백만거북의 공기조화

NFPA 90A에 따르면, 5.3.1.1 Approved fire dampers shall be provided where air ducts penetrate or terminate at openings in walls or partitions required to have a fire resistance rating of 2 hours or more. 2시간이나 그 이상의 fire wall 요건일 시 fire damper를 적용한다. 5.4.1.1 Fire dampers used for the protection of openings in walls, partitions, or floors with fire resistance ratings of less than 3 hours shall have a ..