Floor Opening : An opening in any floor, platform, pavement or yard, through which persons may fall; such as a hatchway, stair or ladder opening, pit or manhole
Ministry of Business, Innovation and Employment, Glossary of terms and acronyms, Wellington, New Zealand 2010. http://wwwsosh.govt.nz/resources/glossary-u.shtml, (Occupn Hlth and Sfty - Brit) {530}