Everything you need to know about seismic design for pallet racking

Seismic risk in italy and seismic design

In Italy, pallet racking must be designed to withstand seismic loads in accordance with the applicable technical standards nationwide. As the entire country is classified according to seismic hazard, a proper seismic risk assessment is an essential part of ensuring the safety of any logistics facility.

Pallet racking is among the most vulnerable structuresin a warehouse during an earthquake. Its height and structural configuration can amplify oscillations even during moderate seismic events, potentially causing loads to fall or compromising the stability of the entire system. Seismic design is therefore essential to protecting personnel, safeguarding stored goods and maintaining operational continuity.

What is seismic design for pallet racking, and why does it matter?

Unlike conventional design, which focuses primarily on static loads such as the weight of stored goods and lateral forces generated during handling operations, seismic design accounts for the dynamic horizontal forces generated by earthquakes. Its purpose is to ensure that pallet racking can withstand the seismic actions specified in the design, while keeping deformations within permissible limits and preventing permanent damage or structural collapse.

The strength of pallet racking depends on more than the steel itself. It is determined by a combination of engineering factors:

• The starting point is the site’s seismic classification, which establishes the expected ground acceleration for the area and provides the foundation for the entire design process.
• This is further influenced by the dynamic interaction between the racking structure and the loads it supports.
• The way loads are distributed, the type of pallets used, storage height and the positioning of goods all play a significant role in determining how the structure responds to seismic forces.

For these reasons, seismic design cannot follow a one-size-fits-all approach. It must be tailored to the specific location of the warehouse and the intended configuration and use of the racking system.

Seismic design standards and regulations: what does the law require?

Seismic safety is governed by specific technical standards that establish the design criteria, calculation methods and safety levels to be met. The main regulatory references are:

• UNI EN 16681: The European standard specifically addressing the seismic design of adjustable steel pallet racking systems.
• NTC 2018 (Italian Technical Standards for Construction): These national standards establish the general criteria for the seismic design of structures. They also apply to industrial racking systems where these form an integral part of a building or have implications for structural safety, including self-supporting racking systems and those exceeding 14 metres in height.
• CSLP Guidelines (2023): These technical guidelines complement the NTC and UNI EN 16681, offering practical guidance on the application of seismic safety criteria to both new racking installations and the assessment of existing systems for seismic vulnerability.

Seismic assessment of used pallet racking systems

What if your warehouse is already in operation or you have purchased second-hand racking? Such systems may have been designed to outdated standards or may never have undergone an assessment against current seismic design requirements. Their compliance with current regulations must therefore be verified rather than assumed.

For existing racking systems, the applicable regulations require an assessment by a qualified engineer. Costly structural modifications are not always necessary:

• The process begins with a technical inspection to assess the condition of the racking, verify that load notices are in place and accurate, and check compliance with the applicable seismic design requirements.
• The inspection also includes a review of the available racking documentation to ensure it is complete and consistent. If the required documentation is missing, the necessary steps must be taken to obtain it.
• If compliance with the applicable seismic design requirements cannot be confirmed, a qualified engineer will carry out a seismic analysis based on the racking system’s current configuration. This calculation determines the structure’s capacity to withstand the seismic actions expected at the specific installation site.

Based on the results of the seismic calculations and technical inspection, three possible outcomes may arise:

1. The racking system meets seismic design requirements. In this case, obtaining the relevant documentation is sufficient to demonstrate the system’s compliance.
2. The racking system partially meets seismic design requirements. In this case, a strengthening plan must be implemented, which may include adding bracing or additional floor anchors. Once the strengthening work has been completed and the relevant documentation obtained, the racking system can be considered compliant with the applicable requirements.
3. The racking system does not meet seismic design requirements for the design loads, even with strengthening measures. In this case, replacement of the affected racking must be planned. In the meantime, the system’s load capacity must be downgraded in accordance with the CSLP Guidelines (2023). This downgrade documents the company’s commitment to meeting seismic safety requirements through the prescribed risk-reduction measures.

The risks of inadequate prevention: safety and legal liability

Failure to follow these requirements can expose a company to significant risks. In the event of an earthquake, racking systems not designed to meet seismic criteria may fail to withstand the expected forces, increasing the likelihood of structural failure or collapse.

The most serious consequences concern workplace safety: a collapse can result in serious or fatal injuries to personnel. This may also lead to significant legal consequences for the employer and other company representatives, who may face civil and criminal liability under Italy’s Consolidated Workplace Safety Act (Legislative Decree No. 81/2008).

In addition to the human and legal consequences, the financial risks can be substantial. Business interruption, loss of stock and potentially higher insurance premiums can place significant strain on any company. While seismic design cannot eliminate the risk of collapse under exceptional seismic conditions, designing in accordance with the applicable standards provides an important basis for regulatory compliance and helps protect the company from insurance and legal liabilities.

Prevent damage. Trust the experts.

Seismic risk prevention is key to protecting your personnel and assets. Whether you are investing in new racking systems or assessing the compliance of existing installations, choosing a partner with the right technical expertise is essential.

Di Massa Srl designs new racking systems in line with the latest seismic design standards and provides existing installations with racking compliance certification and seismic assessments. It also evaluates whether racking systems meet the requirements of the applicable technical standards.

Get in touch today for an expert assessment of your warehouse and take the necessary steps to protect your business.

FAQ – Seismic design of pallet racking systems