Writing Cost Benefit Analysis

Is there a general format for a cost benefit analysis? I work in the CAD department for a furniture manufacturer, and am trying to justify expenditures to expand my department. I have seen detailed templates on-line for federal agencies, but most of these deal with trying to assign dollar values to intangible social benefits. Do I really need to have a ten page preamble outlining empirical assumptions and methodologies, or is there a generally accepted report format for CBAs.