This part applies to demands and requests for factual or expert testimony or for official records or information in legal proceedings, whether or not the United States is a party, except that it does not apply to:
(a) Demands upon or requests for an NSF employee to testify as to facts or events that are in no way related to his or her official duties or to the functions of NSF,
(b) Demands upon or requests for a former NSF employee to testify as to matters in which the former employee was not directly or materially involved while at NSF,
(c) Demands upon or requests for an NSF reviewer to testify as to matters not directly related to that individual's employment by or service to NSF, and
(d) Congressional demands and requests for testimony or records.