Available online at ScienceDirect. Procedia Engineering 172 (2017 )

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1 Available online at ScienceDirect Procedia Engineering 172 (2017 ) Modern Building Materials, Structures and Techniques, MBMST 2016 Doors with specific fire resistance class Daniel Izydorczyk a *, Bartłomiej Sędłak a,, Bartłomiej Papis a, Piotr Turkowski a a Fire Research Department of Building Research Institute Abstract Fire doorsets have a major role in the fulfillment of the rules of buildings fire safety. This paper discusses the main issues related to the fire resistance of fire doors - requirements, test methodology and way of classification of for this type of elements. Comparison of thermal insulation of fire doorsets test specimens depending on the type of structure and side of fire exposure was presented. Temperature rises have been compared on unexposed surface of timber, aluminum and steel doorset leaves in case of the fire acting from the hinge side and the side opposite the hinges. Keywords: fire doors, fire resistance, thermal insulation, fire integrity, smoke control, radiation, fire insulation, temperature comparison. Fire doorsets have a major role in the fulfillment of the rules of buildings fire safety.this paper discusses the main issues related to the fire resistance of glazed aluminum curtain walls - requirements in accordance with the provisions of Polish law, test methodology and way of classification of for this type of elements. Comparison of thermal insulation of fire doorsets test specimens depending on the type of structure and side of fire exposure was presented. Temperature rises have been compared on unexposed surface of timber, aluminum and steel doorset leaves in case of the fire acting from the hinge side and the side opposite the hinges. 1. Introduction Fire doors are used as closures for openings in horizontal fire separations found usually in public buildings, such as hospitals, cinemas, schools and shopping malls, high-rise buildings [1] or special-purpose structures, such as tunnels [5]. This type of buildings and structures must be built so as to make possible efficient and safe evacuation * Corresponding author. Tel.: ; fax: address:d.izydorczyk@itb.pl The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license ( Peer-review under responsibility of the organizing committee of MBMST 2016 doi: /j.proeng

2 418 Daniel Izydorczyk et al. / Procedia Engineering 172 ( 2017 ) of occupants in the event of a fire. Fire doors play a key role in the fulfilment of this requirement [2]. In fire conditions, they are to form a barrier to fire, smoke and heat. Therefore, this type of elements should be appropriately fire-rated with respect to tightness and the fire integrity, fire insulation and smoke control. This article will discuss main aspects of heat flow stopping, i.e. fire insulation. 2. Technical solutions Worldwide, there are many manufacturers of fire doors, and thus there is a great diversity in products of this type. Although each manufacturer uses its own individual design solutions, some common can be found in most cases. The basic issue is the material used to make the door here wooden and metal (most often aluminium or steel) doors can be distinguished. Doors can also be classified according toe their method of opening (hinged, sliding, rollup, etc.) or the number of door leaves (single leaf, double leaf, etc.). A special group are, however, glazed closures, with special fire glazing. This article discusses only the construction of the most commonly used door types, i.e. solid wood and glazed doors, seamless steel doors, profile steel and profile aluminium doors [6]. Example profile cross-sections are presented in fig Fire resistance classification and tests Fig. 1. Sample steel and timber profile cross-sections [8]. Fire resistance class of doors cannot be calculated or assessed based on comparisons. The sole method allowing to obtain a realistic and clear classification of a specific element is the fire resistance testing. According to standard EN :2007+A1:2009, the classifications of fire resistance doors shall be developed based on the tests carried out in accordance with standard EN : 2014 (fire integrity assessment (E), fire insulation assessment (I), and radiation assessment (W)), and the tests carried out in accordance with standard EN 14600:2005 (self-closing feature assessment (C)). The following fire resistance classes are defined: Table 1. Fire resistance classes of doors [7]. class E EI EI W (E fire integrity, I fire insulation, W radiation) The tested piece is heated in accordance to the standard temperature/time curve. This relationship is the model of a fully developed fire in a room, and is determined with formula (1). (1)

3 Daniel Izydorczyk et al. / Procedia Engineering 172 ( 2017 ) Where: T temperature in degrees Celsius; t test time in minutes. During the fire resistance testing of doors, the following performance efficiency criteria are verified: fire integrity, insulation and radiation. Fire integrity (denoted with the symbol E) is the ability of a structure element that acts as a partition to withstand fire applied at one side only, without transferring fire to the unexposed side as a result of flame or hot gas penetration to the other side. Fire integrity assessment is carried out according to three aspects: fractures or holes exceeding specified dimensions, verified by penetration of a gap gauge of diameters of 6 mm and 25 mm (the integrity is compromised when the 6 mm diameter gap gauge can be inserted into the gap caused by fire action and can be moved on a distance of 150 mm or if the 25 mm diameter gap gauge can be pushed right trough the door into the furnace interior), a cotton pad is ignited or glows (when touching the surface of the unexposed side of the tested element for 30 seconds), existence of flame on the unexposed surface (continuous flame lasting more than 10 s). Fire integrity classification (E) also depends on whether the door is also classified in terms of fire insulation. If an element is classified both in terms of fire integrity and fire insulation (I1or I2), the integrity value is determined using one of the three above criteria which is exceeded as the first. If a door is rated without regard to fire insulation, a fire integrity value is determined as the time exceeded against the cracking criteria, holes or sustained flaming, depending on which of these comes first. In this case, the cotton pad ignition criterion is disregarded. Fire insulation (denoted for the doors with symbols I1 or I2) is the ability of a structure element to withstand fire applied at only one side, without transferring the fire to the unexposed side as a result of significant heat transfer from the heated side to the unheated side. Fire insulation assessment is carried out according to the following: in the case of fire insulation class I1: measurement of the mean temperature rise of the unexposed surface of the door leaf, which should be limited to 140 C above the initial mean temperature, measurement at the maximum temperature rise, limited to 180 C at any point of the unexposed door leaf surface, without consideration of the measurement of temperature on the door leaf within the area located at a distance of less than 25 mm from the border line of the visible door leaf edge, measurement of the temperature rise at any point of the door frame, measured at the distance of 100 mm from the visible edge of the unexposed door leaf surface, provided the door frame is wider than 100 mm, or otherwise, at the door frame/supporting structure border, which should be limited to 180 C. in the case of fire insulation class I2: measurement of the mean temperature rise of the unexposed surface of the door leaf, which should be limited to 140 C above the initial mean temperature, measurement at the maximum temperature rise, limited to 180 C at any point of the unexposed door leaf surface, without consideration of the measurement of temperature on the door leaf within the area located at a distance of less than 100 mm from the border line of the visible door leaf edge, measurement of the temperature rise at any point of the door frame, measured at the distance of 100 mm from the visible edge of the unexposed door leaf surface, provided the door frame is wider than 100 mm, or otherwise, at the door frame/supporting structure border, which should be limited to 360 C. According to Table 1, the doors cannot be classified only in terms of fire insulation. The classes denoted with symbols EI1 and/or EI2 refer to the fire integrity and fire insulation capabilities. In this case, reaching of any of the fire integrity criteria also means loss of fire insulation, regardless of whether the individual temperature limits of insulation are exceeded or not. Radiation (denoted with the symbol W) is the ability of the structure element to withstand action of fire applied at only one side, to limit the possibility of transferring fire as a result of significant heat radiation by the element or

4 420 Daniel Izydorczyk et al. / Procedia Engineering 172 ( 2017 ) by its unexposed surface to the nearby materials. The elements for which the radiation criterion has been assessed shall be identified by adding the symbol W to the classification (e.g. EW). Classification of such elements shall be expressed in the time for which the maximum value of radiation, as measured using the method given in standard PN-EN , does not exceed the value of 15 kw/m 2. It is assumed that the element which meets fire insulation properties I1or I2 also meets the W requirements for the same period of time. The fire resistance tests of doors include measurements of displacement measured at the characteristic points of the door assembly, as specified in standard PN-EN [3]. Fire resistance testing shall be carried out on a specially selected sample, which shall be specified by the test laboratory as a result of comparison of the scope of application indicated by the Employer with the scope of applications of the test results, as defined in the test standard (EN for wooden doors) and in standard extending the application of test results (EN for wooden, side-hung and double-swing doors), PN-EN for steel, hinged and double-swing doors, PN-EN for steel, sliding doors, PN-EN for metal, profile, glazed and double-swing doors). These standards specify in detail the test method and provide guidelines to the Employer on how to achieve the widest range of application described later in the rating and in the technical approval (TA). The doors are required to be classified in the scope of fire resistance on both sides, therefore two sample elements shall be tested (each for one side), unless the element is fully symmetrical, i.e. identical on both sides of the axis symmetry as measured in the thickness of the lateral cross section [4]. A hinged timber door in a timber door frame is a special type of structure which is sufficiently predictable to allow identification of the worse test side of the door for such a door set for the opposite direction of fire impact. As wood is charred, when the heated side is on fire, it tries to shrink relatively to the unheated side, with results in the wooden leaf tendency to warp towards the fire at the top and bottom edges. The door frames tends to behave similarly, but because it is mounted in a fixing structure and is usually thicker and/or larger in diameter and consequently more rigid, it cannot move as much as the leaf. If the door opens towards the fire, then, as described above, the upper and lower edge of the leaf will tend to bend in the direction of fire and thus towards the edging strip. It makes it possible for flames to transfer and release hot gases from the furnace, assisted by positive pressure from the interior of the furnace, failing to meet the integrity criterion. If the door opens outside of the furnace, the upper and lower edge of the leaf tends to warp towards the fire and to the edging strip, which tends to improve the door performance. Timber leaves and door frames are an insulating material by nature, so it is unlikely that the fire insulation changes significantly depending on which side the leaf opened to with respect to the direction of heating. In conclusion, favourable timber door test results in a timber door frame when heated from the hinge side (opening inside the furnace) can be transposed without testing onto the opposite side of the door, i.e. the side opposite to hinges. The timber door in a timber frame tested for heating from the hinge side is the only case where identification of the heating direction can be done during the test, allowing to obtain the classification for the opposite direction of action for the criteria of integrity, insulation, and radiation [9]. It must also be noted that only in the case of the timber door in a timber frame the result of the test of the rigid supporting construction can be applied to the same door assembly when installed in a flexible supporting construction, and the test result for the standard flexible supporting construction can be applied to the door installed in a rigid supporting construction. In the case of timber hinged doors suspended in metal door frames, the situation is more complicated. A timber leaf of course tends to bend towards the fire on the top and bottom edges, while the frame is likely to behave differently. Metal expands in fire and thus the door frame expands on the heated side relatively to the unheated side, which may result in bending of the upper and lower edges in a direction opposite to the fire (an opposite tendency than for timber leaves). If the door opens towards the fire, then, the upper and lower edge of the leaf tends to bend in the direction of fire and thus from the edging strip, prematurely comprising the fire integrity. This condition worsens the bending of the metal frame in the opposite direction, outside the fire. If the door opens outside of the fire, the upper and lower edge of the leaf tends to warp towards the fire and to the edging strip, which tends to improve the door performance and thus is supportive of fire integrity. With regard to the fire integrity criterion, there is no clearly defined heating direction, which would be more burdensome. It might seem that the metal frame and the timber leaf opening toward the outside of the furnace is a worse situation, because a larger area of the door frame is exposed to fire and conducts heat to the unheated surface, which is smaller and transfers heat. However, it is not so

5 Daniel Izydorczyk et al. / Procedia Engineering 172 ( 2017 ) because that kind of a door set often loses fire insulation, due to compromised fire integrity. Hinged timber door in a metal door frame is a kind of door structures which is so unpredictable, that for such a door set the inferior test side cannot be determined also when it allows for a complete rating with the opposite direction of the fire impact. For this type of a door set, the heating door side can be identified during testing (a door opening in the direction of the furnace), which makes rating possible for the opposite impact direction only for fire integrity and radiation criteria. For timber door leaves in metal door, the test result in a standard flexible fixing structure is applicable to the same door set of built into rigid structure, but not vice versa. The last leaf-door frame interaction to be discussed relates to a metal leaf suspended in a metal door frame. Metal expands in fire, the heated leaf side tends to expand as compared to the unheated side, and consequently the metal leaf tends to warp outwards the fire on the upper and lower edges. The door frame will behave in a similar way, but because of being attached to a fixing structure it cannot move during the test as much as the leaf, depending on the fixing structure. If the door opens outwards the fire, then, the upper and lower edge of the leaf tends to warp outwards the fire and outwards the edging strip. This makes it possible to compromise fire integrity. If the door opens outside of the fire, the upper and lower edge of the leaf tends to warp towards the fire and to the edging strip, which tends to improve the door performance and thus is supportive of fire integrity. In the case of fire insulation, it can be stated that harsher heating conditions emerge in the case of a leaf opening towards the furnace, as the leaf is heated over its entire length and width and there is no protection by the edging strip. It may also be determined that a door leaf opening outwards of the furnace may be the worst scenario for the door frame, because most of it is exposed to fire and transfers heat to the unheated surface, and the area of the door frame is smaller on the unheated side, from which heat dissipates. It is likely that the difference between the behaviour of the door frame fire insulation and the preservation of fire insulation by the leaf will be a decisive factor in maintaining fire insulation of door set as a whole. Because it can be concluded that the leaf will behave worse when opening towards the furnace, but since the door frame will underperform with the leaf opening outwards, in order to assess the fire insulation of the complete door set, the test item opening in every direction should be tested. For hinged metal door in a metal door frame the inferior test side allowing for a full rating cannot be determined also when for the opposite direction of the fire impact. For this type of a door set, the heating door side cannot be identified during testing (a door opening in the direction outside of the furnace), which makes rating possible for the opposite impact direction only for fire integrity and radiation criteria. For insulated metal door leaves in metal door frames, test results in a rigid standard supporting construction are not applicable to flexible construction, or vice versa, testing should be carried out for every type of the standard supporting structure. The test is ended as a result of one of the following reasons: exceeding criteria, reaching satisfactory results, request of the Ordering Party, hazard to the personnel or potential damage to the testing equipment. 4. A comparison of temperature rises depending on the door construction and the side exposed to fire Comparison has been drawn up for the 5 types of single-leaf fire doors with a declared fire resistance class EI 2 30, tested in the recent years by the Fire Testing Laboratory of the Building Research Institute. The following test items were compared: aluminium door, profile, glazed door leaf dimensions 1400 x 2400 x 84 mm (width x height x thickness) made of three-chamber aluminium profiles, the middle chamber filled with a special insulation insert; the door frame made of the same profiles as the door leaf; steel door, profile, glazed door leaf dimensions 1400 x 2400 x 80 mm (width x height x thickness) made of single-chamber steel profile entirely filled with a special insulation insert; the door frame made of the same profiles as the door leaf; steel door, solid door leaf with dimensions 950 x 2400 x 68 mm (width x height x thickness), made of steel sheet with a thickness of 0.6 mm, the door leaf filling was a timber frame and mineral wool; door

6 422 Daniel Izydorczyk et al. / Procedia Engineering 172 ( 2017 ) frame dimensions 50 x 100 mm (width x depth), made of steel sheet with a thickness of 1 mm and filled with cement mortar, solid timber door with a steel door frame door leaf with dimensions 1140 x 2130 x 40 mm (width x height x thickness), made with a timber frame faced with HDF boards, the leaf filled with mineral wool; door frame dimensions 50 x 100 mm (width x depth), made of steel sheet with a thickness of 1 mm and filled with cement mortar, solid timber door with a timber door frame door leaf with dimensions 1200 x 2500 x 50 mm (width x height x thickness), made with special high density chipboard, double faced with HDF boards, door frame dimensions 50 x 100 mm (width x depth) made with pine timber. All but the last of the above-mentioned doors were tested for the exposure of fire on the hinge side and the side opposite to the hinges. Average temperature rise values were compared over the leaf and the door frame surface, which were measured by thermocouples laid out as shown in Figure 2. Fig. 2. Layout of thermocouples on the unexposed surface of the test specimen [8]. Figure 3 shows the difference between average temperature rises on the door leaf surface opening towards the inside of the furnace and the opening outwards the furnace (average reading from thermocouples 1 to 15). Figure 4 shows the comparison of the average temperature rise at a distance of 25 mm from the visible door leaf edge (average reading of thermocouples 11 to 15) for aluminium and steel profile doors, these were only the thermocouples placed on the door leaf profiles. Figure 5 shows the difference between average temperature rises at a distance of 25 mm from the visible door leaf edge opening towards the inside of the furnace and the door leaf opening outwards the furnace. Figure 6 shows the difference between average temperature rises on the door frame surface for the door leaf opening towards the inside of the furnace and the door leaf opening outwards the furnace. (average reading from thermocouples 16 to 20).

7 Daniel Izydorczyk et al. / Procedia Engineering 172 ( 2017 ) Fig. 3. Difference between average temperature rises on the door leaf surfaces opening towards the inside of the furnace and the door leaves opening outwards the furnace. Fig. 4. Comparison of the average temperature rise on door leaf surfaces, 25 mm from the visible door leaf edge [8].

8 424 Daniel Izydorczyk et al. / Procedia Engineering 172 ( 2017 ) Fig. 5. Difference between average temperature rises on the door leaf surfaces (25 mm from the visible door leaf edge) opening towards the inside of the furnace and the door leaves opening outwards the furnace. Fig. 6. Difference between average temperature rises on the door frame surface for the door leaf opening towards the inside of the furnace and the door leaf opening outwards the furnace. 5. Summary Fire insulating of fire doors depends on many factors related both to their design and the mounting method [8]. Both component materials used to manufacture the door leaf and the door frame are significant. On the basis of the analysis, in Fig. 3, 4, 5, 6 it can be seen how great an impact on the fire insulation is the side from which the door is exposed to fire. Only timber door in a steel door frame on both leaf and door frame surfaces showed inferior insulation under the impact of fire on the hinge side. For the profile steel door steel and seamless door surfaces, fire on the hinge side of the door is by far a worse scenario for the fire insulation. For the profile and seamless steel door frame, a reverse phenomenon can be observed much higher temperature rises were recorded for the door frames opening outwards the furnace. Temperature rises on the door leaf and the door frame surfaces of the aluminium profile doors opening inwards and outwards the furnace were so close to each other, that it s hard to unambiguously determine which direction of fire impact can be considered more devastating in this case. It is impossible to assess the fire resistance rating, or the fire insulation of fire doors on the basis of their design or specification of component materials. Even a slight change in the design or the method of fixing can significantly

9 Daniel Izydorczyk et al. / Procedia Engineering 172 ( 2017 ) affect their properties of fire resistance, and therefore the only method to determine the actual fire resistance rating is appropriate testing. It should be also noted that the fire insulation class is always coupled with the fire resistance class. No door can be rated just in terms of fire insulation, therefore compromised fire integrity entails compromised insulation as well. References [1] D. Izydorczyk, B. Sędłak, P. Sulik, Fire Resistance of timber doors - Part I: Test procedure and classification, Annals of Warsaw University of Life Sciences - SGGW Forestery and Wood Technology 86 (2014) [2] D. Izydorczyk, B. Sędłak, P. Sulik, Fire Resistance of timber doors - Part II: Technical solutions and test results, Annals of Warsaw University of Life Sciences - SGGW Forestery and Wood Technology 86 (2014) [3] D. Izydorczyk, B. Sędłak, P. Sulik, Problematyka prawidłowego odbioru wybranych oddzieleń przeciwpożarowych, Materiały Budowlane 11 (2014) [4] P. Sulik, B. Sędłak, Prawidłowy odbiór przeszklonych drzwi przeciwpożarowych, Świat Szkła 20(2) (2015). [5] P. Sulik, B. Sędłak, D. Izydorczyk, Odporność ogniowa i dymoszczelność drzwi przeciwpożarowych na wyjściach awaryjnych z tuneli badania i klasyfikacja, Logistyka 6 (2014) [6] P. Sulik, D. Izydorczyk, B. Sędłak, Elementy decydujące o awariach wybranych oddzieleń przeciwpożarowych, XXVII Konferencja Naukowo-Techniczna Awarie Budowlane, , Szczecin Międzyzdroje, 2015, pp [7] P. Sulik, B. Sędłak, Odporność ogniowa drzwi z dużymi przeszkleniami, Świat Szkła 20(3) (2015) [8] D. Izydorczyk, B. Sędłak, P. Sulik, Thermal insulation of single leaf fire doors, test results comparison in standard temperature-time fire scenario for different types of doorsets, Applications of Structural Fire Engineering,15-16 October 2015, Dubrovnik, Croatia, pp [9] D. Izydorczyk, B. Sędłak, P. Sulik, Izolacyjność ogniowa drzwi przeciwpożarowych, Izolacje 21(1) (2016)