How to know if a security field in an object, is an activity type or if it is a local value?

For Example, I have the security object CRM_BUHI, which has the fields:

ACTVT

HIER_TYPE

I would like to know, which table in SAP identifies if the field is an activity type (such as the ACTVT is in the list before), or if it is a local value (such as the HIER_TYPE is in the list before).

There are some other activity type fields that are not called ACTVT, so I would like to know if there is a way to validate the information type in a security Field.

Regards

Alan