What is the Db rating for the crappy ATI?

[Matt]

btw, what is ATIs website?

http://www.atisystem.com/index.htm

the siren pictured in the top right in the about us looks like a early whelen 1000 series doesent it?

[coyoteunknown]

btw, what is ATIs website?

http://www.atisystem.com/index.htm

the siren pictured in the top right in the about us looks like a early whelen 1000 series doesent it?

You mean the top/left. I'm unsure of the model name, but there was another thread regarding this siren. It's an early ATI that more/less echoed the Whelen WPS 4000 series. It's not as structurally sound as the Whelen.

Pretty sure image is courtesy of: SirenkiD



http://www.airraidsirens.com/forums/vie ... ati+whelen

[va_nuke_pe]

The picture you show is an RHPSS16 (R mean rotating, HPSS means high power speaker system). ATI developed that design about 3 years ago for a new siren system for Susquehanna Steam Electric Station EPZ. Based on the press release of last fall from PPL Corp (who owns Susquehanna), the system was not put into service. They are in the process of replacing this system now with electro-mechanical sirens from another vendor.

ATI used the same horn design for a few of the sirens around the perimeter of the Indian Point EPZ - they dropped the rotator and set two of them on a pole facing different directions and designated it as the HPSS32 bi-directional. They were located around the perimeter to reduce sound "spillover" outside the EPZ boundaries. The rest of the new sirens are the conventional HPSS32 designs.

Each of these horns uses a 400-watt speaker driver total 1600 watts (hence the 16 in the name for a four-horn configuration and the 32 in the name for an eight-horn configuration). The conventional HPSS32 can use either 400-watt drivers in each horn or can use 4 X 100-watt drivers per horn. The latter design is what is being used at Indian Point for their new siren system that they are trying to bring into service in accordance with the NRC order.

[JasonC]

ATI used the same horn design for a few of the sirens around the perimeter of the Indian Point EPZ - they dropped the rotator and set two of them on a pole facing different directions and designated it as the HPSS32 bi-directional. They were located around the perimeter to reduce sound "spillover" outside the EPZ boundaries. The rest of the new sirens are the conventional HPSS32 designs.

Yes, because we all know that nuclear fallout abruptly ends at exactly 10 miles from a nuke plant. This company is laughable. Why they would design a siren just to no have "spillover" is probably the most pointless thing I've ever heard.

[va_nuke_pe]

I've worked commercial nuclear power for more than 30 years. Just because a gasoline engine and a Molotov cocktail use the same fuel for their energy, it doesn't mean that their effects are the same when they use the same amount of fuel. Nuclear energy for commercial NPPs is far from the "fallout" generator that you are referring to - an A-Bomb.

Realistically, overall probability of a severe accident (meaning core damage occurs) PLUS an airborne releast path to get it out to the general public is less than 1 in a million per year for US designed LWRs - yes even "old" plants like Indian Point. Those big domes - the containment buildings do exactly that - contain the radiation, even if there is a massive release inside of them (TMI-2 accident March 1979 - 70% of the fuel melted, there was a hydrogen deflagration inside containment and almost nothing was released to the public).

The people at risk are those who live within 2 miles of the plant - with people out to 5 miles who are in the downwind sector also at similar risk. And by risk, I don't mean radiation sickness or mutated genes - I just mean getting measurable exposure to radiation - which isn't by itself dangerous to their health. You need a pretty hefty dose to have even a measurable effect on blood chemistry).

IPEC has an EPZ that is geo-political, that in most places goes beyond 10 miles from the station. Why annoy the neighbors with something that isn't going to hurt them in any case? People that far away have more than enough time to just listen to radio or TV or internet or IPOD or whatever and get timely notification. It is the people who are "up close and personal" who need the warning - the rest of it is really not necessary.

[acoustics101]

This is a great example of atmospheric absorption loss working against you. Lower frequencies always do better than higher frequencies both in terms of coverage radius, as well as in penetration of structures and vehicles. You just don't want to go so low that the Fletcher-Munson effect works against you.

It seems some manufactures put all their eggs in the dB at 100 feet basket. I'm guessing it's because they can make their signals smaller and cheaper by shortening the wavelength. There's a whole lot more to it than that. A nuke plant certainly needs a long range signal-not merely a noisy toy! After all what is the intended purpose; to deafen people a block away or to warn people at a useful distance that something is wrong?

Apparently 121dB and 128dB, but their dB ratings aren't clearly published. Their 1000Hz siren tone will also attenuate a lot faster than a comparable siren such as a Whelen that uses a lower tone. I don't feel like doing the math right now, but a much smaller siren from any other manufacture will have a greater cover area as well as the benefit of attracting attention better. This, combined with the numerous problems with several systems (especially the nuke plant one thats already rusting before the system is operational) is downright ridiculous.

[Melvin Potts]

Others have made comments about the ATI high pitch attenuating very rapidly.

I have to agree with them. Today I was about 100 yards away from..and within sight of..the Hillsboro High School ATI when it sounded for the 1st Saturday test.

This was on purpose. I'd hoped to get into the parking lot at shopping mall across street before the test began.

I turned into the parking lot and began moving away from the siren. Its volume level and intensity diminished very quickly, even though I wasn't more than a block..if that far..away from it.

As I've mentioned previously, there's no startup or winddown from these devices; just a steady tone which suddenly cuts off at end of test.

I think the high pitch is one of ATI's biggest problems. DB rating not withstanding, the ATI sound just doesn't carry, and it certainly isn't an impressive sound.

Never heard a Whelen in person(only on internet), but I certainly think it has a better sound than ATI.