21 13 00 Fire-Suppression Sprinkler Systems 21 20 00 Fire-Extinguishing Systems 27 00 00 Communications 27 53 00 Distributed Systems 28 10 00 Electronic Access Control and Intrusion Detection 28 30 00 Electronic Detection and Alarm 27 00 05 Communications Systems 27 53 13 Clock Systems 28 13 10 Door Control Systems

21 00 00 Fire Suppression 27 00 00 Communications 27 11 00 Communications Equipment Room Fittings 27 13 00 Communications Backbone Cabling 27 15 00 Communications Horizontal Cabling 27 40 00 Audio-Video Communications 28 00 00 Electronic Safety and Security 28 10 00 Electronic Access Control and Intrusion Detection 28 13 00 Access Control 28 23 00 Closed Circuit Video System 28 31 00 Fire Alarm Systems 28 33 00 Security Management Systems and Devices 27 51 10 Sound Systems 28 10 10 Security & Intrusion Systems, CCTV 27 51 16 Public Address Systems 27 51 29 Emergency Communications Systems 27 51 30 Building Paging and Intercom System 27 52 23 Wireless Nurse Call System 27 53 13 Clock Systems 27 53 19 Distributed Antenna System 28 30 10 Fire Protection 28 31 11 Electronic Fire Alarm and Detection Systems 10 44 00 Fire Protection Specialties 21 06 25 Fire Suppression & Supervisory Systems 21 13 00 Fire-Suppression Sprinkler Systems 21 20 00 Fire-Extinguishing Systems 26 20 00 Low-Voltage Electrical Transmission 27 20 10 Communications & Data Systems 28 00 01 Access Control 28 30 00 Electronic Detection and Alarm 27 32 10 Telephone & Intercommunication Equipment 28 13 10 Door Control Systems