Outdoor Warning Sirens
Reliable Alerts to Keep Communities Safe
Outdoor warning sirens, known to most people as weather sirens or tornado sirens, are the most effective way to communicate during dangerous weather conditions and other emergencies. This is true across the United States, and especially so in tornado-prone states like Oklahoma, Kansas, Nebraska, South Dakota, and Iowa. And with the different financing options available, including U.S. Homeland Security Grants and U.S.D.A. grants, the time to get a tornado siren for your community has never been better. Click here to see the U.S. regions with the highest risk for tornado activity.
Why Outdoor Warning Sirens?
These days, with municipal budgets tightening, we often hear the question, “Don’t people track storms on television or their cell phones? Do we really need a weather siren too?” We’ve been in the siren business for over a century (check out our History here) and while things have certainly changed, the need for reliable outdoor warning sirens has only grown. In the event of an emergency, severe storm, or tornado, sirens provide alerts even when electricity goes out and cellular towers go out of service – click here to read about cases like this. In many situations, the weather siren works with the television or text alerts to reinforce the need to take precautions. In the event of a serious event with electrical and cellular disruption, your tornado siren may be the only alert keeping your community safe.
Why Omni-directional Sirens?
When you’re researching what kind of siren system best suits your community’s needs, you will certainly hear a lot of technical jargon that, at first glance, may not seem like it makes much of a difference. We’re here to tell you it does and why.
We’ll start with Omni-directional sirens versus rotational sirens. Every Sentry outdoor warning siren is Omni-directional. That means that the siren’s full decibel output is directed 360 degrees around the siren, all the time. There are no gaps in coverage, no blank spots – just full decibel output, all the time. To visualize this superior, time-tested design, our engineers have even put together an animated demonstration of this phenomenon – see the image below.
A rotating siren does just what the name implies – it rotates on an axis, directing sound away from the source. Siren coverage areas are generally calculated by specifying a radius around a center point, where the siren is located. The problem with rotational sirens is that only one section of the circle around the siren is being covered by the siren’s full-decibel output at any given time. Sound waves are very directional, so the only area that will be covered by the siren is the area directly in front of the siren when it is activated. Again, to see the difference in coverage, see the animated image below. The choice is clear.
Let’s remember FEMA’s stance on the issue:
- “..present a distinct advantage.. over rotational devices,” according to FEMA’s warning system guide. It says “a rotational device will have an overall lower dB level when assessed across a given time period than an Omni-directional device operating at the same frequency. Additionally, because sound has a reinforcing effect, Omni-directional devices can act as sound “boosters” with adjacent audible devices.” (4.4.5 FEMA OWS Technical Bulletin 2.0)
- Further, the guide states: “Omni-directional sirens provide a greater area of coverage than do rotating or directional devices. They provide a more constant signal that improves public alerting, therefore Omni-directional sirens can be used to good advantage in areas with high population density and in areas with high ambient noise levels.” (4.4.5 FEMA OWS Technical Bulletin 2.0)
Why Do We Need Continuous Duty Motors?
Many of our competitors offer sirens powered by motors with very finite duty-ratings. If you didn’t happen to know, a motor’s duty rating is the length of time the motor can run at full speed before it overheats and destroys itself. In order to avoid ruining the motor, the motor must be allowed to cool down in between each usage. So, for a siren motor with a duty-rating of 10 minutes, that means that the siren can only be in operation for 10 minutes before it has to be completely shut off to cool down – this cooling period typically lasts around 30 minutes – before it can be used again. Unfortunately, severe weather doesn’t really pay much attention to a siren motor’s duty rating. In the case of a severe storm like a tornado, many sirens systems will be activated, four, five, or six times in a short period of time while tornado warnings are in effect. Having a siren motor with a limited duty-rating could mean that the siren is inoperable once, twice, even three times, right when the community needs it.
This is not the case with Sentry Sirens. We use only continuous-duty siren motors. Sentry’s siren motors are rated for approximately 20,000 hours of continuous, uninterrupted service. This means that there is no cooling period, no shut-down time. The siren works when you need it to work, period. That is the difference of a Sentry.
Which Outdoor Warning Siren Meets Our Needs?
At Sentry Siren we know that each community’s needs and budget are different, and our team of experienced and highly trained technicians offer siren system design to ensure that you get exactly the right product. We offer a wide range of products and can help you design a system that reaches everyone in your community and stays within your budget.
How Will We Install An Outdoor Warning Siren?
Many municipalities know they need a tornado siren or comprehensive outdoor warning system, but find the prospect of digging holes and installing unfamiliar equipment daunting. We offer custom installation for any of our outdoor warning sirens, and we warranty and guarantee the work our licensed and certified crews do.
- Siren 3V8-H
- Siren 3V8
- Siren 7V8-B
- Siren 7V8
- Siren 10V
- Siren 10V2T
- Siren 152T
- Siren 16V1T-B
- Siren 20V2T
- Siren 40V2T