OFFICIALS INVESTIGATING the collapse of the World Trade Center towers in New York in 2001 this week withheld much hoped-for fi nal conclusions about the disaster.
Instead they confirmed and added detail to previous explanations of the collapses, which occurred after hijacked Boeing 767 aircraft were fl own into the towers on 11 September 2001.
Detailed analysis by the National Institute for Science & Technology (NIST) published on Tuesday fl eshed out the preliminary collapse scenario findings released last October.
NIST's fi nal conclusions and potentially highly influential recommendations for changes to codes and building regulations were originally scheduled for release late last year. They are now not expected until this June at the earliest.
NIST declined to comment on whether this week's unprogrammed collapse scenarios publication was in response to criticisms by fire engineering experts after the launch of its preliminary fi dings (NCE 17 February).
It still blames the collapses on a combination of damage to the innovative twin towers structures and the multi-floor fires ignited by burning jet fuel.
. NIST's Dr Shyam Sunder will be one of the principal speakers at NCE's Developing the role of fi e engineering conference in London on 12 April.