Thunderbolt Siren - History

History

The Federal Thunderbolt was the siren of choice by many Civil Defense authorities and emergency management agencies from the early 1950s through the late 1970s. The main marketing point of the Thunderbolt by Federal Signal was the fact that the siren, since it uses a blower to move air through the siren rotor, maintains a high sound output at all siren pitches when the siren is in operation. Normally aspirated sirens lose sound output because of the reduced air flow through their rotors as the siren runs down during the coast down during the wail or attack signal. Since the Thunderbolt was introduced in 1952 during the beginning of Cold War tensions as primarily an attack warning siren the high volume during all phases of the attack signal was stressed in advertising the siren by Federal. The attack signal was a series of wailing tones to alert of immediate danger. One of the most distinguishing features of the Thunderbolt siren's sound is the dramatic volume in the down-pitch phase of the signal. It's usually this part of the signal that carries the farthest and is the most "attention-getting."

With the discontinuation of federal matching funds for civil defense equipment in the late 1970s-early 1980s the sales of the Thunderbolt siren declined. The Thunderbolt was a very expensive siren to purchase new. The January 1, 1979 Federal Signal Price List lists the price of a new 1000 Thunderbolt siren from $6684.25 up to $7716.75 depending on the model. In addition to that the necessary control panels to operate the siren were $837.00 for the main motor control panel and $236.00 for the additional control panel needed to operate the 1003 model of Thunderbolt.

Federal's development of new types of sirens also led to the end of the Thunderbolt. In Late 1988, Federal Signal introduced a new single-tone siren called the 2001 Series. This siren can utilize a DC (battery) backup power feature, enabling the siren to be operated during a power failure, operates on only 2 motors, and requires far less maintenance. As the Thunderbolt only operates on AC power, the introduction of the 2001 Series spelled the end of the Thunderbolt siren, and Federal Signal phased out the Thunderbolt series, as well as many other of its sirens, by 1990.