Service Opening 1 : An opening into the interior of plant or equipment that is designed to permit access to the interior for the purpose of service or maintenance, but not of a size to permit a person to pass through it
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}