Certifications

Fire behavior is the set of physical transformations of a material or building element subjected to the action of fire and is conditioned by the thermal properties of the materials and the methods of their use in the structures.

The reaction to fire classification of building materials refers to the EN 13501-1 standard (Fire classification of construction products and elements).

The legislation establishes:

• Test methodologies.
• Classification of materials.
• Product certification procedure for reaction to fire purposes.

In the legislation, materials are classified according to Euroclasses A1, A2, B, C, D, E, F.

Materials classified A1 and A2 are non-combustible while those in class B are non-flammable combustibles.

The European legislation takes into consideration two further parameters of considerable importance for fire prevention purposes. The first parameter deals with smoke emission, where the values indicated in the standard are:

• (S1) Low smoke emission.
• (S2) Moderate smoke emission.
• (S3) Strong smoke emission.

The second parameter deals with the presence of dripping or incandescent particles that develop during combustion and which can spread the fire (unlike the Italian standard, this index allows to know the behavior of the individual material with regards to this aspect). The values indicated are:

• (d0) Absence of burning drops.
• (d1) Few burning drops and/or incandescent particles.
• (d2) Many burning droplets and/or glowing particles.

Fire resistance is literally defined as the ability of an element or a structure to maintain, during a given period, the required stability, tightness and thermal insulation.

The main parameters for evaluating fire resistance are:

• The resistance R: ability to maintain mechanical resistance under the action of fire.
• The airtightness E: ability to not let flames, vapors or hot gases pass through or produce hot gases on the unexposed side.
• Thermal insulation I: ability to reduce heat transmission.

The symbol REI followed by a number (n) identifies a construction element that maintains mechanical resistance, resistance to flames and hot gases and thermal insulation for a specific time. The number (n) indicates the fire resistance class, calculated and commensurate with the specific design fire load.

The fire resistance classes are: 10, 15, 20, 30, 45, 60, 90, 120, 180, 240 and 360, and express the time, in minutes of exposure to the ISO 834 nominal curve, during which fire resistance must be guaranteed.

Designers and installers are therefore required to carry out an in-depth preventive assessment of the final use for which the sandwich panels will be intended, choose the product with the most suitable characteristics based on their coding and request certification for the specific model identified.

The BROOF certification represents the specific assessment of the risk of external fire spread on roof coverings and the fire reaction classes. The identification of the test method used is generally indicated with (t1), (t2), (t3), where the numerical progression does not indicates greater or lesser fire resistance but different test methods. (t3) – Ignition with burning embers, wind and heat.

The concept of soundproofing material is closely connected to the law of mass, which means that a material is more soundproofing the higher its specific weight.

The human ear, in addition to perceiving only part of the pressure variations that are the basis of the acoustic phenomenon, has a sensitivity that varies with frequency, perceiving sounds of the same level in a different way depending on the frequency.

Below are the auditory sensations corresponding to different sound pressure levels, expressed in decibels, at a frequency of 1000 Hz.

• 0 dB: Hearing threshold.
• 20 dB: Level of perception.
• 35 dB: Sleep disturbance.
• 55 dB: Difficulty in conversation.
• 90 dB: Hearing damage from long exposures.
• 120 dB: Pain threshold and temporary hearing loss.

The soundproofing power R is the quantity, measured in the laboratory, which allows to predict the propagation of sound from the environment in which the source is located to another (receiver), even if separated by a specific building element, which is an external wall , an attic or a window frame. This R value is not sufficient to define the level of performance of a certain element, as its performance in operation will certainly be lower. It is therefore important to evaluate the soundproofing power of the material synthetically and on site, also through the Rw index. The greater the thickness of the panel (and its density), the greater the acoustic insulation will be.

The goal of a sound-absorbing material is therefore to hinder the reflection of acoustic energy.

Acoustic absorbers mainly respond to the needs of environmental acoustic correction which are necessary when there is the need to modify the reverberation times within an environment, and thus to act on the frequency response in the room in question. Reverberation and its characteristics in fact affect the correct intelligibility of words and sounds.

Sound absorption is the most important parameter in the acoustic correction of environments. The index that allows the soundproofing power to be evaluated synthetically and on site is called αw.

In general, total sound absorption follows this logic:

• case 1)
  Total absorption α = 1 (Fibrous materials. Very thick mineral wool mats without metal facings, anechoic chambers);
• case 2)
  Total acoustic reflection: α = 0 (Non-microperforated sandwich panels);
• case 3)
  Partial sound absorption from α = 0 to α = 1 (Micro-perforated sandwich panels αw 0,90 near to the total absorption value).