Fire damper DESIGN GENERAL FIRE CELL DIVISION DISTRIBUTION OF RESPONSIBILITIES FIRE PROTECTION DOCUMENTATION HAGAB FIRE DAMPER DESIGN

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1 Fire damper DESIGN GENERAL Chapter 5 of the BBR (National Board of Housing, Building and Planning's building regulations) specifies the functional requirements which form the basis for fire protection in buildings. Many proposals for solutions have been presented in various construction standards over the years. Previously issued standards specified standardized, detailed solutions for fire protection. So-called function-based solutions were specified for the first time in BBR 94. New experience and adaptation of the standards in the rest of the EU give more scope for designers to use methods that are more suited to the current property. Today, two methods are mainly used for dimensioning the fire protection system in a building. "Analytical dimensioning" and/or "Dimensioning through classification". See also "Practical Solutions Fire protection", published by Svensk Ventilation. DISTRIBUTION OF RESPONSIBILITIES Air treatment installation design forms a part of the overall fire protection system which places greater demands for knowledge of fire protection on the ventilation designer. It is the developer's responsibility to ensure that the property's fire protection meets official authority requirements. The developer must, among other things, appoint a quality manager and a fire expert for the property. In order to meet these requirements, it is important to clarify the conditions which apply before the property's air treatment system can begin to be designed. The purpose of the fire protection documentation is to create a basis and aid to other consultants during the design phase, and to assist in the planning authority's assessment of the developer's knowledge of fire protection. It must also constitute a basis for inspection and certification of expertise as well as for future fire inspections made by the fire services and future conversions. FIRE CELL DIVISION According to BBR, a building must be divided into fire cells which, among other things, separate different activities in the building. Each fire cell must be separated from other spaces with structural elements which prevent the spread of fire and fire gas. Separation refers to sealing against the permeation of gases and flames as well as to heat insulating capacity, so that the temperature on the side not exposed to fire does not present a risk of the fire spreading. The separation requirement also applies, of course, to installations which pass through the structural element separating the fire cells. This means that lead-throughs, necessary storage spaces, suspension devices and joints must also be designed to maintain satisfactory fire protection. See "Lead-throughs in fire cell limits" and "Suspension devices". Fire cell 1 Fire cell 2 Fire cell 3 FIRE PROTECTION DOCUMENTATION According to BBR, fire protection documentation must be established which should specify the structure of fire protection for the current property. The fire protection documentation should include: Fire classes of the building and its components Evacuation strategy Fire cell division Description of fire protection installations The air treatment installation's function in case of fire Plan for inspection and maintenance. 1

2 E 60 Element FIRE CLASSES (BUILDING) Taking into account factors which affect evacuation opportunities in case of fire and the risk of injury in case of collapse, buildings are divided into fire classes Br1, Br2 and Br3. Buildings in class Br1 have the highest requirements for surface finish, load bearing and separating structures. Examples of such buildings are hotels, hospitals and buildings with meeting rooms on the second floor. 60 min +945 C No temperature requirements. Limited leakage cracks. FIRE CLASSES (SEPARATING ELEMENTS) In buildings in class Br1, the fire class of separating elements depends on the fire load. FIRE LOAD IN (MJ/M2) FIRE CLASS 200 EI EI 120 > 400 EI 240 In buildings in class Br2 and Br3, apartment separating elements is in fire class EI 60 and other fire cell separating elements is in fire class EI 30. CLASS DESIGNATIONS The fire resistance of a fire cell separating element is divided into the following class designations: Element in fire class E 60 INSULATING CAPABILITY, I Refers to the maximum temperature rise on the side facing away from the fire. The insulating capability is divided into three groups. Group 1 An average temperature rise of 140 C and a maximum temperature rise at single points of 180 C. Group 2 An average temperature rise of 280 C and a maximum temperature rise at single points of 330 C. Group 3 There are no temperature requirements for structures in group 3. Temperature requirements in group 1 apply, for example, to elements and ventilation ducts, group 2 applies until further notice to pipe lead-throughs, cables, cable racks, etc. and group 3 applies to structures in fire class E. Integrity (density) Insulating capability Bearing capacity E I R SIS edition 2 specifies, among other things, the "standard fire curve", which is the basis for fire classification. E, I and R can be combined in cases where the structure has multiple separating functions in the event of fire. For example, a fire separating wall can be designed for fire class REI 60, which means that the element must maintain the integrity, insulating capability and bearing capacity for 60 minutes when exposed to fire according to the standard fire curve. INTEGRITY (DENSITY), E The requirement for fire class E is deemed to be met if the structure: does not allow permeation of more than single flames for a maximum duration of 10 seconds. does not allow permeation of hot gases or smoke which can ignite a piece of cotton wool. When testing structures where the average temperature on the side facing away from the fire exceeds 300 C, the permeation of hot gases is assessed after measuring the resulting cracks. does not collapse. Temperature rise, T-To, C Time, t, minutes 2

3 BEARING CAPACITY, R Bearing capacity refers primarily to the design of the building's load bearing elements, so that the building is not allowed to collapse within a prescribed period. SAFETY DISTANCE The distance to combustible materials required to prevent ignition and the distance to people evacuating the building to prevent overexposure to heat radiation. The distances will vary according to surface temperature, surface area and critical radiation effect. Safety distance Suspension devices for ventilation ducts AIR TREATMENT SYSTEMS In the context of air treatment, the following distinction is made between fire and fire gas: "Fire" The heat developed by the fire. "Fire gas" The gases formed by combustion. FIRE With regard to protection against the spread of fire via air treatment systems, the following four main methods can be distinguished: WATER SPRINKLERS Water sprinklers dampen the fire and create more favourable fire progression, which normally means that the fire resistance of building elements can be reduced and that the fire insulation of ventilation ducts can be reduced or completely avoided. Fire insulation Safety distance Water sprinkler system Extinguishing gas system FIRE INSULATION The duct system is insulated against fire to meet the requirement for maximum temperature rise in the non-burning fire cell. Note that insulating lengths and the fire class are affected by the choice of method used to protect against the spread of fire gas. For example, the need for insulation increases with fans in operation. EXTINGUISHING GAS SYSTEM In premises with highly sensitive equipment, such as data server rooms, fixed extinguishing devices are often installed to extinguish the fire with "inert" gases. In this case, special pressure relief devices must be fitted. Cable rack Glued laminate beam Seal Insulation 3

4 FIRE GAS Air treatment installations must be designed to ensure satisfactory protection against the spread of fire gas between fire cells. Satisfactory protection against the spread of fire gas between fire cells can be achieved by: separate ventilation systems for each fire cell extending outside the building special pressure-relief devices fire gas dampers with corresponding fire resistance as the current fire cell limit or allowing fire gases to enter the ventilation system, but designing the system so that the spread of fire gas between fire cells is prevented or substantially hindered depending on the room design and activity. The spread of fire gas to evacuation routes and rooms for sleeping should be prevented. SOME METHODS USED TO PREVENT OR GREAT- LY HINDER FIRE SPREAD ARE: Separate systems Fire gas dampers or fire/fire gas dampers Fans in operation Fans in operation converted system Fans in operation with backflow prevention dampers Pressure-relief devices for fire rooms Pressure relief of duct systems in combination with padded fans. To achieve cost-effective protection, it can sometimes be appropriate to use several methods at the same time in the same property. SEPARATE SYSTEMS Each fire cell has separate air treatment systems without an air connection with the other cells. FIRE GAS DAMPERS OR FIRE/ FIRE GAS DAMPERS Fire gas dampers or fire/fire gas dampers are installed against or separated from structural elements with a fire class to prevent the spread of fire gas to an adjoining fire cell. When fire/fire gas dampers are used, the breakthrough must always be insulated against fire in the same fire class as the structural element with the breakthrough. This applies when using fire/fire gas dampers as this type of damper is dimensioned to withstand the spread of both fire and fire gas at the breakthrough. When installing separated from walls, the duct and damper are insulated to an approved method according to the insulation supplier's instructions. FANS IN OPERATION In a building with FTX systems, the comfort fans keep operating in the event of fire. Specific calculations are required to assess the risk of fire gas spreading in all types of fire. To prevent the spread of fire gas, the pressure in the fire room must never exceed the total pressure in the supply air duct to the fire cell. The power supply, temperature resistance of fans and the risk of clogged filters in the exhaust air system must all be guaranteed. Fans in operation can, of course, be applied in systems with only mechanical exhaust air. From the viewpoint of fire gas spread, this system is more favourable because outdoor air devices will act to relieve pressure in the fire room. However, calculations are required to assess the risk of the fire gas spreading. FANS IN OPERATION CONVERTED SYSTEM Regular supply and exhaust air fans for comfort are replaced with common exhaust air fans throughout the system, which start in the event of a fire and create a negative pressure in both the exhaust air and supply air ducts. Specific calculations are required to assess the risk of the fire gas spreading in all types of fire. The calculation must take into account that any resulting negative pressure above closed doors must not prevent or hinder evacuation. The supply and exhaust air system must be completely insulated against fire with respect to the flow of fire gases. The power supply for fire gas fans must be guaranteed. FANS IN OPERATION WITH BACKFLOW PREVENTION DAMPERS In FTX systems, the supply air to each fire cell is equipped with a backflow prevention damper. In the event of a fire, the building's comfort fans keep operating for both supply air and exhaust air. In the initial stage of a fire, the fire gas pressure is relieved via the exhaust air system. The backflow prevention damper closes when the fire pressure eventually exceeds the pressure in the supply air duct to the fire room. This prevents fire gas from penetrating into the supply air system. Ventilation in the rest of the building continues to operate normally, which is a major benefit in case of evacuation. The entire exhaust air system must be insulated against hot fire gases. The supply air duct is insulated at the breakthrough to the served fire cell. 4

5 PRESSURE RELIEF OF FIRE ROOMS One method in combination with fans in operation is to relieve pressure in the fire room mechanically via dampers in the outer wall, so the pressure in the fire room never exceeds the total pressure in the supply air duct to the fire cell. This solution is very sensitive to changes in the fire load inside the room. PRESSURE RELIEF OF DUCT SYSTEMS One method used to hinder the spread of fire gas is the so-called "Pressure drop method 5:1". However, this does not prevent the spread of fire gas and is no longer widely used. LEAD-THROUGHS IN FIRE CELL LIMITS In general, installations that break through fire separating elements must not impair the fire resistance of the element. There are currently a large number of fire sealing systems on the market. Many types of materials are used and product development is progressing quickly. The following types of fire seals can be identified: Boards with supplementary compound or paint. Duct Wall Seal Besides the actual seal, it is also very important that the duct retains its original form in the lead-through. When exposed to fire, the ventilation duct deforms and gaps appear between the seal and the side of the duct, resulting in the spread of fire and fire gas. For this reason, ducts must be braced at the breakthrough to prevent deformation. SUSPENSION DEVICES The fire resistance requirements placed on ducts and components in an air treatment installation also apply, of course, to the suspension devices. When dimensioning the bearing capacity of the suspension devices, it is important to consider the dead weight of the installation and, if appropriate, the dead weight of the duct insulation and its impact in the case of fire. The suspension devices must not impair the fire resistance times of the installation or constitute any danger to the emergency services due to falling installation parts. The suspension device consists of a suspension and an attachment together with a variety of parts, e.g. union piece, tape, hanger, screws, rivets, etc. It is therefore important that all parts in the structure meet the requirements for bearing capacity. The attachment's bearing capacity R in case of fire is tested according to SP FIRE 118. THESE TESTS INCLUDE THE FOLLOWING: Suspension devices with bearing capacity R 15 must be able to bear a load of 0.5 kn for 15 minutes. Casting compounds. Foaming compounds. Expanding seals. Packing bits/modules and the like. Sealing strips, gear, etc. Combinations of the above sealing methods also exist. For all these methods, it is important that the manufacturers provide good installation instructions. When a fire seal or sealing system is type approved, the installation instructions are a requirement to obtain type approval. We must be observant and check the conditions for which the approval applies. There are always restrictions such as the maximum duct area, element type, element thickness, etc. To ensure that the fire seal functions properly, we recommend only using products that have been tested and which meet the relevant test criteria. Suspension devices with bearing capacity R 30 and R 60 must be able to bear a load of 1.0 kn for 30 and 60 minutes respectively. HOWEVER, WITH THE BASIC REQUIREMENT R 60 FOR THE DUCT SYSTEM, SUSPENSION DEVICES IN R 15 CAN BE IN- STALLED IN THE FOLLOWING CASES: Within shafts and plant rooms in fire class EI 60. Based on the low fire load. Within cladding in fire class EI 60. Within courtyards covered with glass. Based on the low fire gas temperature. Within areas fitted with sprinklers. More than 5 m from the fire cell separating element within the last served fire cell. 5

6 DAMPER TYPES WITH FIRE PROTECTION FUNCTION BACKFLOW PREVENTION DAMPER FIRE GAS DAMPER Covered by the harmonized European standard CE mark. The damper is designed to prevent the spread of fire gas in the ventilation system. The damper is open during normal operation. If there is an indication of fire gas, the actuator is disabled and the damper closes. Fire class E or ES. Described in VVS AMA & Kyl can be type approved. The backflow prevention damper is designed to prevent the spread of fire gas in FTX systems with fans in operation in the event of fire. It is positioned in the supply air duct to each fire cell. The damper is open during normal operation. When the fire pressure exceeds the pressure in the supply air duct to the fire cell, the self-acting backflow prevention damper closes, thus preventing the spread of fire gases to the rest of the ventilation system. A fire class cannot be assigned, as the product is included as part of a system solution based on the natural progress of the fire. STANDARDS CE MARK, BBR, TYPE APPROVAL, P MARK, AMA VVS & KYL FIRE/FIRE GAS DAMPER Covered by the harmonized European standard CE mark. The damper is designed to prevent the spread of fire and fire gas in the ventilation system. The damper is open during normal operation. If there is an indication of fire gas, the actuator is disabled and the damper closes. Fire class EI or EIS. CE mark: Classification standard SS-EN , Product standard SS-EN and Testing standard SS-EN Products which meet these European harmonized standards can be given a CE mark. Applies to fire gas dampers and fire/fire gas dampers. BBR: Boverkets Byggregler (National Board of Housing, Building and Planning's building regulations) control the national requirements for Sweden. Fire dampers are subject to the specified SS-EN standards with the "General advice" appendix, which states that the dampers should be activated via smoke detectors or that Analytical dimensioning can be verified. Analytical dimensioning provides scope for adapting fire protection solutions to the specific conditions, through calculations and any supplementary tests. Applies to, for example, system solutions for the evacuation of buildings or for controlling fire gas away from the evacuation routes. PRESSURE RELIEF DAMPER Described in VVS AMA & Kyl can be type approved. The damper is designed to relieve pressure in duct systems. The damper is closed during normal operation. If there is an indication of fire gas, the actuator is disabled and the damper opens. No fire class, because the damper opens a connection to the outside in the event of fire. Type approval: For products not covered by Boverkets Byggregler (BBR), type approval can be issued by an independent third party. The certification includes manufacturing and function controls. Legally binding agreements exist between Boverket, SP Certification and the manufacturer. Applies to backflow prevention dampers, pressure relief dampers. 6

7 P marking of fire dampers: The P mark is a supplementary mark which the industry has joined voluntarily to add requirements not covered by the CE mark. These include automatic function control, approved documentation, reporting, safety distances and insulation, as well as ensuring that the product meets BBR requirements. As a supplement to BBR, the P mark can also be issued for products which do not meet the harmonized standard but have an existing type approval certificate. The P mark is issued by SP Certification. The document is not legally binding, just like a type approval. AMA VVS & Kyl: General material and work descriptions for HVAC&R jobs. CE MARK SS-EN CLASSIFICATION STANDARD Classification based on test data from methods which measure the fire resistance of products for ventilation systems. Fire class E Integrity This fire class has no temperature requirements, only a density requirement when exposed to a standard fire according to the following: Leakage: max. 360 m 3 /h/m 2 at 300 Pa negative pressure. The damper should only allow permeation of single flames lasting a maximum of 10 sec (SS-EN ). A gauge with a diameter of 6 mm should not be able to be fed more than 150 mm through the structure. (SS-EN ) Fire class EI Integrity and insulation This fire class has requirements for both density and maximum temperature rise on the cold side when exposed to a standard fire according to the following: The damper and temperature rise of the connecting duct must not exceed 140 C (average) and 180 C at a single point. The damper should not allow permeation of hot fire gases which can ignite a piece of cotton wool. (SS EN ) Fire class S Fire gas density Dampers in fire class E and EI with increased density against fire gas leak can be given the suffix S if: The damper does not leak more than 200 m 3 /h/m 2 at 300 Pa negative pressure. Other requirements for the fire test are that the damper must close and open 50 times after being installed in the test path. All damper actuators must have a thermal sensor with a break point at 72 C and which closes the damper within 2 minutes. SS-EN Product standard Air treatment section Ducted fire dampers Describes the properties of the product, fire test requirements, cyclic tests, thermal sensor, documentation and production control. The thermal sensor's function must have been approved according to a specific standard. The dampers must undergo 10,000 closing/opening cycles. SS-EN TESTING STANDARD Describes how the testing facility must be equipped and how the dampers must be tested. When the tests and testing/certification body's documentation of the approved tests are ready, the performance of the dampers can be read from the following codes: Fire/Fire gas damper INTACT EI 60(ve ho i<->o)s E Integrity, density when exposed to fire I Insulation against the spread of heat 60 Time requirement for integrity and insulation ve Approved for installation in vertical elements (walls) ho Approved for installation in horizontal elements (floors) i -> o Approved for installation inside fire rooms i <- o Approved for installation outside fire rooms i <-> o Approved for installation inside and outside fire rooms S Increased density against cold fire gases BBR The national building regulations, Boverkets Byggregler, Chapter 5 Fire Protection, refers to the above SS-EN standards and two different ways of dimensioning fire protection in the ventilation system. Simplified dimensioning using ready-made solutions Separate ducts to the outside Fire dampers meeting the fire class of the element The "General advice" states that fire dampers should be activated (close) via smoke detectors. This is a national supplement to the European standard. Analytical dimensioning design through calculations This method places special requirements on verification and documentation. Fans in operation to prevent the spread of fire gas (e.g. BASIC) Other methods of controlling fire gas away from evacuation routes (e.g. RESQUE). 7

8 TYPE APPROVAL For products not covered by Boverkets Byggregler (BBR), type approval can be issued by an accredited certification body. Approvals are preceded by a test at an accredited testing institute. Test reports from the testing institute, installation instructions, material specifications and control systems from the manufacturer are assessed by the certification body, which can issue a type approval following a review. A type approved product meets the requirements of BBR and AMA VVS & Kyl. The documentation has been reviewed and approved by an accredited organization. Annual factory visits are carried out by the testing institute and performance checks are made on the selected products. Type approvals must be renewed every 5 years. There is a legally binding agreement between the affected parties for type approved products. Examples of products which are type approved and not overed by the CE mark are Backflow prevention dampers and Pressure relief dampers. P MARK The P mark is a Swedish quality symbol, which guarantees that the product which bears the mark at least meets with the quality requirements laid down by the EU, in Sweden and the industry's own requirements. The P mark is not mandatory. HAGAB fire dampers have the P mark. The P mark is issued by SP Certification and is intended to help maintain the quality level of fire protection which existed before the CE mark was introduced. The P mark is not an accredited certification and is there fore not a legally binding document. The P mark supplements the CE mark and adds the following requirements to the CE mark: - Documentation that is reviewed and approved by SP SITAC. - Extended documentation in Swedish. - The products meet the requirements of BBR and AMA VVS & Kyl. - The dampers must automatically be function tested every 48 hours and any faults must be indicated im mediately. AMA VVS & KYL AMA VVS & Kyl 12 is intended to serve as a basis for establishing technical descriptions and aims to simplify formulation of the client's requirements for the finished product. The text is organized in a hierarchical structure according to a so-called pyramid rule and can be exemplified as follows: It is organized in a hierarchical structure with codes and headings that can be exemplified as follows: 5 Water & sewerage, HVAC, cooling and process media systems Q Appliances, ducts, actuators, etc. in air treatment systems QJ Dampers, flow devices and air mixing devices QJC Dampers to prevent the spread of fire and fire gas QJC.2 Dampers for combined protection against fire and fire gas Dampers must be equipped with factory installed actuators Dampers must close in the case of power failure The damper must be controlled by a prescribed smoke de tector, positioned and installed according to the smoke detector manufacturer's instructions The damper must be controlled by an actuator connected to a prescribed monitoring and control system CONTROL AND MONITORING CE marked fire dampers must be function tested at least twice per year. P marked dampers must be function tested automatically every 48 hours and any faults must be indicated immediately. According to BBR, the fire dampers must be activated via smoke detectors. The function test must be automatic in order to maintain a high level of safety. The smoke detectors used to activate the fire dampers require a control device. In Sweden, we have always traditionally controlled fire dampers with devices which meet the requirements for automatic function testing, immediate indication and activation by smoke detectors. HAGAB's control and monitoring devices, SEHA, are available in a number of versions for stand-alone systems and networks. All units have the ability to control fans, activate different alarms and regularly perform a function test. - All safety distances and insulation instructions are defined. - Density rating in addition to that specified in SS-EN (if required). 8

9 DETECTION OF FIRE GAS Many protection functions must be activated in the event of a building fire. Alarms must be activated within the building and/or to a rescue centre. Fire dampers and fire doors must close. Fire gas fans must start. Smoke vents and pressure relief dampers must open. It is therefore important to minimize the time between detecting the fire and activating the protection functions so the evacuation time is not delayed. The fastest way to trigger a fire alarm is through the detection of fire gas. POSITIONING OF SMOKE DETECTORS IN VENTILATION DUCTS It is important to consider dilution when using smoke detectors. If it becomes too great, the concentration of particles may reduce so the smoke detector does not respond. The following rules of thumb should be noted: Maximum dilution of 10 to 20 times. Fire gas should not be transported more than about seconds before reaching a detector. Detector design is based on the fact that the air must be in motion. When shutting off the ventilation unit, the fire dampers must therefore also close to ensure maximum fire protection. The dampers will then already be closed in the event of a fire without fire gas being detected. For further information, see for example the Calectro manual "Smoke detectors in air treatment systems". SMOKE DETECTORS IN KITCHEN DUCTS Kitchen ducts in apartment buildings occasionally experience high concentrations of particles. The physical properties of these particles resemble the particles generated in a fire. All smoke detectors are designed to detect particles and to trigger an alarm when specific concentrations are detected. This means that the smoke detector cannot distinguish between genuine fire particles and frying smells, for example. It is therefore the actual concentration of particles entering the smoke detector which determines whether the alarm is triggered. When designing the ventilation in apartment buildings, you should ensure that the dilution of air in the kitchen ducts is high enough to avoid high particle concentrations, which may cause unwanted alarms. In this type of installation, it may be better to use a fire thermostat which breaks at a higher temperature, often 72 degrees. ACTUATORS The fire dampers are always supplied with fitted and tested actuators. These are spring return type actuators with limit switches which register when the damper is open or closed. The damper shaft has a square attachment in the actuator to ensure that the spacing between the damper shaft and the actuator remains constant. These are the type that must be able to close and keep the damper closed even when exposed to fire. The vital components of the actuator are therefore made of metal. CE marked dampers must have a thermal sensor which closes the dampers at 72 degrees. Flodin Fernström Hagab Box 135, Taberg Visit Industrivägen 5, Taberg Phone Fax info@hagab.com Sales Office Jönköping Phone Stockholm Phone