(ASME) The structure that encloses and clamps the rupture disk in position. Rupture disks may be designed in several configurations, such as plain flat, prebulged, or reverse buckling, and may be made of either ductile or brittle material. Rupture disk material is not required to conform to an ASME specification. The material of the rupture disk holder shall be listed in Section II and Section VIII, Division 2 (AR-131) of the ASME Boiler and Pressure Vessel Code.