These may form part of an automatic transfer switch system for standby power. The AGC had a power-saving mode controlled by a "standby allowed" switch. There is a risk of fire from devices in standby mode. Standby servers can be synchronous or asynchronous. There are reports of televisions, in particular, catching fire in standby mode. Every other station becomes a standby monitor. Power on from sleep/off takes longer than power up from standby. The Reducing Consumption section below provides information on reducing standby power. Alternatively, it is said to provide 300 hours of standby time. Windows 98 introduced ACPI 1.0 support which enabled "Standby" and "Hibernate" states. Electric showers may save energy compared to electric tank heaters, which lose some standby heat. The disadvantages of standby power mainly relate to the energy used. Valves on lines for standby systems penetrating containment are normally closed. Having an evacuation system on standby is expensive. They may serve on guard duty or as members of a standby quick reaction force.