The control of smoke and airflow in a building during a fire situation is critical. Managing how smoke and air can travel within and be extracted out of a building is essential for safe evacuation, protecting occupants, helping to contain fires, assisting firefighters and clearing the building of fumes and hazardous smoke post-fire.
While many technical solutions fit under the banner of smoke control, not all systems managing them are equal, and some make this critical and often complex process simpler, safer and more reliable. In all instances a smoke control system becomes an effective tool that should operate with high degrees of redundancy, automation or full manual control as required by the installation, specification and the standards which vary by region.
Among the range of options available in the world of smoke control, the electronic systems that manage them are becoming smarter than ever, and in some cases, can be the building’s fire alarm panel giving access to a wide range of interconnected components that enhances performance in fire situations and delivers significant cost saving benefits.
Understanding the composition of a smoke control system
Smoke control systems can be dedicated, independent of HVAC (Heating, Ventilation and Air Conditioning) systems, possessing their own infrastructure, or non-dedicated, sharing components with other systems including the building’s HVAC system. A comprehensive smoke control system is comprised of a number of elements: The control panel, often a dedicated unit but increasingly integrated into the building’s fire alarm control panel; detection in the form of smoke, CO and other sensors; interface modules that handle the interaction between the panel and fans, dampers, fire doors, elevators, vents, smoke curtains, HVAC and other systems; Fire Fighters’ smoke control stations, interconnecting cabling and containment; and the monitoring of main and backup power sources.
Integrated smoke control solutions, controlled through the fire alarm system, can offer several performance gains and cost saving opportunities to the building owner. These can include a reduction in the costs of installation, programming and maintenance of two separate systems and enabling the responsible parties to access all the smoke control and fire alarm settings through one control panel.
As smoke control is a critical life safety function, a comprehensive understanding of smoke control design, application and local and national code requirements is mandatory to ensure a code compliant, safe system is installed. A consultant or specialist will usually set out how the fans, dampers and smoke vents should operate in a fire situation, this information is often presented as a cause and effect matrix contained in a spreadsheet which is then passed on to an installer to program.
A major barrier to integration is often perceived to be the complexity of programming such a system, this has long presented a challenge to the fire industry. The programming of such Integrated systems to meet specifications is often written in proprietary, manufacturer-specific code, which once written can be complex and time-consuming to decipher unless it’s well documented.
DynamixSmoke, Advanced’s high-performance smoke control solution takes a completely new approach to configuration with its innovative programming matrix, eliminating the need for complex cause and effect equations. This simple matrix solution allows the consultant/specifying engineer’s cause and effect spreadsheet to be imported into the fire panel. Definition of smoke compartments is easy, turning on and off fans, opening and closing dampers under various conditions is auto configured, Interfaces are set for smoke control use and a design check is carried out in the configuration tool to eliminate typical programming errors before testing begins on site.
Such is the criticality of smoke control and its importance in life safety that often, depending on the country’s regulations, once the design is completed and before anything can progress, the design must be reviewed and approved by the local fire authorities as well other interested parties such as the building owners or their representatives.
Standards that establish requirements for the design, installation and testing of dedicated and non-dedicated smoke control systems used to mitigate the impact of smoke from fire are in place to protect life and reduce property loss. Although standards differ around the globe and may include; UUKL, AS 1668.1, NFPA 92 and EN12101-9, the common purpose is that they set the bar for operational capability, classifications and test methods to which smoke control solutions must all adhere.
Smoke control requirements have long been included as a supplement in the UL 864 standards. UUKL is an identifier created by UL to label those products listed under UL 864 as Smoke Control Equipment and has been used widely across the USA, the Middle East and parts of South East Asia, for some time. Although EN54 standards are not directly relevant to smoke control systems, the relevant component parts of the fire system being used for smoke control including; interface modules, smoke and heat sensors and the control panels need to be approved appropriately. In addition, EN54 Part 13 is a good indicator of system compatibility and performance. EN12101 part 9, currently in draft, will specify the product characteristics of control equipment operating as part of smoke and heat exhaust systems, detailing test methods, assessment methods and compliance criteria.
Compliance goes beyond simply the standards to which smoke control solutions need to adhere. To ensure that the system operates correctly when called upon, it is essential that the process of planning, design, installation, commissioning and maintenance are undertaken by competent parties. For example, for the system designer, a comprehensive understanding of the regulatory authority’s guidelines for product, installation and building codes of conduct and a familiarity with the requirements set out is essential.
A best in class system will meet the challenges of these demands while catering for a number of other common challenges of smoke control system requirements. A Purge feature is a manual function of the system that will enable the safe removal of smoke from indoor areas once a fire has been extinguished. Stairwell or lift-elevator shaft/lobby pressurization is a very common requirement that keeps exit routes clear of smoke by maintaining positive pressure in exit routes.
As smoke spreads to different fire compartments of a building it can be necessary to lock out subsequent signals, alternatively the most comprehensive systems will also be able to prioritize the containment or extraction of smoke in specific areas. Periodic testing, especially in dedicated systems, is also crucial to ensuring that fans and dampers will work as expected in an emergency situation. With such critical but complicated systems, testing of correct operation can be a significant investment.
Finally, in buildings without smoke control systems, it is common for any fans (used by HVAC systems) to be shut down in the event of an alarm to prevent the spread of smoke and fire. When the time comes for these fans to be restarted, the risk of overloads to the electrical circuitry can be commonplace. Therefore, a sequential fan restart feature that enables the gradual restart of these fans minimizes the chance of electrical surges.
Whatever options are chosen, the role of smoke control in fire protection is of significant importance and specifiers should be aware of the requirements and the technical options available.
For more information, go to www.advancedco.com/fire-systems/axis/axis-ax/dynamixsmoke.aspx