At ESTUDENER, we design, calculate and manufacture lattice towers —both guyed and self-supporting— with the highest level of technical rigor, and more than 20 years of experience.
A frequent question from our clients (often on behalf of their end customers) is: What ice thickness should I consider for a specific site?
It’s not a trivial question. Let’s shed some light on the topic.
1. Snow and its irrelevance for lattice towers
Snow is crystallized water that falls vertically and accumulates on horizontal or slightly inclined surfaces.
In a lattice tower, there are practically no significant horizontal surfaces that would allow snow accumulation, except for platforms or walkways, where the effect is usually negligible in structural terms.
From both a physical and regulatory perspective, applying snow loads to a lattice tower has no technical justification. This is confirmed by major international standards (ASCE 7, TIA-222-H, and AS/NZS 1170.3) which only consider snow on surfaces where accumulation is possible.
2. Ice: the real hazard for towers
Ice forms when atmospheric moisture (cloud, fog, or supercooled precipitation) freezes or adheres to cold, exposed surfaces —such as structures, cables, or profiles— acting as nucleation points.
It can reach significant thicknesses, form continuous coatings, and has a much higher density than snow.
Unlike snow, ice is highly relevant for structural design, especially in guyed towers, where it not only accumulates on the lattice but also on the guy wires, dramatically increasing the load on the structure. This happens because the added weight combines with the increased wind-exposed surface area.
3. Eurocode and the “regulatory gap”
In Europe, the design of towers is governed by EN 1993-3-1 (Eurocode 3 – Design of steel structures – Towers and masts).
This standard recognizes ice loading as an environmental action, together with wind, but does not define numerical values for either. It refers instead to the National Annexes of each country.
The complementary standard EN ISO 12494 (Atmospheric Icing of Structures) describes the types of ice and their physical properties but does not provide local values, it serves only as a technical guideline.
A new draft standard, EN 1991-1-9 (Eurocode 1 – Actions on structures – Atmospheric icing), compiles all relevant information on icing, but again leaves the reference values to each country’s National Annex.
Each country can (and should) define specific parameters in its National Annex, including wind and ice characterization by location.
For wind, almost all European countries have a National Annex, but for ice, many countries still do not have, leaving designers without clear criteria for selecting ice thickness and density.
4. Can I calculate expected icing from altitude, temperature, and humidity?
The answer is no.
Although latitude, altitude, wind, and humidity influence ice formation, no validated physical or empirical formula can predict ice thickness from these parameters.
EN ISO 12494 explicitly acknowledges this in several sections:
“Atmospheric icing is a highly variable phenomenon depending on local meteorological and topographical conditions.”
“The severity of atmospheric icing varies greatly from site to site, even between nearby locations, depending on exposure, altitude, wind direction, and local climate.”
“The methods presented in this annex are approximate and should be used with caution, since local icing conditions may differ significantly from regional averages.”
5. So what ice load should we choose?
In countries with a national standard, we recommend using the ice thickness and density defined in that standard. Even though there is no absolute certainty that those values will not be exceeded, they provide a reliable reference:
- Germany: 30 mm of ice, density 7 kN/m³, up to 600 m altitude.
- France: 20 mm, 40 mm, and 60 mm depending on altitude; density between 7.2 and 8.4 kN/m³ depending on tower height.
- United Kingdom, Denmark, Croatia, and Poland: National Annexes include ice-related values or guidance.
In countries without a National Annex, indicative values from literature or neighboring countries may be used, but always with caution.
As mentioned earlier, there is no guarantee these values reflect the real conditions at the site.
6. Practical advice for installers
As manufacturers, we provide structures designed to withstand specific wind and ice loads, but we cannot guarantee that these conditions will not be exceeded on site.
Even when standards exist, the data are statistical, and statistics can always be exceeded.
From our experience designing and manufacturing thousands of towers, there is no universal rule that ensures the perfect ice-thickness choice.
What we do know is that towers in humid, high-altitude areas are more vulnerable, and we have witnessed collapses caused by severe icing.
We recommend our installer clients:
- Remind the end client that they must define the ice thickness to be used in design.
- Ensure that the insurance policy covers climatic actions beyond the design loads.
- Apply the values provided in National Annexes whenever available.
- In the absence of standards, consider altitude and humidity as key factors, amplified by tower height.
- Maintain full transparency: always indicate in project documentation the ice thickness and density used in design.
- Never claim that the selected ice thickness “will not be exceeded,” even when following a standard.
Conclusion
Lattice towers can be subject to significant ice loads, especially guyed ones, where ice accretion on the guy wires can multiply structural stresses.
At ESTUDENER, we always offer transparency, experience, and technical rigor in our designs, providing each client with the available information to define reasonable, consistent, and safe ice assumptions.