—(1) Subject to paragraph (3), any document or thing produced to a board by a witness when giving his evidence shall be made an exhibit.
(2) When an original document or thing is produced to a board by a witness, the board may at the request of the witness compare a copy of it or an extract of the relevant parts thereof with the original.
(3) After the board has satisfied itself that such copy or extract is correct and the chairman has certified thereon that the board has compared it with the original and found it correct, the board may return the document or thing to the witness and attach the copy or extract to the record of proceedings as an exhibit.
(4) Every exhibit shall —
be marked with a number or letter and be signed by the chairman or have a label affixed to it bearing a number or letter and the signature of the chairman; and
be attached to or kept with the record of the proceedings unless in the opinion of the chairman it is not expedient to attach it to or keep it with the record.
(5) When an exhibit is not attached to or kept with the record of proceedings under paragraph (4)(b), the chairman shall ensure that proper steps are taken for its safe custody.