About the Sirens
When the Sirens Will Sound
The sirens will only sound during a life-threatening emergency:
- An armed and dangerous person on or near campus
- A major chemical spill or hazard
- A tornado sighting in the area.
What to do
Be prepared to:
- Seek shelter inside now.
- Close windows and doors.
- Stay until further notice.
In the case of a tornado sighting in the area:
- Seek shelter inside or take cover immediately.
- Stay away from windows and doors.
- Stay until further notice.
The sirens also broadcast short pre-recorded voice messages. When the threat is over, the sirens will sound again with a different tone to announce along with the voice message: "All clear. Resume normal activities." The timing will depend on how fast emergency responders can determine that a threat is over.
What the sirens sound like
People on or near campus can expect to hear two different sounds - one to signal immediate action (such as go or remain inside) and another to indicate all clear.
Listen to an audio sample of the siren tone.
Listen to an audio sample of the siren "all clear" tone.
Siren locations
People outside on or near campus may hear the sirens at five locations: Hinton James Residence Hall off Manning Drive; the Gary R. Tomkins Chilled Water Operations Center behind the Dogwood Parking Deck; Winston Residence Hall at the corner of Raleigh Street and South Road; near Hill Hall behind University Methodist Church; and next to University buildings and support facilities near the Giles Horney Building off Martin Luther King Boulevard. If you are inside or driving in a car, don't expect to hear the sirens.
Text messages and other communication
When the sirens are activated, the University also sends a text message to the cell phone numbers registered by students, faculty and staff in the online campus directory. You may keep the number private; the University will only send a text message in emergencies or as part of a test. To register, click the bar above, "Register Your Cell Phone." For details, a text message would direct you to this page.
The University also communicates about an emergency using means including campus-wide e-mail and voice mail (for campus land lines), the Adverse Weather and Emergency Phone Line, 843-1234, for recorded information, and the University Access Channel (Chapel Hill Time Warner Cable Channel 4) along with other campus television channels.
Siren technology
The University's siren system was purchased in spring 2007 from Federal Signal Corp., following about two years of discussion and planning. The system was designed to deliver high-intensity warning signals over a large area using omni-directional speakers. Those speakers are capable of producing a high sound level while making moderate demands on the battery power source. Activation is by dedicated radio frequency and the sirens run on batteries that are continuously charged by a solar panel on each siren pole. The sirens are mounted on poles that are 40 feet from the ground. These characteristics ensure continuous operation regardless of power outages.
Distance for the siren tones
Until future tests are conducted, it is unclear how far the siren sound will carry off the main campus and near UNC facilities off Airport Drive. Federal Signal Corp.'s product specifications indicated that the signal from each of the five siren locations could be expected to carry approximately one-quarter to one-half a mile. The system is designed to be most effective for people outside. Most people inside buildings or in cars or vehicles likely will not hear the siren sound. The product specifications also indicate that the sirens would be heard at a 121 decibel level at 100 feet away. The minimum sound level is 80 decibels.
Activation
The UNC Department of Public Safety will activate the sirens based on conditions on campus or that emergency officials believe will affect campus. The Information Technology Services Control Center can also activate the siren on behalf of public safety if conditions warrant. The siren will sound only in an immediate life-threatening situation or during testing.
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