THE STAINLESS CONSOLE SYSTEM. AGS Sp. z o.o. KNOW HOW IN VENTILATED FACEDES OF MODERN BUILDING

Transcription

1 THE STAINLESS CONSOLE SYSTEM AGS Sp. z o.o. KNOW HOW IN VENTILATED FACEDES OF MODERN BUILDING

2 The standard resolutions of ventilated facade system that are avialable on the market contain: aluminium sub-constructions (that includes brackets) that hermetically grind to the surface of the wall and outside mantles (facade boards) which protects the construction from the weather conditions. The ventilation space that is created between isolation layer and the boards enables unrestrained air flow. These brackets are the main elements that strap a mantle to e.g wall. Constructed from aluminuin or just steel create many heat leakagle bridges, that are responsible for efficient energy use of the building. Efficient energy use - is the goal to reduce the amount of energy required to provide products and services. In Poland these type of demands determines ordinance of the Minister of Transport, Construction and Marine Economy from 5th July 2013 (poz. 926). By the determined directives up to 2021 it is planned to gradually reduce the heat transfer coefficient for wall bariers. Additionally, the procedures of calculations are given which as follow: the value of temperature coefficient which is characteristic for this kind of solution should be calculated as follows: 1) For barriers - according to polish norm from sub ; 2) For heat leakage bridges with usage of spatial model of compartment - by polish norm concerning the calculations of heat flux and the air temperature. The next parameter which should be taken into consederation while talking about ventilated facades is not falling off the parts of a building while fire in strictly determined time. Those demands are included in Polish Building Guidelines in paragraph 225 which states: The elements of isolation mantle should be installed to the building in a way that enables their falling off in case of fire in the time shorter than is required for fireproofing for exterior wall determined in 216 sec. 1 correspondingly to the fireproofing of the building in which are installed

3 Tests concerned falling of the facades during fire Above shows, that when aluminium brakets and main grate are applied, the supporting stucture melts comletely in the place which is the most liabled on fire. It is caused by the temerature of melting of aluminium which is about 630 degrees Celsius. Instead the temperature which was measured during the test was above 800 degrees Celsius. This aspect eliminates also non-metallic connectors, because their temerature of melting is lower than aluminium itself. The next parameter that brackets should meet is the resistance to corrosion. Aluminium brackets avialable on the market, don t have so called chemical compability with alkaline building materials e.g concrete. Permanent cotact with such materials like mortar and concrete cause clear stains and pits (very difficult to remove), which, after some time, can emasculate the whole supporting structure. Present solutions of aluminium consoles apply foil pads EPDM or hard plastic. Unfortunatelly those solutions melt during fire and in cosequence make the facade lose its stability. Another problem is that, EPDM pads increase thermal conductivity of the console to the concrete substratum. It is because the clamp fills all the pinholes between aluminium and concrete creating absolute flat connection. This way the conduction effect between those two materials increases.

4 The answear for all the issues above are developed and patented accordingly with Alicante procedures and in the Polish Patent Office, brackets by AGS Sp. z o.o company. The patent covers such elements like shape, hole drilling that improve thermal isolation and materials from which they can be made. Picture. NO 1. Example of stainless bracket TYPE HI Picture. NO 2.Example of stainless bracket with very high parameters The advantages and superiority of AGS solutions: 1. The bracket HI and HI+ is made of specially designed stainless steel, which allows to reach, having 2mm thickness of the wall, bearing capacity comaped to aluminuim counterpart with 4mm thickness.

5 2. The HI (pic. no. 1) bracket indicates in calculations very good thermal isolation parameters in comparison to aluminiun counterparts. It is caused by tenfold lower parameter λ, which for stainless steel is 16W / (m*k) and for aluminium W/ (m*k). PIC. NO 3. THE DISTRIBUTION OF ISOTHERMS WITH APPLICATION STAINLESS STEEL BRACKET HI PIC. NO. 4. THE DISTRIBUTION OF ISOTHERMS WITH APPLICATION OF ALUMINIUM BRACKET The analysis above show, that HI bracket made of stainless steel (pic. no. 3) without thermo pad successfully restrain cold conduction to a wall covered with mineral wool. The distribution of izotherms show, that in the place where the bracket contacts the wall we have a temperature above 10 degrees of Celsius and the whole wall do not show signs of thermal disabilities.

6 The analysis shown in picture 4 indicates that in case of bracket made of aluminum, also witout thermo pads, isotherm of temperature 0 0 C sank in the wall. Another isotherms showed substantial temperature loss. It must be said, that the analysis was made as a benchmark for HI brackets. On the other hand HI+ bracket has got patented hole drilling which successfully extend the way of temerature through the bracket. It is shown by the hash mark in picture no. 2. So, with very low paramether λ equal 4,3 W/(m*K) isoterms will go almost flat just like on a wall without any couplers. All measurments of multipier λ were carried out in laboraories of Warsaw Polytechics by the hot box. 3. The material of AGS brackets (stainless steel) has got the melting temperature of C. Thus it is lower than the temerature of developed fire according to which fire tests in Building Research Institute are carried out. It fulfils 225 record of Technical Conditions for Buildings and their Exposure. 4. Stainless steel is a material which is chemically compatible with alkaline building materials. Therefore applying pads of any kind, is not necessary and aslo rises thermal isolation of the concept. Under, exemplary calculations are presented: The calculations carried out for double-layer walls cosist of daub from the outside 1cm, ferroconcrete 20 cm and mineral wool 18 cm applied by 4 pins diameter 8mm (the core stainless steel) and 2 brackets that affix ventilation facade to ferroconcrete. Remaining paramethers are: a) Multipier λ of wool which was 0,034 W/m*K b) 2 aluminium brackets width 120mm (bearer) and second 60mm (wind), width 4mm and multipier λ = 160 and 200 W/m*K c) 2 AGS stainless steel bariers width 120mm (bearer) and second 60mm (wind) and multipier λ = 4,3 and 15 W/m*K of comparable bearing capacity to aluminium brackets from point b. After calculating total thermal resistance R T computed heat transfer coefficient U = 0,174 [W/m*K]. The procedure dictates to count corrected multipier of thermal resistance U c. In this range one must take

7 into consideration an amendment for mechanical connectors ( U f ) that is pins attaching so calle second skin ( facade layer of the building) Mulitpier U f for pins that hold wool was 0,011 [W/m*K]. Instead, subject to used brackets (subsection b and c) the result U f are as follow: brackets according to subsection b : for aluminium λ=160 W/m*K - U f =0,327 [W/m 2 *K] for aluminium λ=200 W/m*K - U f =0,4 [W/m 2 *K] brackets according to subsection c : for stainless steel acc.to AGS concept (bracket HI) λ=4,3 W/m*K - U f =0,009 [W/m 2 *K] for stainless steel λ=15 W/m*K - U f =0,031 [W/m 2 *K] Substitue all data to reduction formula where the heat transfer coefficient U c was readjust form as follow: U c = U+ U [W/m 2 *K] U aluminium brackets λ=160 W/m*K U= Uf pins + Uf brackets U= 0,011+ 0,327 = 0,338 [W/m 2 *K] U aluminium brackets λ=200 W/m*K U= 0,011+ 0,4 = 0,411 [W/m 2 *K] U for AGS stainless brackets λ=4,3 W/m*K U= 0,011+ 0,009 = 0,02 [W/m 2 *K]

8 U for AGS stainless brackets λ=15 W/m*K U= 0,011+ 0,031 = 0,042 [W/m 2 *K] Substitue all data to formula where the heat transfer coefficient U c was readjust form as follow: Uc = U+ U [W/m 2 *K] U c for aluminium brackets λ=160 W/m*K and wool with multipier λ=0,034 [W/m*K] Uc = 0,174+0,338 = 0,512 [W/m 2 *K] U c for aluminium brackets λ=200 W/m*K and wool with multipier λ=0,034 [W/m*K] Uc = 0,174+0,411 = 0,585 [W/m 2 *K] U c for AGS stainless steel brackets λ=4,3 W/m*K and wool with multipier λ=0,034 [W/m*K] Uc = 0,174+0,022 = 0,196 [W/m 2 *K] U c for stainless brackets λ=15 W/m*K and wool with multipier =0,034 [W/m*K] Uc = 0,174+0,042 = 0,216 [W/m 2 *K] Presented calculations clearly show that aluminuim brackets do not meet technical paramethers for the highest standards at present and in the future. The results for AGS brackets clearly show that they meet all the expectations and norms. Even those set for Additionally they do that without increasing their thickness.

9 Note, that the amount of brackets was picked for typical cases and corresponded with them static requirements for 1 m 2 of thermal insulation of the wall. That is one bracket 120mmand one win bracket 60mm. In other studies and calculations this aspect is frequently ommited and is for bracket 50mm for 1 square meter. Thus the whole result is distorted. Despite typical brackets for ventilated facades with Alicante procedure, AGS patented other concepts of building connectors. Which as follow: U brackets for ventilated facades and cellings brackets for curtain wall π and T brackets for assemblage windows in heat areas connectors to steel elements so called second skin stools/ground beams for assemblage roof constructions such as blinds FIG. NO 5. PATENTED SOLUTIONS COMPANY AGS Sp. Z O.O.