EN 13497 Determination of Impact Resistance of External Thermal Insulation Composite Systems (ETICS)

The European standard “EN 13497 Thermal insulation products for building applications - Determination of impact resistance of external thermal insulation composite systems (ETICS)” describes the equipment and procedures for determining the impact resistance of plastered ETICS design kits.

In principle, the impact resistance of a design composite thermal insulation system kit is the hard-body impact resistance determined by a steel ball falling onto the surface of the kit. The energy level and the corresponding drop height are selected from the table entitled "Impact energy levels and specified height from the sample surface" given in the standard. Damage is visually assessed (e.g., reinforcement becoming visible or perforated from the outer surface or topcoat) and crack widths are measured.

Equipment used in the tests includes:

General: For the test, a steel ball is dropped from a specific height onto the surface of the test specimen. A second impact (rebound) from the ball must be prevented.
Steel ball requirements: Balls made of the specified grade of cutlery-grade steel according to ISO 3290-1 standard, with the weights and nominal diameters given in the table.
Crack gauge: Used to measure the width of cracks formed when a steel ball strikes the surface of a test specimen. The device should be able to measure from 0,1 mm onwards and be graded in 0,05 mm increments.
Sample support: The support must be straight, not bent, deformed, or absorb impact energy during testing to avoid affecting the test result (e.g., concrete support). The test specimen must be held firmly to prevent movement during testing. Larger specimens tend to show less movement than smaller specimens. The specimen can be fixed, clamped, or glued to the support to maintain contact between them during testing.
Optional tubing for controlling the descent of the steel ball: For this purpose, a vertical tube made of metal or rigid plastic with an inner diameter at least 2 mm larger than the diameter of the steel ball can be used. The walls of the tube should preferably contain regularly spaced holes to prevent the compression of air inside the tube due to the ball's velocity during descent, thus acting as a resistance cushion against the ball's impact with the sample surface.

The test specimen must be sized/dimensions that allow for at least 5 impacts, taking minimum distances into account. It consists of a thermal insulation product and a plastering system. It must be prepared according to the system owner's instructions.

The sealing and conditioning of test samples should be carried out according to the following procedures:

Procedure 1: If exposed to water, the back and edges of the test specimen must be sealed.
Procedure 2: The edges of the test specimens must be sealed.

In the modern construction world, exterior thermal insulation composite systems have become a cornerstone of energy-efficient building design. These multi-layered systems, typically consisting of insulation boards, adhesive, reinforcement mesh, primer paint, and protective topcoat plaster, are applied to the exterior walls of buildings to improve thermal performance, reduce energy consumption, and contribute to sustainability goals. Popular in Europe and beyond, ETICS helps residential and commercial buildings comply with stringent energy regulations while offering a sleek and homogeneous aesthetic.

However, the weakest point of these systems is often their vulnerability to mechanical damage. Everyday hazards such as balls kicked by children, tools dropped during maintenance, and even hailstones can compromise the integrity of the facade, leading to cracks, delamination, or moisture ingress.

The EN 13497 standard provides a rigorous and standardized method for evaluating and classifying the impact resistance of these systems. By ensuring that exterior thermal insulation composite systems can withstand real-world conditions, the standard enables safer and longer-lasting buildings and protects manufacturers, installers, and end-users from costly repairs.

EN 13497 is essentially a performance-based standard that focuses on experimental measurements rather than predictive designs. It categorizes external thermal insulation composite systems into impact resistance categories based on the energy absorbed before visible damage occurs (typically between B1, low resistance, suitable for protected areas, and B3, high resistance, suitable for exposed facades). This classification helps specifiers select systems appropriate to the building's location and use.

This standard meticulously details the test setup to ensure consistency among laboratories:

Sample preparation: A representative section of the exterior thermal insulation composite system kit is applied to a rigid surface such as concrete or drywall, simulating on-site installation. The system should fully cure in approximately 28 days, according to the manufacturer's instructions.
Striking design: Steel spheres or hemispherical strikers of varying diameters (e.g., 50 mm for B1/B2 classes) and masses (0,5-2 kg) are used. These mimic common projectiles such as stones or sporting equipment.
Impact application: The impact device is dropped from a specific height (e.g., 0,5-1,5 m) using a pendulum or free-fall mechanism, delivering kinetic energy levels between 2 J (low impact) and 50 J (high impact). Multiple impacts can be applied to designated areas such as corners, edges, and flat surfaces.
Damage assessment: Following impact, inspectors evaluate the sample under standard lighting for cracks, indentations, or separations. Penetration depth is measured with calipers or ultrasound, and the system passes the test if the damage remains superficial (e.g., a maximum depth of 5 mm for B2 classification).

In conclusion, the EN 13497 standard guarantees that exterior thermal insulation composite systems provide not only insulation but also lasting protection.

For many years, our organization, with its competent and experienced staff, has been understanding the needs of its clients, providing the advanced testing services they require, and assisting in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services to businesses in accordance with the "EN 13497 Thermal insulation products for building applications - Determination of impact resistance of external thermal insulation composite systems (ETICS)" standard.