Probability of spark ignition in intrinsically safe circuits

Book · Fri Jan 01 04:00:00 EST 1988

OSTI ID:6959113

Cawley, J C

This report presents results of recent Bureau of Mines research to establish the probability of spark ignition as a function of current (or voltage, for capacitor circuits) for resistive, inductive, and capacitive circuits in 8.3-pct methane-air atmospheres. The data presented quantify the explosion hazard created when low-power electronic devices catastrophically fail in an explosive mine atmosphere. Previous literature dealt with levels of probability between 10{sup {minus} 3} and 10{sup {minus} 4}. This report extends the probability data to levels as low as 10{sup {minus} 7}. This study has verified that when the probability of ignition, p{sub i} is plotted on a log-log coordinate system versus the current (or voltage), a continuous, straight-line relationship is formed. An interesting result that can be statistically hypothesized is that at some low level of igniting current the ignition process ceases altogether.

• OSTI ID: 6959113
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
012033 -- Coal
Lignite
& Peat-- Underground Mining-- Mine Environment-- (1987-)
016000* -- Coal
Lignite
& Peat-- Health & Safety
ALKANES
ELECTRIC DISCHARGES
ELECTRIC SPARKS
ELECTRONIC CIRCUITS
HAZARDS
HYDROCARBONS
IGNITION
METHANE
MINING
OCCUPATIONAL SAFETY
ORGANIC COMPOUNDS
SAFETY
UNDERGROUND MINING