Smoke Dampers

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Hoyt

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hello,

Our HVAC dept has come to me on a project....they have to add a whole mess of smoke dampers (state kicked it back) to a project.

It appears as if these are 120 volt, but I am unsure the size of the "actuator" - it is a Ruskin model and I do not see how large it is....how big typically are these actuators? How many to a ckt?

Also, i believe I need a fire alarm connection to this unit? I have area smoke detectors. Is this correct?

Thanks,

Hoyt
 
Ask your HVAC dept. to provide you with mfg's 'cut-sheets' (data sheets) for these actuators that should list all the pertinent elec. ratings (specifically voltage & current, & they should be able to do that since they are the ones specifying them). If they can't do that (which unfortunately happens quite often as I have mech. eng's frequently trying to give me BTU's as the elec. info), you may have to contact 'Ruskin' yourself. Yes, you will need a fire alarm conn.
 
Hoyt,

Are these ducts 12" x 12" or are they 6' x 6' ? I know the smaller ones only

draw fractional amps and you can put quite a few on a circuit ( motel job).

If you are working with larger ducts ( AHU with large HP motors ) keep in

mind that a delay may be required to let the blower spin down before closing

the SFD. ( hospital job )

As far as the F.A. connection, on the systems I have worked on the FACP activated the SFD's.
 
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I've never seen fire dampers that did get connected to electricity by any means. They just had fusible links that let them slam shut.
 
ryan_618 said:
Generally speaking you need not connect fire dampers (radiation dampers) to a fire alarm system. There are, however, some very specific instances in which you do.
Click to expand...

Isn't the purpose of fire dampers is to slow the spread of fire (via the ductwork), which should be detected by the fire alarm system in the first place?

Every fire damper I've wired is controlled by the FACP. During an alarm, the dampers close, as well as shutting down the air handling system (otherwise the pressure could blow the duct apart).

mdshunk said:
I've never seen fire dampers that did get connected to electricity by any means. They just had fusible links that let them slam shut.
Click to expand...

I've seen those, too, but usually in return air spaces.
 
480sparky said:
Isn't the purpose of fire dampers is to slow the spread of fire (via the ductwork), which should be detected by the fire alarm system in the first place?
Click to expand...

Sure, but that doesn't mean there has to be a direct connection between the two. For example, a job that I am inspecting right now has literally several hundred, none of which are required to be connected to the fire alarm system.
 
benaround said:
quogue, and how does this relay work ?
Click to expand...
Usually they are wired in a daiseychain loop and power opens the louvers. Upon alarm the relay opens deenergizing the relays and the spring loaded dampers close mechanically.
 
Hoyt said:
hello,

Our HVAC dept has come to me on a project....they have to add a whole mess of smoke dampers (state kicked it back) to a project.

It appears as if these are 120 volt, but I am unsure the size of the "actuator" - it is a Ruskin model and I do not see how large it is....how big typically are these actuators? How many to a ckt?

Also, i believe I need a fire alarm connection to this unit? I have area smoke detectors. Is this correct?

Thanks,

Hoyt
Click to expand...

damper motors are usually rated 7 to 10 VA, this will be found on the actuator somewhere. Typically smoke dampers are connected by FA relay to close when FA system (if a FA system exists) goes into alarm. Also, they may be directly connected to an air handler which in turn is shut down by a FA relay or if you have a Building Automation System in place they could be controlled from there. Many options exist, wiring depends on state and local codes.
 
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Most of the "fire dampers" I have seen had a spring loaded torque motor to close (No power at all - but contacts to show status) and a link to close, or those that were powered (Combo "fire/smoke" dampers) had an acuator to release from the duct detectors or FA, and a motor to reset it - no power to actuator, it would close. From what I remember the motor was not much, and holding acuator even less. On 120 it was like 1/4A per motor, and holding half of that.
 
the two state dampers are easier to monitor, since the states can be read at the panel by a fire marshall, during his inspection.

Most modern systems now have a logic board that integrates fire, smoke, strobe, elevator, downdraft fans, etc,.. and dampers

i think it is expensive. ;)
 
Hoyt said:
hello,

Our HVAC dept has come to me on a project....they have to add a whole mess of smoke dampers (state kicked it back) to a project.

It appears as if these are 120 volt, but I am unsure the size of the "actuator" - it is a Ruskin model and I do not see how large it is....how big typically are these actuators? How many to a ckt?

Also, i believe I need a fire alarm connection to this unit? I have area smoke detectors. Is this correct?

Thanks,

Hoyt
Click to expand...
There should be a set of Approved Engineered Drawings and detailed information for all equipment connected to the Fire Alarm.
 
mdshunk said:
I've never seen fire dampers that did get connected to electricity by any means. They just had fusible links that let them slam shut.
Click to expand...

F/S Dampers with fusible links are typically used to maintain the integrity of a fire/smoke barrier or rated assembly such as a section of duct passing through a fire wall. Another example would be in a plenum ceiling when a return air transfer opening is located in a fire wall that extends above the finished ceiling to the bottom of the deck above.

Electrically actuated F/S dampers are typically interfaced with/actuated by the FACP or "Fire Control Panel in the Fire Control Room". They are also frequently interfaced with the shunt trip circuit in a data processing/IT facility. These dampers are typically associated with smoke control systems (smoke purge, smoke exhaust,and pressurization systems).

They key in all cases=engineered drawings and sequence of operation)

R Bob
 
The dampers that I have hooked up only have 1/8 HP motors that hold the flapper open. Usually a spring closes then. The relay is wired into a dru contact in the fire alarm panel or a contact in a relay base type detector so that on alarm the relay contacts open letting the spring close the damper.
 
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