According to the new national fire test standard gb8624-2012, the fire performance of building materials and products can be divided into four levels

　　Class u, non combustible material

　　Ub1, refractory material (oxygen index above 30, vertical combustion height 15mm, continuous combustion time less than 5S, ignition time less than 30s)

　　Class u B2, combustible material (oxygen index is required to be above 26, and combustion droplets do not cause the combustion of absorbent cotton)

　　Class u B3, flammable material (not required for B3)

　　Rock wool and glass wool are Grade A

　　The fire rating of polyurethane sandwich panel is B1 B2 B3

　　Classification of sandwich panels (2)

　　Metal panel

　　Non metallic panel

　　The metal panel is easy to process and can be made into various shapes. However, in some cases, the non-metallic panel has the function that the metal panel cannot, such as corrosion resistance and impact resistance.

　　Coating type of color coated plate:

　　U polyester coating (PE)

　　U-si modified polyester coating (SMP)

　　U high weather resistant polyester coating (HDP)

　　U fluorocarbon coating (PVDF)

　　We usually say that the color coating generally refers to the polyester coating. The epoxy paint is suitable for the back paint of polyurethane sandwich panel and polyurethane contact.

　　The foam bonding test was carried out before delivery. Generally, it is pure epoxy back paint.

　　U small factory back paint is generally not pure epoxy, but added a part of polyester.

　　On PUR and PIR

　　The difference between PUR and PIR

　　U pur is polyurethane

　　U PIR is polyisocyanurate (polyisocyanurate foam) in Chinese

　　The fire protection performance of PIR is better than that of PUR and the mechanism of difference in fire performance

　　PUR is a foam system formed by reaction of polyether polyol with isocyanate. PIR is formed by reaction of polyester polyol with isocyanate. The crosslinking degree of PUR foam system is mainly dependent on the functionality of polyether polyols. The crosslinking degree of PIR system depends on the excess isocyanate trimer reaction. PIR is much higher than PUR's black material index, PUR index is generally 110-140, and PIR index is generally 250. Under the action of the corresponding catalyst, the excess isocyanate can react to generate six membered rings, which provides crosslinking to the foam group, and at the same time, through its own six membered ring molecular structure, it promotes combustion coking and charring, and improves the fireproof performance of the foam system. Generally, the index above 200 can be called PIR, and below 200 can only be called PIR and pur mixture.

　　Oxygen index

　　Index (OI) refers to the lower oxygen concentration required for flaming combustion of materials in oxygen nitrogen mixture under specified conditions. It is expressed by the volume percentage of oxygen.

　　A high oxygen index indicates that the material is not easy to burn, while a low oxygen index indicates that the material is easy to burn.

　　Generally speaking

　　u The oxygen index of flammable materials is less than 22

　　u The oxygen index of combustible materials is between 26 and 30

　　u The oxygen index of refractory material is more than 30

　　Pentane specific

　　However, taking EPS (foamed polystyrene board) and XPS (extruded board) as examples, when these materials reach B1 level, their oxygen index can easily exceed 32, but polyurethane is difficult to reach 30. Unless the production process is changed, although the oxygen index reaches the standard after changing the process, other physical and chemical properties, such as thermal insulation and firmness, will be discounted, and the cost will also rise sharply.

　　The boiling point of n-pentane is 36.1 ℃, the compatibility of polyether is poor, and the dimensional stability of the board is good.

　　The pentane foam has poor cohesiveness and foam crispness.

　　The boiling point of cyclopentane is 49.3 ℃, the compatibility of polyether is good, and the dimensional stability of the board is worse than that of n-pentane. The thermal conductivity is lower than that of n-pentane.

　　thermal conductivity

　　Thermal conductivity (k value), or thermal conductivity.

　　U thermal conductivity is defined as: the heat per unit cross-section, length of material under unit temperature difference and unit time. The metric unit is watt / meter · Kelvin (w / m-k).

　　U thermal conductivity is used to measure the ability of a material to conduct heat. The higher the thermal conductivity, the less heat loss in the material.

　　Thermal resistance (r value)

　　U thermal resistance is defined as the ability of a material to block the passage of heat per unit area at a specified temperature. Unit: m · Kelvin / watt (m-k / W)

　　The U thermal resistance is used to represent the ability of a material to prevent heat conduction in a certain direction. The higher the R value of the material is, the more suitable it is to be used as thermal insulation material.

　　The R values of u continuous insulation materials can be added

　　Thermal conductivity (U value)

　　The U thermal conductivity coefficient is used to measure the thermal conductivity of the material, which represents the ability of the material to pass through the heat per unit area. The lower the U value, the better the thermal insulation performance of the material, in w / m2 · K.

　　Material thickness / K value = R value; U value is the reciprocal of R value, i.e. u = 1 / R.

　　density

　　The density is generally measured by drainage method (calculated by formula: density = weight / volume). The density of sheet foam is generally 38 to 46kg/m³ (generally full density). The density of polyurethane can be 20-700

　　Small density will cause shrinkage, and high density will affect the closed porosity and thermal conductivity.