Sintered elements for use in hazardous areas comprise a first flame path having a first length and a first pore size, and a second flame path having a second length and a second pore size. The second length is greater than the first length and the second pore size is greater than the first pore size. Sounders and loud speakers for use in hazardous areas comprise a housing having a horn and a rear enclosure, a driver assembly, and a sintered element.