Thank-you, owg.
I'm not in the chemical process industry, so these were new terms to me.
For the purpose of my own understanding, then, is it safe to conclude that 'battery limits' in the context of cost engineering are the direct and indirect costs related to the process (IE, process structural supports, piping, process controls, DCS, field instruments).
And in other words, you have your 'major equipment' and everything else to hook up the major equipment to make it work (piping, controls, instrumentation, structural, mechanical, electricals) are covered in ISBL/OSBL factors.
l.