The anatomy of a smoke control system

Posted by Conor Logan on 14/10/21 11:00

Smoke Control systemWhile it’s often understood that the basic function of a smoke control system is to control the movement of smoke in a fire to help keep buildings and their occupants safe, we also frequently get asked what components go into designing an effective smoke control system.

To answer that question in simple terms, we can compare a well-designed smoke control system to a human body, as all the same basic elements are needed to keep each functioning properly:

  • Decision-making control panel (brain)
  • Sensors and detectors (eyes/ears)
  • Equipment and devices (muscles)
  • Cable Network (nervous system)
  • Power Supplies (cardiovascular system)

Control System (brain):

ControlsAny well-designed smoke control system should have an application-specific control system as fire alarm systems are not always appropriate as life-safety control systems. The control system is the main user interface and will control your whole system. From the control system, a manager will be able to see the system status, activate the system and also override any automated actions; the system will make decisions based on automated cause and effect.

Controls should be designed with resilience, reliability and backup as a priority to prevent failure in case of an emergency.

Sensors and detectors (eyes and ears):

The eyes and ears of a smoke control system are made up of smoke detectors, heat detectors, manual call points, override switches, pressure sensors and temperature sensors. Reacting to differences in their environments or to previously programmed cause and effect, these devices are the first warning that activates the smoke control system’s safety equipment. They are integrated with other elements within the building, including the fire alarms, sprinklers, the building management system and more.

Equipment and devices (muscles):

The power switching panels (motor control panels) in your smoke control system provide all the power that allows the different pieces of equipment in your system to operate as they should. They are used for switching high-powered 3 phase fans and don’t have any specific standard on construction. External panels are available and form 2 arrangements are standard; form 4 is possible, but not required and is often expensive.

Input/output (I/O) devices also fall into the ‘muscle’ category. These usually connect to an addressable network, take power and communications signals and control devices and motors. There are multiple input/output devices within a system and are usually distributed around the building local to the equipment they are controlling – care should be taken to ensure that they are protected from vandalism, heat and damage.

Cables (central nervous system):

The cables in your system act as the central nervous system, relaying signals and power to the areas where they are needed. These should be installed with metal clips to maintain installation in a fire. To comply with regulations, fire rated cabling to Category 3 of BS 8519 is required for Life Safety System – this requires the cabling to be tested under fire conditions for heat, water jet and impact for 2 hours.. 3 Phase Power Cables should be classed as F120 and comms/230Vac/24Vdc Cables should be PH120+.

Power Supply (Cardiovascular System):

To get a good understanding of the power supply requirements for a smoke control system, we recommend looking at the official guidance. The code of practice that governs the selection and installation of fire-resistant power and control cable systems for life safety, fire-fighting and other critical applications is BS 8519:2020. It also makes reference to the recommendations of BS9999 and BS9991, with regard to the design and installation of the electrical distribution systems for life safety and fire-fighting equipment.

Competent Testing, Service and Maintenance:

servicing imageJust as with a human body, your smoke control system should have regular check-ups and tests to ensure everything is healthy and working as it should. At Colt, we recommend you do a simple weekly ‘in-house’ test, with more robust professional testing at 3 monthly intervals followed up by an annual inspection and full maintenance visit from a fully trained engineer at certified company. Under the RRO, for life safety equipment such as smoke control, it’s the building owner or operator’s responsibility to ensure systems are in working order.

Most smoke control systems are installed for life safety purposes. If a system is found to be faulty or underperforming we recommend a full risk assessment is carried out to determine if any compensatory measures are required to maintain safety prior to rectification of the problem.

If you want to know more or need help designing or maintaining an effective smoke control system that meets all the latest government guidelines and regulations, talk to one of our experts today.

Conor Logan Conor Logan is Associate Technical Director of Colt UK, Smoke and Climate Control Division. Conor designs innovative smoke control and HVAC systems and was Chairman of the Smoke Control Association for over 9 years.

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Topics: Smoke Control, Smoke ventilation, HVAC, Controls