Polyurethane Systems for building and industry

Reaction to fire in final use condition. Comparison of constructive solutions of polyurethane (PU) and mineral wool (MW)

ANPE has conducted a study on the fire performance of different constructive solutions in final use condition.

resistencia-poliuretano-fuego

ANPE is the Italian association of rigid polyurethane foam manufacturers. The tests were carried out in the LS Fire Testing Institute and the assemblies of the construction systems have followed the recommendations included in the technical documentation of the manufacturers.

The constructive elements represented in the assemblies have been the following:

  • Internal reinforcement of the façade: Interior insulation of facades with insulation system with a laminated gypsum board.
  • SATE façade: Façade insulation on the outside, ETICS (External thermal Insulating Composite Systems).
  • Roof: Roof insulation under waterproofing bituminous membranes.

In the comparative study, two types of products have been analyzed: polyurethane (PU) sheets and mineral wool (MW) sheets.

The main conclusion is the absence of differences in the behaviour against fire in the final condition of use of the compared systems, despite the different individual Euroclasses of the insulating products.

We are showing below a brief description of the tests carried out and the particular conclusions of each case.

 

Internal reinforcement of façades (insulation system with laminated gypsum board)

The Room Corner Test - RCT (ISO 9705) is used as a test method to evaluate the fire performance in final use condition. The RCT evaluates the behaviour of constructive systems at an early stage and the development phase of a fire until it is completely developed.

The sample is a system formed by a laminated gypsum board with thermal insulation located on the face that is not exposed to fire. The thermal insulating materials compared were:

 

Polyurethane board (PU)

Mineral wool pannel (MW)

Coating

Fibreglass in both sheets

No coating

Thickness

80 mm (70 mm PU + 10 mm PYL)

110 mm (100 mm MW+10 mm PYL)

Thermal resistance

2,5 m2K/W

2,95 m2K/W

Euroclass

B-s1,d0

A2-s1,d0

Conductivity

0,026 W/mK

0,036 W/mK

 

The difference in thickness is justified because both systems must satisfy the same thermal protection requirement of the façade. As the PU is more insulating, the required thickness is lower.

During the test, the heat released and the amount of smoke generated are practically the same and the damage produced in the samples is practically the same in both systems. In neither case has the flashover been reached.

It can be concluded that both systems tested show similar results, despite the different classification of the individual insulating products.

Videos: tests of polyurethane's resistance to fire

 

Façade with insulation on the outside (ETICS)

The ETICS (External thermal Insulating Composite Systems) test uses an experimental method to simulate a fire scenario with a garbage container or a vehicle next to the facade.

The ETICS system assemblies included the usual layers: adhesive, thermal insulation products, base mortar, frame and finishing mortar.

The thermal insulating products are defined in the table below:

 

Polyurethane board (PU)

Mineral wool pannel (MW)

Coating

Glassfibre in both sheets

No coating

Thickness

100 mm

140 mm

Thermal resistance

3,85 m2K/W

3,85 m2K/W

Euroclass

Polyurethane (PU) E

SATE system (PU) : B-s1,d0

Mineral Wool (MW): A1

SATE system (MW): A1

Conductivity

0,026 W/mK

0,036 W/mK

 

The difference in thickness is justified because both systems must satisfy the same thermal protection requirement of the façade. As the PU is more insulating, the required thickness is lower.

The main conclusion is that both ETICS systems have very similar fire performance, although the insulation products have different individual Euroclasses. Both assemblies maintain their integrity until the end of the test, without appreciating differences in the parameters evaluated during the test.

 

Roofs with waterproofing based on bituminous membrane

The test method used is CEN / TS 1187 Test 2, which consists of evaluating the propagation of an external fire on the roof.

A 2 mm thick bituminous membrane is used on the insulating products, defined below:

 

Polyurethane board (PU)

Mineral wool pannel (MW)

Coating

Glassfibre in one sheet

No coating

Thickness

70 mm

100 mm

Thermal resistance

2,5 m2K/W

2,75 m2K/W

Euroclass

B-s1,d0

A1

Conductivity

0,028 W/mK

0,036 W/mK

 

The difference in thickness is justified because both systems must satisfy the same thermal protection requirement of the roof. As the PU is more insulating, the required thickness is lower.

The results of the essays provide the following conclusions:

The polyurethane product (PU) is carbonized, which prevents the propagation of flames, limiting the damage to the membrane, obtaining a Broof classification (t2).

On the other hand, the mineral wool product (MW) does not prevent the propagation of flames and does not pass the test, obtaining a Froof classification (t2). The classification of the individual mineral wool product (A1) does not prevent the bad behaviour in the final use condition.

 

Would you like to watch the three videos of the tests comparing the reaction to fire of polyurethane and mineral fibre? Download them now.

Videos: tests of polyurethane's resistance to fire

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