what is the name of the clear plastic sheeting
that can be affixed to internal windows to give
added glazing protection?

Michael H., January 2013

Secondary Double Glazing is possibly what you mean.

I have it in one room - sliding glass panels in lightweight aluminium frames. I would guess that the same can be had with plastic panes - not sure.

Several years ago much was made in the UK press of a scientist at Harwell who used clingfilm as a cheap double glazing alternative.

https://www.youtube.com/watch?v=_IYuEI6mLRw

http://www.thisismoney.co.uk/money/experts/article-2081663/Does-double-glazing-cling-film-windows-stop-heat-loss.html

Peccavi, January 2013