TSH System, the Gesellschaft für Systemlösungen des Tischler- und Schreinerhandwerks, holds the DIBt approvals for fire doorset constructions and licenses them to joinery manufacturers, who then build under the approval and its surveillance regime. Published approvals include the allgemeine bauaufsichtliche Zulassung Z-6.20-2284 for T30 and T30RS doors in Sperrtürbauweise and Z-6.20-2266 for T30 and T30RS in Massivrahmenbauweise. It also licenses fire-rated glazing under a Schott approval.