Control Panels, Fire Alarms and Commissioning
An electrically operated smoke vent is an important part of a building’s fire safety system. For the vent to operate as intended, more is required than simply fitting an actuator. The installation must form a complete and coordinated control system.
The control panel, backup power supply, fire alarm interface, control devices and system logic must all be adapted to the building and its fire safety design.
This article explains how smoke vent control systems work and what information should be established before design, installation and commissioning.
This article provides a general introduction to smoke vent control systems. It does not replace the project fire strategy, cause-and-effect matrix, electrical design, wiring diagram or the manufacturer’s installation and commissioning instructions. System selection, installation and testing must be carried out by the responsible designers and installers in accordance with the requirements of the individual project.
What is included in a smoke ventilation system?
An electrical smoke ventilation system will typically include:
- a smoke vent,
- an electrical actuator or opening mechanism,
- a control panel,
- battery backup or another designed backup power solution,
- a manual smoke control point,
- an interface with the building fire alarm system,
- smoke or heat detectors,
- switches for comfort ventilation,
- optional rain and wind sensors.
The control panel is the central part of the system. It supplies power to the actuators, receives signals from connected devices and controls how the vents open and close.
Depending on the control panel and system design, it may also monitor connected functions and indicate faults, alarms or open and closed positions.
The difference between smoke ventilation and comfort ventilation
In some systems, the same vent can be used for both smoke ventilation and everyday ventilation. However, the two functions must remain clearly separated.
Smoke ventilation
In the event of a fire, the vent must open in accordance with the building fire strategy and the agreed cause-and-effect matrix.
Activation may come from:
- the building fire alarm system,
- a smoke detector,
- a heat detector,
- a manual smoke control point.
The fire function must follow the agreed control logic and will normally take priority over comfort ventilation.
Comfort ventilation
Comfort ventilation is used for normal air circulation and temperature control. The vent may, for example, be operated by:
- a local push button,
- a key switch,
- a thermostat,
- a remote control,
- a building management system.
The system may also be connected to rain and wind sensors. Depending on the configuration, these can close or restrict the comfort opening during unsuitable weather conditions.
Comfort ventilation functions must not unintentionally prevent the vent from operating as required in a fire situation.
What does the control panel do?
The control panel manages the system power supply and control signals and, depending on the model, monitors connected functions.
A control panel may, for example, manage:
- automatic opening during a fire,
- manual smoke ventilation activation,
- comfort opening and closing,
- smoke and heat detectors,
- manual smoke control points,
- signals from the building fire alarm system,
- rain and wind sensors,
- fault indications,
- open and closed position indications,
- several actuator groups or smoke control zones.
The choice of control panel is influenced by:
- actuator voltage and current consumption,
- the number of vents,
- the number of actuator groups,
- the number of smoke control zones,
- the external signals to be connected,
- monitoring and indication requirements.
The control panel must therefore be selected according to the actual system load and required functions, rather than solely according to the number of vents.
Battery backup and emergency power
The smoke ventilation system may need to remain operational if the building’s normal power supply fails. Control panels with battery backup or another designed emergency power solution are therefore commonly used.
The required battery capacity and standby period must be established for the individual project and may be influenced by:
- the building fire strategy,
- the selected control panel,
- actuator current consumption,
- the number of vents and actuator groups,
- the presence of an emergency generator,
- applicable standards and project requirements.
The same battery or backup power solution should not be assumed to be suitable for every building.
Key switch or push button?
The appropriate control device depends on how the vent is intended to be used.
A standard push button is primarily used for simple local control and comfort ventilation.
A key switch is used when operation must be restricted to authorised personnel, for example for:
- servicing,
- functional testing,
- maintenance,
- controlled roof access,
- manual override.
It is not sufficient to specify only that a key switch is required. The following must also be defined:
- Should the switch be momentary or maintained?
- Should it open only, or both open and close?
- Should it provide open-stop-close control?
- Is it intended for comfort ventilation, servicing or override?
- Which signals should it be able to influence?
- Which signals should have higher priority?
The more clearly the required function is described, the easier it is to select the correct control device and prepare an accurate wiring diagram.
Manual smoke control point
A manual smoke control point is used to activate the smoke ventilation system manually.
When activated, it sends a signal to the control panel, which opens the vents or smoke control zones defined in the cause-and-effect matrix.
During reset, both the device that initiated the alarm and the other active alarm signals must return to their normal state. If a signal remains active, the control panel may continue to indicate fire mode or prevent the system from returning to normal operation.
Connection to the building fire alarm system
The smoke ventilation system can be activated by a signal from the building fire alarm system. For this to work correctly, the interface between the systems must be clearly defined.
The following should be established:
- Who is responsible for providing the interface?
- What type of signal will the fire alarm system provide?
- Is the signal monitored?
- Which vents or zones should open?
- Is a time delay required?
- How should activation and faults be indicated?
- How should the systems be reset?
- Who is responsible for each part of the process?
There should also be an agreed cause-and-effect matrix.
The cause-and-effect matrix describes how the system must respond to events such as:
- a fire alarm signal,
- activation of a manual smoke control point,
- detection of smoke or heat,
- a power failure,
- a system fault,
- a manual override.
An unclear cause-and-effect matrix or zone layout is a common cause of problems during wiring and commissioning.
Selecting the actuator and opening mechanism
The actuator and opening mechanism must be suitable for the individual smoke vent.
The following factors may need to be considered during selection and sizing:
- vent dimensions and weight,
- vent construction,
- required opening position,
- actuator stroke,
- opening time,
- supply voltage,
- actuator current consumption,
- number of opening points,
- applicable external loads.
The vent, actuator, brackets and control panel must be considered as one coordinated system.
Functions and performance vary between different actuators and opening systems. Selection and installation must therefore always be based on the documentation for the specific product.
Checks before commissioning
Before the system is put into operation, the following should be checked:
- the correct vents, actuators and control panel have been installed,
- the vents can move without mechanical obstruction,
- the actuators have been installed correctly,
- the cabling is of the correct type and size,
- cables and connections are clearly identified,
- batteries are installed and connected,
- manual smoke control points and other control devices are correctly positioned,
- the current wiring diagram is available,
- the cause-and-effect matrix has been agreed,
- responsibilities between the relevant contractors are clearly defined.
Cable selection and electrical sizing must be carried out by the responsible designer or installer in accordance with the manufacturer’s instructions and project requirements.
Changes to the number of actuators, vent type, cable length or control functions can affect the load on the control panel and must therefore be checked before connection.
Functional testing of the smoke ventilation system
During commissioning, each signal and function should first be tested individually and then together with the other connected systems.
Testing should include:
- Checking the incoming power supply, protective devices and batteries.
- Testing each actuator and smoke vent.
- Testing push buttons and key switches.
- Testing manual smoke control points and detectors.
- Testing the fire alarm interface.
- Confirming that the correct vents and smoke control zones open.
- Confirming the priority between smoke ventilation and comfort ventilation.
- Testing backup operation where required by the project.
- Checking the system reset sequence.
The results should be recorded in a commissioning report and handed over together with relevant system documentation, such as:
- as-built drawings,
- current wiring diagrams,
- equipment schedules,
- the cause-and-effect matrix,
- operation and maintenance instructions.
What information is required during design?
The following information is normally needed to select suitable actuators, control panels and accessories:
- type and number of smoke vents,
- actuator voltage and current consumption,
- number of actuator groups and smoke control zones,
- required fire mode operation,
- required comfort ventilation operation,
- information about the fire alarm interface,
- number of manual smoke control points and detectors,
- requirement for key switches,
- requirement for rain and wind sensors,
- cable lengths,
- backup power requirements,
- an agreed cause-and-effect matrix.
The earlier this information is established, the easier it becomes to design, install and commission the system correctly.
Summary
A reliable smoke ventilation system requires the smoke vent, actuator, control panel, backup power supply and external signals to be properly coordinated.
The most important points are to:
- select the control panel according to the actual system load,
- clearly separate smoke ventilation and comfort ventilation,
- define the function of each switch and signal,
- prepare a clear cause-and-effect matrix,
- confirm the battery and backup power requirements,
- carry out and document functional testing.
Elkington helps customers select and coordinate smoke vents, actuators, control panels and accessories based on the stated functions and conditions of each project.
The final fire safety design, electrical design and system integration must be carried out by the responsible designers and installers.
