The IfcDuration identifies a quantity of time (or a "lenght" of an event occurring in time).

This lexical representation for IfcDataTime is PnYnMnDTnHnMnS, where nY represents the number of years, nM the number of months, nD the number of days, 'T' is the date/time separator, nH the number of hours, nM the number of minutes and nS the number of seconds. The number of seconds can include decimal digits to arbitrary precision.

EXAMPLE  P2Y10M15DT10H30M20S (duration of two years, 10 months, 15 days, 10 hours, 30 minutes and 20 seconds).

NOTE  See extended format representation of duration as defined in ISO 8601. The restrictions defined in XML Schema Part 2 apply.

HISTORY  New type in IFC4