Structural Fire Protection Research Articles

The research of influence polymeric compounds on the effectiveness of intumescent coatings for the fire-protection of construction structures

This article focuses on the devoted to the investigation of the influence polymeric binders on the flame retardant characteristics of intumescent species. It has been found that polymeric binders are the most preferable in the intumescent type of fire retardant compositions, with the thermal destruction of which graphite-like crystalline structures are formed. The chloroparaffin to improves the swelling of intumescent coatings based on acrylic binders by lowering the temperature of their thermal degradation, which occurs under the influence of the dehydrating agent - chlorohydrogen, which catalyzes the processes of carbonization and graphitization into the compounds.

Optimising design decision-making for steel structures in fire using a hybrid analysis technique

Steel structures can be protected against the effects of fully-developed fires by the use of sprayed on materials, board systems and intumescent paints, etc. or by using sufficiently large unprotected elements. This paper presents how optimum decisions for the protection of steel structures in fires can be achieved in a performance-based design environment, given conflicting structural fire design decision criteria and multidisciplinary fire design stakeholder views. In particular, a novel hybrid analysis approach is proposed for combining stakeholder views on the different fire protection options and the numerical outcomes of structural fire analysis. As for the stakeholder views, reference is made to benefits and costs criteria priorities for assessing competing options resulting from a previous study from the same authors. The fire protection structural performance is numerically and probabilistically assessed according to a parametric study. The proposed approach is exemplified by making reference to a limit state structural fire design of single steel elements. A synthesis and ranking technique is then applied to integrate the qualitative results obtained in terms of benefits and costs priority scores; and the quantitative measures of failure probabilities and costs for the different fire protection options. The results show that the ranking technique accounts for multidimensionality in synthesising the structural fire design decision problem. The results also show that intumescent paints and board systems are the most cost-effective options in different stakeholder influence scenarios, given a general selection of steel structural fire protection. The hybrid technique is proposed to support an optimal and cost-effective structural fire design decision-making for buildings in a performance-based design environment.

A hybrid steel–shape memory alloy reinforced concrete beam design for optimum fire resistance capacity

In structural design for reinforced concrete beams in fire, the traditional way to satisfy the fire resistance requirements is to provide adequate concrete cover, or axis distance, to the steel reinforcements. The purpose is to reduce the rate of temperature rise in the steel reinforcements, in which strength deteriorates with rising temperature. Past research shows that a shape memory alloy (SMA) reinforced concrete beam is able to increase both the strength and stiffness of the beam when the temperature in the SMA increases. However, the gain in strength by SMA at rising temperature reaches a peak at a critical temperature, about 300°C, beyond which its strength starts to decrease. At present there is no guidance for the design of hybrid steel–SMA reinforced concrete beams to obtain the optimal recovery stress as required by the fire resistance level. This paper describes a conceptual design of a hybrid steel–SMA reinforced concrete beam and the process to obtain the optimal position of the SMA reinforcements in the cross-section so as to maximise the strength of the beam in fire. This research is a world first to use this concept for structural fire protection of concrete beams.

Обеспечение огнесохранности конструкций учебно-тренажерных комплексов для подготовки спасателей-пожарных

Изучены способы и средства обеспечения огнесохранности строительных конструкций учебно-тренажерных комплексов для подготовки спасателей пожарных. Исходя из теплофизических свойств материалов, их доступности и стоимости в Республике Беларусь определены средства огнезащиты от многократного высокотемпературного воздействия (до 1200 °С). Разработана методика испытаний системы огнезащиты, которая позволяет дать оценку термостойкости и теплоизолирующей способности испытываемого образца, подвергаемого идентичному огневому воздействию реальных условий эксплуатации.

Performance of Palm Oil Clinker as a Bio-Filler with Hybrid Fillers in Intumescent Fire Protective Coatings for Steel

Intumescent coatings are an effective method for fire protection of steel structures. The search for more environmental friendly intumescent coatings has led to the utilization of palm oil clinker (POC) as a bio-filler in solvent-borne intumescent coatings in order to improve fire protection performance, mechanical strength and water resistance of steel structures. In this research, POC and hybrid fillers are mixed with an acrylic binder and then blended with flame-retardant additives in order to produce intumescent coatings. The samples were tested using Bunsen burner test, thermogravimetry analysis, surface spread of flame test, field emission scanning electron microscopy, static immersion test, and adhesion strength test. It was found that the optimum composition of POC and hybrid fillers gives the best fire protection performance with the lowest equilibrium temperature (171.3°C), high thermal stability, good water resistance and excellent mechanical properties. The results of the surface spread of flame test show that Sample A3, A4, and A6 were classified as Class 1, which is the best classification. For Sample A6 (a hybrid formulation), the addition of aluminium hydroxide gives better water resistance with the lowest rate of weight change (<0.2%), while the addition of magnesium hydroxide enhances the bonding strength of the coating up to 125% compared with Sample A1 which only has a single filler POC. It can be concluded that the optimum composition of POC and hybrid fillers results in intumescent coating with the greatest fire protection performance.

Fire Protection of Concrete Tunnel Linings with Waste Tyre Fibres

The damages caused by fire-induced explosive spalling of concrete in tunnels can be tremendous; it could result in enormous economic cost and potential loss of human life. For this reason, the structural fire protection of concrete tunnel linings plays an important role in the tunnel design. Polypropylene fibres have been used in concrete to prevent explosive spalling of concrete exposed to fire. On the other hands, thousands of tonnes of polymer fibres are generated worldwide as a by-product of the recycling of end-of-life tyres. Storage of these fibres is a problem, since it is flammable, of low density (and so very large in volume) and can be carried away by wind and pollutes the surrounding environment. They are also too agglomerated or contaminated with rubber to find any alternative use, and are generally disposed of by incineration. The polymer fibre recycled from tyres has equal high quality and durability as manufactured fibres. Finding ways of introducing these fibres in concrete can potentially reduce the use of virgin fibres and delivery a more environmental-friendly spalling-mitigation solution. This paper shows the preliminary outcomes of this research, which indicates the potential of using these recycled fibres to prevent fire spalling instead of manufactured polypropylene.

A group-AHP decision analysis for the selection of applied fire protection to steel structures

Decisions related to selecting the most suitable fire protection for steel structures subject to fully developed fires are critical to addressing design and construction uncertainties. Fire design stakeholders are faced with the challenge of managing their divergent opinions to make design decisions given the many options or engineered solutions available to meet performance objectives. This paper demonstrates the viability of a group-Analytic Hierarchy Process (AHP) as a multi-criteria decision analysis (MCDA) technique for managing fire design stakeholder opinions on economic, safety, environmental and societal considerations toward selecting suitable fire protection for steel structures. Based on 22 structural fire design decision criteria gathered from literature and expert opinion, 36 New Zealand stakeholders from 12 fire design stakeholder categories have been interviewed to elicit ratings from their relative comparisons of the structural fire design decision criteria. The Geometric Mean Method-Analytic Hierarchy Process (GMM-AHP) is used to assess four applied fire protection options or alternatively to use unprotected steel. The results show the seamless aggregation of multiple stakeholder desires, the importance levels of different stakeholder opinions and the systematic approach in ranking the proposed fire protection options. The ranking shows that given a general selection of passive fire protection by stakeholders having equal weights, there is a stronger preference for the concrete encasement of steel.

Огнезащита стальных конструкций плитным материалом PYRO-SAFE AESTUVER T

Providing required (statutory) parameters of fire resistance of R 60-R 180 steel beam structures involved in ensuring the overall sustainability of buildings and structures is not possible without the use of structural fire protection. Widespread method of structural fire protection involves the use of plate materials. The use of this type of fire protection allows for the production of works without the use of “wet processes”, which is very important for the Far North with a short period of time of positive temperatures. Fire-retardant treatment of steel structures with plate materials may also be carried out without stopping the production process in the reconstruction of buildings and structures. One of the members of the group of fire retardant materials are slabs PYRO-SAFE AESTUVER T, whose composition as a filler includes perlite, glass fiber, and as a binder - cement. The article describes current research aimed at obtaining baseline data to determine fire retardant efficiency of slabs PYRO-SAFE AESTUVER T and features of the calculation of fire resistance of coated steel rod elements in order to ensure regulatory requirements for fire resistance. The studies of fire resistance performance of coatings for steel structures allowed us to obtain the variation of thermal conductivity and heat capacity of fire retardant material, when impacted by fire. To obtain these dependencies, fire tests of steel-lined columns were conducted on the bench equipment for fire tests of building structures on the experimental base of VNIIPO of Emercom of Russia (All-Russian Research Institute for Fire Protection of Ministry of Russian Federation for Civil Defense, Emergencies and Elimination of Consequences of Natural Disasters). Parameters of cladding, such as density, humidity, emissivity, thermal conductivity and thermal capacity under normal conditions were taken from reference literature. Then, in the presence of experimental data, thermo-physical characteristics (thermal conductivity and heat capacity) of the material at elevated temperatures were calculated with a computer program by solving the inverse heat conduction problem. The obtained parameters of the thermal characteristics for a given flame retardants, allowed to construct warm-up nomograms of unlimited steel plates, depending on the thickness of the steel and the thickness of cladding with PYRO-SAFE AESTUVER T slabs. As a result of the research, the obtained nomograms of fire resistance of steel structures with PYRO-SAFE AESTUVER T fire protection plates may be used for the design of passive fire protection systems at construction sites. In combination with the calculation method, these nomograms allow to reduce the usage of fire-retardant material in cladding thereby increasing the economic efficiency of fire protection of this type. In Federal State Budgetary Establishment VNIIPO the “Instruction on the calculation of the actual limit of fire resistance of steel structures with fire-retardant frameless facings made of PYRO-SAFE AESTUVER T slabs” was developed.

Optimized fire protection of cultural heritage structures based on the analytic hierarchy process

Fire safety constitutes a significant part of engineering design practice that frequently lead designers to face critical decision-making type of questions. Especially in the case of fire protection of cultural heritage structures, the challenges that engineers confront are sometimes very difficult to deal with. Conventional prescriptive-based fire protection codes cannot be implemented for the protection of such structural systems; on the other hand, performance-based design (PBD) procedures can provide reliable solutions for this type of structures. Fire safety upgrading of historic structures can be expressed as multi-criteria decision making (MCDM) problems. In this context, we propose a model based on the analytic hierarchy process (AHP) that is able to assess the overall fire safety level of a structure in terms of the fire protection measures implemented. Moreover, a generic selection and resource allocation (S&RA) model is applied that in conjunction with the proposed AHP model leads to optimized solutions. In this study, the implementation of the proposed optimized fire protection upgrade framework along with its advantages is presented for the case of the Mount Athos monastery of Simonos Petra and results are discussed.

Robustness assessment of a generic steel fire-protected moment-resisting frame under travelling fire

Due to their vulnerability to high temperatures, steel structures are typically protected against fire by insulation materials, as recommended by fire codes. The fire resistance rating of a protected member is determined based on a standard fire test, which simulates post-flashover fire conditions. Empirical evidence has shown that fires in large open-plan compartments do not burn uniformly, and a method called “traveling fire” has been introduced in previous research to simulate the effects of spreading fires. An investigation is performed here to examine the robustness of a generic four-story moment-resisting steel structure with one-hour fire resistance rating subjected to travelling fire. Various fire sizes are considered: 12.5, 25, 50 and 100% of the floor area. The results show that while no collapse occurs during the 12.5, 50 and 100% fire sizes, the structure collapses under the 25% fire size at 85 min due to the inability of the system to transfer the load after one of the columns buckles. This seems to be in contradiction with traditional belief that a fire covering a larger portion of the floor plan would reduce the safety margin. The investigation performed underlines that the fire protection of structures based on the standard time-temperature curve does not necessarily provide adequate resistance under travelling fires. With the lack of adequate fire regulations codified for large compartments, more research is required before arriving at a better understanding of the application of travelling fire to large compartments.

Economic Comparison of Fire Fighting Measures of Gypsum-Based Materials

Fire resistance of building structures is important not only in terms of prevention of hazards to human health, but also from the economic point of view. The choice of method of fire protection of steel structures depends on the responsible choice of finish or cladding material and suitable technology implementation. Although the assessment of fire risk is a priority, when selecting the decisive criteria we must not also forget the cost of fire protection measures. This article aims at economic comparison of the two fire protection measures for the steel column of rolled profiles.

A simple method to predict temperature development in a protected steel member exposed to localized fire in large spaces

SummaryTemperature development is a key issue for fire protection of steel structures. However, until now, there has been little systematic approach to predict the steel temperature development during the whole process of a localized fire in large spaces. The smoke temperature development in large spaces is different from that in normal enclosure fires as they have lower maximum temperatures and non‐uniform temperature distributions. In the present study, a whole process prediction method for the development of smoke temperatures in a large space localized fire is proposed. The prediction method accurately reflects the temperature curves (in the growing, fully developed and decay phases) and the uniform temperature distribution in large space localized fires. Based on basic heat transfer principles and the proposed smoke temperature development model, a new relationship is proposed to predict the temperature development in a protected steel member exposed to localized fire in large spaces. There is only one variable, t (time), in the proposed relationship, and thus, it is very simple to implement in evaluating temperatures, and it accurately reflects the development of the whole fire process (growing, fully developed and decay phases). Copyright © 2016 John Wiley &amp; Sons, Ltd.

FIRE PROTECTION OF WOODEN STORAGE CONTAINERS FOR EXPLOSIVE AND PYROTECHNIC PRODUCTS

Analysis of the emergency storage facilities for explosive and pyrotechnic products is conducted. It is established that one of the greatest risks is their flammability. Since the explosive and pyrotechnic products are stored in wooden containers, there is a need for their fire protection. To determine the efficiency of fire resistant containers for packaging explosive products it is designed operating range of testing method. This method is necessary to establish mass loss, measuring the growth temperature and response time of the squibs. The results of the efficiency of the fire retardant treatment of wood and organic coated coating showed that when exposed to high–temperature destruction of the construction detonation of the squibs didn’t happen. Tests to determine the quality of the fire retardant treatment of wood coatings showed that the temperature on the inner surfaces of the untreated sample was more than 760 ºC, samples with fire retardant coatings – no more than 128 °C. The conclusion of the feasibility of using fire–retardants is not based on inorganic and organic binders for the treatment of wooden structures. Method of determining the fire protection is used to assess the efficiency of the fire protection of wooden structures. Method comprises determining the ratio of the sample rate of burnout, the temperature increment and the ignition time of untreated and treated samples. As a result of the firing testing it is established a speed burnout reduction of samples of the container with treated coatings compared with untreated coatings is decreased by 2,4-4,4 times and respectively fire protection efficiency factor of treated samples of the container compared to untreated is increased by1.8-4.1 times.

Multi-layer polymer metal laminates for the fire protection of lightweight structures

A multi-layer polymer metal laminate (PML) system is described, which can be used to thermally insulate lightweight structural materials, such as aluminium or carbon fibre reinforced plastic (CFRP) composite, when exposed to fire. The system comprises many thin adhesively-bonded metal foils, bonded directly to the structural substrate. When exposed to fire the PML adhesive thermally decomposes with the generation of volatiles, causing the foils to delaminate and inflate, thus greatly reducing its thermal conductivity. The expanded PML slows heat transfer from the fire into the structural substrate, resulting in lower temperatures and increased structural survivability. The fire protection effects of two different thicknesses of PML are demonstrated here for both aluminium and CFRP substrates. Fire exposure tests demonstrate that the substrate temperatures are reduced and the time to failure under load is substantially improved. The protection offered is equivalent or superior to conventional fire protection materials such as ceramic fibre mat or intumescent coatings. The advantage of the PML is that, in non-fire conditions, it contributes to the appearance and load-bearing capability of the structure without being prone to damage or water absorption.

Solving Heat Conduction Problems in Movable Boundary Domains under Intensive Physical-Chemical Transformation Conditions

Results of solving problems of simulating temperature fields in domains with movable boundaries of characteristic zones of intensive physical-chemical and thermomechanical transformations to be realized in materials upon high-temperature heating have been presented. Intumescent fire-protective coatings based on organic and mineral materials are the object of study. Features of numerical realization of input equation systems taking into account, in particular, a dynamics of considerable increase and subsequent decrease of the intumescent layer thickness have been considered. Example calculations for structures of metal and wood protected with various coatings are given. Results of calculating two-dimensional temperature fields in polymer composite square-shaped structures with internal cruciform load-bearing elements have been presented. The intumescent coating is arranged on the external surface of a structure. The solution of the above-listed problems is of important significance to provide fire protection of different-purpose structures and products.

Material Solutions for Passive Fire Protection of Buildings and Structures and Their Performances Testing

In buildings and in civil engineering structures, both active and passive fire protection are used. Active fire protection includes automatic fire detection and fire suppression systems while the passive fire protection's main purpose is to attempt to contain fires or slower their spread. The aim of fire protection system's usage is to maintain the temperature of the building component (structural steel element, electrical installation) bellow the critical temperature during fire but also is intended to contain a fire in the origin fire compartment for a limited period of time. In this paper the passive fire protection material solutions were described and their action mode explained. Starting with thermal insulation barrier, endothermic building materials including concrete and gypsum and also novel solution based on alkali activated binders. Concrete is considered to be fire protective, however, in some specific cases, dense and low permeable concrete (i.e. high performance concrete) has a tendency to spall in explosive way under fire. Several fires in structures have caused the spalling of concrete elements that jeopardized the structure stability. In this specific case polypropylene fibres (PP) added to the concrete mix act as a passive protection system. Another group of passive fire protection materials, described in this document, are the intumescent and ablative materials for steel structure protection. The present manuscript describes also the techniques of passive fire protection testing in fire conditions.

Огнезащита материалов, изделий и конструкций из древесины: испытания и экономика

Огнезащита материалов, изделий и конструкций из древесины: испытания и экономика

Fire Scenarios for Multi-storey Façades with Emphasis on Full-Scale Testing of Wooden Façades

This paper briefly reviews the main fire scenarios for exterior facade claddings on multi-storey buildings, together with available full-scale test procedures and performance requirements in different countries. It is obvious that there is no international agreement or approach on how to evaluate the fire safety of facade claddings. Two series of full-scale fire tests of wooden facades, in accordance with the Swedish SP Fire 105 test, are presented: one series for different proportions of untreated wood (partial wood and structural fire protection with a fire shield above the window), and another series for fire-retardant-treated wood. The results are compared with data from the intermediate scale Single Burning Item test and the small scale cone calorimeter test. A main conclusion is that SP Fire 105 is a useful tool to evaluate the fire behaviour of facade claddings, but it should be complemented with more objective measurements. Claddings with partial wood and the use of a fire shield above the window fulfil the requirements. Wood claddings treated with fire retardants (FR) may fulfil the requirements, if the amount of FR is high enough. It is also essential to demonstrate the weather durability of the FR treatment. Good agreement has been found with the other test methods used. The need to use fire stops behind multi-storey facade claddings to avoid the spread of fire in cavities is underlined.

Damage mechanisms in cementitious coatings on steel members under axial loading

Cementitious coatings have been widely used as fire protection for steel structures, but they are vulnerable to structural deformations or vibrations, which may lead to reduction in their effectiveness and cause severe economic loss in the event of a fire. For buildings in practice, the problem can be critical because the coatings are assumed to be in good condition as they are usually hidden underneath architectural finishes, making it difficult and expensive to carry out routine inspection. To determine the actual fire resistance of a building after a moderate or severe loading event or a relatively long period of service, it is imperative to understand the performance of the coatings and to develop effective damage estimation methodologies. Loading conditions in a real buildings can be complex, however as there is inadequate previous work in this field, it is considered more important at this stage to determine the fundamental damage mechanisms in cementitious coatings on steel members subjected to axial loading, as investigated in this paper through experimental and numerical studies. At first, tests are carried out to obtain mechanical properties of the coating and the bond properties between the coating and the steel substrate. Then, a series of monotonic loading tests are conducted on axially loaded steel members to observe damage propagation in coating specimens. Subsequently, a cohesive zone finite element (CZFE) scheme is presented for modelling the damage with both interfacial and internal damage considered. The effectiveness of the proposed CZFE scheme is validated by comparison with different numerical approaches, interlaminar stress analysis and monotonic loading tests. From monotonic loading tests and CZFE numerical analyses, damage mechanisms in cementitious coatings on axially loaded steel members are clearly revealed. Under tensile loading, the damage begins with interfacial cracks at both ends, followed by transverse cracks within the coating resulting in its ultimate fracturing into segments. Under compressive loading, the damage also initiates at the ends with interfacial cracks and propagates towards the centre until the coating completely peels off. The findings from this research build a solid foundation for estimating the damage of cementitious coatings for trusses and large space structures, as most of the structural components in these structures are axially loaded. This work also provides an effective approach for further research on understanding damage mechanisms in cementitious coatings in steel frame structures under more realistic loading conditions.

Damage mechanisms in cementitious coatings on steel members in bending

Cementitious coatings are widely used as fire protection for steel structures but they are vulnerable to damage from structural deformations. In this paper, damage mechanisms in cementitious coatings on steel members in bending are investigated. A series of monotonically loaded beam tests are conducted to observe the occurrence of cracks and their propagation leading to final failure. The experiments are then simulated using a cohesive zone finite-element scheme, capable of modelling interfacial damage between the coating and steel substrate as well as internal coating damage. The results of the experimental and numerical studies clearly reveal the distinct damage mechanisms of cementitious coatings on both tension and compression sides of structural steel members in bending. Findings from this study provide the foundation for developing practical methods to determine the condition of cementitious coatings on steel structures after a short-duration extreme loading event (earthquake, blast, windstorms), where there is minimal external damage to the building fabric or long-duration cumulative damage from moderate levels of repeated non-monotonic loading. It is very unlikely in either of these cases that the integrity of cementitious fire protective coatings has been investigated in current practice.