Oakland Fire Department: Outdoor Warning Sirens FAQ

What do the sirens look like?
What kind of sound will the siren make?
What does it mean when I hear a siren?
If I'm inside my home or office, will I hear the siren?
If I'm driving, will I hear the siren?
How will I be affected if I'm standing near the siren when it is activated?
What is the sound range of the siren?
The siren points away from my area, so how will I hear it?
How does the siren system operate?
How long will it take to install the siren?
Why was this site chosen for a siren?
Who authorized or approved this particular site?
When will the rest of the sirens be installed and where?

What do the sirens look like? (top)
The siren resembles a large bell turned on its side, sitting on a small platform.
For a description see the Federal Warning Systems website.
What kind of sound will the siren make? (top)
The sound is a steady signal. Initially, it will sound like a fire truck siren, then increase in pitch and sound a constant tone signal until the alert is complete. At the end of the 3-minute alert, the siren will shut down. During the shutdown, the siren will decrease in pitch for 20-30 seconds until it turns off. In addition, there will be an "All Clear" signal indicating that the emergency is over. The "All Clear" signal is a 1-minute wavering tone, followed by a 30-second steady 'test signal'.
What does it mean when I hear a siren? (top)
A siren sound alert means that there is an emergency in your area, potentially dangerous condition or impending threat. You should turn the radio and tune into local emergency broadcast news stations KGO (810AM), KCBS (740AM), KNBR (680AM) or the City's 530AM radio and listen for instructions. Emergencies would be a wildfire, flooding, a large building fire with toxic smoke or a chemical release into the air.
If I'm inside my home or office, will I hear the siren? (top)
The siren system is designed to alert people outdoors. Some people will be able to hear the siren indoors, depending on how close the indoor location is to the nearest siren and depending on the volume of other noise indoors, such as a TV, radio, or machinery.
If I'm driving, will I hear the siren? (top)
It depends on how close you are to the siren when it goes off and whether your car windows are open or closed. You may or may not hear the siren.
How will I be affected if I'm standing near the siren when it is activated? (top)
The sirens are very loud and no one should stay close to them during an activation. The sirens are installed in accordance with FEMA guidelines, which means that they are mounted approximately 45 feet above ground, so that if you are standing underneath it, no harmful permanent hearing damage will occur. Also, the siren rotates during activation, so that the loud sound level will occur in a single direction for a short period of time.
What is the sound range of the siren? (top)
The siren sound range is approximately 1 mile. The sound range will vary based on location and conditions, such as hill terrain, a tall building or high outdoor noise levels. In the hill area, sirens are placed so that the overlap each other, so as to provide better sound coverage.
The siren points away from my area, so how will I hear it? (top)
The sirens are a directional design to project a more powerful sound alert in a specific direction. During activation the sirens will rotate 360 degrees to provide sound coverage in all directions. The siren will rotate 4 times per minute.
How does the siren system operate? (top)
The sirens will be activated from the City's Fire Dispatch Communications Center. The siren system will be radio-operated using the City's two-way radio system. It is computer-controlled using digital technology with a manual system back-up. During an emergency, the siren(s) can be activated to turn one siren on, several sirens in a particular area or complete system activation. A back-up system operation will reside at the City's Police Dispatch Communications Center. The sirens are monitored on a daily basis and problems are reported to the dispatch center. For security, the sirens have vandal/tamper alarms on them. If someone attempts to damage or break into the unit, the intrusion will be reported and police will be dispatched to that siren location.
How long will it take to install the siren? (top)
The first nine sirens will be installed over a 30-day period. Installation of a single siren takes one or two days.
Why was this site chosen for a siren? (top)
The city was divided into two sections; highest risk hazardous materials areas and highest fire hazard areas. Within these areas, suitable city-owned or controlled properties with a minimum impact to the surrounding areas were selected. Most siren sites are located in city parks, fire stations, corporation yards, schools, utility areas and open spaces.
Who authorized or approved this particular site? (top)
The Fire Department Office of Emergency Services and the vendor recommended these sites which were approved by the City Council.
When will the rest of the sirens be installed and where? (top)
The remainder of the sirens (18) will be installed when funds are authorized by City Council. The sirens will be placed in the highest risk hazardous materials zones primarily along the 880 corridor and the highest risk fire hazard areas in the hills, between February 2001 at the earliest and May 2002 at the latest.