Claim: In a coal mine containing highly explosive coal dust or methane, the wire mesh of a Davy lamp must be very tightly spaced; while for flame arresters (a device that never stops fuel combustion by extinguishing the flame) used as a safety device, it must be protected from damage due to being dropped or struck by another object.
Evidence: A flame arrester (also spelled arrestor), deflagration arrester, or flame trap is a device that stops fuel combustion by extinguishing the flame.