Bureau of Mines Report of Investigations/l986 

Self -Contained Self -Rescuer Field 

Evaluation: First-Year Results 

of 5-Year Study 

By N. Kyriazi, J. G. Kovac, J. Shubilla, W. Duerr, 

and J. Kravitz 

UNITED STATES DEPARTMENT OF THE INTERIOR 
Report of Investigations 9051 

Self -Contained Self -Rescuer Field 

Evaluation: First-Year Results 

of 5-Year Study 

By N. Kyriazi, J. G. Kovac, J. Shubilla, W. Duerr, 

and J. Kravitz 

UNITED STATES DEPARTMENT OF THE INTERIOR 

Donald Paul Hodel, Secretary 

BUREAU OF MINES 

Robert C. Horton, Director 
Library of Congress Cataloging in Publication Data: 

Self-contained self-rescuer field evaluation. 

(Report of investigations ; 9051) 

Bibliography. 

Supt. of Docs. no.: 1 28.23:9061. 

1. Self-contained self-rescuer (Mine rescue equipment)-Testing. I. Kyrtaxi, Nicholas. 11. 

Series: Report of investigations (United States. Bureau of Mines) ; 9061. 
CONTENTS 

Abstract ....................................................................... Introduction ................................................................... 2 

Experimental procedure ......................................................... 2 

Results and discussion ......................................................... 4 

CSE .......................................................................... 4 

Draeger ...................................................................... 4 

MSA .......................................................................... 4 

Ocenco ....................................................................... 5 

PASS ......................................................................... 5 

General results .............................................................. 6 

Conclusions .............................................................. 11 

Appendix.--Participating mines ................................................. 12 

ILLUSTRATIONS 

Breathing and metabolic simulator .......................................... 3 

CSE units. first 6 months ................. .................................. 7 

Draeger units. first 6 months ............................................ 7 

MSA units. first 6 months .................................................. 8 

Ocenco units. first 6 months ............................................... 8 

CSE units. second 6 months ................................................. 9 

Draeger units. second 6 months ............................................. 9 

MSA units. second 6 months ................................................. 10 

Ocenco units. second 6 months .............................................. 10 

PASS units. second 6 months.. .............................................. 11 

TABLES 

1 . Self-contained self-rescuers received for evaluation ....................... 2 . Weights and ages of human subjects for treadmill tests ..................... 3 . BMS breathing and metabolic parameters ..................................... 4 . Performance parameters for BMS and human-subject tests ..................... 
UNIT OF MEASURE ABBREVIATIONS USED IN THIS REPORT 

degree Celsius min minute 

hour mm millimeter 

kilogram Pet percent 

liter s second 

pound Yr year 

liter per minute 

+ 
SELF-CONTAINED SELF-RESCUER FIELD EVALUATION: 

FIRST-YEAR RESULTS OF 5-YEAR STUDY 

By N. Kyriazi,' J. G. Kova~,~ J Sh~billa, KyriaziW. ~ D~err,~ and J. Kravitz5 

ABSTRACT 

A joint effort by the Bureau of Mines and the Mine Safety and Health 

Administration (MSHA), U.S. Department of Labor, was undertaken to determine how well self-contained self-rescuers, deployed in accordance 

with Federal Regulations (30 CFK 75.1714), held up in the underground 

environment. This report presents findings regarding laboratory-tested 

breathing apparatus from the first year oE a 5-yr program as well as 

other related findings. The SCSR's were tested on human subjects and on 

a breathing and metabolic simulator. These results indicate that the 

apparatus, if well-treated, perform as expected except for mantifacturing 

defects or quality control problems, which are identified. However,when 

the apparatus are carried in and out of the mine every day and stored 

at the working section, they may suffer abuse that can be extreme. 

Physical signs of abuse, unless extremely obvious, frequently 

are not detected by the miners or the mine operators; this poses a danger to a potential user in case of emergency. Recommendations include 

improved training in inspection procedures. 

l~iornedical engineer. 

2~upervisory mechanical engineer. 

3~ngineering technician. 

4~eneral biological scientist. 

Pittsburgh Research Center, Bureau of Mines, Pittsburgh, PA. 

5~hief, Mine Emergency Operations, Mine Safety and Health Administration, U.S. Department of Labor, Pittsburgh, PA. 
INTRODUCTION 

On June 21, 1981, coal mine operators 

in the United States 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 self-rescuer that has 

an oxygen source. The Bureau of Mines is 

involved with the Mine Safety and Health 

Administration, U.S. Department of Labor, 

(MSHA) in a 5-yr in-mine evaluation of 

SCSR's now deployed in underground coal 

mines. In this study, MSHA's responsibility is to identify the participating 

mines and to procure from those mines the 

SCSR's to be tested. The Bureau replaces 

those SCSR1s with new units and tests the 

SCSR's in the laboratories of the Life 

Support Group at its Pittsburgh Research 

Center. The objective of this 5-yr 

program is to evaluate the in-mine, operational durability of SCSR's. Of utmost 

concern is the successful performance of 

any SCSR that passes its inspection criteria. Such apparatus will be relied upon 

to function successfully in an emergency. 

Apparatus that fail inspection criteria 

are expected to be removed from service. 

In a related study with MSHA, the Bureau is evaluating the performance of 

SCSR's that have been deployed by MSHA 

inspectors for 3 yr. In the first part 

of the MSHA inspectors' SCSK study, a 

sampling of four apparatus was tested in 

the Life Support laboratories. The second phase consisted of 14 apparatus that 

were worn by MSHA inspectors while they 

walked around a track as fast as conditions permitted in the experimental mine 

at the Pittsburgh Research Center. 

EXPERIMENTAL PROCEDURE 

This program involves testing approximately 100 SCSR's per year for 5 yr,,with 

the first year split up into two, 6-month 

intervals. This report describes findings through the second 6-month period. 

Testing was done using human subjects on 

a treadmill or a breathing and metabolic 

simulator (BMS). In the first 6-month 

period, 90 pct of the tests were performed using a BMS and 10 pct using human 

subjects. The apparatus collected from 

the participating mines for the second 

6-month test period were tested by human 

subjects on the treadmill because the BMS 

was unavailable. 

The SCSR's tested were manufactured by 

CSE, Draeger, MSA, Ocenco, and PASS 

(table l), and were sampled according to 

market share. The sampling was modified 

to ensure that at least 10 SCSR1s from 

each manufacturer were sampled annually. 

MSHA chose the participating mines with 

regard to type of mining machinery, seam 

height, and SCSK deployment mode in order 

to obtain a representative cross section 

of U.S. mines. The list of participating 

.mines is shown in the appendix. 

Five human subjects were used in the 

treadmill tests. Their weights and ages 

are given in table 2. 

The treadmill test consisted of the 

treadmill-equivalent of the 1-h man-test 

4 from 30 CFK 11 used by the National 

Institute for Occupational Safety and 

TABLE 1. - Self-contained self-rescuers received for evaluation 

Type of SCSR 

CSE AU-gAl.............. 

Draeger OXY-SR 60B...... 

MSA 60-min SCSR......... 

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

PASS 700................ 

Total.............. 

Estimated 

market share, 

PCt 

2 0 

2 1 

04 

54 

0 1 

100 

1st 6 months 

Rec'd 

2 1 

6 

13 

24 

0 

64 

Total 

tested 

2 5 

2 1 

14 

44 

6 

110 

Tested 

2 1 

6 

13 

18 

0 

58 

2d 6 months 

Rec'd 

5 

15 

2 

20 

10 

52 

Tested 

4 

15 

1 

2 0 

6 

46 
TABLE 2. - Weights and ages of human 

subjects for treadmill tests 

Health (NIOSH), U.S. Department of Health 

and Human Services, in its testing and 

certification program. The BMS test consisted of the average metabolic work 

rate exhibited by the 50th-percentile 

miner weighing 87 kg (191.8 lb) while 

performing the 1-h man-test 4. The metabolic parameters (at STPD) are given in 

table 3. The BMS is shown in figure 1. 

The parameters monitored were C02, 02, 

temperature, and breathing resistance in 

the BMS and the treadmill testing. In 

the BMS tests, average inhaled levels of 

Subject 

A......................... 

B*........................ 

C......................... 

D*...........*.*.......... 

E........*..*.......*.... 

TABLE 3. - BMS breathing and 

metabolic parameters 

O2 consumption rate.........L/min. . 1.35 

C02 production rate.. ....... L/min.. 1.30 

Ventilation rate........ .... ~/min.. 31.9 

Tidal volume (per breath).. ..... L.. 1.Zr 

Respiratory frequency 

breathslmin.. 26.5 

Peak flow rate .............. L/min.. 126 

gas concentration were measured; in the 

treadmill tests, only minimum values of 

C02 and maximum of 4 were able to be 

measured. Average inhaled gas levels 

take into account the effect of dead 

space in an apparatus, but minimum values 

reflect only scrubber performance and do 

not indicate the actual concentration of 

gas inhaled. The BMS measures average 

inhaled values by having separate paths 

for inhalation and exhalation in the 

internal flow loop and, therefore, 

Age, 

y r 

20 

33 

34 

26 

41 

Weight 

FIGURE 1.-Breathing and metabolic simulator. 

kg 

64 

82 

64 

93 

80 

lb 

141 

181 

141 

205 

176 
collects all of the gas that is actually 

inhaled. 

The termination criteria were a collapsed breathing bag, indicating an 

RESULTS AND 

Problems were encountered with several 

of the apparatus; consequently, some were 

not tested. Of those not tested, some 

were rejected because they failed their 

inspection criteria; others failed while 

being tested. Special-case results are 

categorized by type of apparatus. General results are discussed later. 

CSE 

One CSE SCSR was rejected owing to damage (no intact lead seal and rattling of 

internal components). When opened, it 

spilled out its components and could not 

have been used. This unit should have 

been removed from service. If there is 

internal damage to a CSE apparatus, it 

rattles when shaken, or the oxygen bottle 

gauge has shifted and cannot be easily 

read. 

When a CSE SCSR is dropped on the lower 

case latch, the case bottom is pushed 

in, which causes the breathing bag to be 

punctured. Although this can be easily 

seen, sometimes it is not recognized. 

Improved training in inspection procedures would correct this situation. 

DRAEGER 

In the second phase of the MSHA inspectors' SCSR study, in which SCSR's were 

worn by MSHA inspectors, we found two 

Draeger SCSR's with broken clamps around 

the flow-splitting valve housing, which 

is at the interface between the breathing 

hose and breathing bag. During the test, 

one of the two users experienced the separation of the breathing hose from the 

breathing bag, rendering the unit unusable. The other unit held together. 

Draeger has undertaken a recall to replace this clamp. 

One other discovery was that a significant percentage of the Draeger SCSR's 

had breathing hoses that were crimped 

where they were folded for packaging. 

exhausted oxygen source or average inhaled gas levels of >4 pct C02 or 615 pct 

02. 

DISCUSSION 

Uncrimping the hose is simple, but it 

must be mentioned in the training procedure for using the apparatus. 

There have not been any cases, other 

than the broken clamps mentioned above, 

in which a Draeger SCSR passed its inspection criteria and yet was not usable. 

Inspection of 13 Draeger SCSR's that had 

been subjected to the explosion forces in 

the McClure Mine disaster showed that 

even apparatus with significant damage 

performed normally and could have been 

used in attempting escape. 

There have been two cases in which 

Draeger SCSR's were sent in from various 

MSHA districts with reports that they 

failed to function properly. Upon testing, the apparatus were found to function 

normally. Improper use could have caused 

such problems to occur. Again, improved 

training is recommended in both inspection and donning procedures. 

MSA 

Coughing occurs during the first several breaths when using many MSA SCSR's. 

Although the specific cause is unknown, 

it is attributed to one of several 

possibilities: 

1. Talcum powder in the breathing circuit, which is used to keep the rubber 

parts from sticking together. 

2. KO2 fines that were not fully vacuumed out of the circuit at the time of 

manufacture. 

3. KO2 particles that escaped the filters of the chemical bed. 

While one case can be attributed to cause 

3 above, we believe that the majority of 

cases can probably be attributed to cause 

1 or 2, since no damage to the filters or 

beds was found in most cases. In any 

case, MSA is planning to apply warning 

stickers to its apparatus advising that, 

should coughing occur, the apparatus is 

not defective and should not be removed, 
that any dust will settle promptly, and 

that coughing will cease. 

Several early apparatus, produced for 

the Bureau and MSHA and now used by MSHA 

inspectors, had internal component structures that were dislocated from their 

shock mounts and were in danger of falling out of the lower case halves; this 

would have made them difficult to use. 

The condition was caused by one or more 

severe drops; however, no damage to the 

outer case was visible. This problem has 

been resolved in commercially available 

production models. 

OCENCO 

One Ocenco EBA 6.5 SCSK, which was used 

in the Greenwich Collieries escape, was 

found to have its check valves reversed; 

this made it very difficult to activate 

the demand valve. This was considered to 

be a quality control problem and was resolved by NIOSH and the manufacturer. 

The major problems with the Ocenco SCSR 

are its stiff demand valve and its strong 

outer case. The pressure required to 

elicit 30 Ljmin from the demand valve is 

approximately 200 mm H20, compared with 

approximately 40 mm H20 for the CSE demand valve. Upon high oxygen usage rates 

(over 1.8 L/min), the demand valve comes 

into use. Unless aware of this fact, the 

user is likely to think that the apparatus is malfunctioning. When 12 Ocenco 

EBA 6.5 SCSK's were used in Greenwich . Collieries mine fire, 5 testimonies indicated that the users felt that they 

could not get enough air, and either removed the mouthpiece or nose clip, 

breathed around the mouthpiece, or slowed 

down. Training would remedy this problem 

to some degree, but the best solution is 

to replace this demand valve with one 

that is not as stiff. 

The strength of the clear, outer case 

of the Ocenco enables it to withstand 

shock better than its internal components. In the case of the Greenwich 

Collieries mine fire, 12' of 17 units used 

for escape sustained internal damage sufficiently severe that they should have 

been removed from service. LiOH from 

the scrubber was found in the breathing 

circuits of five of these damaged units. 

In all the cases but one that we have 

seen (including Greenwich), the damage 

was evident, although it was not recognized by the miners, the mine operators, 

or the MSHA inspectors. Improved training in inspection procedures obviously is 

necessary. In one case, damage was not 

evident by inspection: the oxygen bottle 

was full, the bottle band was in place, 

and there were no cracks in the case. 

When the unit was opened, the breathing 

bag was found to contain several grams of 

LiOH; LiOH also was found in the mouthpiece and in the case. Upon close inspection, one could detect fine white 

particles of LiOH through the clear but 

scratched outer case. It is doubtful, 

however, that anyone would have noticed 

its presence unless one was looking for 

it. It is recommended that any unit with 

a severely scratched and gouged case be 

removed from service because it has 

suffered sufficient abuse to make it 

suspect. 

A lesser problem is the tight-fitting 

case halves, which are extremely difficult to open without proper training. It 

is recommended that training include special mention of the opening procedure. 

PASS 

Two of the PASS SCSK's , for reasons 

still unknown, underwent a decrease in 

oxygen concentrations to below 15 pct, 

requiring termination of the tests. When 

these units were later dismantled and 

tested, the oxygen flow rates were found 

to be in compliance with specification. 

Since other apparatus were run immediately after their failures with no problems, 

malfunctioning measurement equipment was 

ruled out. One possible explanation is 

that the constant-flow regulators were 

initially clogged with some particulate 

matter that later freed itself. Since 

these incidents could not be repeated nor 

the causes pinpointed, they were not pursued, although they were reported to 

NIOSH. 

One SCSR being tested by a human subject on a treadmill permitted high inhaled C02 concentrations during the first 

several breaths. It was found that the 

inhalation check valve was missing. This 
was considered to be a quality control 

problem and has been handled by NIOSH. 

GENERAL RESULTS 

All of the SCSR's that completed testing performed satisfactorily within a 

range of acceptable values. Performance 

parameters of individual units, divided 

by make and distinguished by test subject 

or type, are shown in figures 2 through 

10. There are two sets of graphs, representing the first and second 6-month periods of the program. The parameters 

monitored are as follows: average 

inhaled O2 concentration, average inhaled 

C02 concentration, inhaled gas temperature, and inhalation and exhalation 

breathing resistances. The parameters 

monitored were averaged over each test 

duration and are plotted on the vertical 

axis. Individual tests are plotted on 

the horizontal axis. 

Average performance parameters for each 

type of apparatus for the First and second 6-month periods are presented in 

table 4. Only BMS test results were used 

for calculation in the first 6-month 

period. 

TABLE 4. - Performance parameters for BMS and human-subject tests 

- 

BMS TESTS (1st 6 MONTHS) 

CSE................. I 19 1 2.5k0.3 1 75+ 8 1 -637 48+3 

Manufacturer 

Draeger............. 

MSA................. 

~cenco.............. I 16 .6+ .2 1 36+ 11 1 41+1 1 ---- 55t 6 1 4a3 - HUMAN-SUBJECT TESTS (2d 6 MONTHS) ---- 

CSE................. I 4 1 2.3t0.4 1 59-t 8 1 47+ 6 

Number 

of tests 

1 :::+ -6 I ::+ 4 1 Draeger ......... ....I 1 z:? 7 1 24?6 

MSA................. 2 1 

Ocenco.............. 2 0 1.2+ .4 61r 10 38+ 2 35+ 7 24+ 8 

PASS................ 1.4+ .6 79+ 6 38+ 2 43+ 7 171.4 

C02 level, 

Pet 

O2 level, 

Pet 

Temp., 

O C 

Breathing resistance, 

mm H2 0 
TEMPERATURE, BREAT

"C 

02, pet TEMPERATURE, BREATHING 

"C rnrn 
027 PCt TEMPERATURE, BREATHING 

OC 

- 

mm 

- 0 

- 0 

- 0 

- 0 

- 0 

- 0 - - 0 - - . - I I I I I.. 

TEMPEFATURE, BREATH

C 
KEY 

Subject A 

FIGURE 6.-CSE units, second 6 months. 

60 

FIGURE 7.-Draeger units, second 6 months. 

C 

W 

0 40 z 

I I I 

- - 

D 

- 

0- - w- 60 

0 

Z 

2 

zR 20- 

[L I 

E 

- -20 

I 

-40 

-s8~z~t~~r

- 0 

40-• A - e.. .a A. - KEY m 8 

Subject A - - A Subject 8 

- - 

- - W Subject C - 

0 Subject E - • . . . . 

. - A 

AA 0 

1111a-n31410t1 

W 

a 

-60 

- 60 

W 

a 

3 

s $0" 40- 

a 

5 

W 

20 

80 

C 

60 

cG 

0 

40 

3 

+ 

0 

Q 

6 2 

0 

0 

I 

OE O- 

? I I I 

E E 

II I I a -20-. 

- - 

w 

[L 

m -40 

w" 

3 

- 

I I I a @e*ee@e~~A.~.~ 

. I I I 20 

- 

+ - 0 

80 

7 0 eAAA... 

I I I 60 .IIV 

- A - 

A 

2- . A - - -. 8 - 

- - 

- Z 

""""111'11 

I 6 1 

- - 

- - 

- - 

I I I 

INDIVIDUAL UNITS INDIVIDUAL UNITS 

3 

+ 

0 

CL 

0 - 

0" U I 

0 
0 

INDIVIDUAL UNITS 

FIGURE 8.-MSA units, second 6 months. 

0. 

0.. 

. . . + 

u KEY Q Subject A 

A Subject B ON 40 . Subject C 

+Subject D 

0 

INDIVIDUAL UNITS 

FIGURE 9.-Ocenco units, second 6 months. 
I I I I I 

- 

- - 

A A - KEY 

- Subject A A 

A Subject 6 

- rn Subject C rn 

4 Subject D I I I 0 

INDIVIDUAL UNITS 

FIGURE 10.-PASS units, second 6 months. 

CONCLUSIONS 

A number of quality control problems 

were discovered in this phase of the 5-yr 

field evaluation. These problems were 

reported to NIOStl, MSIIA, and the appropriate breathing-apparatus manufacturer. 

In each case, corrective action has 

been taken to solve the quality control 

problem. 

Certain SCSR's collected during this 

period were damaged by daily, in-mine 

use and should have been removed from 

service. The damage was generally apparent and visible and should have been 

detected if the SCSR's had been properly 

inspected. 

Coughing occurred during the first several breaths when using many of the 

SCSR's. According to the manufacturers, 

the coughing is not due to inhalation of 

KO;! or LiOH; instead, it is caused by inhalation of the talcum powder used in the 

breathing hoses and bags to keep them 

from sticking together during storage. 

Training should include mentioning the 

possibility of coughing upon initial donning of an SCSK. 

In general, providing that there are no 

quality control problems, the results of 

the first-year evaluation suggest that 

SCSR's that pass their inspection criteria can be counted on to provide a safe 

level of life support capability for mine 

escape purposes. No problems have arisen 

involving subtle performance degradation 

due to the mining environment. Rather, 

there have been either quality control 

defects or blatant abuse of the apparatus 

by the users. A dangerous situation occurs if the user does not recognize damage to the apparatus. This should be 

rectified through training. 
APPENDIX.--PARTICIPATING MINES 

Mine Operator Mine 

First 6 months: 

Bethlehem Mines Corp ........................................ Consolidation Coal Co ....................................... Dominion Coal Co ............................................ Eastern Associated Coal Corp ................................ Emery Mining Corp ........................................... G . M . & W . Coal Co .......................................... Mears Enterprises. Inc ...................................... DO ........................................................ Pittston Coal Sales Co ...................................... Rochester & Pittsburgh Coal Co .............................. Southeastern Mining Co ...................................... Valley Camp Coal Co ......................................... Second 6 months: 

Bethlehem Mines Corp ........................................ Consolidation Coal Co ....................................... Diamond Shamrock Coal Co .................................... Dominion Coal Co ............................................ G . M . & W . Coal Co .......................................... Ike Coal Co.. Inc ........................................... Inland Steel Coal Co ........................................ J & R Coal Co.. Inc ......................................... Jim Walter Resources. Inc ................................... Keystone Coal Mining Corp ................................... Long Flame Coal Co.. Inc .................................... Peabody Coal Co ............................................. Pyro Mining Co .............................................. DO ........................................................ S . S . Joe Burford Coal Co ................................... U.S. Steel Mining Co., Inc .................................. Westmoreland Coal Co ......................................... 

Beth-Elkhorn No .26 

Mathies 

Young's Branch No .15 

Wharton No .4 

Deer Creek 

Grove No .1 

Penn Hills No .2 

Dixon Run No .3 

Jewel1 Ridge No . 21-A 

Emi le 

No . 8 

Valley Camp No .1 

Beth-Elkhorn No .26 

Pursglove No .15 

No . 10 

Young's Branch No .15 

Grove No .3 

No . 3 

No . 1 

No . 1 

Bessie 

Emilie No .1 

NO . 25-B 

No . 10 

Pyro No .9 

Wheatcrof t 

Coal Bank Fork No .8 

Maple Creek No .2 

Eccles No .6 

a U.S. GOVERNMENT PRINTING OFFICE: 1986-605017140. 083