For each BREF, the European IPPC Bureau sets up a Technical Working Group (TWG) to carry out the exchange of information on BAT. A TWG usually consists of between 100 to 200 experts.
The European IPPC Bureau organises the work of the TWG, fosters the exchange of information, makes a scientific and technical analysis of the vast amount of information exchanged, proposes compromise solutions on issues when views of TWG members differ, and writes the BREF. The European IPPC Bureau acts as a neutral, technically competent and permanent body to all TWGs.
The procedure used to elaborate or review a BREF includes a few plenary meetings of the TWG, sub-group meetings, visits to installations, and submission of draft BREFs for comments.
Practical arrangements for the exchange of information are laid down in the specific guidance documents referred to in Article 13 (3)(c) and (d) of the Industrial Emissions Directive (IED), 2010/75/EU.
These documents aim in particular at guiding the European IPPC Bureau and members of the technical working groups (TWGs) in the drawing up and reviewing the whole series of BREFs.
Once it has been finalised, each BREF is presented by the European IPPC Bureau to DG Environment at the forum (Information Exchange Forum, IEF) established by the IED (ex IPPC Directive) .