STYRONIT AND COMPARISON TO OTHER INSULATION MATERIALS USED FOR ENCASEMENT

Encasement which is defined as the cladding application to the exterior wall surfaces with thermal insulation materials, is widespreadly carried out in Turkey by use of various kinds of insulation materials. Stone wool, EPS and XPS which are usually seen, are used for these types of applications. In addition to these materials, technical investigations performed showed that ready-to-use Styronit stucco and coating material could also be evaluated for the encasement of the external building walls as insulation material. Each insulation material used for encasement application differs in performances according to their technical specifications. These, although they are all insulation materials, show off differences in accordance with their general properties like; density, thermal conductivity, combustability class, dimensional stability, vapour diffusion, sound insulation values etc. In general the comparison of these materials can be outlined as follows:

Density:

The density of EPS materials must be 15 kg/m3 at least if they are used for encasement process. According to the Turkish standard, TS 825 it is compulsory for the density of all types of EPS materials used for insulation purposes, to be at least 15 kg/m3 and above even if they are not used in encasement applications. In order to provide proper adherence surface for the stucco, XPS materials used for intermediate layer in multi coat applications are produced with rugged or rugged-corrugated shapes. According to the Turkish standard, TS 825, the density of the EPS materials with rugged or rugged-corrugated shapes is defined as 20 kg/m3 and above. Despite the fact that there is not any criterion related to the density of stone wool predefined by standards, for the safety of application, the density of the stone wool boards used for encasement process must be at least  150 kg/m3,and preferably 170 kg/m3. In general, the bulk density of the stuccos applied onto the wall surfaces for insulation purposes must not be greater than 640 kg/m3, and the bulk density of the stuccos applied onto the chicken wire must not be greater than 770 kg/m3. The density of the stuccos used for insulation after setting must not be greater than 850 kg/m3 and that of stucco applied onto metal screening must not be greater than 1400 kg/m3. From the density point of view, one can take advantage of  using ready-to-use Styronit stucco as a siding material applicable to wall surfaces since it is light and also an insulation material. The average bulk density of he ready-to-use Styronit stucco material  is 580 kg/m3 and the density value of the set and dried stucco after application is 260 kg/m3 on average.

Coefficient of Thermal Conductivity:

The coefficient of thermal conductivity of the insulation materials relavant to the densities mentioned above are shown in the following table. These are the calculated values predefined by Turkish standard, TS 825, and these tabulated values are used even in the cases when the actual values of the products are less than them. The real indicator of the thermal insulation ability is the resistance to thermal conductivity defined by the quotient; thickness of the insulation material devided by  the coefficient of thermal conductivity.

Combustability Class:

EPS and XPS, which are the insulation materials manufactured from oil derivative polystyrene have maximum operation temperature of 75°C. Because of these disadvantages, their usage of them  in foreign countries are limited in the attached and multi-storey buildings which have high potential fire risk. According to the Fire Protection Regulation come into force at the end of 2002 after being issued on Turkish Official Gazette, application fields of the said materials are limited. These materials, according to DIN 4102 standard are flammable materials and have flammability class, B1. Adding some fireproof additives during production phase of these materials, slightly increases the flammability class but can not make it completely non-flammable. Flammability class of the stone wool (a.k.a. mineral wool), according to DIN 4102 standard, is A and have an excellent performance at 750°C maximum operation temperature. Operation temperature of Styronit is approximately 190°C. Styronit is a non-flammable substance. Since it can not be burned when exposed to direct flame and has a volumetric consistency up to 190°C, it could be reliably used as substitute in the cases where EPS and XPS boards are used as insulation material.     

Styronit  surface as shown under microscope

Dimensional Consistency :

The dimensional stability of the insulation materials which are used under coating and grouting have a particular importance. Especially, owing to the reasons in the production technology, It takes approximately 6-7 weeks for EPS insulation boards to reach the final dimensional stability. Material has to experience some part of this term as in the block form and the other part of it as in the board form. Since both of EPS and XPS insulation boards have a porous structure, they do not show any dimensional instability under changing  temperatures. Both of the products have higher elongation coefficients and larger dimensional changes when compared to stone wool boards used for encasement. But, the dimensional consistency of the Styronit siding material under the effects of temperature shows lower values compared to the dimensional consistency observed in EPS, XPS and stone wool.

Vapour Diffusion :

In Turkish standard TS 825, the vapour diffusion resistances of EPS and XPS insulation materials are given as µ = 80-250, and the vapour diffusion resistance of stone wool is given as µ = 1. Low values of the vapour diffusion resistances of the materials in the wall cross sections are usually preferred in order for the walls to breathe. The vapour diffusion resistance after setting of stucco samples made of ready-to-use Styronit stucco material ranges between µ = 1,0 -2,0. Therefore, in the encasement applications performed with  Styronit siding material, wall cross sections having lower vapour diffusion resistance compared to EPS and XPS products could be attained..

Sound Insulation :

The main principle in sound insulation is to put the materials with low dynamic hardness (soft) into structural cross section to block the sound transmission and to absorb mechanical (action) energy of the sound transmitted in air via insulating material. EPS and XPS, because of their confined porous structure, are not good for sound insulation. Stone wool with its open porous and fibrious structure is a good sound insulation material. In case of the applications with ready-to-use Styronit stucco, open porous and fibrious structure occurs after setting of stucco and this makes Styronit a good sound insulation material. That's why the ready-to-use Styronit stucco and coating material is a suitable product for the exterior siding and coating applications where the sound insulation is important.

In the selection of the insulation materials especially used for the crowded facilities like schools, hospitals, marketting centers, multi-storey buildings etc., flammability class, dimensional consistency, vapour diffusion and sound insulation properties of the materials have to be taken into consideration as well as the thermal insulation properties.

Sound Insulation :

The physical properties of this sample block have been set and  the sound absorption property of the block has been tested and analized to determine the sound absorption properties against the sound created in the air at the frequency range of 1/3 octave prescribed in the Turkish standards, TS 2382 and TS 1477. Block properties are shown at the table and sound absorption results are given on the graph.

The sound insulation properties of ready-to-use Styronit stucco after setting

Sound Absorption (dB)
	Frequency (Hz)

Frequency-sound absorption relation of the ready-to-use Styronit stucco sample after setting. 

Thermal conductivity analysis of the ready-to-use Styronit stucco samples.