Cellular Concrete Block Fire Resistance Test

The Research and Development sector of MSE Engenharia is exploring innovative construction systems. Among the outstanding projects is the development of non-autoclaved cellular concrete blocks aimed at sealing walls, which combine efficiency, quality and sustainability, reflecting the company's commitment to innovation. These hollow cellular concrete blocks are distinguished by their light weight, ease of installation and excellent thermal and acoustic insulation properties, so they can be widely used in residential and industrial works.

In one of the phases of the project, the fire resistance test was carried out at the Technological Research Institute (IPT), in São Paulo. The test followed the criteria of ABNT NBR 10636-1:2022, with the objective of evaluating the performance of the blocks in fire situations, verifying their ability to maintain building safety, even in extreme conditions.

To carry out the test, a wall sample was constructed and after 60 days of curing, it was submitted to a furnace that simulates the real conditions of a fire, reaching temperatures greater than 1000 ºC. The furnace temperature is controlled and increases progressively, following a time and temperature curve established by the standard, which reflects the typical temperature increase in a real fire.

‍

During the test, three essential parameters are evaluated and monitored: integrity, thermal insulation, and mechanical action.

• Integrity (E): assesses whether the wall is capable of maintaining its compartmentalizing function during the test and not allowing excessive cracking so that flames or hot gases pass to the opposite side, preventing the fire from spreading.
• Thermal insulation (I): measures the wall's ability to limit the temperature rise on the side not exposed to fire, protecting adjacent rooms from excessive heat.
• Mechanical Action (M): assesses impacts on the wall, even after withstanding high temperatures.

‍

The trial lasted 240 minutes (4 hours). Throughout this period, the wall performed very well, because even under intense and constant heat, the wall did not lose its stability and integrity (E). The first crack was observed after 150 minutes of continuous exposure to fire, which evidences the high resistance of the blocks. But even after this fissure appeared, the wall continued to function as a barrier against flames. It should be noted that during the course of the test, cracks large enough to justify the use of the meters were not found.

‍

Thermal insulation (I), which measures the temperature rise limit of the face not exposed to fire, was exceeded after 164 minutes of testing. In addition, after 210 and 235 minutes, cotton pad tests were carried out in the joint area. At no time did the cotton become inflamed, that is, it was not passing enough heat for the cotton to catch fire.

‍

Check out the video:

At the end of the test time, to analyze the “Mechanical Action (M)” criterion, three impacts were performed with energy of 20 J, at three different points on the surface not exposed to fire. The results were also satisfactory for this criterion, as there was no compromise to the integrity of the wall.

Finally, the wall of hollowed cellular concrete blocks obtained excellent fire resistance results, being classified as E-M-180 and EI-M-150, according to ABNT NBR 16945:2021. Thus, it was found that even after four hours of exposure to fire, the wall maintained its integrity and prevented the passage of flames to other environments, offering essential protection for the safety of users.

‍

‍

‍