ISO
8601:2000(E)
20
©
ISO
2000
All
rights
reserved
5.5
Time-intervals
5.5.1
Means
of
specifying
time-intervals
A
time-interval
shall
be
expressed
in
one
of
the
following
ways:
a)
by
a
start
and
an
end;
b)
by
a
duration
not
associated
with
any
start
or
end;
c)
by
a
start
and
a
duration;
d)
by
a
duration
and
an
end.
5.5.2
Separators
and
designators
A
time
interval
is
expressed
according
to
the
following
rules:
a)
a
solidus
[/]
shall
be
used
to
separate
the
two
components
in
each
of
5.5.1
a),
c)
and
d).
b)
for
5.5.1
b),
c)
and
d)
the
designator
[P]
shall
precede,
without
spaces,
the
representation
of
the
duration.
c)
other
designators
(and
the
hyphen
when
used
to
indicate
omitted
components)
shall
be
used
as
shown
in
5.5.4
and
5.5.5
below.
NOTE
In
certain
application
areas
a
double
hyphen
is
used
as
a
separator
instead
of
a
solidus.
5.5.3
Representation
of
duration
5.5.3.1
Format
with
time-unit
designators
In
expressions
of
time-interval
or
recurring
time-interval
duration
can
be
represented
by
a
data
element
using
time
unit
designators.
The
number
of
years
shall
be
followed
by
the
designator
[Y],
the
number
of
months
by
[M],
the
number
of
weeks
by
[W],
and
the
number
of
days
by
[D].
The
part
including
time
components
shall
be
preceded
by
the
designator
[T];
the
number
of
hours
shall
be
followed
by
[H],
the
number
of
minutes
by
[M]
and
the
number
of
seconds
by
[S].
In
the
examples
[n]
represents
one
or
more
digits,
constituting
a
positive
integer
or
zero.
In
basic
and
extended
format
the
complete
representation
for
duration
shall
be
nYnMnDTnHnMnS
or
nW.
For
reduced
precision,
decimal
or
truncated
representations
of
this
format
the
following
rules
apply.
a)
If
necessary
for
a
particular
application
the
lowest
order
components
may
be
omitted
to
represent
duration
with
reduced
precision.
b)
If
necessary
for
a
particular
application
the
lowest
order
component
may
have
a
decimal
fraction.
The
decimal
fraction
shall
be
divided
from
the
integer
part
by
the
decimal
sign
specified
in
ISO
31-0:
i.e.
the
comma
[,]
or
full
stop
[.].
Of
these,
the
comma
is
the
preferred
sign.
The
decimal
fraction
shall
at
least
have
one
digit.
If
the
magnitude
of
the
number
is
less
than
unity,
the
decimal
sign
shall
be
preceded
by
a
zero
(see
ISO
31-0).
c)
If
the
number
of
years,
months,
days,
hours,
minutes
or
seconds
in
any
of
these
expressions
equals
zero,
the
number
and
the
corresponding
designator
may
be
absent;
however,
at
least
one
number
and
its
designator
shall
be
present.
Note
that
the
removal
of
leading
non-zero
components
is
not
allowed.
d)
The
designator
T
shall
be
absent
if
all
of
the
time
components
are
absent.
