A flameproof housing (202) includes a display aperture (212), a shoulder (207) adjacent to the display aperture (212), a transparent panel (230) including an outer face (231) and a perimeter (232), and a fastener element (236) configured to hold the transparent panel (230) against the shoulder (207). A perimeter interface region (264) between the perimeter (232) of the transparent panel (230) and the interior surface (203) of the flameproof housing (202) creates a perimeter gap that does not exceed a predetermined flameproof gap limit and a face interface region (260) between the outer face (231) of the transparent panel (230) and the shoulder (207) creates a face gap that does not exceed the predetermined flameproof gap limit.