About " Halon " - there isa bit of confusion about the current versions versus the "old" versions of several decades ago.
start with this link for up to date facts and data and how used, tech specs, etc
Halotron ? Halotron I
Note on Halon - Halon is an oxygen displacement suppression system and as such not ideal in areas of the aircraft where passengers or crew are present as an automatic system. The EE/AV bay is not isolated from the cockpit air - only by ducting and air pressure differences are the two areas kept separate.