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English: Summary of Results of Building Construction Research Project of the Ministry of the Interior of the German State/Province of North Rhine-Westphalia, Dr.-Ing. Karl-Theodor Teichen, Otto-Graf Institut, Stuttgart Reports:

• F 80 448/Tei/tr, 15. March 1979,
• III.1-80706/Tei/tr, 27. June 1983
• III.1-8999/Tei/tr, 23. October 1984
• When heated, as a result of a fire, steel first expands and then collapses. The purpose of the research project was to quantify the motion and forces developed, as well as the effect upon loaded cable trays and through-penetration firestops. Mortar firestops, of sufficient thickness, can resist both the expansion and collapse of penetrating steel cable trays. Soft seals already become wobbly during the expansion phase, permitting smoke migration. During the collapse of a loaded cable tray, soft seals are completely torn open. Since the tray motion is complete within 10 minutes of exposure, it is not necessary to test a firestop’s reaction to such penetrant motion and forces during a fire test, as even the weakest firestops themselves (apart from penetrant fire behaviour) is unlikely to take significant fire damage within 10 minutes of exposure.