Cable trays for proper sectorization in buildings

You will find in this post a small guide of the alternatives to carry out a correct sectorization to the fire. In particular, we will be focused on the electrical trays since the electricity is a key factor that must be sealed in the passage between different sectors of a building.

To achieve the perfect sectorization of cable trays, there are two main systems: on the one hand, to use high-density rock wool with an ablative coating and, on the other, to use the so-called intumescent pillows.

Using High Density Rock Wool and an Ablative Coating

This is the most common method for this type of electrical installations. In this sense, mercor tecresa® has developed the well-known Tecsel® System. It consists of two steps: first, we will place by pressure rock wool of 145 Kg / m3 of density in different thicknesses. This thickness depends on the required fire resistance. Then, we will apply by airless spray, gun or roller, 1.5mm of Tecbor® Joint Paste Ready to Use on both sides of the tray. This system is valid for passages of trays in partitions and frames.

Additionally, the ablative coating (20 cm wide) must be applied in the tray and the cables. This will prevent the passage of the heat by radiation through the metallic elements to the sector adjacent to.

If a new cable is added to the installation, it is possible to drill the seal – thanks to the high density of the Rock Wool – and re-coat the area with Tecbor® Joint Paste Ready to Use.

Using Intumescent Pillows

We will place elongated the intumescent pillows that completely fill the gap between the cable tray and the partition. In case of fire and thanks to the intumescent material that is included inside, these pillows swell slightly preventing the passage of smoke and flames, equally acting as a temperature insulator.

Despite its advantages and protective qualities against fire, this system is not recommended in trays that go through floors as the pillows could lose their firmness. On the other hand, we must highlight the importance of the maintenance and the supervision of the installation. The lack of even a pillow in the installation affects its correct operation. Therefore, it is essential to carry out periodic reviews and confirm that all the necessary pillows are in the correct place.

For the fire protection of the electrical trays, the market offers other alternatives such as foams or mortars with a previous formwork. However, the cost and complexity of application rise with respect to the mentioned solutions.

Contact our technical team for further information about our products.