Bureau of Mines Information Circular/l986 

Evaluation of Safety Shutoff Valve 

System on Methane Gas Pipelines 

Under Mine Fire Conditions 

By Patrick A. Kinek, Thomas E. Marshall, 

and Gerald L. Finfinger 

UNITED STATES DEPARTMENT OF THE INTERIOR 
UNITED STATES DEPARTMENT OF THE INTERIOR 

Donald Paul Hodel, Secretary 

BUREAU OF MINES 

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

Kinek, Patrick A 

Evaluation of safety shutoff valve system on methane gas pipelines 

under mine fire conditions. 

(Information circular United States Department of the Interior, 

Bureau of Mines ; 9065) 

Bibliography: p. 7. 

Supt. of Docs. no.: I 28.27: 9065. 

1. Coalbed methane drainage. 2. Relief valves. 3. Mine fires. 

4. Coalbed methane-Pipe lines. I. Marshall, Thomas E. 11. Finfinger, Gerald L. 111. Title. IV. Series: Information circular (United 

States. Bureau of Mines) ; 9065. 
CONTENTS 

Page 

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

Introduction ................................................................... 2 

Acknowledgments ................................................................ 2 

Survey of valve manufacturers .................................................. 2 

Investigation of insulation techniques ......................................... 3 

Field tests of ball valves ..................................................... 3 

Field test of the "fire bagw ................................................... 6 

Conclusions .................................................................... 6 

References ...................................................................... 7 

ILLU IONS 

1 . Test setup for temperature durability evaluations .......................... 4 

2 . Components of brass valve .................................................. 5 

3 . Results of fire test ....................................................... 5 

4 . Closeup of a brass valve protected with a "fire bagm ....................... 6 
UNIT OF MEASURE ABBREVIATIONS USED IN THIS REPORT 

O C degree Celsius lb/ft3 pound per cubic foot 

- 

f t2 square foot 

gal gallon 

h hour 

in inch 

mi n minute 

pa pound per square inch, 

gauge 

s second 

lb pound (mass) 
EVALUATION OF SAFETY SHUTOFF VALVE SYSTEM ON METHANE GAS 

PIPELINES UNDER MINE FIRE CONDITIONS 

By Patrick A. Kinek, ' Thomas E. Marshall, and Gerald L. Finfinger 

ABSTRACT 

The purpose of this investigation was to evaluate the integrity of the 

existing shutoff valves and actuators used under high-temperature conditions in the Bureau of Mines' horizontal borehole methane drainage pipeline system and to determine the potential for improvement in the 

sys tem. 

In the field tests, both fire-safe ball valves and standard brass ball 

valves were initially subjected to a 30lnin pan fire without thermal 

protection. Neither valve could maintain line pressure beyond 11 min in 

a fire that reached temperatures between 500" and 700" C. 

Based on the test results, it was concluded that the brass ball valve 

used in the Bureau's methane drainage pipeline system can be retrofitted 

with an inexpensive "fire bag" to substantially increase its integrity 

under mine fire conditions. 

- - - - -- - - - - - -- - . 

 inin in^ engineer. 

2~ngineering technician. 

3~upervisory geologist. 

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

Methane gas is an inherent safety hazard in underground coal mining. In response to this hazard, the Bureau of 

Mines instituted a methane drainage program that has undertaken numerous improvements over the years (1-3).4 - A maj or objective of these improvements has 

been in the area of the pipeline safety 

system. This system consists of numerous 

fail-safe mechanisms that control drainage of methane gas under normal and emergency conditions. One emergency condition for which the system had not been 

tested was its behavior when subjected to 

a mine fire. Although the occurrence of 

a mine fire in the life of a mine is very 

infrequent, the effects of mine fires can 

be dramatically worsened by gas leaks 

from underground methane gas pipelines. 

The Bureau and the Mine Safety and 

Health Administration (MSHA) are concerned about this fire hazard because the 

implementation of methane drainage programs in U.S. coal mines will increase as 

gassier mines are worked. Although only 

a handful of drainage programs currently 

exist, one mine with a methane drainage 

operation has already had a fire that resulted in extensive property damage (4). 

At the request of MSHA, the ~ureau-undertook the present investigation to determine the integrity of the existing 

shutoff valves and actuators used in its 

methane drainage pipeline system when 

subjected to high temperatures such as 

those encountered in a mine fire, and to 

study the potential for improvement in 

the system. 

ACKNOWLEDGMENTS 

The cooperation and efforts of members Chemist, were instrumental in the initial 

of the Fire and Explosions Group, Bureau investigation of valve manufacturing and 

of Mines, Pittsburgh Research Center, insulation techniques. The authors would 

are greatly appreciated. In particular, also like to thank Frank Perzak for his 

Charles P. Lazzara, Supervisory Research effort in setting up and monitoring the 

Chemist, and Frank Perzak, Research fire tests at Lake Lynn Laboratories. 

SURVEY OF VALVE MANUFACTURERS 

The investigation began with an inquiry 

to determine whether any ball valve manufacturer or commercial testing company 

did any high-temperature performance design and testing on ball valves used to 

regulate gas. It was found that all 

high-temperature ball valve designs assumed that a liquid was being regulated 

(usually a petroleum product), and that 

all performance criteria (leakage rates) 

during testing of valves were based upon 

the regulation of a test liquid (water). 

It appeared that previous to the Bureau 

inquiry, no one had ever asked for a ball 

valve that would regulate gas under fire 

conditions. The basis for the industry's 

current design of fire-safe valves is 

the ability of a liquid under pressure to 

create a "bubble seal" between the ball 

and the valve body after the ~ef lon5 seat 

has burned away. Since a single gas 

phase does not have this property, existing fire-safe valves are not applicable 

to the methane drainage system. 

One manufacturer suggested the use of 

either ball valves with seats, seals, and 

body parts made out of expensive materials (i.e., graphite, stainless steel, 

etc.) or more expensive, custom-designed 

wafer valves. However, both of these 

solutions would have meant an 8- to 10- 

fold increase over the cost of the presently used valves. Accordingly, it was 

decided to see if the present ball valve 

or a more expensive, fire-safe ball valve 

could be insulated from the high temperatures resulting from a mine fire. 

4~nderlined numbers in parentheses re- 5~eference to specific products does 

fer to items in the list of references at not imply endorsement by the Bureau of 

the end of this report. Mines. 
INVESTIGATION OF INSULATION TECHNIQUES 

The insulation technique had to be (1) 

relatively inexpensive, (2) easily retrofitted, and (3) accessible when valve 

maintenance was required. Only two insulation techniques are currently being 

used in the valve and actuator industry. 

The first technique is the application of 

a thin coating of epoxy-based substance 

which during a fire swells up and chars 

(an intumescence), forming an insulation 

barrier. However, its use was not recow 

mended because of the temperatures and 

duration of the type of fire under consideration and because of expense. 

The alternative available insulation 

technique was a "fire bag" made from 

inexpensive ceramic fiber and fiberglass (~aowool, $1.70/f t2) .6 A 2-inthick, 8-lb/f t3-density material was 

used. The fiberous material is wrapped 

in an inexpensive, fire-resistant jacket 

($0.80/ft2), having a silicon rubber 

coating with a fiberglass base that provides a weather-resistant barrier. The 

total cost of materials used to construct 

the "fire bag" (1 ft2 of Kaowool, 2 ft2 

of fire-resistant jacket material, and 

two hose clamps) was approximately $6. 

This more than satisfied the first specification of low relative cost. 

The second requirement was that the insulation technique had to be easily retrofitted. The "fire bag" was measured 

and cut in the field with a tape measure 

and a simple utility knife. Approximately 10 to 15 min was required to construct it. Since all the valve-actuator 

components in a mine would be identical, 

the same pattern can be used for all the 

valves. 

The third requirement of valve accessibility was achieved as the fire-resistant 

jacket can be easily removed and replaced 

by loosening the two hose clamps. 

FIELD TESTS OF BALL VALVES 

Field tests were conducted at the 

Bureau's Lake Lynn Laboratory. A series 

of pan fire tests was performed on the 

ball valves, using kerosene as the bulk 

fuel and heptane as the starter fuel. 

The test set up consisted of two 

10-ft sections of 2-in-diam, standard, 

schedule 40 steel pipe connected to 

either end of the ball valve. The ends 

of the pipe were supported, so that the 

valve was suspended over the fire pan 

(fig. 1). One pipe section was sealed 

and pressurized with nitrogen gas. The 

nitrogen gas leakage rate was monitored 

with a pressure gauge and a flow meter. 

Three thermocouples were used to monitor 

the temperature of the fire, the outside 

valve body temperature, and the internal 

temperature of the valve body around the 

Teflon seat (fig. 2). The pressure 

gauge, flow meter, and elapsed time were 

continuously monitored with a video 

camera. Thermocouple temperatures were 

monitored using strip chart recorders and 

a microprocessor. 

6~rices for equipment are based on July 

Two ball valves were initially tested 

without an actuator or any thermal protection: a fire-safe valve and the 

brass valve currently used by the Bureau. 

The fire-safe ball valve was constructed 

of stainless steel with a Teflon seat and 

an asbestos stem seal. The Bureau valve 

has a brass body with a Teflon seat and a 

Teflon stem seal; its cost is about onefourth that of the fire-safe valve. 

For each test the valves were turned to 

the closed position so that nitrogen gas 

could fill the pipeline. A line pressure 

of 20 psig was put on the valves to simulate the low pressures observed in a 

shutoff methane drainage pipeline. Line 

pressure in a shutoff methane drainage 

pipeline can reach in situ gas pressures 

well in excess of 20 psig if allowed to 

build for 24 h or more. However, in a 

mine fire emergency, shutoff valves at 

the collars of the holes would be closed 

as soon as the fire was detected by the 

pipeline safety system or by mine personnel. Thus, during the subsequent critical minutes of the early life of the 

fire, line pressure would remain low. 

1984 data. 
FIGURE 1. - Test setup for temperature durability evaluations. 
FIGURE 2. - Components of brass valve. 

Initially, in each test, a pan fire 800 

using 15 gal of kerosene was ignited under the unprotected valve, producing temperatures of 500' to 700' C over a 30-min 

period. Both valves recorded an internal temperature of 500" to 550° C on 

the seats at 11 min (fig. 3); this is the d 

[r temperature range in which Teflon polymer 

begins decomposing extensively. Not sur- 2 400 

prisingly, for tests with both valves the u 

a flow meter began rising after approxi- 2 

mately 11 min, indicating a leak in the 

system through the valve. 

An important observation was that the o Brass valve 

inexpensive brass valve performed as well A Steel fire-safe valve 

as the more expensive fire-safe valve. 

Low line pressure and the absence of a 

liquid medium rendered the fire-safe 

valve as ineffective at high temperatures TIME, min 

as the brass valve. Given this finding, FIGURE 3. - Results of fire test. 

it was decided to use only the brass 

valve for the "fire bag" tests. 
ppp p(gg, 

4). The initial reason that PVC pipe was 20 s the PVC pipe burst, confirming its 

chosen to carry air to the actuators was effectiveness as a fire warning mechathat it is inexpensive and would break nism. As a result, air pressure on the 

easily if there were a roof fall on the actuator was released, causing the valve 

pipeline (1). Line pressure would drop to close and stopping the flow of nitroonce the Fipe was broken, causing all gen gas. After 40 min of fire exposure 

valves in the system to move to the at temperatures between 500' and 700' C, 

closed position and thus halting methane the ball valve seat and stem seal were 

gas flow. Given the fact that the PVC still intact and maintaining line prespipe being used had a low melting point, sure. The internal temperature on the 

it could also serve as a fire warning Teflon seat was only 380' C at the end of 

mechanism. The same series of shutoff the 40lnin period (fig. 3), as compared 

events would occur once the PVC pipe with 550' C after 11 min without the 

burned through as when the pipe was "fire bag" (fig. 3). 

broken by a roof fall. 

CONCLUSIONS 

The results of the investigation indicate that the ball valves now used in the 

Bureau's methane drainage pipeline system 

can be retrofitted with an inexpensive 

"fire bag" to substantially increase the 

system's short-term integrity under mine 

fire conditions. It was also established 

that the more expensive fire-safe ball 

valves are no more effective at sealing 

a low-pressure gas line under hightemperature conditions than a thermally 

unprotected brass ball valve. 

It was also found that normal 1/2-in 

PVC pipe can function not only as a roof 

fall warning system, but also, because of 

its low melting point, as a fire warning 

system for methane gas pipeline. 
REFERENCES 

1. Tongue, Dm W., Dm D. Schuster, R. 

Niedbala, and Dm Ma Bondurant. Design 

and Recommended Specifications for a Safe 

Methane Gas Piping System (contract 

50155145, Energy Applications Inc.). BuMines OFR 109-76, 1976, 97 pp.; NTIS PB 

259 340/A~. 

2. Prosser, La J., G. La Finfinger, 

and J. Cervik. Methane Drainage Study 

Using an Underground Pipeline, Marianna 

Mine 58. BuMines RI 8577, 1981, 29 pp. 

3. Irani, Ma C., Fa F. Kapsch, Pa W. 

Jeran, and S. J. Pepperney. A Fail-Safe 

Control System for a Mine Methane Pipeline. BuMines RI 8424, 1980, 11 pp. 

4. Mann, Fa C., J. V. Bowman, and 

W. W. Hulvey. Report of Investigation 

(Underground Coal Mine). Mine Fire and 

Explosion, VP-5 Mine (ID No. 44-03795), 

VP-5 Mining Company, Vansant, Buchanan 

County, Virginia. Mine Safety and Health 

Administration, Apr. 15, 1982, 14 pp.