Why second Tag Number Extention in SEQUENCE?

Developers
1

In the ASHRAE standard 135-2020, section 20.2.16, there is an example of “Context-tagged SEQUENCE value with context tag number greater than 14”.
The Tag Number Extension appears as expected after the opening tag.
It also appears again after the closing tag.
Why the second, seemingly extra, Tag Number Extension?

2

Hi Bob

The ‘Tag Number Extension’ is to accommodate tag numbers greater than 14… and will be used for opening tags, closing tags, or ‘other’ tags… if ever these get defined.

The ‘opening’ tag and ‘closing’ tags are meant to match, i.e. have the same value, and if this value is > 14, then the extension has to invoked… in this case, for the closing too.

Hope this helps.
Ed

3

Ed,
Thanks for the reply.
I see it now. And, really, it has nothing to do with SEQUENCE; it’s an extended opening or closing tag.
Best,
Bob Wirka