Federal Signal Model series

* W.S. Darley & Co.
 Succeeded by | * Federal Signal STH-10
* Federal Signal STL-10

The **Federal Signal Model** series is a series of medium sized omnidirectional sirens produced by Federal Signal over the span of 50 years, going through many design changes and variants throughout the years. Popular as fire sirens, tons of these sirens remain in service despite being discontinued roughly 35 years ago. They were also rebranded and resold by other siren manufacturers, such as GCS and W.S. Darley & Co..

While the Model 2 is part of this series, it is covered in its own article and will not be covered in this article. See link for more details.

## History and Design

The earliest sirens in the Model series began production in 1929 as the Fedelcode series, manufactured by the Federal Electric Company. These sirens were designed to replace the antiquated Type Mach. B, which had lackluster performance. Unlike the later Model series sirens, Fedelcodes came in a wide variety of shapes and sizes throughout the years. Single rotor Fedelcodes came in three main sizes, the **C1 1/2**, **C2 1/2** (or **B2 1/2**), and **C3 1/2**. The designs included a weatherproof housing to prolong the life of the siren inside. The Fedelcode was designed with a very steep cowl, or "skirt" to project sound downwards and be dispersed by a building roof, as roof mounts were the most popular mounting style at the time. Fedelcode sirens came with the option to add a coding damper, which used a motor-driven (early) or electromagnetic (later) damper to block and unblock the siren's intake, allowing it to produce a "pulse" of noise. This was used to tell volunteer firefighters where a fire was, using a numbered series of "fire zones" and blasting a number of pulses corresponding to which zone the fire was in. These coded models generally have the additional designation of "OC", such as the Type Mach. **5OC** or **7OC**.

By the time the Fedelcode series had been discontinued in the 1950s, the series had been streamlined to feature only the Model 2, C1 1/2, C2 1/2, and C3 1/2, with the rest being discontinued. The weatherproof housing was now changed, adding screens for the output and intake, and most notably, changing the design of the cowl to project sound further outwards, as pole mounting was becoming more popular. Up until 1959, C2 1/2 and C3 1/2 sized models also included a service door for the motor, with subsequent sirens lacking the door. Dual tone models were also introduced. The C3 1/2 size was still available with a coding damper for a short time before it was discontinued, as siren coding had become obsolete in favor of simpler methods. The sirens in this series were also sold by other companies who partnered with Federal Signal, such as GCS and W.S. Darley & Co. These sirens had their own custom housings but were otherwise identical to their Federal counterparts.

The first and third generation of the Model 500, Federal's mid-range rotating siren, made use of the C3 1/2's rotor, while the 2nd generation models used the STH-10's rotors. The 15" rotor from the C2 1/2 model was also later reused by Federal Signal for the popular 2001 series.

There were three different rotor sizes available for this siren, with each model having a unique housing. These sirens were designated as "**CX 1/2**" on the tag, though Federal Signal simply used the Model X naming scheme. Some have "B" instead of "C" on the tag for unknown reasons. Motor horsepower can vary even with the same rotor size, which can make identifying sirens in this series difficult without seeing the tag. The known variants of this siren were:

### C1 1/2

The **C1 1/2** was the smallest size available in the Model series, as well as the quietest. The C1 1/2 is a siren that bridged the gap between the small Model 2 and the larger sirens in the series and was only a small step up from the Model 2. The C1 1/2 makes use of a 13" aluminum rotor, which was available in only 12-port single tone. The siren was driven by a 3 hp AC motor exclusively, giving it the Type 3 designation. It was available in either single or three-phase AC. The C1 1/2 is able to reach 105 dB at 100 ft.

The C1 1/2 is easy to differentiate from the other two sizes. The C1 1/2 uses a shorter weatherproof housing, with a single, small skirt helping to project the sound downwards and outwards from the rotor. There are 4 openings underneath the skirt with a mesh screen that exposes the rotor and stator, as well as 4 openings above the skirt where the intake pulls air. The siren uses a rotor-over-motor configuration, and air is drawn into the siren's intake through the upper openings on the housing. The siren uses a rain shield on top which both protects the siren itself, and projects the sound from the siren's intake outwards.

The housing itself is attached to the siren by several screws. The C1 1/2 has a distinctly short housing due to the small motor used, and the skirt is much smaller than the larger models and not as wide as the top rain shield. The C1 1/2 also lacks an eyebolt on the housing, as the A-frame was often substituted with an angle iron or simply left with nothing. No 1 ph models have been strictly identified, though it is presumed they would be slightly taller than 3 phase models.

The C1 1/2 was the shortest-lived model in the series, as it did not last beyond the 1950s. The siren performed barely better than the Model 2, which was much smaller, cheaper, and easy to run. The C1 1/2 sold poorly, and it was ultimately discontinued. The C1 1/2 is the rarest model today, with very few in service and in private possession compared to the other models. The siren was also sold under Federal Electric for a short period, with their own special housing designs, commonly mistaken as GCS sirens. It is unknown if W.S. Darley & Co. ever sold these sirens.

### C2 1/2

The **C2 1/2** was the middle size available in the series. The C2 1/2 was a step up from the C1 1/2, using a 15" aluminum rotor. The siren was originally available in 8, 12, and possibly 6 port single tone, and 9/12-port dual tone became an option soon after. Dual tone models have the "TT" designation. The siren is driven by either a 3 hp or 5 hp AC motor, with 5 hp being by far the most common for this size. The siren was available in single or 3 ph AC but were not designated as "A" or "B" as these predated phase designations by model. The C2 1/2 was able to reach 107 dB at 100 ft, matching the performance of the larger C3 1/2.

In appearance, the C2 1/2 resembles an enlarged C1 1/2. Between 1948 and 1952, the siren used a housing nearly identical to its Fedelcode counterpart, before being redesigned. The siren uses a tall cylindrical weatherproof housing, with a single skirt that helps project the sound from the rotor downwards and outwards. There are 5 openings underneath the skirt with a mesh screen that exposes the rotor and stator, as well as 5 openings above the skirt where the intake is located. The siren uses a rotor-over-motor configuration, and air is drawn into the siren's intake through the upper openings on the housing.

The siren uses a rain shield on top which both protects the siren itself, and projects the sound from the siren's intake outwards. The housing itself is attached to the siren by an A-frame attached to the stator, held together by two bolts. An eyebolt connects the A-frame with the top of the housing, which the C1 1/2 lacks. The skirt on the C2 1/2 has the exact same width as the rain shield, which makes them easy to differentiate from the C3 1/2, though short run models during late Federal Electric and early Federal Enterprises were sometimes equipped with wider skirts. From 1948 until 1959, the siren had a large service door allowing easy access to the motor. It was later removed for unknown reasons. Single phase models can often (though not always) be differentiated by their slightly taller housings compared to the 3 ph models, due to using a taller motor.

Later on, during production, a dual tone model was unveiled, using a 9/12-port rotor and stator. The 3 hp Type 3(TT) and 5 hp Type 5(TT) were designed for civil defense purposes, often being installed alongside larger sirens. These were painted yellow from the factory to differentiate them from standard units. These were discontinued at the same time as the single tone model. The C2 1/2 was discontinued around 1976, when FS&S became the Federal Signal Corporation. The C2 1/2 was redundant by this time, as it performed identically to the C3 1/2, and it was not worth the cost of producing two identically performing sirens.

### "Canadian Model 5s"

For an unknown length of time, Federal Signal sold a variant of the C2 1/2 for the Canadian market, which was nicknamed by enthusiasts as the "**Canadian" Model 5** as its actual model name is currently unknown. In a similar vein to the Model 2-3Z, the Canadian Model 5 used an improved weatherproof housing to protect the siren from harsh Canadian winters, with a taller, steeper rain shield and a much larger, steeper skirt to help force snow to slide off of the siren instead of building up. These sirens are exclusive to Eastern Canada, with units having been found in the provinces of Quebec and New Brunswick.

The siren is one of the most common sirens in Quebec. Little is known about these sirens, including what the internals look like, and what the tags say. These sirens heavily resemble some H.O.R. Siro-Drones, but lack the skirt supports and follow Federal Signal's quirk of single-phase units being taller than three-phase units. Until an enthusiast travels to Quebec, the mystery of these sirens will likely remain unsolved.

### C3 1/2

    The **C3 1/2** was the largest, loudest, and most successful size in the series. The C3 1/2 was a significant step up from the previous models, using an 18.5" aluminum rotor. The siren was available in 8 or 12-port single tone, or 9/12-port dual tone. Dual tone models have the "T" (FS) or "TT" (Enterprises/FS&S) designation. The siren is driven by either a 5 , 7.5, or 10 hp AC motor, although all are more or less identical in performance and appearance. The siren was available in single or three-phase AC, with three-phase models being designated Model 5A/7A and single-phase models being designated Model 5B/7B. The C3 1/2 was able to reach 107 dB at 100 ft, matching the performance of the C2 1/2, though the frequent changes in housing proportions could enhance/worsen performance by generation. The reason for the C3 1/2's existence was to skirt regulations about motor horsepower, and is the reason why the C3 1/2 ultimately became the standard model.

The C3 1/2 has a distinctive appearance compared to the other models, using a significantly wider skirt to help project the sound from the rotor downwards and outwards evenly. This skirt could be customized from the factory, as one was ordered with an even larger skirt than normal. Between 1948 and 1952, the siren used a design reminiscent of the Fedelcode C3 1/2, before switching to the design it used for the rest of its production run. The siren uses a tall cylindrical weatherproof housing, with a single wide skirt that helps project the sound from the rotor downwards and outwards. On the C3 1/2, the skirt is much wider than the rain shield.

There are 5 openings underneath the skirt with a mesh screen that exposes the rotor and stator, as well as 5 openings above the skirt where the intake is located. The siren uses a rotor-over-motor configuration, and air is drawn into the siren's cylindrical intake through the upper openings on the housing. The siren uses a rain shield on top which both protects the siren itself, and projects the sound from the siren's intake outwards. The housing itself is attached to the siren by an A-frame attached to the stator, held together by two bolts. An eyebolt is included on top of the siren to mount the A-frame to the housing.

At some point, Federal experimented with new intakes for the C3 1/2, which started out as a cone shaped intake with a custom flat sided A-frame to fit the extra wide intake. This was later simplified to a straight cylindrical intake to save on materials, make more room for the regular A-frame, and create a more focused sound beam that would hit the top of the shroud and be deflected outwards from the intake screens. From 1948 until 1959, the siren had a large service door allowing easy access to the motor. It was later removed for unknown reasons. Single phase models can often (though not always) be differentiated by their slightly taller housings compared to the 3 ph models, due to using a taller motor.

Later on, during production, a dual tone variant of the siren was introduced, using a 9/12-port rotor and stator. The 5 hp Model 5T(T) and 7.5 hp Model 7T(T) were designed for civil defense purposes, often being installed alongside larger sirens. 10 hp units could also be ordered, generally still designated as Model 7T(T). Dual tone units were painted yellow from the factory to differentiate them from standard units. Due to using a less efficient dual tone rotor, the Model 5T(T) and 7T(T) perform at only 108 dB at 100 ft. These were discontinued around the 1980s, when the need for dual tone sirens was nearing the end.

By the time FS&S had become the Federal Signal Corporation 1976, the C1 1/2 and C2 1/2 had been discontinued, leaving the C3 1/2 as the only model left in production. To simplify the naming scheme, Federal Signal opted to simply name the siren the Model 5, regardless of whether or not it was 5 or 7.5 hp, and 10 hp units were usually named Model 7s. The 8-port units ceased production around the same time, leaving 12-port single tone and 9/12-port dual tone as the only option until the dual tone was discontinued in the 1980s. The siren would continue to be produced until 1987, when it was finally discontinued in favor of the STH-10 and STL-10.

Federal Signal would eventually release the Model ECLIPSE in 2006, continuing the Model 5's purpose as a general purpose/fire siren. Today, the C3 1/2 is one of the most common sirens in North America, being found at fire stations, factories, and other places across the continent.