SC B4 is currently composed of 4 Advisory Groups (AGs) and 16 Working Groups (WGs). Additionally, B4 participates in 5 further Joint Working Groups. Note that the Terms of Reference of each AG, WG or JWG can be found by clicking on the number of the group. AGs have been set up to advice the Chairman on specific issues. They do not have a fixed duration for their existence. WGs carry out the main work within the Study Committee, in accordance with the Term of Reference, which will have been approved by the Technical Committee. The WG is led by a convenor, and the members of the WG are drawn from the Regular Members of B4 and experts. Occasionally, joint working groups (JWG) are created with other Study Committees, to carry out a task which requires expertise which partly exist within the scope of B4 and partly within the scope of another Study Committee.