Sentry F-2

**Company** | Sentry Siren, Inc.

 **Decibel rating (100ft)** | 117 dB @ 10ft (outdoors)
 **Type of siren** | Directional Electromechanical

The **Type/Model F-2** (Factory siren, version 2) is a small industrial electric siren produced by Sentry Siren, Inc, and formerly the Sterling Siren Fire Alarm Company. Intended as a small industrial or rural fire siren, these sirens are the main competitor to the Federal Signal Model A and Model L.

The Sentry F-2 continues to be sold by Sentry Siren, as well as its dealers such as Edwards and W.S. Darley & Co. The siren is fairly popular in the industrial market, as well as with rural fire stations who do not need a larger siren. The F-2 is very commonly used on drawbridges to alert of the bridge raising as well.

Due to being easy to run, these sirens often end up in the hands of collectors. They are also quite popular in both the industrial and fire department markets, as they're suitable for short range indoor and outdoor use. However, they are greatly outsold by Federal's offerings.

## History and Design

The Model F-2 was released sometime in the 1960s by Sterling Siren, as a refined version of their existing Type F industrial siren. The Type F had become antiquated, and other siren designs were outperforming and outselling it. As a result, Sterling would give the siren a complete redesign that would be later carried over by Sentry Siren.

The siren's specifications remained the same, using the same rotor, stator, and motor, with the only change to the stator being the addition of finger guards, which the Type F lacked. The siren uses an 8-port rotor and stator, driven by a 1/5HP high speed universal motor that operates at 14,000RPM. The siren's housing was switched from steel to stainless steel, greatly improving the siren's weather and corrosion resistance. The siren's flared intake was replaced by a smaller conical intake, and the large bell-shaped skirt was replaced with a conical skirt that sits flush with the rear motor cover, which is now larger and more rounded. The stand was redesigned as well, being flush with the bottom of the siren, wider and with 4 screw holes. Unlike the Type F, the F-2's mount was cast to the bottom of the siren and could not swivel up or down. When Sentry took over around 1973, the stand was simplified to little more than three thin sheets of metal with holes for mounting the siren to ceilings, floors or walls, which were attached to the sides of the siren and could pivot up or down. The siren is balanced well enough to stand despite the stand being very thin. The power cable now feeds through the bottom middle of the siren as well. These design changes make the F-2 much simpler and easier to manufacture. The F-2 continued to be sold by Sentry Siren, Inc after they took over operations, with minimal changes to the siren over the years such as differing tags. Unlike the Type F, the F-2 could be ordered with a 250V AC/DC motor if desired.

    Two additional models were introduced by Sentry, the F-5 and F-10. Very little is known about these sirens, as their existence can only be found through Sentry's website on the Wayback Machine. However, it is known that these sirens had universal AC/DC motors, running on either 12VDC or 120/240VAC. The F-5 was rated at 104 dB at 10ft, while the F-10 was rated at 107 dB at 10ft. Both sirens were weaker in performance than the F-2, which likely led to their demise. It is unknown whether or not any of these were sold or even produced in the first place, as there are no existing units of either of these. The sirens vanished from Sentry's site in 2001.