Division 3.3 Heat exchangers Original text. Later amendments are not shown. 3.3.1Division 3.3.1 3.3.2Division 3.3.2 3.3.3Division 3.3.3 3.3.4Provisions regarding the approval of hydrogen valves ← Division 3.2.1.4 Division 3.3 Division 3.3.1 →