All evidence from the record which is to be relied upon at hearing shall be submitted to the board and to other parties with their briefs.

(1) All relevant evidence, including hearsay evidence, is admissible if, in the opinion of the presiding officer, the offered evidence is the kind of evidence upon which reasonably prudent persons are accustomed to rely in the conduct of their affairs. The presiding officer shall exclude evidence that is irrelevant, immaterial, or unduly repetitious.

(2) The board's experience, technical knowledge, competency, and specialized knowledge may be used in evaluation of evidence.

(3) If not inconsistent with subsection (1) of this section, the presiding officer may refer to, but shall not be bound by, the Washington rules of evidence.

(4) Documentary evidence submitted with briefs in the form of copies or excerpts, or by incorporation by reference, is subject to the following:

(a) That all documents so presented and examined be deemed authentic unless written objection is filed within ten days after receipt. A party will be permitted to challenge such authenticity at a later time only upon a clear showing of good cause.

(b) When only portions of a document or portions of a proceeding are to be relied upon, the offering party shall adequately identify and prepare the pertinent excerpts and shall supply copies of such excerpts for attachment as exhibits to a brief. However, the whole of the original document or recording shall be made available for examination and for use by all parties to the proceeding.

(c) That documentary evidence not submitted with the briefs and not in the record or supported by a timely filed motion to supplement the record pursuant to WAC 242-03-565 not be received in evidence in the absence of a clear showing that the offering party had good cause for the failure to produce the evidence sooner, unless it is submitted for impeachment or rebuttal purposes.