BS 5839-9 Fire detection and fire alarm systems for buildings. Code of practice for the design, installation, commissioning and maintenance of emergency voice communication systems*, 2021-09-10 Update
BS 6259:2015 history
2015BS 6259:2015 Code of practice for the design, planning, installation, testing and maintenance of sound systems
1997BS 6259:1997 Code of practice for the design, planning, installation, testing and maintenance of sound systems