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Products: AS-P Smoke Control, Automation Server Smoke Control, IP-IO Smoke Control, MP-C Smoke Control, MP-V Smoke Control
Functionalities: Smoke Control
Product version: 2.0

FSCS Basics

Other than responding to the initial fire alarm in an attempt to localize and minimize smoke migration, the other primary function of a smoke control system is to provide the firefighters with a means of overriding and controlling selected portions of the HVAC system (dedicated and non-dedicated equipment). The conditions in a facility can change significantly subsequent to the initial alarm signal. When firefighters arrive at the scene, it is desirable to provide them with the necessary controls to revise the smoke control system operation. This must be presented to the firefighters in a form that can be easily interpreted and operated to permit them to direct the smoke control response after that initial alarm. Within a listed smoke control system, the override capability for firefighters is accommodated with the provision of a Firefighter's Smoke Control Station (FSCS).

An FSCS is required on all smoke control systems according to the National Fire Protection Association (NFPA) 92 standard. The FSCS is designed to permit the firefighters to monitor and manually override the equipment used for smoke control. The FSCS must have the highest priority control over all smoke control equipment. Requirements for the FSCS as described in the NFPA-92 guidelines and required for the UL 864 UUKL listing are described in this SmartStuxure smoke control system guide. Check with local building codes and fire authorities to determine if there are any additional requirements that the FSCS must implement for the particular locations or applications.

This figure shows a typical FSCS. Since the FSCS is custom-made for each application, the layout and image will vary from project to project. While your FSCS will not appear the same as the figure, it will still be capable of performing the same functions. The sections that follow describe FSCS requirements. For more information on the FSCS requirements, see the NFPA 92 Standard.

action_zoom_plus_stroke Sample FSCS Panel

Sample FSCS Panel

The FSCS provides the capability to observe the current state of all critical equipment participating in the smoke control system. It also provides the authorized user with the ability to override the current state of equipment in the system. The FSCS design will be unique to each project with the objective of the FSCS presenting a graphic of the facility showing the location and function for the various, equipment elements in the system. LED indicators positioned on or next to equipment images will illuminate to show the current state of the equipment and also to present a fault LED illumination if the equipment fails to achieve the state directed by the automated smoke response or override from the FSCS. Switches positioned on the face of the panel next to the applicable equipment images are used to override the current state (such as open or close a damper, or direct a fan to run or stop).

As described here, the FSCS is a wall-mounted panel providing indicator lamps showing the operational state of selected equipment. Most FSCS panels are designed with customized graphics depicting an easily interpreted diagram of the facility showing the physical layout/location of equipment in the facility being controlled. The FSCS often depicts a simple overview of the air distribution/ducting system in the facility, along with the configuration of major HVAC devices, such as Air Handling Units and major dampers used to block air/smoke transfer. The objective is for the firefighter to be able to easily view the diagram and gain immediate insight into the location of the equipment, the status of the equipment and the control options offered by the system. The desired result is for firefighter to have a quicker and better understanding of how to influence smoke migration in the facility.

In addition to the equipment status display and override function, the FSCS must enunciate faults in the system. This includes faults in the operation or communications between the the control system components and the failure of the selected equipment to actually activate. For example, the FSCS should enunciate when a fan that was overridden to the ON state fails to be sensed as running.

Primary FSCS Functions, Features, and Requirements

The NFPA-92 Standard for Smoke Control Systems, 2018 document describes the requirements for the FSCS as providing the following functions and attributes:

  • The FSCS should be installed in a location within the building acceptable to the authority having jurisdiction.

  • The FSCS should include a status indication, fault condition indication and manual control for all smoke control equipment.

  • The status indicators and controls should be labeled and arranged to convey the intended system/equipment objectives.

  • Operator control, status indications and fault indications shall be provided for each smoke control zone, each piece of smoke control equipment used, or a combination of the two.

  • Positive status indications (ON and OFF) shall be provided individually or by zone in accordance with previous requirement for each of the following:

    1) A dedicated smoke control system fan

    2) Non-dedicated fans used for smoke control with a capacity larger than 2000CFM

  • Fan ON status should be sensed by pressure difference, an airflow switch, or other positive proof of airflow.

  • A positive status indication (fully open and fully closed) of the damper position shall be provided if individual, damper controls are provided on the FSCS.

  • The FSCS shall provide a pushbutton momentary (self-restoring) switch for activating a LAMP TEST function. The lamp test function activates all LED indicators provided on the panel while the button is pressed.

  • The FSCS shall present building and system diagrams and graphics showing the type and location of all smoke control equipment (fans, dampers etc.) The building areas affected by the equipment shall also be clearly indicated.

  • FSCS override controls shall have the highest priority control over all smoke control systems and equipment

  • Where manual controls for smoke control equipment are also provided at other building locations, the control mode selected from the FSCS shall prevail.

  • FSCS controls shall override or bypass other building controls such as Hand-Off-Auto and start/stop switches located on fan motor controllers, freeze detection devices, and duct smoke detectors except as provided in the following requirement:

  • The FSCS fan control capability shall not be required to bypass Hand-Off-Auto or start/stop switches located on motor controllers of non-dedicated smoke control system fans where both of these conditions exist:

    1) Such fan motor controllers are located in mechanical or electrical equipment rooms or in other areas accessible only to authorized personnel.

    2) Using a motor controller switch to turn a fan on or off will cause an off-normal indication at the building’s main control center during normal HVAC or building control operations of the non-dedicated fan.

  • FSCS control shall not take precedence over fire suppression, electrical protection, or personnel protection devices.

  • When stairwell pressurization systems are provided, manual activation and deactivation control of the stairwell pressurization systems shall be provided at the FSCS.

  • The FSCS is permitted to provide an override switch to restart the stairwell pressurization fan(s) after shutdown from the smoke detector.

NFPA-92 Annex-H

NFPA-92 Annex- H Firefighter's Smoke Control Station (FSCS) Considerations provides additional information which is not part of the NFPA document requirements, but is included for informational purposes. The information associated with the FSCS includes the following:

  • The FSCS should be located close to other firefighters’ systems within the building.

  • The FSCS should provide a means to ensure that only authorized users access the FSCS.

  • Where acceptable to the authority having jurisdiction, the FSCS should be provided within a specific location or room, separated from public areas by a suitably marked and locked door.

  • The FSCS location, separate room, room location, size, access means, and other physical design considerations should be acceptable to the authority having jurisdiction.

  • The FSCS design should graphically present the physical building arrangement, smoke control systems and equipment, and areas of the building served by the equipment.

  • Status indicators should be provided for all smoke control equipment by pilot lamp-type indicators as follows:

    1) Smoke control fans and other critical operating equipment should have a Green lamp indicating the operating state.

    2) Smoke control and other critical equipment that may have two or more states or positions, such as dampers should use: Green (OPEN) and Yellow (CLOSED)

    The position of each piece of equipment should be indicated by lamps and appropriate legends. Intermediate positions (that is, modulating dampers that may not be fully open or fully closed) may be indicated by not illuminating either of their pilot lamps.

    3) Smoke control system or equipment faults should be indicated with an Amber/Orange lamp

  • Using the positions of multi-position control switches to indicate the status of a controlled device should not be done in lieu of pilot-lamp-type status indicators as described previously

  • The FSCS should provide control capability over all smoke control system equipment or zones within the building.

    Wherever practical, it is recommended that control be provided by zone, rather than by individual equipment. This approach will aid firefighters in readily understanding system operation and will help to avoid problems caused by manually activating equipment in the wrong sequence or by neglecting to control a critical component.

  • Control by zone should be accomplished as follows:

    PRESSURE-AUTO-EXHAUST control over each zone that can be controlled as a single entity relies on system programming to properly sequence all devices in the zone to produce the desired effect. In systems utilizing common supply or return ducts, or both, inclusion of an ISOLATE mode is desirable. To enable the use of the system to flush smoke out of a zone after the fire has been extinguished, a PURGE (equal supply and exhaust) mode can also be desirable.

  • If control over individual pieces of equipment is deemed necessary, the following control options should be provided:

    • ON-AUTO-OFF control over each individual piece of operating smoke control equipment that can also be controlled from other sources within the building. Controlled components include the following:

      • All stairway pressurization fans

      • Smoke exhaust fans

      • HVAC supply, return, and exhaust fans in excess of 2000 CFM

      • Elevator shaft fans

      • Atrium supply and exhaust fans

      • Any other operating equipment used or intended for smoke control purpose

    • ON-OFF or OPEN-CLOSE control over all smoke control and other critical equipment associated with a fire or smoke emergency and that can be controlled only from the FSCS.

    • OPEN-AUTO-CLOSE control over all individual dampers relating to smoke control that are also controlled from other sources within the building. HVAC terminal units, such as VAV mixing boxes that are all located within and serve one designated smoke control zone can be controlled collectively instead of individually. HVAC unit coil face bypass dampers that are arranged so as not to restrict overall airflow within the system can be exempt. Additional controls might be required by the authority having jurisdication.

The FSCS control actions and priorities should be as follows:

  • ON-OFF, OPEN-CLOSE. These control actions should have the highest priority of any control point within the building. Once issued from the FSCS, no automatic or manual control from any other control point within the building should contradict the FSCS control action.

    • Where an automatic means is provided to interrupt normal, non-emergency equipment operation or produce a specific result to safeguard the building or equipment (for example, duct freeze stats, duct smoke detectors, high-temperature cutouts, temperature-actuated linkage, and similar devices) such means should be capable of being overridden or reset to levels not exceeding levels of imminent system failure by FSCS control action. The last control action as indicated by each FSCS switch position should prevail.

    • Control actions issued from the FSCS should not override or bypass devices and controls intended to protect against electrical overloads, provide for personnel safety, and prevent major system damage. These devices include overcurrent protection devices and electrical disconnect switches, high limit static pressure switches, and combination fire or smoke dampers beyond their degradation temperature classifications, meeting ANSI/UL 555, Standard for Fire Dampers, or ANSI/UL 555S, Standard for Smoke Dampers.

  • AUTO. Only the AUTO position of each 3-position FSCS control should allow automatic or manual control action from other control points within the building. The AUTO position should be the normal, non-emergency, building control position. When an FSCS control is in the AUTO position, the actual status of the device (on, off, open, closed) should continue to be indicated by the status indicator(s) described previously. 

  • FSCS Response Time- For smoke control purposes, the FSCS response time should be the same as for automatic or manual smoke control action initiated from any other building control point. FSCS pilot lamp indication of the actual equipment status should not exceed 15 seconds after operation of the respective feedback device.

  • The location of smoke control systems and equipment within the building should be indicated by symbols within the FSCS graphics.

  • Where zoned smoke control is used, a sufficient number of smoke control components to convey the intended operation of the smoke control systems and equipment should be shown. Normally, these components would include major ducts, fans, and dampers that are part of the smoke control system.

  • Where control is provided over individual fans and dampers used for smoke control, these components should be shown on the FSCS graphic panel and where appropriate, should also be shown connected to their respective ducts with a clear indication of the direction of airflow.

  • With either zoned or individual equipment control, the building areas served by the smoke control systems should be shown on the FSCS graphics. Status indications for damper positions should be shown where their inclusion would aid in understanding system operation and can be omitted where their inclusion would hinder understanding of the system, such as on an already densely populated panel. Damper position can also be omitted where no separate control over damper position is provided.

Serial Interface- Modbus

The Modbus protocol is used for serial communications to an intelligent FSCS panel. The protocol controls the query and response cycle which takes place between master and subordinate devices. In this application, the FSCS panel operates as the Modbus master device and the Smoke Control Server operates as a Modbus subordinate device responding to commands from the FSCS.

The protocol supports a single master and up to 247 subordinate devices on a common line, but the FSCS application implements a simple one-to-one interface. The Modbus master initiates all transactions. A transaction comprises a single query and single response frame. The Modbus protocol defines the format of the message frames. The information in the message is the address of the intended receiver, what the receiver is to do, the data needed to perform an action, and a means of checking for errors.

The Modbus protocol supports two different modes of transmission which defines the structure of the individual, units of information within a message, and the numbering system used to transmit the data. The modes are referenced as ASCII and RTU with the ASCII mode using ASCII characters to form the command and response messages and the RTU using binary formats with both modes providing the same basic capabilities for communicating. The EcoStruxure BMS smoke control system FSCS interface uses the RTU mode of transmission.

Modbus Address Point Mapping

The Smoke Control Server FSCS application program defines the mapping of the Modbus data elements to the BACnet variables transported over the Ethernet IP network to other Automation Servers, or AS-Ps and on to the subordinate field controllers positioned below the Automation Servers, or AS-Ps

There are four basic types of Modbus data elements: Coils, Holding Registers, Inputs and Output Registers. All four are supported by the Automation Server, or AS-P but only the Modbus Holding Registers (4X registers in the register address range of 40001 to 400256) are used in the smoke control application. These registers deliver override and control information from the FSCS and deliver equipment and system status information to the FSCS for display.

The Smoke Control Server and the FSCS do not utilize battery backup standby power and will cease communications when AC power is lost. Failure of the Automation Server or AS-P to respond to the FSCS prompts a failure indication on the FSCS panel, assuming the FSCS still has power.

FSCS Smoke Control Server

The Smoke Control Server used to manage the FSCS provides two RS-485 interfaces. Channel A or B can be configured for the Modbus RTU protocol to interface with the FSCS panel. The other RS-485 channel can be used to communicate with BACnet MS/TP or Infinet-2 controllers. The Smoke Control Server also provides an Ethernet 10/100 IP network interface for communications with the other Smoke Control Servers in the system, WorkStation(s), and optionally, the port may be used to communicate with the Fire Alarm Panel using BACnet/IP.

On the Channel configured to support the FSCS panel, the Smoke Control Server acts as a Modbus subordinate device and waits for commands and requests from the FSCS operating as the Modbus master.

The Smoke Control Server receives the override switch positions from the FSCS (via the Modbus protocol). The FSCS application program in the Smoke Control Server uses the switch information to construct the applicable override command structures which it sends to the other Smoke Control Servers and field controllers in the smoke control system.

Where possible, the use of BACnet COV subscriptions are recommended between the Smoke Control Server managing the FSCS and all other Smoke Control Servers interfacing with field controllers. In addition, it is recommended that COV subscriptions be extended to the BACnet family of field controllers (MP-C, MP-V, b3, MNB, etc.). The objective of the subscriptions is to achieve the most efficient and expedient information collection from the field for display on the FSCS panel, and to communicate the override commands outbound from the FSCS override switches to the field controllers.

The COV notifications are routed through the Smoke Control Servers serving the BACnet MS/TP buses and IP level field controllers (MP-X family). In the case of Infinet i2 field controllers, the Smoke Control Servers managing each group of controllers facilitates the COV subscriptions with the server that manages the FSCS. The Smoke Control Servers handling Central I/O modules used in smoke control will also facilitate COV subscription exchanges with the FSCS smoke control server.

The FSCS Smoke Control Server application program formats and maps the discrete status information from the system’s controllers into the appropriate Modbus registers and delivers the status information to the FSCS upon request. The FSCS uses this information to illuminate the designated indicators and/or sound the audible alert.

The Smoke Control Server occupies one address on the RS-485 Modbus bus extending from the FSCS panel and responds to polling from the FSCS internal Z-Card(s). For operation with the FSCS, the Smoke Control Server should be configured for the following:

Parmeter Name


MODBUS Address




Baud Rate




Stop Bits


The integrity of the RS-485 Modbus communication channel is supervised by the processor board (Z-Card) in the FSCS panel. The FSCS should be installed close to the Fire Alarm Panel (FAP) (such as indicated in the NFPA 92 standard). The Smoke Control Server managing the FSCS will also frequently be used to manage the FAP and will be installed in an approved enclosure positioned adjacent to the FAP or FSCS panel, or may be installed in the FSCS panel.

ADI Panel

The EcoStruxure BMS smoke control system is designed to operate with FSCS panels manufactured by Automation Displays, Inc. (ADI). This system guide provides the requirements and basic information for specifying an FSCS Panel to be ordered from ADI. Panels used with the EcoStruxure BMS smoke control system must be configured, constructed, and programmed in accordance with the capabilities and features provided and allowed by ADI under their FSCS panel UL 864 listing.

The FSCS panel is UL 864 listed by ADI using an FSCS model designation format of SXW-xxxxxx. The 6 digit suffix (xxxxxx) is assigned by ADI at the time of the order and will be unique to each panel's project design. By the nature of the defined FSCS requirements, the panels will each be unique to the specific projects encountered by the Branch or VAR/Partner engineering groups. The SXW-xxxxxx sequence number creates a unique reference designation for the customized drawings and documentation associated with generating each panel.

To order FSCS panels to be used with EcoStruxure BMS smoke control systems, please contact:

Automation Displays Inc.

3533 N. White Ave. Eau Claire, WI 54703

Tel: 715-834-9595 Fax: 715-834-9596


Contact: OEM Sales Manager

The Schneider Electric Branch or VAR/Partner will generate FSCS panel drawings detailing the design of the FSCS panel required for the specific project. Be sure to communicate with ADI support personnel regarding questions you may have on the panel details and construction features. You can also contact Schneider Electric Product Support Services with questions.

The panel drawings created by the Schneider Electric Branch or VAR/Partner should detail a panel design that meets the requirements and presents an easily interpreted system diagram, equipment definitions and operating controls. The choices of equipment to be presented and the override/display functionality must address the FSCS panel requirements as detailed in this system guide.

General FSCS Panel Information

The FSCS panel is constructed with multi-position toggle or rotary switches for control of individual fans and dampers, or consolidated pressurize and exhaust control over the individual zones. High intensity LEDs indicate the equipment status or the detection of equipment faults or communication failures. A multi-color graphic depicting the building and equipment is created to provide a clear picture relating each switch and indicator to the appropriate smoke control zone, and the equipment function in the zone. Critical areas like stairways, elevator shafts, main fresh air ducts, and main exhaust ducts can be highlighted by using distinct colors.

The FSCS panel surface is typically a multi-colored polyester film which is protected by a non-glare textured coating. The artwork can include black lines and legends with a multi-colored background or a black background with multi-colored lines and legends. You may choose from ADI's chart of standard colors. High intensity LEDs providing status indications do not protrude through the polyester-film front panel, so the front surface is easily cleaned.

The ON-AUTO-OFF control of fans or OPEN-AUTO-CLOSE control of dampers is typically accomplished by three position toggle, rotary switches or interlocking push-button switches. Two position switches are applied when applicable such as ON-OFF, OPEN-CLOSE, and Auto-Open, typically associated with dedicated equipment only controlled from the FSCS. Three position switches can also be applied to the zone mode type of override control with selections such as PRESSURIZE-AUTO-EXHAUST. The switches are wired to terminals which are sub-plate mounted in the enclosure. Momentary pushbutton switches are utilized for functions such as LAMP TEST and CLEAR FAULT.

LEDs are available in red, green, amber, yellow and bi-state configurations.The LEDs are T-1 ¾ size, mounted on printed circuit boards, and provide 170,000 hours of continuous or pulsed operation.

The enclosure can be a flush or surface-mount, back box with standard sizes of 36 inches (914 mm) x 24 inches (610 mm), 48 inches (1220 mm) x 36 inches (914 mm) and 60 inches (1524 mm) x 48 inches (1220 mm). ADI can also support custom and larger sizes. All enclosures are constructed in accordance with requirements specified in UL 864 (v9) section 7.

FSCS panels will be constructed with integral power supplies which are powered from standard 120 VAC line voltage.

Some panel mounting options available from ADI include:

  • Wall mount back boxes

  • Stainless steel frames

  • Stainless steel enclosures

  • Security door, with or without a viewing window

  • Key locks

  • Torx pin head security screws

  • Southco knuckle hinges

  • Stainless steel hinges

Consult with ADI regarding additional features, options and construction alternatives available under ADI’s UL 864 FSCS panel listing.

Switch and LED Reference Designations

When the FSCS panel design is completed, you will receive a drawing showing the final artwork and Switch/LED layout for approval. You will also receive a version of the panel drawing showing the graphics along with reference identification numbers assigned to all switch and LED components.

The LEDs and switches are also summarized in two tables typically in Microsoft Excel spreadsheet formats. The LED table will list all of the sequentially numbered LED positions, their function, Modbus register, bit position, and the ADI connection point in the FSCS. The switch table presents the same type of information. The FSCS design drawing shows the switch numbers (for example, S###) and LED numbers (for example, L###) assigned to each switch and LED presented on the panel.

These designations are used to correlate LED and Switch positions with the Modbus protocol data presentation of the switch and LED information. This information is required by the Smoke Control Server application programming engineer to ensure the application program is properly interpreting the switches from the FSCS. This is also needed for the application program to generate the correct Modbus register sequence and data content to present the correct LED status on the FSCS. The S### and L### designations are used in the programming/mapping tables to associate the switch or LED with the Modbus Register positions. One of the L### designations controls the audible Sonalert. For more information, see Basic Application Functions

Common or Mandatory FSCS Elements and Functions

The following sections detail the functionality of the mandatory and common element functions associated with FSCS panel designs.

Panel Enable Key Lock

The FSCS panel shall provide a key operated Panel Enable switch. The status of this key switch is used by the Automation Server, or AS-P program to enable or disable most other switches and keep them from affecting the automatic system mode.

When the key is in the DISABLE position, the FSCS panel (and Automation Server, or AS-P program) must be programmed to function as follows:

  • The FSCS panel continues to notify the Smoke Control Server of the state of all switches on the FSCS.

  • The Smoke Control Server program will ignore the state of all equipment override switches and will pass through the AUTOmatic mode selection.

  • The Smoke Control Server will disable/ignore the CLEAR FAULT pushbutton switch.

  • If the Silence Alarm is provided as a pushbutton switch, the Smoke Control Server will be programmed to disable/ignore the Silence switch.

  • If the Silence Alarm is provided as a key operated switch, the Smoke Control Server will be programmed to permit the Silence signal to pass and execute.

  • The Lamp Test pushbutton switch will still operate.

  • The Audible Alert will still operate (internal to the FSCS).

  • The Smoke Control Server program will continue to drive FSCS indicator lamps to show the current state of all systems and equipment.

  • The FSCS Enable key can be removed from the lock in this Disable position.

When the key is in the ENABLE position, the FSCS panel (and Automation Server or AS-P program) must be programmed to function as follows:

  • The FSCS panel continues to notify the Smoke Control Server of all current override switch positions including the enable switch.

  • The program in the Smoke Control Server will recognize the enable status as being active and will enable the equipment override directions from the collection of FSCS switches and transport those override commands to the field controllers.

  • When ENABLED, the Smoke Control Server program will continue to quickly update the field controllers of any subsequent changes on the FSCS override switches.

  • All overrides currently invoked in the switches but ignored while the panel was disabled, will immediately take effect.

  • The Reset Alarm/Fault pushbutton switch will prompt the Smoke Control Server program to execute the reset/clear function.

  • If the Silence Alarm is provided as a pushbutton switch, the Smoke Control Server program will now execute the Silence function when requested by the pushbutton.

  • If the Silence Alarm is a key-operated switch, it will always be accepted by the Smoke Control Server program and executed regardless of the panel enable switch.

  • The Audible Alert continues to operate on any fault as when the panel was disabled. However, it can now be silenced.

  • The Lamp Test pushbutton switch will still operate (internal to the FSCS).

  • The Smoke Control Server program will continue to drive all indicator lamps to display the current state of all systems and equipment.

  • The FSCS Enable key cannot be removed from the lock in this Enable position.

    The system designer should check with authorities having jurisdiction to determine which facility personnel should have possession of a Panel Enable key.

Lamp Test Pushbutton

The FSCS panel shall provide a Lamp Test pushbutton switch to allow the operator to check the operation of all indicator lamps (LEDs). Pressing this button will cause all indicators (LEDs) to illuminate. The panel should be configured such that the Lamp Test pushbutton function will operate regardless of whether the panel is enabled or disabled.

The status of the panel Lamp Test switch shall also be available in the Modbus register data from the panel. This allows the Smoke Control Server application to monitor and report when the Lamp Test function is performed. The Smoke Control Server and its program are not involved with the FSCS Lamp Test Function. The Lamp Test is performed by the Z-Card internal to the FSCS.

Audible Alert

The FSCS panel must provide an audible SonAlert horn that sounds upon FAULT detection. When the Smoke Control Server program detects an equipment FAULT, the program must illuminate the applicable LED(s) AND activate the Audible Horn. The program must continuously sound the horn while the equipment FAULT is active. If the equipment FAULT is corrected (eliminated), the program will be configured to extinguish the LED and horn. If the FAULT remains active, the horn can be silenced within the Smoke Control Server by user activation of the SILENCE switch. If the FAULT condition remains active for 24 hours, the Smoke Control Server program should be configured to reactivate the horn.

The Smoke Control Server program should activate the audible horn again if a different equipment point changes to the FAULT condition.

The Smoke Control Server program should also activate the audible horn upon the detection of an active smoke alarm signal. As with the other audible alerts, the key-operated SILENCE switch may be used to turn off the sound while the smoke alarm remains active.

Silence Audible Switch

The FSCS must be configured with a SILENCE audible switch. This can be either a pushbutton switch or a key operated momentary switch.

If the FSCS is configured with a simple pushbutton SILENCE switch, the switch must not function when the panel’s key operated enable switch is in the DISABLE position. When the panel is ENABLED, the SILENCE pushbutton should be processed by the Smoke Control Server program and executed. If the FSCS is configured with a key operated momentary SILENCE switch, the Silence function should be executed by the program in the Smoke Control Server at all times with the panel ENABLED or DISABLED. The key operated switch ensures the person has authority to SILENCE the panel and the panel enable key is not required. The example system FSCS panel is shown configured with the key operated SILENCE switch.

Clear Fault Pushbutton

The FSCS panel shall provide a Clear Fault pushbutton switch to allow the operator to reset/extinguish faults which have a latching indicator. This would pertain to faults produced by the weekly Self Test of the dedicated equipment. Faults prompted by the weekly self-test program should be latched within the Smoke Control Server where the specific test operation is managed.

The status of the Clear Fault pushbutton switch is available in the Modbus register data from the panel. If the panel is enabled, then the Smoke Control Server program will accept and execute the Clear Fault function. If this function is not exclusive to the Smoke Control Server managing the FSCS, the Smoke Control Server program must pass the Clear Fault signal to the applicable Smoke Control Server where the reset/clear is needed.

The FSCS Smoke Control Server will need to ensure a minimum active state to accommodate a potentially short active signal from the FSCS panel. This may be accomplished with a program one-shot that emits a 10 second pulse signal to the other controllers when a pushbutton press is detected.

System Communications Fault Indicator

The Smoke Control Server handling the FSCS is responsible for supervising communications to the other Smoke Control Servers and collecting the communications status from the Smoke Control Servers managing subordinate field bus networks and the BACnet I/P fire panel. The detection of a fault in the communications to the other Smoke Control Servers, or the reporting of a communications fault by the other Smoke Control Servers should prompt the SYSTEM COMMS FAULT LED to illuminate.

The SYSTEM COMMS FAULT LED functions as a summary indication which is active (LED is steady state ON) when the FSCS application in the managing Smoke Control Server has detected or been informed of a communications problem to any controller participating in the smoke control application. When the cause of the SYSTEM COMMS FAULT indication is unknown, the Building Operation WorkStation can be used to investigate and identify the cause of the fault indication. It is helpful to generate a Communications Summary screen to show the status of the communications to all controller nodes. This will show the communications status to all controllers and makes it easy to see the specific controller prompting the FAULT indication.

The SYSTEM COMMS FAULT will cause the activation of the audible alert. The alert will continue to sound until the communication fault is eliminated, or the key SILENCE switch is activated. If the silence function is used, the visual fault indication remains active and the Smoke Control Server application program shall be configured to reactivate the audible in 24 hours if the COMMS FAULT remains active.

FSCS Communications Fault Indicator

The FSCS Z-Card supervises the RS-485 communications to the managing Automation Server or AS-P. If the FSCS detects a fault in Modbus communications with the Smoke Control Server, the FSCS will illuminate and latch the FSCS COMMS FAULT LED. Clearing this fault requires that the communication first be restored/repaired to the Smoke Control Server, and then the latched indicator can be cleared by using the key-operated SILENCE switch to extinguish the FSCS COMMS FAULT.

The audible alert will also sound upon the activation of the FSCS COMMS FAULT. The horn will continue to sound until the key operated SILENCE switch is activated. If the communication problem to the Smoke Control Server has been resolved, the SILENCE will also extinguish the FSCS COMMS FAULT LED. If the FAULT remains active, the horn will reactivate in 24 hours. This is handled within the FSCS Z-Card firmware.

Equipment Fault Display

In addition to the equipment status display and override function, the Smoke Control Server managing the FSCS is responsible for providing an indication of equipment faults detected in the system. The equipment elements selected for status display and override control on the FSCS panel will also incorporate proof sensors that will be monitored by the controller directing the equipment control state. The controller directing the equipment must report an equipment FAULT if the equipment proof point does not indicate the equipment reached the commanded state. For example, the FSCS should enunciate when a fan that was overridden to the ON state fails to be sensed as running. The equipment FAULT status is transferred to the Smoke Control Server managing the FSCS for visual presentation and audible notification.

The equipment fault indications are grouped with the other equipment status indicators and the override switch related to the equipment on the FSCS panel graphics. The equipment fault indicator will remain illuminated until the fault is corrected.

The FSCS panel design can get complex with hundreds of LEDs and switches. A summary equipment fault indicator should be provided in the same area as the system communications fault which is also a summary system indication. The summary Equipment Fault LED should be active any time the Smoke Control Server application has any of the individual equipment fault LEDs illuminated. An active summary indicator lets the operator know they need to examine the whole panel to identify the cause.

When an equipment fault is activated, the Smoke Control Server application must also activate the audible SonAlert (horn). This alert will continue to sound until the equipment fault is eliminated, or the key SILENCE switch is activated. If the silence function is used, the visual fault indication remains active and the Smoke Control Server application program shall be configured to reactivate the horn in 24 hours if the equipment fault remains active.

Manual Override Fault

Within the EcoStruxure BMS smoke control system, several of the field controllers and I/O modules have manual override switches on their face panel. During installation, setup and system commissioning, these can be valuable tools. After the system is put into service, these switches become potential sources for inadvertently disabling the system or a portion of the system. The status of all override switches associated with outputs participating in the smoke control applications must be monitored by the supervising Automation Servers, or AS-Ps. The Manual Override status must be transmitted continuously to the Smoke Control Server managing the FSCS panel. The Smoke Control Server application must produce a FAULT indication if any of these switches are not found in the AUTOmatic position.

The FSCS panel design should include a summary LED indication identified as a MANUAL OVERRIDE FAULT. The managing Smoke Control Server application should be set up to activate that LED when any controller points participating in the smoke control application have a manual override active. The LED should remain active until all applicable manual override switches on the controllers are returned to the AUTO position.

Like the other FAULTS, this manual override fault will prompt activation of the audible SonAlert. Also, like the other faults, if the SILENCE is used, the audible alarm must reactivate after 24 hours if the override persists. In other words, the manual override is considered a problem that cannot be allowed to persist.

The Building Operation WorkStation can be set up with a MANUAL OVERRIDE SUMMARY screen showing the override condition for controllers participating in the smoke control application. This screen can be used to help identify the cause of a MANUAL OVERRIDE FAULT indication seen on the FSCS. Application examples for Function Block and Script programs that supervise the override switches on the I/O modules and MS/TP or Infinet 2 controllers are included in this guide. For more information, see Basic Application Functions .

Alarm Indication

A presentation of the zone alarm status should be provided on the FSCS to allow recognition of when the system is responding to an alarm condition and which zone alarm is active. The following figure shows an alarm indication from the example FSCS panel. A SMOKE ALARM LED is provided within the graphic of each of the four control zones and stairwell presented on the face of the example FSCS panel. These LEDs will illuminate when the system responds to an alarm condition.

action_zoom_plus_stroke FSCS Zone Alarm Graphics

FSCS Zone Alarm Graphics

Equipment Status Display and Override

The equipment status display and override includes the individual equipment override and zone-based override.

Individual Equipment Override

The FSCS individual equipment status display and override control can be presented as shown in the following extract from the example system FSCS panel.

action_zoom_plus_stroke Equipment Status and Override Display

Equipment Status and Override Display

The example FSCS presents ON/AUTO/OFF and OPEN/AUTO/CLOSE control of the individual pieces of equipment serving each of the zones; with equipment display and override switch groups such as those shown.

Zone-Based Override

The example FSCS also demonstrates the zone based pressurize and exhaust mode of operation. The Zone Override technique presents a zone status display and override control with graphics such as those in the following figure. This allows a single switch to activate PRESSURIZE or EXHAUST mode with the Smoke Control Server application directing the multiple pieces of equipment to the necessary state.

action_zoom_plus_stroke Zone-Based Override and Status

Zone-Based Override and Status

In an arrangement such as this where individual equipment override and zoned override are provided, one needs to take precedence over the other when in conflict. An example of such conflict would be- if ZONE 4 is set to PRESSURIZE with the zone mode switch and the Supply Air (SA) Damper serving ZONE 4 set to the CLOSED position (instead of AUTO) with the individual equipment control. Between the two FSCS override modes, the individual equipment control is configured in the Smoke Control Server application to have higher priority over the PRESSURIZE/EXHAUST mode switch. In the example, all equipment elements would be set to the appropriate state for PRESSURIZE with the exception of the Supply Air (SA) Damper which would be set to the CLOSED position due to the higher priority individual control switch.

Weekly Self-Test

There will frequently be some equipment participating in the smoke control system that is never activated (state change) unless there is a smoke control response sequence active, or a manual override from the FSCS. That equipment is referred to as dedicated smoke control equipment. Since normal HVAC control cannot be depended upon to exercise the equipment and expose any operational problems, the dedicated equipment must be exercised by a weekly self-test routine as programmed in the Smoke Control Servers. The weekly self-test is frequently set to operate afterhours in the facility to minimize influence on the normal comfort controls. The example system was programmed to perform self-test every Saturday night at midnight.

In the example system, the dedicated equipment includes the Stairwell Air Handler Unit (AHU #3) and the six Smoke Dampers for floors or zones 2, 3 and 4:

  • FL2 SA Smk Damper

  • FL2 RA Smk Damper

  • FL3 SA Smk Damper

  • FL3 RA Smk Damper

  • FL4 SA Smk Damper

  • FL4 RA Smk Damper

Each of these devices need to be activated during the weekly self test and the equipment proof point is used to confirm the equipment operated properly. Unlike the transient self-extinguishing equipment faults described previously, any equipment faults detected during the weekly self-test must be latched in the application program to hold the visual LED indication showing what piece of equipment caused a self-test failure.  

In a building that was unoccupied over the weekend, it is necessary to hold the possible failure status information until Monday morning. If a failure occurred, the building operator would arrive to find the FSCS sounding the audible alert and the visual FAULT LEDs on the FSCS would be reviewed to identify which equipment caused the self-test fault alarm.

Since the FAULT is latched, the CLEAR FAULTS pushbutton switch will be required to clear/reset the FAULT condition (after first recording the source of the fault). The equipment fault indication will be cleared if the condition is not still active, and the Panel Enable key operated switch has been placed in the ENABLE position. The CLEAR FAULTS can optionally also be set up in the Smoke Control Server application to also silence the active, audible horn along with extinguishing the FAULT LED if the fault conditions are no longer present.

FSCS Operating Instructions Sheet

This Operating Instructions Sheet summarizes the FSCS indicators and controls.


Only authorized personnel should use this instruction sheet.

Table: LED Indicators




ALARM has been received for the zone.


Equipment FAILURE

Controller Communications FAULT or OVERRIDE FAULT






FAN is OFF (Indication optional)

Press the LAMP TEST button to test all indicators. Replace faulty indicators.

Press the CLEAR FAULTS button to clear Equipment or Controller faults. The panel enable key must be in the ENABLE position to clear the faults.

Table: Panel ENABLE Key




Override switches are disabled

This is the normal position when the alarm response is not in process or a fault is not being investigated


Override switches are enabled

CLEAR FAULT switch enabled

All LED status and fault indicators are operational in both key positions.

All override switches should be in the AUTO position before turning the KEY to the ENABLE position in order to avoid inadvertent override actions.

Table: Override Switches




Equipment or zone is under Automatic control



Force the Fan to turn ON  

Force the Fan to turn OFF  



Force the Damper to OPEN  

Force the Damper to CLOSE  



Pressurize the entire Zone

Exhaust the entire Zone

  • Basic Application Functions
  • Fundamentals of Smoke Control
  • Smoke Control Operational Overview
  • EcoStruxure BMS Smoke Control for BACnet MS/TP