................................................ 21 

Conclusions................................................................................................................................... 22 

Acknowledgements....................................................................................................................... 23 

References..................................................................................................................................... 26 

Appendix 1.................................................................................................................................... 27 

FIGURES 

FIGURE 1. BREATHING AND METABOLIC SIMULATOR...................................................................... 3 

FIGURE 2. TREADMILL TESTING....................................................................................................... 3 

FIGURE 3. UNCASED AND CASED CSE SR-100 SELF-RESCUER........................................................ 4 

FIGURE 4. CASED AND UNCASED DRAEGER OXY K-PLUS SELF-RESCUER ...................................... 4 

FIGURE 5. CASED AND UNCASED MSA LIFE-SAVER 60 SELF-RESCUER .......................................... 4 

FIGURE 6. CASED AND UNCASED OCENCO EBA 6.5 SELF-RESCUER ................................................ 4 

FIGURE 7. PARTIALLY UNCASED AND UNCASED OCENCO M-20 SELF-RESCUER ............................. 4 

FIGURE 8. CSE SR-100 TEST RESULTS............................................................................................. 8 

FIGURE 9. DRAEGER OXY K-PLUS TEST RESULTS ........................................................................... 9 

FIGURE 10. MSA LIFE SAVER 60 TEST RESULTS ............................................................................ 10 

FIGURE 11. OCENCO EBA 6.5 TEST RESULTS ................................................................................. 11 

FIGURE 12. OCENCO M-20 TEST RESULTS...................................................................................... 12 

FIGURE 13. CSE SR-100 DECIBEL LEVEL VERSUS CO2 LEVEL ....................................................... 16 

TABLES 

TABLE 1. – SCSRS COLLECTED FOR EVALUATION ........................................................................... 3 

TABLE 2. – BMS AND HUMAN-SUBJECT METABOLIC PARAMETERS .................................................. 6 

TABLE 3. – WILCOXON RANK SUM TEST RESULTS ............................................................................ 7 

TABLE 4. – APPARATUS FAILING VISUAL INSPECTION .................................................................... 13 

TABLE 5. – SUMMARY OF COLLECTED DEVICES............................................................................. 14 

TABLE 6. –CSE SR-100 4% CO2 BREAKTHROUGH TIMES, MINUTES .............................................. 17 

iv 
 

UNIT OF MEASURE ABBREVIATIONS USED IN THIS REPORT
 

breaths/min breaths per minute 

dB decibel(s) 

kg kilogram(s) 

L liter(s) 

L/breath liter(s) per breath 

L/min liter(s) per minute 

mL/min milliliter(s) per minute 

mm H2O millimeter(s) of water (pressure) 

ppm parts per million 

v 
Abstract 

The National Personal Protective Technology Laboratory (NPPTL) of the National Institute for 

Occupational Safety and Health (NIOSH) has undertaken a collaborative study with the Mine 

Safety and Health Administration (MSHA) to determine how well self-contained self-rescuers 

(SCSRs), deployed in accordance with Federal regulations (30 CFR 75.1714), withstand the 

underground coal mining environment with regard to both physical damage and aging. 

Apparatus tested included the CSE SR-100, the Draeger OXY-K Plus, the MSA Life-Saver 60, 

and the Ocenco EBA 6.5 and M-20. 

This report presents findings regarding laboratory-tested SCSRs in the tenth phase of testing, 

from July 2004 to March 2006. The SCSRs were tested on a breathing and metabolic simulator 

and on a human subject walking on a treadmill. The tests performed in this study are not the 

tests used for certification (Title 42 of the Code of Federal Regulations, Part 84). The tests 

performed in this study continue until the apparatus are empty to enable comparison of new 

versus deployed apparatus. The method for obtaining deployed SCSRs for this evaluation was 

not a random selection from the deployed population of SCSRs. We sought older apparatus with 

visible environmental impact rather than newer apparatus, and we attempted to sample a wide 

range of deployment modes. Although the results of these tests are useful for observing 

performance of the tested SCSRs, they are not representative of all deployed SCSRs. This report 

is the last of 10 report phases begun in 1982. Previous reports describe phases 1 through 9 

[Kyriazi et al. 1986; Kyriazi and Shubilla 1992, 1994, 1996, 2000, 2002, 2004, 2006] A new 

evaluation protocol, with revised sampling strategies, test methods, and reporting procedures, is 

currently being designed to enhance the applicability of the results. 

The results of these studies suggest that the large majority of SCSRs that pass their inspection 

criteria can be relied upon to provide a safe level of life support for mine escape purposes. 

However, the storage and handling in the mining environment seems to have caused performance 

degradation in some of the apparatus. In this phase, phase 10, we found some CSE SR-100s (93 

tested) that exhibited high CO2 levels, stuck-together breathing hoses, starter-O2 failure, 

breathing hose punctures and tears, high breathing pressures, and loose particulates in the 

breathing hose. The loose particulates caused coughing in human-subject tests. One MSA LifeSaver 60 (20 tested) in this phase had a stuck-open relief valve. One Ocenco EBA 6.5 (50 

tested) had an unattached O2 supply hose. An unexplained phenomenon occurred with two 

Ocenco M-20s (20 tested): low O2 flow rates preventing their successful use. Almost all of the 

failures noted involved units that failed their inspection criteria. 

1 
 

SELF-CONTAINED SELF-RESCUER FIELD EVALUATION: TENTH-PHASE RESULTS 

Introduction 

On June 21, 1981, U.S. coal mine operators 

were required to make available to each 

underground coal miner a self-contained 

self-rescuer (SCSR). The regulations (30 

CFR 75.1714) require that each person in an 

underground coal mine wear, carry, or have 

immediate access to a device that provides 

respiratory protection with an oxygen (O2) 

source for at least 1 hour as approved 

according to the requirements found at Title 

42, Code of Federal Regulations, Part 84 (42 

CFR, Part 84). The SCSRs are sealed to 

protect them from the underground mining 

environment. The sealed case that protects 

the apparatus from environmental and 

physical damage also makes it difficult to 

inspect. No functional assessment can be 

made prior to actual use. In order to assure 

proper functioning in an emergency, NPPTL 

and MSHA are jointly conducting a longterm field evaluation (LTFE) of SCSRs 

deployed in underground coal mines. 

NPPTL and MSHA locate mines willing to 

participate in the study and trade deployed 

SCSRs for new ones; NPPTL then tests the 

deployed SCSRs. The objective of this 

program was to evaluate the in-mine 

operational durability of deployed SCSRs. 

Of utmost concern is the successful 

performance of any SCSR that passes its 

approved inspection criteria. Such apparatus 

must function successfully to enable a miner 

to escape safely during an emergency. 

Mines must conduct regular inspections of 

deployed units to ensure SCSR readiness. 

The criteria for these inspections are 

established by the manufacturers and 

include damage assessments of specific 

components by either visual inspection or 

other non-destructive testing. Among the 

visual inspection criteria are evaluating the 

use indicators or gauges provided on the 

unit, checking the service life date, and 

visually assessing physical indications of 

wear. Users must comply with the 

manufacturer’s specified conditions of use. 

SCSRs failing inspection or not complying 

with the conditions of use no longer meet 

the NIOSH/MSHA approval and should 

have been removed from service; however, 

we tested all units collected including some 

that we judged to fail inspection criteria 

since they were considered viable units by 

the users and were in service when 

collected. The test results and data analysis 

include all units tested. 

The sampling strategy used in the initial 10 

phases of the LTFE program has had some 

changes in the mines and in the numbers of 

units of each approved type sampled. At 

various phases sampling has concentrated on 

smaller mines, segregated mines by seam 

height, and the number of units collected has 

varied. The protocol followed in each of the 

earlier phases is noted in the report for that 

phase. The replacement of used units with 

new units from the same SCSR 

manufacturer likely introduced a sampling 

bias in the program, where an old or 

damaged unit from the mine could be 

replaced by a new unit from NIOSH. 

2 
 

Evaluation Procedure 

194 SCSRs were tested in the tenth phase of 

the study, from July 2004 to March 2006. 

Previous reports describe phases 1 through 9 

[Kyriazi et al. 1986; Kyriazi and Shubilla 

1992, 1994, 1996, 2000, 2002, 2004, 2006]. 

Ninety percent of the apparatus were 

targeted to be tested on a breathing and 

metabolic simulator (BMS) (Figure 1) and 

10% on human subjects on a treadmill 

(Figure 2). 

Figure 1. Breathing and Metabolic Simulator 

Figure 2. Treadmill Testing 

In this phase, however, due to 

the lack of trained subjects meeting Human 

Subject Review Board constraints, we had 

only one test subject and were able to 

conduct only seven treadmill tests. 

The SCSRs tested were manufactured by 

CSE Corp., Dragerwerk AG, Mine Safety 

Appliances Co., Inc. (MSA), and Ocenco, 

Inc. The number collected for this phase is 

indicated in Table 1. 

Table 1. – SCSRs collected for evaluation 

Apparatus Number 

Collected 

Number 

Tested 

CSE SR-100 ............... 93 93 

Draeger OXY K-Plus . 22 21 

MSA Life-Saver 60 .... 20 20 

Ocenco EBA 6.5......... 50 50 

Ocenco M-20.............. 14 14 

Total ....................... 199 198 

One OXY K-Plus test was aborted due to equipment 

malfunction. 

Sampling Strategy 

NIOSH selected the participating mines with 

regard to type of mining operation, coal bed 

height, and SCSR deployment mode in order 

to obtain a wide range of deployment 

impact. Deployment modes included 

permanent storage on the ground, on a mantrip or mining machine, daily carry-andstore, and belt-worn. At on-site visits, 

NIOSH staff, accompanied by MSHA 

inspectors, new units are exchanged for 

deployed units judged to meet the 

manufacturer’s criteria, and the mines are 

advised to remove rejected units from 

service. Mines selected for participation in 

Phase 10 are identified in the 

Acknowledgements. 

3 
Figure 3. Uncased and Cased CSE SR-100 Self-rescuer Figure 4. Cased and Uncased Draeger OXY K-Plus 

Self-rescuer 

Figure 5. Cased and Uncased MSA Life-Saver 60 Selfrescuer 

Figure 6. Cased and Uncased Ocenco EBA 6.5 Selfrescuer 

Figure 7. Partially Uncased and Uncased Ocenco M-20 

Self-rescuer 

4 
O2 Constant-Flow Rate 

 The O2 constant-flow rate is checked 

on the Ocenco EBA 6.5, a compressed-O2 

apparatus. The required flow rate is 1.5 

L/min at ambient temperature and pressure, 

dry (ATPD). 

Breathing Circuit Tightness 

All apparatus in this study are 

checked for breathing circuit leak tightness 

after opening. The leak test used was 

developed by Draeger for its BG-174 rescue 

breathing apparatus. It is performed to 

determine how well the apparatus isolates 

the user from the environment, which may 

be irrespirable in an emergency. Passing 

this test is not a requirement of the current 

regulations for these apparatus, however. 

The test permits a decay in breathing circuit 

pressure from -70 to -60 mm H2O in 1 

minute. We have determined that just 

passing the test is equivalent to a leak rate of 

approximately 1 mL/min assuming an 

internal volume for both the apparatus and 

test stand of 1 L. To give this some 

perspective, an in-leakage rate of 87 mL/min 

in a 10% CO atmosphere at a peak 

inhalation flow rate of 250 L/min (all 

volumes in this report are given at standard 

temperature (0o

 C) and pressure, dry, unless 

otherwise noted) will result in a CO inleakage concentration of 35 ppm, the 8-hour 

threshold limit value (TLV). The 250 L/min 

peak inhalation flow rate is used because 

this occurs at roughly an 80 L/min 

ventilation rate, the highest likely such rate 

that can reasonably be expected of a user. 

At such a maximal work rate, inhalation 

pressure should not exceed -300 mm H2O, 

the highest negative pressure tolerated by 

80% of test subjects in a recent study 

[Hodgson 1993]. At the leak test pressure of 

-70 mm H2O, the proportional in-leakage 

rate resulting in the 8-hour TLV would be 

20 mL/min at a peak inhalation flow rate of 

58 L/min. The Draeger leak test, therefore, 

can be considered to err on the safe side. 

Metabolic Load 

The BMS test consisted of the 

average metabolic work rate exhibited by 

the 50th-percentile miner weighing 87 kg 

while performing the 1-hour man-test 4 as 

described in 42 CFR 84. However, even 

though the average work rate is the same, 

LTFE testing is not equivalent to 

certification testing. The certification 

testing imposes high and low work rates that 

the average work rate, used in the LTFE, 

does not. Also, the stressor levels are 

continuously monitored in the LTFE, 

whereas they are sampled only between 

work activities in the certification testing. In 

addition, LTFE testing continues until the 

apparatus is empty, whereas testing during 

certification ends at a predetermined time— 

the rated duration—even though the 

capacity of the apparatus usually exceeds 

this. Therefore, an apparatus that fails 

LTFE testing would not necessarily fail 

certification, and vice versa. In the LTFE 

treadmill testing, the human subject walked 

at whatever speed and grade elicited an O2 

consumption rate of 1.35 L/min. The 

metabolic parameters for both BMS and the 

human subject are given in Table 2. 

5 
 

Table 2. – BMS and human-subject metabolic parameters 

Metabolic workload BMS Human 

Subject 

02 consumption rate L/min. 1.35 1.35 

CO2 production rate L/min. 1.15 1.15 

Ventilation rate L/minute. 30.0 29 

Tidal volume L/breath. 1.68 1.93 

Respiratory frequency breaths/min. 17.9 15 

Peak respiratory flow rate: 

 Inhalation L/minute 89 Not measured 

 Exhalation L/minute 71 Not measured 

Monitored Stressors 

In both the BMS and treadmill testing, the 

stressors monitored were inhaled levels of 

CO2 and O2, end-of-inhalation wet- and drybulb temperatures, and peak inhalation and 

exhalation breathing pressures. In the BMS 

testing, however, average inhaled values of 

gas concentration were measured as opposed 

to the minimum levels of CO2 and maximum 

levels of O2 in the treadmill testing. 

Average inhaled gas values include the 

effect of apparatus dead space, whereas 

minimum levels of CO2, for example, are 

only the lowest level of gas concentration 

during inhalation. The BMS measures 

average inhaled values by electronically 

summing all of the CO2 and O2 over each 

inhalation cycle, weighted by the

instantaneous flow rate. The BMS also 

measures minimum inhaled CO2 levels. 

Test Termination Criteria 

Tests on the BMS were terminated upon 

exhaustion of the O2 supply as indicated by 

inhalation pressures reaching -200 mm H2O; 

coinciding with an empty breathing bag. If 

average inhaled CO2 values exceed 10% or 

O2 values fall below 10%, the accuracy of 

the metabolism of the BMS becomes 

questionable. Tests were, therefore, 

terminated at those points or shortly 

thereafter. In addition, if pressures exceed 

the range of the pressure transducer 

(approximately 500 mm H2O) the accuracy 

of the gas analyzers is affected providing 

another reason for test termination. 

Treadmill tests were terminated when the O2 

supply was exhausted, if minimum inhaled 

CO2 exceeded 4%, if maximum inhaled O2 

fell below 15%, or if the test subject stopped 

because of subjectively high breathing 

pressures or temperatures. 

Wilcoxon Rank-Sum Test 

The Wilcoxon rank-sum test was performed 

for each monitored stressor to determine 

whether or not the deployed units behaved 

differently from new units. The test 

evaluates the hypothesis that the two 

samples are from populations with the same 

mean. The values from both samples are 

ranked in ascending order of magnitude. If 

the sum of the ranks of the smaller sample 

(T) (in this case, new units) falls within the 

acceptable range for the given sample sizes, 

then there is not sufficient evidence at the 

specified probability level (α = 0.05, twosided) to say that the means of the two 

samples differ. The rank-sum test does not 

rely upon the assumptions that either the 

new- or deployed-unit data are normal 

distributions or that they have identical 

variances, as does the t-test for two 

populations of independent samples. One 

limitation of the Wilcoxon rank-sum test is 

that it does not distinguish between large 

and small differences in values. The results 

of the α = 0.05, two-sided, Wilcoxon ranksum tests are presented in Table 3. The 

probability of T falling outside the given 

range is 0.05 if the populations have the 

same mean. 

6 
 

 

 

 

Table 3. – Wilcoxon rank sum test results 

Apparatus Duration 

Range T 

SR-100 101-211 138 

Average 

inhaled CO2 

Range T 

101-211 131 

Average 

inhaled O2 

Range T 

101-211 154 

Wet-bulb 

temperature 

Range T 

96-200 236 

Dry-bulb 

temperature 

Range T 

101-211 242 

Inhalation 

pressure 

Range T 

101-211 174 

Exhalation 

pressure 

Range T 

101-211 160 

OXY K-Plus 45-105 72 42-96 86 44-100 64 44-100 84 45-105 107 45-105 70 45-105 84 

Life-Saver 

60 58-124 92 45-105 64 58-124 98 54-114 79 58-124 100 58-124 123 58-124 92 

EBA 6.5 29-91 48 29-91 40 29-91 69 28-88 87 28-88 88 29-91 78 29-91 40 

M-20 17-51 52 17-51 46 17-51 34 17-51 50 17-51 54 17-51 50 17-51 26 

T = Sum of the ranks of the smaller sample (new units). 

CSE Induced Noise Test 

CSE developed a test to identify apparatus 

that have sustained internal damage, based 

on a correlation between loose particles in 

the chemical bed and CO2 breakthrough 

during the last rest interval of a 1-hour Man 

Test #4. This was established by testing SR100s on the CSE breathing simulator 

performing NIOSH variable-work rate 

certification tests. The Acoustic Solids 

Movement Detector (ASMD) analyzes the 

noise induced in the unit by shaking it in a 

controlled manner. The noise produced by 

the SCSR when shaken is used as an 

indicator of shock and vibration damage 

incurred by the chemical bed within the 

SCSR. In the field, this assessment is made 

using a hand-held instrument provided by 

CSE. A laboratory version of the ASMD 

test involves rotating the SR-100 in an 

anechoic chamber to measure the noise 

levels in decibels (dB). Various frequency 

ranges are weighted differently and result in 

a composite dB rating for each apparatus. A 

unit with a composite rating of higher than 

60 dB fails the test. NIOSH performs the 

laboratory version of the ASMD test as part 

of the LTFE inspection. Excessive noise as 

evaluated by either of the test instruments is 

an indication of chemical-bed damage that 

may adversely affect the performance of the 

SCSR. SCSRs failing the ASMD test must 

be removed from service. 

Problem Investigation Procedure 

Any problems encountered with SCSRs, 

such as hidden damage or anomalous 

performance, were reported for investigation 

under the Certified Product Investigation 

Program (CPIP). These investigations and 

their outcomes are reported in Appendix 1. 

Results and Discussion 

Experience with each model of apparatus is 

discussed separately. The minute-average 

values of the monitored stressors were 

averaged over the entire test duration and 

are presented graphically (Figures 8-12) for 

each apparatus by stressor. The values for 

new units tested on the BMS can be 

compared with those for deployed units also 

tested on the BMS. To some extent, they 

may also be compared with those for 

deployed units tested on the human subject 

on a treadmill. Because the human subject 

differs from the BMS in respiratory 

frequency, treadmill tests cannot be 

considered equivalent to the BMS tests even 

though the O2 consumption rate is the same. 

Missing data points indicate test equipment 

malfunction or inability to instrument 

apparatus. 

7 
Figure 8. CSE SR-100 test results 

8 
Figure 9. Draeger OXY K-Plus test results 

9 
 

Figure 10. MSA Life Saver 60 test results 

10 
Figure 11. Ocenco EBA 6.5 test results 

11 
 

Figure 12. Ocenco M-20 test results 

12 
Manufacturer’s Inspection Criteria 

Some apparatus were found to fail their inspection criteria either after cleaning or 

performing the induced noise test. Table 4 lists the apparatus failing inspection and the reason 

for failure. 

Table 4. – Apparatus failing visual inspection 

Model SN Reason Performance evaluation 

CSE SR-100 49791 High dB level Terminated for 10% CO2 

CSE SR-100 50243 High dB level Terminated for 10% CO2 

CSE SR-100 54559 High dB level 6.4% CO2 when empty 

CSE SR-100 55078 High dB and severely dented 

top lid Terminated for 10% CO2 

CSE SR-100 55138 High dB level 9.2% CO2 when empty 

CSE SR-100 57046 High dB level 8.5% CO2 when empty 

CSE SR-100 64967 High dB level Terminated for 10% CO2 

CSE SR-100 68802 High dB level 9.0% CO2 when empty 

CSE SR-100 76194 Top moisture indicator cracked 7.5% CO2 when empty 

CSE SR-100 76695 Top moisture indicator cracked 4.1% CO2 when empty 

CSE SR-100 81496 High dB and severely dented 

bottom lid Terminated for 10% CO2 

CSE SR-100 82355 High dB and dent in top front 

seal Terminated for 10% CO2 

CSE SR-100 90491 High dB level 5.5% CO2 when empty 

CSE SR-100 91812 Bottom moisture indicator 

cracked OK 

CSE SR-100 92620 Moisture indicator cracked OK 

CSE SR-100 92988 Bottom moisture indicator 

cracked OK 

CSE SR-100 96917 High dB level 5.9% CO2 when empty 

CSE SR-100 99361 High dB level 5.7% CO2 when empty 

Draeger OXY K-Plus ARLN 0099 Outwardly dented and loose 

belt plate OK 

Draeger OXY K-Plus ARLN 0478 Dented belt plate OK 

Draeger OXY K-Plus ARME 0159 Red tamper clip missing OK 

Ocenco EBA 6.5 91010115 Dented canister OK 

Ocenco EBA 6.5 91020198 Dirt inside case and rusty 

canister OK 

Ocenco EBA 6.5 94020147 Crack in case bottom OK 

Ocenco EBA 6.5 94080019 Dented canister OK 

Ocenco EBA 6.5 94080023 Stress cracks in case bottom; 

shifted bottle band OK 

Ocenco EBA 6.5 94080024 Shifted bottle band OK 

Ocenco EBA 6.5 94080245 Cracks in case bottom OK 

13 

The apparatus were tested for reasons of scientific interest; however, if performance 

problems were encountered, the manufacturers were not considered responsible since the 

apparatus should have been removed from service. 
 

 

 

 

 

Table 4. – Apparatus failing visual inspection 

Model SN Reason Performance evaluation 

Ocenco EBA 6.5 97080496 Misaligned gasket OK 

Ocenco EBA 6.5 97080550 Spray painted corner 

prevented inspection OK

Ocenco EBA 6.5 97080861 Crack in case bottom and 

spray-painted case
 OK

Ocenco EBA 6.5 99030820 Top strap unanchored on one 

side, then fell off OK

Ocenco EBA 6.5 99031179 Screw loose on top strap; SN 

tag fell inside case OK

Ocenco M-20 511184 Security ball missing OK 

Ocenco M-20 511196 Security ball missing OK 

Ocenco M-20 511383 Security ball missing OK 

Ocenco M-20 511415 Security ball missing Terminated for 10% CO2 

LiOH fused to regulator 

Ocenco M-20 511426 Security ball missing occluded O2 flow preventing 

use 

All 14 M-20s were beyond their service lives by 3-4 months 

Table 5. – Summary of collected Devices 

Apparatus Number 

Collected 

Number failing 

Inspection 

Number 

Tested 

Terminated before 60 

minute

Pass Fail 

inspection inspection 

CSE SR-100............... 93 18 93 1 14 

Draeger OXY K-Plus. 22 3 21 0 0 

MSA Life-Saver 60 ... 20 20 0 0 

Ocenco EBA 6.5........ 50 12 50 1 hose 

disconnected 

Ocenco M-20............. 14 all out of date 

5 visual problems 14 3

 Total....................... 199 198 

One OXY K-Plus test was aborted due to equipment malfunction. 

 Units were terminated either for low O2 or high CO2 

14 
CSE SR-100 

Eighteen of 93 (19%) units failed their 

inspection criteria (See Table 4.). Eighty-six 

of the 93 units passed the leak-tightness test. 

Of the seven new units that were leak-tested, 

6 passed the test. The leak test is not 

required by CSE, nor by NIOSH for 

certification. 

The Wilcoxon rank-sum tests for the CSE 

SR-100 showed that, as in the past three 

phases, wet- and dry-bulb temperatures were 

significantly higher in new units than in 

deployed units. Since temperature is 

indicative of chemical reaction, this 

apparently shows deployed units having 

lower levels of chemical reaction. Since no 

statistically significant difference was found 

with regard to CO2 levels, however, 

however, this is not considered an important 

finding. 

Test Termination 

Most of the tests were terminated empty, but 

seven were terminated for high CO2 levels 

and two for low O2 levels. Of the seven 

tests terminated for high CO2 levels (10% 

average inhaled CO2) six apparatus failed 

inspection criteria and should have been 

removed from service: five apparatus had 

noise-test dB levels higher than 60; one 

apparatus had a cracked moisture indicator 

lens and a large dent in the bottom lid. The 

other apparatus passed its inspection criteria 

and had a punctured breathing hose in 

addition to the high CO2 levels. The two 

apparatus with tests terminated for low O2 

levels (10% average inhaled O2) both passed 

their inspection criteria. One also had a 

punctured breathing hose and no starter O2. 

The low O2 level in this apparatus when 

terminated at 68 minutes can be attributed to 

the in-leakage of ambient air through the 

hose puncture. The other apparatus had 

insufficient starter O2 and lasted only 17 

minutes before O2 levels fell below 10%. 

No obvious reason was found for this 

behavior. 

Induced Noise Test 

The correlation coefficient between the dB 

levels obtained in the ASMD induced-noise 

test and the test-average, average inhaled 

CO2 levels (Figure 13) was 0.71 for the 

apparatus tested in this phase. 

15 
Decibel level vs Test-average, average-inhaled CO2 

Test-average, average-inhaled CO2 

6 

5.5 

5 

4.5 

4 

3.5 

3 

2.5 

2 

1.5 

1 

0.5 

0 

0 10 20 30 40 50 60 70 80 90 100 110 120 130 

Decibel level 

Figure 13. CSE SR-100 decibel level versus CO2 level 

 

High Breathing Pressures 

Twenty-nine deployed apparatus 

reached exhalation breathing pressures of 

+200 mm H2O while 23 reached inhalation 

pressures of -300 mm H2O. These pressures 

were the limits of tolerance for 80% of test 

subjects in a study contracted by the Bureau 

of Mines (Hodgson, 1993). Two new units 

also exceeded these pressures; one of which 

was terminated for high breathing pressures 

at 60 minutes. 

Premature CO2 Breakthrough 

Table 5 shows that 61 of 93 

deployed apparatus tested experienced CO2 

breakthrough before expenditure of the O2 

supply. Four in eight of the new units also 

experienced CO2 breakthrough before 

expenditure of the O2 supply. The response 

to high inhaled levels of CO2 will be 

increased ventilation rates in most users, 

approximately doubling with 4% CO2. 

Increased ventilation rates will result in 

higher breathing pressures experienced by 

the user. Breathing resistance in the SR-100 

increases rapidly toward end-of-life even in 

some new apparatus, and elevated CO2 

levels will only add to this. 

16 
Table 6. –CSE SR-100 4% CO2 breakthrough times, minutes 

Type of unit and 

test method 

CO2 

breakthrough 

time 

Test 

duration 

Maximum 

CO2 

Deployed: BMS 17 51 10.0 

18 52 10.6 

18 64 10.3 

22 50 10.6 

22 51 10.0 

22 66 10.0 

24 56 10.3 

29 76 9.0 

33 46 10.5 

39 70 9.2 

45 68 8.5 

47 73 9.0 

51 70 8.5 

52 65 10.0 

54 61 4.3 

54 64 5.5 

55 66 7.5 

57 67 6.0 

57 71 5.9 

59 69 6.7 

59 71 7.2 

60 60 4.0 

60 69 6.4 

61 63 5.1 

61 65 4.9 

61 68 6.0 

61 71 6.1 

61 73 8.5 

62 63 4.2 

63 66 4.6 

63 68 5.4 

63 73 7.5 

64 65 4.1 

64 68 4.9 

65 65 4.0 

65 65 4.2 

65 66 4.4 

66 67 4.4 

66 68 4.4 

66 68 4.6 

66 68 4.6 

66 69 4.9 

17 
 

Table 6. –CSE SR-100 4% CO2 breakthrough times, minutes 

CO2 Type of unit and Test Maximum breakthrough test method duration CO2 time 

New: BMS 

66 69 5.1 

67 67 4.0 

67 67 4.1 

67 68 5.7 

67 69 4.6 

67 69 4.8 

67 71 5.9 

68 68 4.4 

68 69 4.2 

68 69 4.4 

69 69 4.1 

69 69 4.1 

69 70 4.1 

69 70 4.2 

69 72 4.6 

70 70 4.0 

70 70 4.1 

71 72 4.1 

72 72 4.0 

49 67 8.3 

51 65 6.5 

58 66 5.6 

63 69 5.6 

Insufficient Starter Oxygen/Manual 

Start/Coughing/Hypoxia 

Fifteen units had little or no starter oxygen, 

requiring a manual start before beginning or 

shortly after beginning the test. Manual 

starts consist of exhaling into the apparatus 

until the breathing bag is full (3-6 breaths). 

Since exhaled breath contains sub-ambient 

levels of O2 (approximately 17%) the 

inhalation levels of O2 will start at that point 

and decline unless the chemical in the bed is 

very reactive. With the SR-100 inhalation 

O2 levels drop below 15% within a couple 

of minutes, bottoming out at approximately 

12% before rising. One apparatus with 

insufficient starter oxygen required four 

manual starts before the chemical reaction 

kicked in after 20 minutes, terminating for 

high CO2 at 68 minutes. 

In both of the human-subject tests, the user 

coughed to some degree when donning the 

apparatus. This was due to the inhalation of 

loose particles of corn starch which the 

manufacturer uses in the breathing hose to 

absorb saliva. The corn starch prevents the 

saliva from reaching the KO2 bed where it 

would speed up the chemical reaction and 

waste O2. After noticing the corn starch in 

the breathing hoses, it was decided to shake 

out the loose particles before testing the 

units. This resulted in dislodging small 

pieces of metal (end-cuttings from the wiremesh heat-exchanger) from the hoses, 

occurring in 21 apparatus. (The 

18
 
manufacturer has added a step during 

manufacture to blow out the loose metal 

cuttings.) Given these circumstances, the 

donning procedure was changed such that 

the human subject is now instructed to wet 

down the loose particles by exhaling 

repeatedly into the unit. Since this dilutes 

the starter O2 and is essentially a manual 

start, as the manufacturer instructs in case of 

lack of starter O2 (which happened in 16% 

of the units tested), we decided to delay 

activating the starter O2 to see if the O2 

levels fell like they did in BMS tests. They 

did. However, when O2 fell below 15%, the 

user was instructed to activate the starter O2. 

Miscellaneous 

Ten units had breathing hoses with 

severe creases with the hose walls sticking 

to each other. A modest effort to unstick the 

hose and open the flow path was attempted; 

however, in previous phases, the hoses tore 

when attempting to unstick them. 

Therefore, if the hoses were badly stuck, 

they were left stuck and partially occluded. 

The manufacturer has asserted that this 

degradation is caused by heat exposure. 

In eight units, there was evidence of dirt 

and/or past water leakage into the case. The 

color indicators were blue in all units. All 

had some degree of performance 

degradation, either high CO2, low O2, or 

high breathing pressures. 

There were four instances in which the 

breathing hose was either punctured or slit, 

apparently from being pressed against sharp 

internal components. Such holes would 

permit toxic gases and nitrogen to enter the 

breathing circuit in emergency use, 

compromising the effectiveness of the 

apparatus. In response, the manufacturer 

has changed its packing procedures. 

The lids were stuck and difficult to remove 

on four apparatus to varying degrees. 

Conclusions. 

Of 15 units terminated at less than 60 

minutes duration, only one unit passed the 

initial inspection. Almost 20% of the 

samples obtained for CSE units did not pass 

the manufacturer’s Inspection criteria. 

Draeger OXY K-Plus 

Three of 22 units (14%) failed their 

inspection criteria (See Table 4.). All the 

deployed units passed the leak-tightness test; 

three new units passed the test and one 

failed. 

The Wilcoxon rank-sum tests for the 

Draeger show that new units had 

significantly higher dry-bulb temperatures 

than deployed units. Dry-bulb temperature 

is indicative of chemical bed reaction; 

however, since there were no performance 

problems in any of the deployed units, this is 

of no concern to users. 

All units were terminated empty, the 

preferred mode for termination. 

One apparatus had a loose back plate that 

was (inexplicably) outwardly dented and 

should have been removed from service; it 

performed normally, however. 

The computer controlling the BMS froze 

twice during one test causing delays in 

testing. After a 15-minute delay the second 

time, the apparatus could not be restarted 

and the test was aborted. The apparatus had 

been performing normally before that, 

however. 

19 
 

MSA Life-Saver 60 

All 20 of the Life-Saver 60s passed their 

inspection criteria (See Table 4.). Twelve 

deployed units passed the leak-tightness test 

and eight failed; all three new units passed. 

The Wilcoxon rank-sum tests show that new 

units were not significantly different from 

deployed units in any measured parameter. 

After adding in four more baseline tests of 

new units having lower durations of the 

three previous baseline tests, the statistical 

significance of lower durations in deployed 

units found in previous phases has 

disappeared. This could be for a number of 

reasons including actual performance 

difference in the two batches of new units, 

actual performance differences in the 

samples of deployed units, or difference in 

some testing parameter between the first 

batch of new units tested in 1999 and the 

second batch tested in 2004. In any case, 

the difference is minimal. 

All units were terminated empty, the 

preferred mode for termination. 

The chlorate candle of one unit activated 

immediately upon opening the apparatus 

case. This occurred on one of three new 

units, also. Although this would not 

necessarily compromise successful use of 

the apparatus, users should be made aware 

that it could happen. In contrast, the candle 

of one unit did not fire until minute 55 of the 

test. 

One apparatus had its ID strap inside-out as 

well as its relief valve stuck open. The relief 

valve was manually closed before starting 

the test and the apparatus performed 

normally. A user would have been at risk of 

inhaling toxic gases in the ambient air 

through the relief valve if it were open to 

ambient as found. 

OCENCO EBA 6.5 

Twelve of 50 (24%) units failed their 

inspection criteria (See Table 4.). Nine 

deployed units passed the leak-tightness test 

and 41 failed; one new unit passed the test 

and three failed. The leak-tightness failures 

are observed to be due either to leakage 

between the rubber mouthpiece boot and the 

hard-plastic check-valve frame or back-flow 

through the relief valve. 

The Wilcoxon rank-sum tests show that new 

units were not significantly different from 

deployed units in any measured parameter. 

All tests were terminated empty, the 

preferred mode for termination. One caveat: 

the O2 supply hose of one unit was not 

attached to the breathing bag making the 

unit unusable unless the user were very 

familiar with the apparatus and could reattach the hose which we did for testing. It 

performed normally and terminated empty 

as well. 

The wide range of average inhaled O2 test 

averages is due to the difference in the 

apparatus O2 regulator flow rates, which 

ranged in this phase from 1.02 to 1.90 L/min 

ATPD. The O2 concentration in a breathing 

circuit will rise if the O2 supply rate is 

higher than the O2 consumption rate. 

We tested numerous apparatus with visible 

damage that should have been removed from 

20 
service (see Table 4.). Four units had cracks 

in their outer cases indicating severe impact, 

one of which also had a shifted cylinder 

band. Two units had dented canisters, one 

severely so and had LiOH in the O2 supply 

hose which undoubtedly would have caused 

coughing. Three units had displaced 

canister gaskets. One unit had a rusty 

canister. One had a case strap that was 

unattached on one side which fell off 

completely during cleaning. The EBA 6.5 is 

difficult to open without the presence of the 

case straps. Another had loose screws on 

the case straps and a serial number tag that 

had fallen inside the case and could not be 

read. Finally, the O2 supply hose of one unit 

tore when removing it to measure the O2 

flow rate. This indicates material decay, 

although it would not have prevented 

successful use of the apparatus unless 

someone pulled on it. 

OCENCO M-20 

All 14 of the apparatus had exceeded their 

service life dates by three or four months 

and had been removed from service. Since 

the M-20 is not in wide use and is difficult 

to obtain, we took the apparatus knowing 

that they were technically out of 

compliance. In addition to being beyond the 

end of their service lives, five of the units 

(36%) failed their inspection criteria for 

additional reasons (see Table 4.). Three 

deployed units passed the leak-tightness test; 

12 failed. Two new units passed the leaktightness test; one failed. 

The Wilcoxon rank-sum tests show that the 

durations of deployed units were 

significantly lower than new units and that 

the dry-bulb temperatures of deployed units 

were significantly lower than new units. 

Both differences were small, however, and 

are only of academic interest. 

One unit was terminated simultaneously 

empty and with 10% CO2 at 18 minutes. Its 

security ball was missing, however, so we 

cannot say with certainty that it had not been 

previously opened. One unit was terminated 

at four minutes due to low (10%) O2. 

Another unit was terminated at two minutes 

with insufficient bag volume. These last 

two suffered from low O2 flow as described 

below. 

Two apparatus were found with large 

quantities of LiOH powder in the breathing 

bag that apparently escaped the chemical 

bed, working its way through the bottom 

filter. This has been found in the past with 

no apparent effect on performance. In these 

cases, however, the O2 flow rate on both 

units was severely reduced resulting in low 

O2 levels and insufficient breathing bag 

volume, both preventing successful use of 

the apparatus. Dismantling of the apparatus 

revealed hardened LiOH powder adhered to 

the outside of the demand valve/O2 

regulator. It is assumed that the same 

phenomenon is found on the inside of the 

regulator, restricting O2 flow. We cannot 

explain the phenomenon of powdered LiOH 

in the breathing bag adjacent to LiOH fused 

to the surface of the anodized aluminum 

regulators. If it is caused by the passage of 

time, we would certainly urge all users to 

pay close attention to the service life date. 

Since the other 12 apparatus did not 

experience this phenomenon, however, time 

alone is unlikely the cause. Ocenco 

provided no insights or explanation other 

than to point out that the apparatus were 

beyond their service life dates. 

21 
 

 

 

Five apparatus showed evidence of mine 

dust in-leakage. In addition, the security 

ball seal of five units were missing. These 

factors did not correlate with any 

performance problem, however. 

Conclusions 

The results of this study suggest that the 

large majority of SCSRs that pass their 

inspection criteria can be relied upon to 

provide a safe level of life support for mine 

escape purposes. However, the mining 

environment seems to have caused some 

performance degradation in all the apparatus 

to some degree. The CSE SR-100 is 

exhibiting problems of CO2 exceeding 4% 

(66%), stuck-together breathing hoses 

(11%), starter-O2 failure (16%), breathing 

hose punctures and tears (4%), breathing 

pressures exceeding +200 mm H2O or -300 

mm H2O (31%), and loose particulates in the 

breathing hose (23%). The loose 

particulates caused coughing in humansubject tests. 

We found no significant problems with the 

Draeger OXY K Plus in this phase. 

The MSA Life-Saver 60 had only one 

significant problem in this phase: a stuckopen relief valve that would have 

compromised its successful use unless 

closed before using. 

In this phase, the only significant finding for 

the Ocenco EBA 6.5 was an unattached O2 

supply hose. Unless re-attached, this unit 

could not have been used for a successful 

escape. 

An unexplained phenomenon occurred with 

the Ocenco M-20: low O2 flow rates 

preventing their successful use. This 

phenomenon was seemingly caused by 

hardened deposits of LiOH on the anodized 

aluminum regulator occluding the O2 flow. 

We have seen LiOH in the breathing bag 

before; we have not seen a performance 

effect until now. Since the apparatus had 

exceeded their five-year service lives by 

three months, Ocenco could not be held 

accountable for this problem. 

22 
 

 

 

 

 

 

Acknowledgements 

Without the cooperation of the coal mines and MSHA field offices, this study would not be 

possible. The following coal mines and MSHA field offices participated in the tenth phase of this 

study: 

23 

MSHA Office: Wilkes-Barre District Office Dis 1 

 

Mine Name: 

Mailing Address: 

7 ft. Slope 

R.D. 2, Box 118 C, Hegins, PA 17938 

 

Mine Name: 

Mailing Address: 

Buck Mt. Slope, S&M Coal Co. 

1744 East Ave., Tower City PA 17980 

 

Mine Name: 

Mailing Address: 

Joliett Coal Co. #3 Vein Slope 

837 E. Grand Ave. Tower City PA 17980 

 

Mine Name: 

Mailing Address: 

Orchard Coal Co. Orchard Slope 

214 Vaux Ave Tremont PA 17981 

 

Mine Name: RS&W Coal Co. 

Mailing Address: 207 Creek Rd Klingerstown PA 17941 

 

Mine Name: 

Mailing Address: 

Little Buck Coal Co. #2 Slope 

57 Lincoln Rd. Pine Grove PA 17963 

 

Mine Name: 

Mailing Address: 

R&D Coal Co. Buck Mountain Slope
 

P.O. Box 214 Vaux Ave. Tremont PA 17981 

 

Mine Name: R&R Coal Co. 

Mailing Address: 538 W. Center St. Donaldson PA 17981
 

 

Mine Name: 

Mailing Address: 

Six M Slope #1 

482 High Rd Ashland PA 17921 

MSHA Office: New Stanton Dis. Office Dis. 2 

 

Mine Name: Enlow Fork Mine 

Mailing Address: 920 East Finley Dr., West Finley, PA 15377 

MSHA Office: Morgantown District Office Dis. 3 

 

Mine Name: 

Mailing Address: 

Double H Mining Co. Inc., Cabin Mine 

P.O. Box 338 Morgantown, WV 26501 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Mine Name: Odyssey Energy Mine #1 

Mailing Address: PO Box 431 Bruceton Mills 26525 

Mine Name: Dana Mining, Prine #1 Mine 

Mailing Address: 2141 Lazzelle Union Rd. Maidsville WV 26541 

Mine Name: Whitetail Kittanning 

Kingwood mining, Rt 1 Box 294C Newberg WV 

Mailing Address: 26410 

MSHA Office: Mt. Hope District Office Dis. 4 

Mine Name: Ambush Mining #2 

Mailing Address: H.G. Caretta WV 

Rocksprings Development Co.; Camp Creek 

Mine Name: Mine 

Mailing Address: P.O. Box 390 East Lynn WV 15512 

Mine Name: Pinnacle Mining Co., LLC; Pinnacle Mining Co 

Mailing Address: P.O. Box 330, Pinville, WV 28474 

Mine Name: US Steel Mining Co. # 50 

Mailing Address: Box 338 Pineville WV 24874Pinnacle Creek Rd. 

MSHA Office: Pikeville District Office Dis 6 

Mine Name: Excel Mining, Mine #3 

Mailing Address: 100 Fae Ramsey Lane, Pikeville KY 41501 

Mine Name: Consol Mil Creek 

Mailing Address: PO Box 10 Deane KY 41812 

Mine Name: Excel Mining, LLC Mine# 2 

Mailing Address: HC6T Box 615 Pilgrim, KY 41250 

Mine Name: Patrick Processing LLC. 

Mailing Address: 458 Village Lane, Hazard KY 41701 

MSHA Office: Barbourville District Office, Dis. 7 

Mine Name: Bledsoe Coal, Shamrock Coal 

Mailing Address: P.O. Box 349 Bledsoe Ky. 40810 

Mine Name: Bell County Coal Corp., Coal Creek 

Mailing Address: RT. 1 Box 290 Middlesboro KY 

24 
 

 

 

 

 

 

Mine Name: Consol KY, Jones Fork Rt 80 Slope 

Mailing Address: P.O. 13 Mousic KY 

Mine Name: Lake View Mine 

Mailing Address: P.O. Box 784 Hazard KY 41702 

Mine Name: Stillhouse Mining LLC, NO 1 Mine 

Mailing Address: P.O. Box 1226 Norton, VA 24273 

Mine Name: Tennco Inc. Valley Creek #2 

Mailing Address: P.O. 16 Harrsgate TN 37752 

MSHA Office: Vincennes Dis. Office Dis. 8 

Mine Name: Air Quality Mine, Black Beauty 

Phone No.: 812-743-2910 

25 
 

References 

Hodgson, JL [1993]. Physiological costs and 

consequences of mine escape and rescue. 

University Park, PA: The Pennsylvania State 

University. Contract nos. J0145038 and 

J0345327. U.S. Bureau of Mines. 

Kyriazi N [1996]. Performance comparison 

of second-generation oxygen self-rescuers. 

Pittsburgh, PA: U.S. Department of Energy, 

RI 9621. 

Kyriazi N, Shubilla JP [1992]. Selfcontained self-rescuer field evaluation: 

results from 1982-90. Pittsburgh, PA: U.S. 

Department of the Interior, Bureau of Mines, 

RI 9401. 

Kyriazi N, Shubilla JP [1994]. Selfcontained self-rescuer field evaluation: 

fourth-phase results. Pittsburgh, PA: U.S. 

Department of the Interior, Bureau of Mines, 

RI 9499. 

Kyriazi N, Shubilla JP [1996]. Selfcontained self-rescuer field evaluation: fifthphase results. Pittsburgh, PA: U.S. 

Department of Energy, RI 9635. 

Kyriazi N, Shubilla JP [2000]. Selfcontained self-rescuer field evaluation: 

sixth-phase results. Pittsburgh, PA: U.S. 

Department of Health and Human Services, 

Public Health Service, Centers for Disease 

Control and Prevention, National Institute 

for Occupational Safety and Health, DHHS 

(NIOSH) Publication No. 2000-128, IC 

9451. 

Kyriazi N, Shubilla JP [2002]. Selfcontained self-rescuer field evaluation: 

seventh-phase results. Pittsburgh, PA: U.S. 

Department of Health and Human Services, 

Public Health Service, Centers for Disease 

Control and Prevention, National Institute 

for Occupational Safety and Health, DHHS 

(NIOSH) Publication No. 2002-127, RI 

9656. 

Kyriazi N, Kovac JG, Shubilla JP, Duerr 

WH, Kravitz J [1986]. Self-contained selfrescuer field evaluation: first-year results of 

5-year study. Pittsburgh, PA: U.S. 

Department of the Interior, Bureau of Mines, 

RI 9051. 

Kyriazi N, Shubilla JP [2006]. Selfcontained self-rescuer long term field 

evaluation: combined eighth and ninth phase 

results. Pittsburgh, PA: U.S. Department of 

Health and Human Services, Public Health 

Service, Centers for Disease Control and 

Prevention, National Institute for 

Occupational Safety and Health, DHHS 

(NIOSH) Publication No. 2007-103, RI 

9671. 

26 
 

Appendix 1 

Certified Product Investigation Program (CPIP) 

Investigations Initiated from LTFE 10 

Task 

Number 

Date 

Opened 

Date 

Closed Type Description Approval Number Resolution 

CSE 

TN-13958 

TN-14363 

2/28/2005 

1/27/2006 

8/10/2005 

9/22/2006 

CSE SR - 100 

CSE SR - 100 

High CO2 unit had moisture 

active bed. 

Visible holes and 

punctures in breathing 

hose. 

TC-13F-0239 

TC-13F-0239 

Improper user handling 

of unit 

O2 exceeded 

requirements and CO2 

off gas measured was 

with acceptable ranges. 

MSA 

TN-14163 8/12/2005 3/13/2006 MSA Lifesaver 

60 

Tear in breathing bag of 

Lifesaver 60. TC-13F-0385 

Tested units met O2 

requirements and units 

in field were 

approaching end of 

service life. 

Ocenco 

TN-14261 

TN-14366 

10/24/2005 

1/30/2006 

3/24/2006 

16/6/2006 

OCN M – 20 

OCN M – 20.2 

Low O2 flow and demand 

valve malfunction. 

Presence of lithium 

hydroxide in mouthpiece of 

respirator caused user to 

cough. 

TC-13F-0269 

TC-13F-0386 

Units were three 

months beyond the end 

of carried-service 

interval. 

30 stored units were 

tested in Man Test 4 

and met performance 

requirements. 

27 
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