238 Chapter 9 Increasingly, expensive polluting batteries have made UPSs in larger data centers fall out of favor compared to flywheel power supplies, which is a cleaner, batteryless technology to supply interim power. Maintenance of this technology is half as costly as UPS and offers the same functionality [19]. There has to be provision for rechargeable emergency luminaries within the server room as well as all areas occupied by administrators so that entry and exit are not hampered during a power failure. Provision for fire detection and firefighting must also be made. As mentioned previously, Halon gas fire-suppression systems are appropriate for server rooms because sprinklers will inevitably damage expensive servers if the servers are still turned on during sprinkler activation. Sensors have to be placed close to the ground to detect moisture from plumbing disasters and resultant flooding. Master shutoff valve locations for water have to be marked and identified and personnel trained on performing shutoffs periodically. Complete environmental control packages with cameras geared toward detecting any type of temperature, moisture, and sound abnormality are offered by many vendors. These sensors are connected to monitoring workstations using Ethernet LAN cabling. Reporting can occur through emails if