Penn State is required to abide by the Cost Accounting Standards (CAS), which are established in OMB Circular A-21. A summary of Penn State's obligations under A-21 can be found in RA01 (Determining the Allowability, Allocability, and Reasonableness of Costs on Sponsored Projects).
A description of standard cost categories can be found in RA03 (Preparing Budgets).
Some costs are allowable under certain conditions but not others (e.g., clerical salaries, office supplies, photocopies, communication costs, mail services, memberships, subscriptions, general purpose equipment, and furniture). Please refer to Penn State's Cost Accounting Standards FAQ for guidance regarding when these costs can and cannot be charged. Further guidance on this issue can be found in RAG01 (Departmental Administration Costs).