Mayflower, AR (KFSM) Wind engineers at Texas Tech have completed an initial forensic exam of the failed safe room from the April 27th, 2014 Mayflower, AR Tornado which caused 1 fatality. The door was taken apart and all components and their manufactures were identified.
The conclusion reached in the report states the door assembly was sub-standard and did not match the tested FEMA P-320 recommendations. Specifically, the door (although steel) was not designed to be used as part of a tornado safe room. The door contained no steel stiffeners in it’s core but instead contained honeycomb cardboard. Additionally, the frame of the door was not anchored to the wall and was instead filled with grout. They stated the hardware and deadbolts were ‘residential grade’ and were subject to shearing forces upon impact.
The experts said the flying debris that damaged the door was likely not something large. The assumption is that it was a OSB sheet such as the one pictured below.
The researchers said: ” Door failure resulted from the improper usage of a door, frame, and hardware not intended for tornado safe rooms. Just because it was a steel door did not qualify it to be a tornado safe room door.”
The initial report was prepared by Larry Tanner and Ernst Kiesling who are planning on 2 additional phases to this research project including a peer-reviewed research paper with revised guidelines and recommendations from additional wind tests on similar doors using high-speed photography. The report did not specify the installer or if similar shelters had been constructed in Arkansas. You can read the report in it’s entirety here: Shelter Door Failure Analysis