Every year the technology improved, and since the late 70-ies of XX century facade systems are widely used to create energy-efficient buildings in Europe and the United States.In Russia, they appeared much later: the construction of buildings with the use of this technology began in the mid 90s.
Today facade systems are commonly used in the construction and reconstruction of buildings of various types.Among several design solutions have gained great popularity ventilated facade systems, the benefits of which include high thermal performance, wide range of materials for the exterior finish and the possibility of installation regardless of the current time of year, temperature and humidity.
insulating properties of ventilated facade system, its durability, reliability and safety are dependent on the type of insulation material, as well as respect for the important conditions for its installation.Try to understand what requirements must comply with thermal insulation in the construction of modern ventil
requirements of the law and legitimate
Market introduction of new building materials and technologies several years ago proved that the norms developed in recent years, is no longer able to regulate all aspects of construction.Features of the application of certain technologies demanded a full upgrade the regulatory framework.One such technology was the construction of a ventilated facade system.Her partial description can be found in the SNIP 23-02-2003 "Thermal protection of buildings" as well as SP 23-101-2004 "Design of thermal protection of buildings", but, according to experts, this is not enough.
Recently, the tendency to develop a set of standards that provide flexible control of all aspects of the building materials and technologies.The basic document of the new regulatory framework is the Federal Law №184 "On Technical Regulation" dated 27.12.02, as amended and supplemented on 01.05.07 was one of the key provisions of the law is the need to establish technical regulation which would establish the basic requirements for the safety of buildingsand facilities.
for ventilated façade systems are most relevant to the requirements of fire safety.Prior to the relevant technical regulations, which are expected in mid-2008, establishes the requirements SNIP 21-01-97 "Fire safety of buildings and structures."In accordance with ventilated facade system on a mandatory basis should be tested on the basis of which is determined by the class of fire danger and the maximum possible height of the building, equipped with a front system of this type.Methods of test for determining the allowable height of the building was developed by specialists of the Center of fire research CNIISK.VAKucherenko.In addition, the center carried out tests curtain facade systems in accordance with GOST 31251-2003 "Building structures.Methods for determination of fire hazard.Exterior walls from the outside "with the assignment of a particular class of fire danger throughout the system.
As for insulation, the experts say about the need to use when creating a ventilated facade systems materials, non-flammable in accordance with GOST 30244-94 "Building materials.Methods of test for flammability. "Class NG are wool density 40 kg / m3 and thermal insulation based on stone wool, which can not melt, withstanding a temperature of about 1000 ° C and at the same time provide the necessary fire rating.
addition to regulations that set requirements for fire safety, ventilated facade systems, there are other standards.In particular, the requirements for thermal insulation (including to the accompanying technical documentation) are contained in the document "Recommendations for the composition and content of the documents and materials provided for the technical evaluation of the suitability of products.Facade thermal insulation system with an air gap "developed FSI DSF State Construction Committee of Russia jointly with the Center for Studies of fire CNIISK.VAKucherenko 2004.
following regulations, which reflects the requirements of insulation - is "Technical recommendations for the design, installation and operation of hinged facade systems" created in 2005 by the Center State "ENLAKOM" for regulatory authorities, design offices and contractors in Moscow.
In addition, the requirements for certain characteristics of thermal insulation materials set some guests, examples of which will be presented in the next section.
As mentioned above, the existing building regulations do not impose requirements to a number of key properties of thermal insulation in the construction of ventilated façade systems.For this reason, manufacturers of thermal insulation materials set them to their own products based on the experience of the application as well as European standards.
first condition - a low thermal conductivity of the material in the course of its operating system.According to experts, the key here is the concept of "in service", which is due to a change in thermal performance of insulation under the influence of moisture.Thus, the thermal conductivity in the operation largely depends on the material properties such as hydrophobicity, which is discussed later.
low thermal conductivity in addition to the operation, an important requirement for thermal insulation in the construction of ventilated facades is durability.Experts say that the life of the thermal insulation for ventilated facades of high-rise buildings should be around 50 years.This is due to the high durability of the design of buildings of this type.
requirements for fire safety were discussed in the previous section of this article.It remains to again note the fact that the need for strict requirements for thermal insulation due to the high fire danger of the design ventilated facade system: the emergence of the effect of the thrust in the air space in case of fire contributes to the spread of flame.
insulation must be hydrophobic.This is due to the fact that entering the thickness of the thermal insulation material, the moisture substantially reduces its thermal performance.Reasonable figures are as follows: in the case of brief partial immersion and the rate of water absorption in water is 300 g / m2, and in the case of prolonged immersion - 500 g / m2.Define them in accordance with GOST R EN 1609 and EN 12087 GOST R, respectively.
important property of thermal insulation is low absorption (sorption) of water vapor from the air.The reason is similar: the replacement of the air with water vapor in the pores of the insulation contributes to the deterioration of thermal performance of insulation.In accordance with the method of GOST 17177 "Building materials and products Thermal insulation.Test methods "looks reasonable maximum sorption rate of 2%.
insulation in the construction of ventilated facade system must have a low air permeability.It is caused by forced convection, which, along with the natural, there is in the air gap ventilated façade system and leads to an increase in heat loss.The method of determining the index of air permeability is contained in GOST R EN 29053 "Acoustic Materials.Methods for determination of resistance to air permeability. "According to the recommendations of experts, the maximum rate of air permeability for thermal insulation materials in the construction of ventilated facade system - 60 * 10-6 (m3 / m * s * Pa).An effective measure for improving the thermal resistance of walling, if the material does not match the figures shown, the thermal insulation layer is to increase the use of any diffusion membranes.
Requirements for installation of insulation
During installation ventilated facade systems there are additional requirements for the thermal insulation related to both ease and speed of installation works, and with the reliability and durability of the front system as a whole.
One major requirement is the density of the upper and lower layers of insulation.The top layer should be more rigid for several reasons.First of all, it determines the hardness of the upper layer of insulation resistance to pressure facade anchors: the larger it is, the less strain exposed plate.In addition, this material is virtually not deformed during transportation and offers much greater resistance to air permeability.According to current practice, the optimal density of the upper layer of insulation should be at least 70-80 kg / m3.In turn, the less hard bottom layer provides a snug fit to the surface of the facade thermal insulation and to compensate for uneven walls.
Previously, the most common solution was to use two layers of insulating material having different densities.However, a much more rational in terms of assembly is the decision of the dual density plates.Experience shows that it can reduce the use of up to 25 minutes of working time for the installation of 1 m 2 of thermal insulation, as well as save on the facade dowels.As an example, should lead specifically designed for the construction of ventilated facade system boards of rock wool ROCKWOOL FAN BATTS A bottom layer with a density of 45 kg / m3, which provides qualitative adhesion to the surface regardless of the roughness, and the density of the upper layer - 90 kg / m3,which guarantees a high resistance to deformation and air permeability.
An important property of thermal insulation installation of ventilated facade high-rise buildings is the peel strength layers.The reason is that, at high altitudes, the pressure of the wind several times stronger than in the vicinity of the ground.In the presence of the lining (rain screen) wind is not able to damage the insulation, but at the stage of mounting threat of separation layers becomes very real.Therefore, a sufficient criterion look 3 kPa, according to GOST R EN 1607 "Thermal insulation products for building applications.Method for determination of tensile strength perpendicular to the face. "
In conclusion, it should be noted that the absence of a number of performance requirements for thermal insulation in the construction of ventilated facade systems - is a temporary phenomenon.At this stage, the observance of all the necessary parameters of insulation, even if they are not fixed in the building regulations is a guarantee of efficiency, reliability, safety and long life of the ventilated façade system.
Press-service of the company ROCKWOOL Russia