Final Report Summary - FACOMP (Polymeric nanocomposite profiles for curtain walls)
Executive Summary:
Curtain walls are being constituted in one of the most used facade systems at the present time due to its facility of construction, lightness and to the great variety of materials and finished textures that are possible to obtain. The curtain walls are constituted by two elements clearly differentiated:
- The structural profiles of the curtain wall (the one in charge to support the glass or the coating panels and to join structurally the facade to the building)
- And the coating material which is the one that provides the final finished one. Generally this finishing is glass although exists the possibility of using other materials if it's required to give an opaque finish to the end item.
At the present times the materials more used for the structural profiles are aluminium and steel. These materials have a widely extended use although they often present/display problems of supply and recycling. Besides, its thermal behaviour is not appropriate since they are materials of great thermal transmission.
This project is intended to define a new system and a new nanomaterial to be used in substitution of the steel and aluminium for structural profiles. The system to develop must fulfil the same or better mechanical characteristics than the steel and aluminium, must be lighter, weather resistant and with better thermal and acoustic behaviour. The introduction of a new material will also imply a redesign or an adaptation of characteristics of the rest of materials that compose the curtain wall (joints, silicone adherence, glass, etc).
The materials that were used for the profiles were polymeric nanocomposites reinforced with fibres and nanoparticles. These materials exhibit several advantages:
- Design flexibility: the composites can be produced with irregular forms and different sections and finishes.
- Lightness: the density of the polymers is much less than that of their competitors (steel, aluminium, etc.), what allows the reduction of dead charges. Moreover, they have high specific properties and offer economic and logistic advantages due to their facility in transport, assembly and reparation
- Maintenance: they offer excellent weatherability and outdoor behaviour.
- Chemical behaviour: they show excellent behaviour against corrosion because they can be free of metallic materials
- Electric properties: polymers have very low electric conductivity and they don't show electromagnetic interferences
- Mechanical properties: they show high mechanical performance like strength, stiffness and tenacity
- Fire properties: the use of a nanoclay will provide the composite of good fire behavior
Project context and objectives:
The main objective of the project was the definition, development and verification of new composite materials for its use like structural profiles in curtain wall systems in substitution to metallic profiles. The new material will be able to eliminate the problems currently experienced with aluminium. The following list compares the advantages of composites over the disadvantages of aluminium.
Disadvantages of aluminium
- Very limited performance features as an insulator
- Permits condensation
- Liable to rust and become scratched
- Liable to become corroded within a short period of time
- Mechanical joining of the corners does not act as an effective sealant, enabling air and water to pass through
- The corners are joined using screws that become loose over the course of time
Advantages of composite materials
- Excellent thermal insulation
- Resistance to condensation
- Long-lasting
- Immune to pollution
- Low air permeability
- High degree of water tightness
- Easy to clean
- Minimal maintenance
- Stability as regards colour
- High level of sound insulation
However, there were other objectives on this project, which can be divided into different areas:
Scientific objectives
- Development of profiles of composites with the following characteristics:
- Mechanical performance equal or better than aluminium profiles
- Better thermal insulation and weatherability than aluminium profiles
- Easy recyclability
- Optimisation of the composite formulation and processing technique
- Optimisation of delamination or intercalation of nanoclays in the polymer via melt processing
- Enhancement of the mechanical properties by fiber and nanoclay reinforcement
- Enhancement of fire properties by introduction of nanoclays
- Development of curtain walls with the developed composite profiles
Industrial objectives
- Light curtain wall structures easy for assembly.
- Less complex profiles for constructing the curtain wall due to the fact no thermal bridge break needs to be incorporated into them.
- Introduction of a well known technology as that of composites technology into a new market area
- Development of a new route for the manufacturing of curtain walls
- Opening of a new line of materials for any type of constructive element. This will increase the possibilities of using these materials for any project an architect can develop
- Development of a new facade system that will allow SMEs to compete with products of major quality and versatility in construction sector
- Longer life of structural parts (at least five yrs more). The better weatherability properties and chemical resistance (no corrosion) of composites will lead to products with longer life.
- Obtaining of a curtain wall system that fulfill the following properties:
- Air permeability: A3
- Water tightness: R6
- Wind resistance: Valid for a pressure of 1200 Pa
- Thermal isolation (U): 2 W/m²K
five acoustic: 40dB
Economical objectives
- Improvement of the competitiveness of the SMEs
- Reduction of costs due to the longer life of products. There is no need to change the structures in longer times (at least five yrs). Likewise, the number of profiles used to construct the curtain wall is less.
- Development of a new market area for composites
- Reduction of costs in manufacture and transportation due to the less energy required for transformation and lightness of the materials
Environmental objectives
- Energy and fuel consumption savings due to lightness of profiles and constructive systems in manufacture and transportation
- Energy savings indoor due to the good thermal isolation properties of the composites
- Environmental assessment of the composites must be equal or better than that of metallic parts
- Recyclable materials
Social objectives
- Increased safety of workers when assembling the structures. This is because these structures are lighter and thus, easier to man over.
- Improvement on citizen's safety by reducing the risks caused by the deterioration of buildings due to corrosion
Project results:
In order to accomplish the objectives of the project, the work was divided into the following work packages:
WP1: Management
Within the scope of this WP all activities to control and supervise the project were planned and executed in co-operation with the project partners.
WP2: Dissemination and exploitation activities
The overall objective of this workpackage was to disseminate the project results
WP3: Analysis of the materials
Analysis of the commercially available different type of materials to be used. Definition of the characteristics of the composite materials to be used. Definition of the mechanical and thermal characteristics that the composites must fulfill.
Selection of the materials with the best characteristics to be used for the development of the composites.
WP4: Formulation of the composites
Formulation and fabrication of the composites to be employed by different processing techniques.
WP5 Determination of the characteristics
Determination of the physical, thermal, fire and mechanical properties of the composites with different reinforcements and matrices, and processed by different techniques.
WP6: Simulation:
Determining the structural and thermal behaviour of the materials created using simulations by finite elements. Definition and readaptation of geometric characteristics based on the results obtained. Redefinition of the formulations based on the results of the simulations.
WP7: Prototype preparation and construction of the curtain walling
Prototype preparation of the composite profiles.
Construction of a module of facade at real scale with the produced profiles.
WP8: Validation of the new façade
Verification of the new system created within the project by means of the tests foreseen in the product standard for light facades UNE-EN 13830: 2004. Cooperation of the characteristics with current commercial curtain wall system of aluminium or steel.
WP9: Environmental design and market analysis
Environmental analysis of the new system. Comparative with the current systems. Market analysis of the new system.
WP1: Management
The FACOMP partners assumed full technical and financial responsibility for the management of the project. This involved appointment of a project co-ordinator (TECNALIA) and project co-ordination committees. The project co-ordinator assumed overall responsibility for liaison between the partners and the Commission. The following committees and responsible persons were elected:
Management board
TECNALIA: Miguel Mateos project co-ordinator
SICOMP: Patrik Fernberg
TECHNOCLADD: Xavier Ortuzar
EXEL: John Hartley
ISOTES: Claudio Cantore
ENAR: Jesús Cerezo
Technical coordination board
TECNALIA: Miguel Mateos
SICOMP: Patrik Fernberg Technical coordination for composites
TECHNOCLADD: Xavier Ortuzar Technical coordination for curtain walls
Exploitation and dissemination board
TECNALIA: Miguel Mateos
SICOM: Patrik Fernberg
TECHNOCLADD: Xavier Ortuzar project exploitation manager
EXEL: John Hartley
SIKA: Uwe Bankwitz
ISOTEST: Claudio Cantore
ENAR: Jesús Cerezo
During the project five meetings were held:
- Kick off meeting: 28th October 2008 in TECNALIA's facilities (Azpeitia, Spain)
- six months meeting: 17th March 2009 in Swerea-SICOMP's facilities (Piteå-Sweden)
- Mid Term meeting: 15th September 2009 in ISOTEST's facilities (Torino, Italy)
- 18th month meeting: 11th may 2010 in EXEL's facilities (Runcorn, UK)
- Review and final meeting: 27th October 2011 in TECNALIA's facilities (Azpeitia, Spain)
Besides, on 4th November 2010 a teleconference meeting was held between TECNALIA, SICOMP and EXEL. During the whole project a regular communication by e-mail took place among all partners.
WP2: Dissemination and exploitation activities
All the work carried out within this WP regarding the use and dissemination of foreground is widely detailed in point 4.2 of this report. However, as a summary it can be concluded that there are two exploitable results:
- Definition and design of a new façade system to be used in substitution of aluminium and steel.
- Development of a composite material to be used as structural profile with advantageous properties such as thermal properties, resistance to weathering, lightweight.
The partners will exploit and disseminate the project results at two levels:
- Local strategies will be used by industrial partners to use the results within their companies
- Advanced strategies will be used in order to achieve a wider exploitation of the results of the project as well as a proper dissemination of those results to the whole European industry as well as to research organisations.
WP3: Analysis of the materials
Evaluation of characteristics
In order to select the raw materials, the target values had to be considered. These values were calculated according to the requirements that curtain walls must withstand. Results are shown below:
Young's modulus (GPa) Minimum value: 70 maximum value: 210
Flexural, tensile and compression strength (MPa) Minimum value: 130 maximum value: 275
Flexural modulus (GPa) Minimum value: 55 maximum value: 200
Thermal expansion coefficient (um/mºC) Minimum value: ten maximum value: 23
Working temperature Minimum value: -40 0C maximum value: 90ºC
Density (g/cc) maximum value <2.2
Besides there were some additional design requirements:
- Duration of structure: 50 yrs.
- Fire resistance: 30, 60, 90 or 120 min.
- Fracture toughness: The material must be sufficiently tenacious against fractures to avoid fractures at the lowest temperature foreseen in service during the foreseen life time of the structure.
- Surface Strength: Capacity to support impacts, evaluated with different methods (e.g. Brinnell).
- Joints: Compatibility with screws of stainless steel A2 and aluminium
Selection of materials
Initially thermoplastic and thermosetting composites were considered. After a deep research the following polymers were selected considering their potential to be used in profiles:
Iso-Polyester
Thermoset
Young's modulus: 3.8 GPa
Tensile strength: 42 MPa
Heat deflection temperature, HDT: 135 0C
Density: 1.10 g/cc
Price: ~2.5 /kg
Epoxy-vinyl ester
Thermoset
Young's modulus: 3.6 GPa
Tensile strength: 85 MPa
Heat deflection temperature, HDT: 150 0C
Density: 1.17 g/cc
Price: ~4 /kg
PBT
Thermoplastic
Young's modulus: 2.5 GPa
Tensile strength: 60 MPa
Density: 1.3 g/cc
Price: 2.5-3 /kg
PBT + 30 %GF
Thermoplastic
Young's modulus: 10.5 GPa
Tensile strength: 145 MPa
Heat deflection temperature: 120-130 0C
Density: 1.55 g/cc
Price: 2.5-3 /kg
PBT + 50 %GF
Thermoplastic
Young's modulus: 16 GPa
Tensile strength: 140 MPa
Heat deflection temperature: 120-130 0C
Density: 1.73 g/cc
Price: 2.5-3 /kg
Basalt and glass fibers were selected as reinforcement. Chopped fibres were used for TP polymers and roving for TS ones.
Among nanofillers, nanoclays were selected:
- Dellite HPS is a nanoclay deriving from a naturally occurring especially purified montmorillonite. It has moisture of 4-8 %, specific weight of 2.2 g/cc and cation exchange capacity of 128 Meq/100g.
- Dellite 43B is a nanoclay deriving from a naturally occurring montmorillonite especially purified and modified with a quaternary ammonium salt (dimethyl benzylhydrogenated tallow ammonium). It has a moisture of 3 % and specific weight of 1.6 g/cc.
Both nanoclays can be applied in polyesters and epoxy resins. Among the advantages they offer these ones can be highlighted when using dosages of around 5 % based on total system weight:
- Thermal stability
- Stiffness
- Chemical resistance
- Fibres reduction
- Flame retardant and antidropping
Nanoclays usually exhibit good fire performance when they are combined with traditional fire retardants. So, the following traditional fire retardants were considered:
- Aluminium hydroxide
- Ammonium polyphosphate
- Intumescent system: ammonium polyphosphate + melamine + pentaerythritol
WP4: Formulation of the composites
Thermosetting composites
- Manufacturing of test plates
Manufactured plates were used for material characterisation, i.e. mechanical tests, DSC and water uptake testing. To simulate the pultrusion process the method of filament winding was used. The winding was done with wet fibres, since any type of infusion would lead to filtration of clay particles. The manufacturing steps can be summarised as follows:
- Wet winding on an aluminium plate
- Bagging and then use vacuum to get rid of air bubbles and excess resin to increase the fiber content
- Curing in oven
- Removing the finished composite plate
- Manufacturing of profiles: prototype tube
Profiles were going to be manufactured industrially by pultrusion where a pulling action is used to get the material from the nozzle to avoid damaging and misalignment of the fibres. In this process fibres are pulled through a resin bath where they are impregnated. Then, the reinforcement and the uncured resin pass through a heated die where the resin is cured and the profile shaped.
The purpose of manufacturing a tube as a prototype profile was to test and fine tune the processing techniques. The quality of the tube was ok. Sedimentation of clay was not an issue because of the resin container was constantly stirred during manufacturing.
Thermoplastic composites
Thermoplastics were processed in a single screw extruder, after compounding with the nanoclays in a double corrotating screw extruder. During compounding the nanoclay must delaminate, what will depend on the shear stress and extrusion speed? So two screw speeds were used in the project:
- 20 rpm: it gave rise to a residence time of 1 min and 50 sec - 80 rpm: it gave rise to a residence time of 1 min and 10 sec
Formulation of the composites
During the project several parameters were analysed in both types of composites:
- Nanoclay type
- Nanoclay content
- Fiber type
- Fire retardant type
- Fire retardant content
Thus, several formulations were prepared for characteristics analysis.
WP5 Determination of the characteristics
Thermosetting composites
- Density
It was determined the density of several formulations with different nanoclay type and content. Besides, the calculated density was obtained with the rule of mixtures. It was concluded that increasing the amount of clay decrease the resin density increase. This meant that the shrinkage was reduced by the clay. The addition of the fire retardant increased the density of the systems. The final composite had a density of 1.73 g/cc.
- Water uptake
Most formulations showed values between 4.2 and 5.2 %. Nanoclay content equal or below 5 % lowered the maximal moisture content by approximately 1%. Furthermore, HPS lowered the maximal moisture content slightly more than the other clays.
- SEM microscopy
Nanoclay 43B had the best dispersion and mixing properties. Mixing time (5, 10 or 15 min) did not have a significantly impact on dispersion.
- Void content analysis
It was calculated by microscopy analysis. Typical values for void content for composites manufactured by filament winding are in the range -5 %. Our composites showed values between 1 and 4 %
- Interlaminar shear strength
It was calculated at room temperature and at 50 0C to simulate hot outdoor conditions. Results showed that epoxy composites gave rise to higher values than polyester composites and they were temperature dependent. However, values higher than 45 MPa were obtained for all composites.
- Young modulus
Polyester composites showed the highest values and were temperature independent. Nanoclay had no effect and results fitted very well with those calculated theoretically.
- Tensile strength
Nanoclays reduced the strength, probably because it introduced defects (agglomerates) due to bad dispersion. On the whole, values between 1100 and 1200 MPa were obtained.
- Thermal properties
Glass transition temperature was determined. Polyester composites showed higher values than epoxy which were around 150 and 140 0C, respectively.
- Fire performance
Fire testing was performed according to the standard ISO 11925-2: Reaction to fire tests. Single flame source test. It was determined the specimen length that was burned. Besides it was observed dripping, smoke generation and appearance of the sample.
Results showed that epoxy composites gave rise to better fire performance than polyester composites. However, when no fire retardant was added big flames were formed in the specimen even after having switched off the flame source. Besides lower part of the specimens were completely burned and very little resin remained after the test. The addition of fire retardants improved notably fire behavior of the composites. Fire retardants gave rise to auto-extinguishing composites, flame in the samples was extinguished after switching off flame source.
It was also observed that a lot of black smoke was generated during test in both protected and non-protected composites. However, the addition of the nanoclay reduced notably smoke generation, thus giving rise to safer materials.
- Adhesion tests
Adhesion between thermosetting and thermoplastic composites was determined with two products:
- Sikasil SG20: it is a monocomponent sealant from SIKA
- Sikasil SG-500: it is a bicomponent sealant from SIKA
Sikasil SG20 provided better results. Moreover breakage was cohesive in all cases. However, Sikasil SG500 showed adhesive breakage in some of the tests. Thus, the monocomponent sealant was selected to be used in the curtain wall.
- Ageing tests
The following ageing tests were conducted on specimens of different colours (orange, yellow, blue, black, natural, white, silver grey and brown):
- Ageing under Xenon lamp
- UVA light + water spray
- UVB light + condensation
- Weather-O-meter
Evaluation methods were visual observation, grey scale method, blue wool scale and colorimetric analysis.
Results showed that White, Black, Yellow and Orange samples stood Xenon-light at 65 % of humidity without noticeable changes in the colour. So, their colour retention was very good. Anyway, white sample showed strong yellowing under UV-B light. However, the same colours behaved differently when exposed to humidity without the action of light. While white and orange samples didn't show any significant colour change, yellow and black ones showed strong lightening due to humidity. Thus, depending on the type of façade (if profiles are going to be exposed to humidity + light or only light) different colours should be selected.
For profiles under humidity + light selected colours were yellow and orange. For profiles just under light selected colors were blue, brown and black.
Thermoplastic composites
- Mechanical tests
Composites of neat PBT
The nanoclay had little effect on the flexural properties. However, they improved notably flexural properties.
Composites reinforced with glass fibre
The addition of the nanoclay and the fire retardant to glass fibre filled PBT gave rise to decreases in the flexural strength, especially at higher glass fibre contents (50 %).
Composites reinforced with basalt fibre
At the same fibre content mechanical results for basalt reinforced PBT composites were similar to glass fibre filled composites. Moreover, addition of fibres to compounding step improved homogeneity of the composites. Silanisation of basalt fibres provided an increase of 10 % in the modulus, but it did not compensate the consequent processing difficulties.
Composites reinforced with glass and basalt fibres
Composites were reinforced with 30 % of glass fibre, 20-23 % of basalt fibre, nanoclay and fire retardant. Results showed that the addition of the nanoclay and the basalt fibres provided notable improvements in the flexural modulus of glass fibre filled composites. However, it was far away from the specifications for curtain walls (12 GPa vs 55 GPa).
- Fire tests
Combinations of fire retardant with nanoclays improved fire performance by reducing dripping and deformation, especially when organically modified nanoclay was used. Among the different fire retardants tested, melamine cyanurate provided the best overall results. Moreover, composites reinforced with combinations of glass and basalt fibre gave rise to the best results.
- Vicat softening temperature (VST)
Combinations of fire retardant and nanoclay reduced the VST. However, values above 200 0C were obtained.
- Ageing tests
Two carbodiimide compounds were tested to evaluate possible improvement on weathering performance. However, no improvement of flexural properties was provided.
Density
Density of the best nanocomposite was 1.64 kg/m3. This value was approximately 40 % lower than the density of aluminium (2.7 kg/m3).
WP6: Simulation and curtain walling drawing
Firstly a study of current curtain walls was made. Then, and after selected thermoset composites, simulations were developed to verify the behaviour of the material using different types of profiles. Finally, we defined the geometry of the curtain wall profiles based on the structural features that were obtained in the simulations. The work developed is listed below:
- Requirements for a light façade
The following requirements were considered:
- Structural
- Thermal
- Acoustic
- Hygrothermal
- Fire protection
- Tightness
- Systems currently used
Stick system has been used for a long time. It is a system where all parts are prefabricated and then assembled as a mechanism in the building site. Among its benefits we can highlight its ease of placement, the fact that there is no need for large facilities in the factory because all parts can be purchased and assembled independently and its economy. Among its disadvantages we can highlight the fact that, since it must be assembled entirely in the building site, there are often many failures in its assembly with the inconveniences this entails. Furthermore, the almost manual assembly implies a greater amount of time which ultimately can result in economic problems.
Unitised system has been developed in last year's. This system is built and assembled entirely in the factory. Because there are limitations to transport, the facade should be divided into modules of an appropriate size. This system ensures a higher component quality and safety because all the components are assembled in the factory. Likewise, assembly on the building site becomes easier because the modules can be placed very quickly due to a lack of works after their placement. A system like this implies a higher expenditure during manufacturing process but offers both a higher quality of the work and a higher speed of execution.
- Election of the system to be developed in the project
It was decided that the system to develop within this project had to be a Unitised or modular system because it involves the following benefits:
- Fewer tasks to perform
- Quality in the execution
- Time saving on-site assembly
- Unneeded auxiliary elements (scaffolding)
- Absence of on-site improvisation
Simulations
The main goal of this task was to compare the simulation results obtained for the new material with those of other materials such as aluminium which is employed in these types of profiles, in order to establish advantages and disadvantages or to reconsider initial hypothesis.
For the Horizontal load, maximum pressure/suction values of 1200 Pa, equal to 120 kg/m2, being a standard level in façade design, were established.
For Vertical load, in addition to the dead weight of the module, the weight of a 8/16/5 + 5 double glasing, equal to 40 kg/m2 was established. This load must pass on to the transoms though setting blocks located at one tenth of the span
Acceptance criterion for the deflection was L/200 or 15 mm as is stated in the regulation UNE-EN 13830: 2004. We considered that deflections greater that 15 mm were not admissible.
Results are shown below (first figure corresponds to tension in MPa and second one to deflection in mm).
Solid mullion 50.20
- Aluminium: 148 86
- Orthotropic composite 1: 133 468
- Orthotropic composite 2: 146 - 511
- Orthotropic composite 3: 175 156
- Isotropic composite: 148 133
Square tube 50.50.2
- Aluminium: 249 145
- Orthotropic composite 1: 212 746
- Orthotropic composite 2: 241 854
- Orthotropic composite 3: 297 - 267
- Isotropic composite: 250 224
Tube 185.50.2
- Aluminium: 100,9 - 16,4
Tube 190.50.2
- Aluminium: 96,7 - 15,2
Tube 215.50.2
- Orthotropic composite: 92,3 18
- Isotropic composite: 79,1 - 17
Tube 225.50.2
- Orthotropic composite: 78,9 16
- Isotropic composite: 76,1 - 15,1
Tube 230.50.2
- Orthotropic composite: 75,4 - 15,1
- Isotropic composite: 73,2 14,2
The conclusions obtained as regards the behaviour of the materials can be summed up into:
- It was a material with a smaller rigidity than aluminium, and for this reason we had to reduce the initial hypothesis, which were too demanding.
- Since it was a material with a lower Elasticity Modulus it was necessary to make profiles with larger sections to cover the same spans.
- The behaviour of the material in the perpendicular direction to the fibre was better that the other two options.
- The behaviour of the orthotropic material could be compared to the isotropic material only if it was performing in the perpendicular direction to the fibre.
- It was necessary to compare the tension results to be able to fully validate the unit's performance.
- New profile geometry
The results obtained in the simulations highlighted that the material developed in the project had slightly lower structural behavior than aluminium, thus the developed profiles had to have a slightly higher section than those of aluminium. However, due to a lower specific weight of the material compared to that of aluminium, this slight increase of the sections did not mean a weight gain but a reduction of the total per meter.
With the existing data it was developed a first complete system of a modular curtain wall.
- Simulations on the new geometry profile
- Influence of the fiber direction on the deformation and the stress of the project mullion.
- Fiber direction perpendicular to longitudinal section of the profile (wind load parallel to fibers): the deformation of the profile was higher that the established in the 13830 standard
2- Fiber direction parallel to longitudinal section of the profile (wind load perpendicular to fibers): the maximum deformation of the profile was far below the 15 mm establish in the standard (6 mm)
- Transom profile deformation under glass weight and wind pressure
- Complete modular simulation under glass weight and wind pressure
It can be concluded that
- Orthotropic characteristics of the material caused different behaviour in two planes perpendicular one to each other. It was observed that in the planes that were not perpendicular to the fibers the behaviour of the profile was worse, being the deformation almost three times greater.
- The results obtained with the dimensions of the defined module were good, being less than the admissible 15 mm.
Besides, thermal simulations were carried out on sections of the transom and the mullion. Here are the results:
- Mullion with all the parts with the composite material: Um mullion= 1.9 W/m2K
- Mullion with all interior hollow steel parts of 1 mm in thickness: Um mullion = 3.1 W/m2K
- Transom 1 with all composite material (without insulation panel): Um transom= 1.6 W/m2K
- Transom one with steel (without insulation panel): Um transom= 2.0 W/m2K
- Transom two with all composite material (without insulation panel): Um transom= 1.7 W/m2K
- Transom two with steel (without insulation panel): Um transom= 2.2 W/m2K
Taking into account these values, the dimensions of the simulated sections and three possibilities for the thermal transmittance of the double glasing, the thermal transmittance coefficient of the curtain wall can be calculated:
Without low emissivity
All composite Glass U = 2.8 Ucw: 2.79 W/m2K
With steel part glass U = 2.8 Ucw: 3.04 W/m2K
Low emittance with air
All composite Glass U= 1.7 Ucw: 2.26 W/m2K
With steel part glass U= 1.7 Ucw: 2.51 W/m2K
Low emittance with argon
All composite Glass U = 1.1 Ucw: 1.91 W/m2K
With steel part glass U = 1.1 Ucw: 2.16 W/m2K
WP7. Prototype preparation and construction of a curtain walling
Four thermoset composite profiles had to be manufactured. So, the same number of dies and infeeds had to be built to adapt to the pultrusion line. These are the profiles to be built:
- Pressure clip profile
- Transom profile
- Semi transom profile
- Semi mullion profile
Before building the dies the plans were readjusted to avoid manufacturing problems (i.e. rounding of corners). Then the dies with the required infeed were designed by using a computational program (solidworks). Finally the dies had to be built according to those plans. The project was finished when two dies and one infeed were completed.
Besides, a thermoplastic polymer profile was needed to act as a tight between the glass and the structural profiles. So, a nozzle was manufactured to adapt it to an extruder. Initially, PBT was chosen due to its combined properties of mechanical performance and flexibility. However, during manufacturing several problems arose:
The material had little flow resistance: the appearance was undesired and the tolerances could not be maintained.
- Cooling in the calibration zone was slow, thus the material crystallised turning it more fragile.
Initially, these problems were tried to solve by blending polybutylene terephthalate (PBT) with polycarbonate (PC). However, blends were still more rigid and did not accomplish with the requirements.
In order to avoid façade manufacturing problems, simulation of the manufacturing process was carried out. Currently used profiles with different designs were sealed and mounted at small scale to evaluate sealing conditions and the type of working force required.
Besides it was defined the size of the curtain wall at real scale as well as those of the profiles:
- At least three modules in width and a support comprising two forgings, with a distance of 3.2 m between them.
- Size of the profiles:
For air-water windload tests:
- Thermoplastic profile: 10 m
-Pressure clip: 40 m
- Transom: 6 m
- Semi-transom:12 m
- Mullion: 28 m
For noise insulation test:
- Thermoplastic profile: 8.94 m
- Pressure clip: 31.84 m
- Transom: 4 m
- Semi-transom: 8 m
- Mullion: 23.84 m
WP8. Validation of the new façade
This WP could not be accomplished because the prototype was not built during the scheduled timetable.
WP9. Environmental design and market analysis
Task 9.1. Analysis of the life cycle of the installations
The most important processes to evaluate the life cycle assessment (LCA) of the composites were the raw materials, manufacturing processes and disposal. Manufacturing process were the key point because several input and output were associated to pultrusion process.
When developing LCA of a certain material and process, several indicators might be considered. After analysing those possible indicators, the following ones were considered as the most relevant ones:
- Greenhouse effect: CO2
- Acidification: SO2
- Photochemical oxidants: C2H4
- Eutrophication: PO4
Task 9.2. Study of economical viability
As far as the market analysis is concerned, it has to be compared the cost associated to aluminium and composite materials.The average prices of raw materials are the following:
- aluminium 2/kg.,
- composite 50/50: 2.1/kg. (glass fibre 1.7/kg., polyester 2.5/kg).
Taking into account that workman in building, anchors, transport and machines, class, joints and sealants and workman in factory remain unchanged, the price for aluminium and composite curtain wall will be 213 and 215 /m2, respectively. Thus, the increase in price of the composite curtain wall is hardly 1% with respect to that of aluminum.
This WP was not accomplished completely because data related to final prototype were missing.
Potential Impact:
Potential impact
Despite not building the prototype physically on time, simulation results showed that it is possible to manufacture a polymeric curtain wall with thermoset composites as main material combined with other secondary materials like certain thermoplastic polymer and sealant, by using a proper profile design able to fulfil all the requirements of the application and being able to be processed easily while being economically viable.
The project results will lead to different impacts addressed below.
Improvement of quality of life
Metallic structures have a limited life due to their problems of corrosion. Corrosion induces several problems in the quality of life of citizens:
- Corrosion induces failure of structures, so replacement or amendment is required. This situation gives rise to the necessity of works in buildings and thus, troubles for the neighbours, for the traffic, for pedestrians, etc.
The substitution of metallic structures by composites removes such problems because composites don't corrode, so they have longer life and replacement of parts will be carried out less often.
Furthermore, due to the high thermal conductivity of the metallic parts the inner surfaces of such elements reach very low temperatures in winter (cold wall), causing condensation of the relative air humidity inside the building. This unpleasant effect may give rise to considerable flaws in the walls, curtains, parquet and furniture. However, composite materials minimize the risk of condensation due to their high level of thermal insulation.
Improvement of working conditions and safety
Composites have less density than metallic parts, so they are much lighter, even more than aluminium. Lighter structural parts will be easier to move, transport and assembly. So, facade builders will have much less danger when working with this new material in comparison with metal.
Improvement of environment
The processing temperature of the main composites is below 150 0C, while those of aluminium and structural steel are 660 0C and 825 0C. These data indicates that the energy required to manufacture composites is much less than that to process metals. The energy saving will have a positive effect for the environment.
On the other hand, thermal conductivity of metals is much higher than that of composites. Thermal bridge breaks are used to diminish this problem, however, this solution is worst than using an isolator like plastics, besides increasing complexity of the system. So, a reduction of thermal conductivity will lead to a reduction of the energy consumption.
Improvement of employment
This project will contribute to the improvement of the competitiveness of the different SMEs involved in the project because they will obtain a novelty for the facade sector based on a product with better characteristics than those already in the market.
It is expected that the improvement of the competitiveness of SMEs will improve their sales rates. As a result of this trend, they will improve their economical situation, which will probably cause an improvement on their employment rates.
Reducing dependence of critical raw materials
Aluminium is considered in the report of the ad-hoc working group on defining critical raw materials of 2010 as too critical due to its economic importance. So, new alternatives are being searched to reduce its dependence.
Dissemination and exploitation
Several dissemination activities were carried out:
- Project web site (http://www.facomp.eu)
- Presence in internet magazines and newsletter: 14 news and articles appeared published in internet related to FACOMP
- Press magazines and papers: four papers were published
- Conferences in congresses: two conferences were given in Spain and Finland
- Poster in the event of the European construction technology platform
- Presence in fairs: VETECO (Spain), Joint Evaluation Committee (JEC) composites show forum (France), CONSTRUMAT (Spain) and BATIMAT (France)
Regarding exploitation, two exploitable results were defined in the project:
- Definition and design of a new façade system to be used in substitution of aluminium and steel.
- Development of a composite material to be used as structural profile with advantageous properties such as thermal properties, resistance to weathering, lightweight.
It was agreed that the result defined as 'development of a composite material' will not be patented because no relevant novelty is proposed over current patents. However, the exploitable result 'Definition and design of a new façade system' is susceptible of being patented. It will be decided after building and testing the prototype (tasks that will be carried out by the partners on their own).
Partners envisaged two different types of exploitation strategies:
- Local strategies include the exploitation activities carried out by industrial partners, who will use the results within their companies.
- Advanced strategies include the activities carried out by partners, in order to achieve a wider exploitation of the results of the project to the whole European industry as well as to research organisations.
However, all activities carried out as exploitation and dissemination activities are explained in detail in the section 'Use and dissemination of foreground'.
List of Websites:
Project web site: http://www.facomp.eu
Name Surname Company Country e-mail telephone
Miguel Mateos TECNALIA Spain
Miguel.mateos@tecnalia.com +34 661874516
Julen Astudillo TECNALIA Spain
Julen.astudillo@tecnalia.com +34 647402258
Miriam García TECNALIA Spain
Miriam.garcia@tecnalia.com +34 647402327
Jesús Cerezo ENAR Spain enar@envolventesarquitectonicas.es +34 916303770
Miguel Ángel Núñez ENAR Spain
enar@envolventesarquitectonicas.es +34 916303770
John Hartley EXEL UK John.hartley@exel.net +44 7770443486
Claudio Cantore ISOTEST Italy info@isotest.it +39 0119310318
Jonas Engstrom SICOMP Sweden
jonas.k.engstrom@swerea.se +46 91174440
Patrik Fernberg SICOMP Sweden patrik.fernberg@swerea.se +46 91174440
Xavier Ortuzar TECHNOCLADD Spain xortuzar@technocladd.com +34 938641701
Anton Ettlin SIKA Switzerland ettlin.anton@ch.sika.com +41 566485405
Curtain walls are being constituted in one of the most used facade systems at the present time due to its facility of construction, lightness and to the great variety of materials and finished textures that are possible to obtain. The curtain walls are constituted by two elements clearly differentiated:
- The structural profiles of the curtain wall (the one in charge to support the glass or the coating panels and to join structurally the facade to the building)
- And the coating material which is the one that provides the final finished one. Generally this finishing is glass although exists the possibility of using other materials if it's required to give an opaque finish to the end item.
At the present times the materials more used for the structural profiles are aluminium and steel. These materials have a widely extended use although they often present/display problems of supply and recycling. Besides, its thermal behaviour is not appropriate since they are materials of great thermal transmission.
This project is intended to define a new system and a new nanomaterial to be used in substitution of the steel and aluminium for structural profiles. The system to develop must fulfil the same or better mechanical characteristics than the steel and aluminium, must be lighter, weather resistant and with better thermal and acoustic behaviour. The introduction of a new material will also imply a redesign or an adaptation of characteristics of the rest of materials that compose the curtain wall (joints, silicone adherence, glass, etc).
The materials that were used for the profiles were polymeric nanocomposites reinforced with fibres and nanoparticles. These materials exhibit several advantages:
- Design flexibility: the composites can be produced with irregular forms and different sections and finishes.
- Lightness: the density of the polymers is much less than that of their competitors (steel, aluminium, etc.), what allows the reduction of dead charges. Moreover, they have high specific properties and offer economic and logistic advantages due to their facility in transport, assembly and reparation
- Maintenance: they offer excellent weatherability and outdoor behaviour.
- Chemical behaviour: they show excellent behaviour against corrosion because they can be free of metallic materials
- Electric properties: polymers have very low electric conductivity and they don't show electromagnetic interferences
- Mechanical properties: they show high mechanical performance like strength, stiffness and tenacity
- Fire properties: the use of a nanoclay will provide the composite of good fire behavior
Project context and objectives:
The main objective of the project was the definition, development and verification of new composite materials for its use like structural profiles in curtain wall systems in substitution to metallic profiles. The new material will be able to eliminate the problems currently experienced with aluminium. The following list compares the advantages of composites over the disadvantages of aluminium.
Disadvantages of aluminium
- Very limited performance features as an insulator
- Permits condensation
- Liable to rust and become scratched
- Liable to become corroded within a short period of time
- Mechanical joining of the corners does not act as an effective sealant, enabling air and water to pass through
- The corners are joined using screws that become loose over the course of time
Advantages of composite materials
- Excellent thermal insulation
- Resistance to condensation
- Long-lasting
- Immune to pollution
- Low air permeability
- High degree of water tightness
- Easy to clean
- Minimal maintenance
- Stability as regards colour
- High level of sound insulation
However, there were other objectives on this project, which can be divided into different areas:
Scientific objectives
- Development of profiles of composites with the following characteristics:
- Mechanical performance equal or better than aluminium profiles
- Better thermal insulation and weatherability than aluminium profiles
- Easy recyclability
- Optimisation of the composite formulation and processing technique
- Optimisation of delamination or intercalation of nanoclays in the polymer via melt processing
- Enhancement of the mechanical properties by fiber and nanoclay reinforcement
- Enhancement of fire properties by introduction of nanoclays
- Development of curtain walls with the developed composite profiles
Industrial objectives
- Light curtain wall structures easy for assembly.
- Less complex profiles for constructing the curtain wall due to the fact no thermal bridge break needs to be incorporated into them.
- Introduction of a well known technology as that of composites technology into a new market area
- Development of a new route for the manufacturing of curtain walls
- Opening of a new line of materials for any type of constructive element. This will increase the possibilities of using these materials for any project an architect can develop
- Development of a new facade system that will allow SMEs to compete with products of major quality and versatility in construction sector
- Longer life of structural parts (at least five yrs more). The better weatherability properties and chemical resistance (no corrosion) of composites will lead to products with longer life.
- Obtaining of a curtain wall system that fulfill the following properties:
- Air permeability: A3
- Water tightness: R6
- Wind resistance: Valid for a pressure of 1200 Pa
- Thermal isolation (U): 2 W/m²K
five acoustic: 40dB
Economical objectives
- Improvement of the competitiveness of the SMEs
- Reduction of costs due to the longer life of products. There is no need to change the structures in longer times (at least five yrs). Likewise, the number of profiles used to construct the curtain wall is less.
- Development of a new market area for composites
- Reduction of costs in manufacture and transportation due to the less energy required for transformation and lightness of the materials
Environmental objectives
- Energy and fuel consumption savings due to lightness of profiles and constructive systems in manufacture and transportation
- Energy savings indoor due to the good thermal isolation properties of the composites
- Environmental assessment of the composites must be equal or better than that of metallic parts
- Recyclable materials
Social objectives
- Increased safety of workers when assembling the structures. This is because these structures are lighter and thus, easier to man over.
- Improvement on citizen's safety by reducing the risks caused by the deterioration of buildings due to corrosion
Project results:
In order to accomplish the objectives of the project, the work was divided into the following work packages:
WP1: Management
Within the scope of this WP all activities to control and supervise the project were planned and executed in co-operation with the project partners.
WP2: Dissemination and exploitation activities
The overall objective of this workpackage was to disseminate the project results
WP3: Analysis of the materials
Analysis of the commercially available different type of materials to be used. Definition of the characteristics of the composite materials to be used. Definition of the mechanical and thermal characteristics that the composites must fulfill.
Selection of the materials with the best characteristics to be used for the development of the composites.
WP4: Formulation of the composites
Formulation and fabrication of the composites to be employed by different processing techniques.
WP5 Determination of the characteristics
Determination of the physical, thermal, fire and mechanical properties of the composites with different reinforcements and matrices, and processed by different techniques.
WP6: Simulation:
Determining the structural and thermal behaviour of the materials created using simulations by finite elements. Definition and readaptation of geometric characteristics based on the results obtained. Redefinition of the formulations based on the results of the simulations.
WP7: Prototype preparation and construction of the curtain walling
Prototype preparation of the composite profiles.
Construction of a module of facade at real scale with the produced profiles.
WP8: Validation of the new façade
Verification of the new system created within the project by means of the tests foreseen in the product standard for light facades UNE-EN 13830: 2004. Cooperation of the characteristics with current commercial curtain wall system of aluminium or steel.
WP9: Environmental design and market analysis
Environmental analysis of the new system. Comparative with the current systems. Market analysis of the new system.
WP1: Management
The FACOMP partners assumed full technical and financial responsibility for the management of the project. This involved appointment of a project co-ordinator (TECNALIA) and project co-ordination committees. The project co-ordinator assumed overall responsibility for liaison between the partners and the Commission. The following committees and responsible persons were elected:
Management board
TECNALIA: Miguel Mateos project co-ordinator
SICOMP: Patrik Fernberg
TECHNOCLADD: Xavier Ortuzar
EXEL: John Hartley
ISOTES: Claudio Cantore
ENAR: Jesús Cerezo
Technical coordination board
TECNALIA: Miguel Mateos
SICOMP: Patrik Fernberg Technical coordination for composites
TECHNOCLADD: Xavier Ortuzar Technical coordination for curtain walls
Exploitation and dissemination board
TECNALIA: Miguel Mateos
SICOM: Patrik Fernberg
TECHNOCLADD: Xavier Ortuzar project exploitation manager
EXEL: John Hartley
SIKA: Uwe Bankwitz
ISOTEST: Claudio Cantore
ENAR: Jesús Cerezo
During the project five meetings were held:
- Kick off meeting: 28th October 2008 in TECNALIA's facilities (Azpeitia, Spain)
- six months meeting: 17th March 2009 in Swerea-SICOMP's facilities (Piteå-Sweden)
- Mid Term meeting: 15th September 2009 in ISOTEST's facilities (Torino, Italy)
- 18th month meeting: 11th may 2010 in EXEL's facilities (Runcorn, UK)
- Review and final meeting: 27th October 2011 in TECNALIA's facilities (Azpeitia, Spain)
Besides, on 4th November 2010 a teleconference meeting was held between TECNALIA, SICOMP and EXEL. During the whole project a regular communication by e-mail took place among all partners.
WP2: Dissemination and exploitation activities
All the work carried out within this WP regarding the use and dissemination of foreground is widely detailed in point 4.2 of this report. However, as a summary it can be concluded that there are two exploitable results:
- Definition and design of a new façade system to be used in substitution of aluminium and steel.
- Development of a composite material to be used as structural profile with advantageous properties such as thermal properties, resistance to weathering, lightweight.
The partners will exploit and disseminate the project results at two levels:
- Local strategies will be used by industrial partners to use the results within their companies
- Advanced strategies will be used in order to achieve a wider exploitation of the results of the project as well as a proper dissemination of those results to the whole European industry as well as to research organisations.
WP3: Analysis of the materials
Evaluation of characteristics
In order to select the raw materials, the target values had to be considered. These values were calculated according to the requirements that curtain walls must withstand. Results are shown below:
Young's modulus (GPa) Minimum value: 70 maximum value: 210
Flexural, tensile and compression strength (MPa) Minimum value: 130 maximum value: 275
Flexural modulus (GPa) Minimum value: 55 maximum value: 200
Thermal expansion coefficient (um/mºC) Minimum value: ten maximum value: 23
Working temperature Minimum value: -40 0C maximum value: 90ºC
Density (g/cc) maximum value <2.2
Besides there were some additional design requirements:
- Duration of structure: 50 yrs.
- Fire resistance: 30, 60, 90 or 120 min.
- Fracture toughness: The material must be sufficiently tenacious against fractures to avoid fractures at the lowest temperature foreseen in service during the foreseen life time of the structure.
- Surface Strength: Capacity to support impacts, evaluated with different methods (e.g. Brinnell).
- Joints: Compatibility with screws of stainless steel A2 and aluminium
Selection of materials
Initially thermoplastic and thermosetting composites were considered. After a deep research the following polymers were selected considering their potential to be used in profiles:
Iso-Polyester
Thermoset
Young's modulus: 3.8 GPa
Tensile strength: 42 MPa
Heat deflection temperature, HDT: 135 0C
Density: 1.10 g/cc
Price: ~2.5 /kg
Epoxy-vinyl ester
Thermoset
Young's modulus: 3.6 GPa
Tensile strength: 85 MPa
Heat deflection temperature, HDT: 150 0C
Density: 1.17 g/cc
Price: ~4 /kg
PBT
Thermoplastic
Young's modulus: 2.5 GPa
Tensile strength: 60 MPa
Density: 1.3 g/cc
Price: 2.5-3 /kg
PBT + 30 %GF
Thermoplastic
Young's modulus: 10.5 GPa
Tensile strength: 145 MPa
Heat deflection temperature: 120-130 0C
Density: 1.55 g/cc
Price: 2.5-3 /kg
PBT + 50 %GF
Thermoplastic
Young's modulus: 16 GPa
Tensile strength: 140 MPa
Heat deflection temperature: 120-130 0C
Density: 1.73 g/cc
Price: 2.5-3 /kg
Basalt and glass fibers were selected as reinforcement. Chopped fibres were used for TP polymers and roving for TS ones.
Among nanofillers, nanoclays were selected:
- Dellite HPS is a nanoclay deriving from a naturally occurring especially purified montmorillonite. It has moisture of 4-8 %, specific weight of 2.2 g/cc and cation exchange capacity of 128 Meq/100g.
- Dellite 43B is a nanoclay deriving from a naturally occurring montmorillonite especially purified and modified with a quaternary ammonium salt (dimethyl benzylhydrogenated tallow ammonium). It has a moisture of 3 % and specific weight of 1.6 g/cc.
Both nanoclays can be applied in polyesters and epoxy resins. Among the advantages they offer these ones can be highlighted when using dosages of around 5 % based on total system weight:
- Thermal stability
- Stiffness
- Chemical resistance
- Fibres reduction
- Flame retardant and antidropping
Nanoclays usually exhibit good fire performance when they are combined with traditional fire retardants. So, the following traditional fire retardants were considered:
- Aluminium hydroxide
- Ammonium polyphosphate
- Intumescent system: ammonium polyphosphate + melamine + pentaerythritol
WP4: Formulation of the composites
Thermosetting composites
- Manufacturing of test plates
Manufactured plates were used for material characterisation, i.e. mechanical tests, DSC and water uptake testing. To simulate the pultrusion process the method of filament winding was used. The winding was done with wet fibres, since any type of infusion would lead to filtration of clay particles. The manufacturing steps can be summarised as follows:
- Wet winding on an aluminium plate
- Bagging and then use vacuum to get rid of air bubbles and excess resin to increase the fiber content
- Curing in oven
- Removing the finished composite plate
- Manufacturing of profiles: prototype tube
Profiles were going to be manufactured industrially by pultrusion where a pulling action is used to get the material from the nozzle to avoid damaging and misalignment of the fibres. In this process fibres are pulled through a resin bath where they are impregnated. Then, the reinforcement and the uncured resin pass through a heated die where the resin is cured and the profile shaped.
The purpose of manufacturing a tube as a prototype profile was to test and fine tune the processing techniques. The quality of the tube was ok. Sedimentation of clay was not an issue because of the resin container was constantly stirred during manufacturing.
Thermoplastic composites
Thermoplastics were processed in a single screw extruder, after compounding with the nanoclays in a double corrotating screw extruder. During compounding the nanoclay must delaminate, what will depend on the shear stress and extrusion speed? So two screw speeds were used in the project:
- 20 rpm: it gave rise to a residence time of 1 min and 50 sec - 80 rpm: it gave rise to a residence time of 1 min and 10 sec
Formulation of the composites
During the project several parameters were analysed in both types of composites:
- Nanoclay type
- Nanoclay content
- Fiber type
- Fire retardant type
- Fire retardant content
Thus, several formulations were prepared for characteristics analysis.
WP5 Determination of the characteristics
Thermosetting composites
- Density
It was determined the density of several formulations with different nanoclay type and content. Besides, the calculated density was obtained with the rule of mixtures. It was concluded that increasing the amount of clay decrease the resin density increase. This meant that the shrinkage was reduced by the clay. The addition of the fire retardant increased the density of the systems. The final composite had a density of 1.73 g/cc.
- Water uptake
Most formulations showed values between 4.2 and 5.2 %. Nanoclay content equal or below 5 % lowered the maximal moisture content by approximately 1%. Furthermore, HPS lowered the maximal moisture content slightly more than the other clays.
- SEM microscopy
Nanoclay 43B had the best dispersion and mixing properties. Mixing time (5, 10 or 15 min) did not have a significantly impact on dispersion.
- Void content analysis
It was calculated by microscopy analysis. Typical values for void content for composites manufactured by filament winding are in the range -5 %. Our composites showed values between 1 and 4 %
- Interlaminar shear strength
It was calculated at room temperature and at 50 0C to simulate hot outdoor conditions. Results showed that epoxy composites gave rise to higher values than polyester composites and they were temperature dependent. However, values higher than 45 MPa were obtained for all composites.
- Young modulus
Polyester composites showed the highest values and were temperature independent. Nanoclay had no effect and results fitted very well with those calculated theoretically.
- Tensile strength
Nanoclays reduced the strength, probably because it introduced defects (agglomerates) due to bad dispersion. On the whole, values between 1100 and 1200 MPa were obtained.
- Thermal properties
Glass transition temperature was determined. Polyester composites showed higher values than epoxy which were around 150 and 140 0C, respectively.
- Fire performance
Fire testing was performed according to the standard ISO 11925-2: Reaction to fire tests. Single flame source test. It was determined the specimen length that was burned. Besides it was observed dripping, smoke generation and appearance of the sample.
Results showed that epoxy composites gave rise to better fire performance than polyester composites. However, when no fire retardant was added big flames were formed in the specimen even after having switched off the flame source. Besides lower part of the specimens were completely burned and very little resin remained after the test. The addition of fire retardants improved notably fire behavior of the composites. Fire retardants gave rise to auto-extinguishing composites, flame in the samples was extinguished after switching off flame source.
It was also observed that a lot of black smoke was generated during test in both protected and non-protected composites. However, the addition of the nanoclay reduced notably smoke generation, thus giving rise to safer materials.
- Adhesion tests
Adhesion between thermosetting and thermoplastic composites was determined with two products:
- Sikasil SG20: it is a monocomponent sealant from SIKA
- Sikasil SG-500: it is a bicomponent sealant from SIKA
Sikasil SG20 provided better results. Moreover breakage was cohesive in all cases. However, Sikasil SG500 showed adhesive breakage in some of the tests. Thus, the monocomponent sealant was selected to be used in the curtain wall.
- Ageing tests
The following ageing tests were conducted on specimens of different colours (orange, yellow, blue, black, natural, white, silver grey and brown):
- Ageing under Xenon lamp
- UVA light + water spray
- UVB light + condensation
- Weather-O-meter
Evaluation methods were visual observation, grey scale method, blue wool scale and colorimetric analysis.
Results showed that White, Black, Yellow and Orange samples stood Xenon-light at 65 % of humidity without noticeable changes in the colour. So, their colour retention was very good. Anyway, white sample showed strong yellowing under UV-B light. However, the same colours behaved differently when exposed to humidity without the action of light. While white and orange samples didn't show any significant colour change, yellow and black ones showed strong lightening due to humidity. Thus, depending on the type of façade (if profiles are going to be exposed to humidity + light or only light) different colours should be selected.
For profiles under humidity + light selected colours were yellow and orange. For profiles just under light selected colors were blue, brown and black.
Thermoplastic composites
- Mechanical tests
Composites of neat PBT
The nanoclay had little effect on the flexural properties. However, they improved notably flexural properties.
Composites reinforced with glass fibre
The addition of the nanoclay and the fire retardant to glass fibre filled PBT gave rise to decreases in the flexural strength, especially at higher glass fibre contents (50 %).
Composites reinforced with basalt fibre
At the same fibre content mechanical results for basalt reinforced PBT composites were similar to glass fibre filled composites. Moreover, addition of fibres to compounding step improved homogeneity of the composites. Silanisation of basalt fibres provided an increase of 10 % in the modulus, but it did not compensate the consequent processing difficulties.
Composites reinforced with glass and basalt fibres
Composites were reinforced with 30 % of glass fibre, 20-23 % of basalt fibre, nanoclay and fire retardant. Results showed that the addition of the nanoclay and the basalt fibres provided notable improvements in the flexural modulus of glass fibre filled composites. However, it was far away from the specifications for curtain walls (12 GPa vs 55 GPa).
- Fire tests
Combinations of fire retardant with nanoclays improved fire performance by reducing dripping and deformation, especially when organically modified nanoclay was used. Among the different fire retardants tested, melamine cyanurate provided the best overall results. Moreover, composites reinforced with combinations of glass and basalt fibre gave rise to the best results.
- Vicat softening temperature (VST)
Combinations of fire retardant and nanoclay reduced the VST. However, values above 200 0C were obtained.
- Ageing tests
Two carbodiimide compounds were tested to evaluate possible improvement on weathering performance. However, no improvement of flexural properties was provided.
Density
Density of the best nanocomposite was 1.64 kg/m3. This value was approximately 40 % lower than the density of aluminium (2.7 kg/m3).
WP6: Simulation and curtain walling drawing
Firstly a study of current curtain walls was made. Then, and after selected thermoset composites, simulations were developed to verify the behaviour of the material using different types of profiles. Finally, we defined the geometry of the curtain wall profiles based on the structural features that were obtained in the simulations. The work developed is listed below:
- Requirements for a light façade
The following requirements were considered:
- Structural
- Thermal
- Acoustic
- Hygrothermal
- Fire protection
- Tightness
- Systems currently used
Stick system has been used for a long time. It is a system where all parts are prefabricated and then assembled as a mechanism in the building site. Among its benefits we can highlight its ease of placement, the fact that there is no need for large facilities in the factory because all parts can be purchased and assembled independently and its economy. Among its disadvantages we can highlight the fact that, since it must be assembled entirely in the building site, there are often many failures in its assembly with the inconveniences this entails. Furthermore, the almost manual assembly implies a greater amount of time which ultimately can result in economic problems.
Unitised system has been developed in last year's. This system is built and assembled entirely in the factory. Because there are limitations to transport, the facade should be divided into modules of an appropriate size. This system ensures a higher component quality and safety because all the components are assembled in the factory. Likewise, assembly on the building site becomes easier because the modules can be placed very quickly due to a lack of works after their placement. A system like this implies a higher expenditure during manufacturing process but offers both a higher quality of the work and a higher speed of execution.
- Election of the system to be developed in the project
It was decided that the system to develop within this project had to be a Unitised or modular system because it involves the following benefits:
- Fewer tasks to perform
- Quality in the execution
- Time saving on-site assembly
- Unneeded auxiliary elements (scaffolding)
- Absence of on-site improvisation
Simulations
The main goal of this task was to compare the simulation results obtained for the new material with those of other materials such as aluminium which is employed in these types of profiles, in order to establish advantages and disadvantages or to reconsider initial hypothesis.
For the Horizontal load, maximum pressure/suction values of 1200 Pa, equal to 120 kg/m2, being a standard level in façade design, were established.
For Vertical load, in addition to the dead weight of the module, the weight of a 8/16/5 + 5 double glasing, equal to 40 kg/m2 was established. This load must pass on to the transoms though setting blocks located at one tenth of the span
Acceptance criterion for the deflection was L/200 or 15 mm as is stated in the regulation UNE-EN 13830: 2004. We considered that deflections greater that 15 mm were not admissible.
Results are shown below (first figure corresponds to tension in MPa and second one to deflection in mm).
Solid mullion 50.20
- Aluminium: 148 86
- Orthotropic composite 1: 133 468
- Orthotropic composite 2: 146 - 511
- Orthotropic composite 3: 175 156
- Isotropic composite: 148 133
Square tube 50.50.2
- Aluminium: 249 145
- Orthotropic composite 1: 212 746
- Orthotropic composite 2: 241 854
- Orthotropic composite 3: 297 - 267
- Isotropic composite: 250 224
Tube 185.50.2
- Aluminium: 100,9 - 16,4
Tube 190.50.2
- Aluminium: 96,7 - 15,2
Tube 215.50.2
- Orthotropic composite: 92,3 18
- Isotropic composite: 79,1 - 17
Tube 225.50.2
- Orthotropic composite: 78,9 16
- Isotropic composite: 76,1 - 15,1
Tube 230.50.2
- Orthotropic composite: 75,4 - 15,1
- Isotropic composite: 73,2 14,2
The conclusions obtained as regards the behaviour of the materials can be summed up into:
- It was a material with a smaller rigidity than aluminium, and for this reason we had to reduce the initial hypothesis, which were too demanding.
- Since it was a material with a lower Elasticity Modulus it was necessary to make profiles with larger sections to cover the same spans.
- The behaviour of the material in the perpendicular direction to the fibre was better that the other two options.
- The behaviour of the orthotropic material could be compared to the isotropic material only if it was performing in the perpendicular direction to the fibre.
- It was necessary to compare the tension results to be able to fully validate the unit's performance.
- New profile geometry
The results obtained in the simulations highlighted that the material developed in the project had slightly lower structural behavior than aluminium, thus the developed profiles had to have a slightly higher section than those of aluminium. However, due to a lower specific weight of the material compared to that of aluminium, this slight increase of the sections did not mean a weight gain but a reduction of the total per meter.
With the existing data it was developed a first complete system of a modular curtain wall.
- Simulations on the new geometry profile
- Influence of the fiber direction on the deformation and the stress of the project mullion.
- Fiber direction perpendicular to longitudinal section of the profile (wind load parallel to fibers): the deformation of the profile was higher that the established in the 13830 standard
2- Fiber direction parallel to longitudinal section of the profile (wind load perpendicular to fibers): the maximum deformation of the profile was far below the 15 mm establish in the standard (6 mm)
- Transom profile deformation under glass weight and wind pressure
- Complete modular simulation under glass weight and wind pressure
It can be concluded that
- Orthotropic characteristics of the material caused different behaviour in two planes perpendicular one to each other. It was observed that in the planes that were not perpendicular to the fibers the behaviour of the profile was worse, being the deformation almost three times greater.
- The results obtained with the dimensions of the defined module were good, being less than the admissible 15 mm.
Besides, thermal simulations were carried out on sections of the transom and the mullion. Here are the results:
- Mullion with all the parts with the composite material: Um mullion= 1.9 W/m2K
- Mullion with all interior hollow steel parts of 1 mm in thickness: Um mullion = 3.1 W/m2K
- Transom 1 with all composite material (without insulation panel): Um transom= 1.6 W/m2K
- Transom one with steel (without insulation panel): Um transom= 2.0 W/m2K
- Transom two with all composite material (without insulation panel): Um transom= 1.7 W/m2K
- Transom two with steel (without insulation panel): Um transom= 2.2 W/m2K
Taking into account these values, the dimensions of the simulated sections and three possibilities for the thermal transmittance of the double glasing, the thermal transmittance coefficient of the curtain wall can be calculated:
Without low emissivity
All composite Glass U = 2.8 Ucw: 2.79 W/m2K
With steel part glass U = 2.8 Ucw: 3.04 W/m2K
Low emittance with air
All composite Glass U= 1.7 Ucw: 2.26 W/m2K
With steel part glass U= 1.7 Ucw: 2.51 W/m2K
Low emittance with argon
All composite Glass U = 1.1 Ucw: 1.91 W/m2K
With steel part glass U = 1.1 Ucw: 2.16 W/m2K
WP7. Prototype preparation and construction of a curtain walling
Four thermoset composite profiles had to be manufactured. So, the same number of dies and infeeds had to be built to adapt to the pultrusion line. These are the profiles to be built:
- Pressure clip profile
- Transom profile
- Semi transom profile
- Semi mullion profile
Before building the dies the plans were readjusted to avoid manufacturing problems (i.e. rounding of corners). Then the dies with the required infeed were designed by using a computational program (solidworks). Finally the dies had to be built according to those plans. The project was finished when two dies and one infeed were completed.
Besides, a thermoplastic polymer profile was needed to act as a tight between the glass and the structural profiles. So, a nozzle was manufactured to adapt it to an extruder. Initially, PBT was chosen due to its combined properties of mechanical performance and flexibility. However, during manufacturing several problems arose:
The material had little flow resistance: the appearance was undesired and the tolerances could not be maintained.
- Cooling in the calibration zone was slow, thus the material crystallised turning it more fragile.
Initially, these problems were tried to solve by blending polybutylene terephthalate (PBT) with polycarbonate (PC). However, blends were still more rigid and did not accomplish with the requirements.
In order to avoid façade manufacturing problems, simulation of the manufacturing process was carried out. Currently used profiles with different designs were sealed and mounted at small scale to evaluate sealing conditions and the type of working force required.
Besides it was defined the size of the curtain wall at real scale as well as those of the profiles:
- At least three modules in width and a support comprising two forgings, with a distance of 3.2 m between them.
- Size of the profiles:
For air-water windload tests:
- Thermoplastic profile: 10 m
-Pressure clip: 40 m
- Transom: 6 m
- Semi-transom:12 m
- Mullion: 28 m
For noise insulation test:
- Thermoplastic profile: 8.94 m
- Pressure clip: 31.84 m
- Transom: 4 m
- Semi-transom: 8 m
- Mullion: 23.84 m
WP8. Validation of the new façade
This WP could not be accomplished because the prototype was not built during the scheduled timetable.
WP9. Environmental design and market analysis
Task 9.1. Analysis of the life cycle of the installations
The most important processes to evaluate the life cycle assessment (LCA) of the composites were the raw materials, manufacturing processes and disposal. Manufacturing process were the key point because several input and output were associated to pultrusion process.
When developing LCA of a certain material and process, several indicators might be considered. After analysing those possible indicators, the following ones were considered as the most relevant ones:
- Greenhouse effect: CO2
- Acidification: SO2
- Photochemical oxidants: C2H4
- Eutrophication: PO4
Task 9.2. Study of economical viability
As far as the market analysis is concerned, it has to be compared the cost associated to aluminium and composite materials.The average prices of raw materials are the following:
- aluminium 2/kg.,
- composite 50/50: 2.1/kg. (glass fibre 1.7/kg., polyester 2.5/kg).
Taking into account that workman in building, anchors, transport and machines, class, joints and sealants and workman in factory remain unchanged, the price for aluminium and composite curtain wall will be 213 and 215 /m2, respectively. Thus, the increase in price of the composite curtain wall is hardly 1% with respect to that of aluminum.
This WP was not accomplished completely because data related to final prototype were missing.
Potential Impact:
Potential impact
Despite not building the prototype physically on time, simulation results showed that it is possible to manufacture a polymeric curtain wall with thermoset composites as main material combined with other secondary materials like certain thermoplastic polymer and sealant, by using a proper profile design able to fulfil all the requirements of the application and being able to be processed easily while being economically viable.
The project results will lead to different impacts addressed below.
Improvement of quality of life
Metallic structures have a limited life due to their problems of corrosion. Corrosion induces several problems in the quality of life of citizens:
- Corrosion induces failure of structures, so replacement or amendment is required. This situation gives rise to the necessity of works in buildings and thus, troubles for the neighbours, for the traffic, for pedestrians, etc.
The substitution of metallic structures by composites removes such problems because composites don't corrode, so they have longer life and replacement of parts will be carried out less often.
Furthermore, due to the high thermal conductivity of the metallic parts the inner surfaces of such elements reach very low temperatures in winter (cold wall), causing condensation of the relative air humidity inside the building. This unpleasant effect may give rise to considerable flaws in the walls, curtains, parquet and furniture. However, composite materials minimize the risk of condensation due to their high level of thermal insulation.
Improvement of working conditions and safety
Composites have less density than metallic parts, so they are much lighter, even more than aluminium. Lighter structural parts will be easier to move, transport and assembly. So, facade builders will have much less danger when working with this new material in comparison with metal.
Improvement of environment
The processing temperature of the main composites is below 150 0C, while those of aluminium and structural steel are 660 0C and 825 0C. These data indicates that the energy required to manufacture composites is much less than that to process metals. The energy saving will have a positive effect for the environment.
On the other hand, thermal conductivity of metals is much higher than that of composites. Thermal bridge breaks are used to diminish this problem, however, this solution is worst than using an isolator like plastics, besides increasing complexity of the system. So, a reduction of thermal conductivity will lead to a reduction of the energy consumption.
Improvement of employment
This project will contribute to the improvement of the competitiveness of the different SMEs involved in the project because they will obtain a novelty for the facade sector based on a product with better characteristics than those already in the market.
It is expected that the improvement of the competitiveness of SMEs will improve their sales rates. As a result of this trend, they will improve their economical situation, which will probably cause an improvement on their employment rates.
Reducing dependence of critical raw materials
Aluminium is considered in the report of the ad-hoc working group on defining critical raw materials of 2010 as too critical due to its economic importance. So, new alternatives are being searched to reduce its dependence.
Dissemination and exploitation
Several dissemination activities were carried out:
- Project web site (http://www.facomp.eu)
- Presence in internet magazines and newsletter: 14 news and articles appeared published in internet related to FACOMP
- Press magazines and papers: four papers were published
- Conferences in congresses: two conferences were given in Spain and Finland
- Poster in the event of the European construction technology platform
- Presence in fairs: VETECO (Spain), Joint Evaluation Committee (JEC) composites show forum (France), CONSTRUMAT (Spain) and BATIMAT (France)
Regarding exploitation, two exploitable results were defined in the project:
- Definition and design of a new façade system to be used in substitution of aluminium and steel.
- Development of a composite material to be used as structural profile with advantageous properties such as thermal properties, resistance to weathering, lightweight.
It was agreed that the result defined as 'development of a composite material' will not be patented because no relevant novelty is proposed over current patents. However, the exploitable result 'Definition and design of a new façade system' is susceptible of being patented. It will be decided after building and testing the prototype (tasks that will be carried out by the partners on their own).
Partners envisaged two different types of exploitation strategies:
- Local strategies include the exploitation activities carried out by industrial partners, who will use the results within their companies.
- Advanced strategies include the activities carried out by partners, in order to achieve a wider exploitation of the results of the project to the whole European industry as well as to research organisations.
However, all activities carried out as exploitation and dissemination activities are explained in detail in the section 'Use and dissemination of foreground'.
List of Websites:
Project web site: http://www.facomp.eu
Name Surname Company Country e-mail telephone
Miguel Mateos TECNALIA Spain
Miguel.mateos@tecnalia.com +34 661874516
Julen Astudillo TECNALIA Spain
Julen.astudillo@tecnalia.com +34 647402258
Miriam García TECNALIA Spain
Miriam.garcia@tecnalia.com +34 647402327
Jesús Cerezo ENAR Spain enar@envolventesarquitectonicas.es +34 916303770
Miguel Ángel Núñez ENAR Spain
enar@envolventesarquitectonicas.es +34 916303770
John Hartley EXEL UK John.hartley@exel.net +44 7770443486
Claudio Cantore ISOTEST Italy info@isotest.it +39 0119310318
Jonas Engstrom SICOMP Sweden
jonas.k.engstrom@swerea.se +46 91174440
Patrik Fernberg SICOMP Sweden patrik.fernberg@swerea.se +46 91174440
Xavier Ortuzar TECHNOCLADD Spain xortuzar@technocladd.com +34 938641701
Anton Ettlin SIKA Switzerland ettlin.anton@ch.sika.com +41 566485405