AC156 Updates: What Changes for the Seismic Qualification of Non-Structural Components

detail of a desk with document AC156

The structural integrity of modern buildings involves far more than just columns, beams, and foundations. During a seismic event, life safety and building operability depend heavily on secondary systems. Consequently, the seismic qualification of non-structural components has become a pivotal focus for the global construction and engineering sectors.

The primary international benchmark for validating these elements, the ICC-ES AC156 criteria, has recently been updated. This regulatory evolution introduces critical amendments for manufacturers seeking compliance through rigorous shake table testing.

Which Non-Structural Components Require Seismic Certification?

Non-structural components account for the vast majority of a building’s total financial and functional asset value. Should these systems fail during an earthquake, the consequences can range from severe financial loss to life-threatening hazards that obstruct emergency evacuation routes.

Key elements demanding meticulous seismic qualification include:

  • Architectural features: suspended ceilings, partition walls, external cladding, and glazing systems.

  • Electrical systems: switchgear, uninterruptible power supplies (UPS), and cable trays.

  • Mechanical and HVAC plant: air conditioning units, chillers, boilers, and ventilation ductwork.

  • Fire protection assets: sprinkler piping, pumps, and suppression control panels.

  • IT and Telecoms: server racks, data centres, and sensitive communication equipment.

Ensuring these critical installations remain robust post-earthquake is vital to safeguarding human lives and maintaining essential business continuity.

The Regulatory Framework: Understanding ICC-ES AC156

To ensure these components withstand severe ground motion, engineering teams rely on verified international protocols. While IEEE standards govern electrical equipment for power stations and IEC regulations dictate seismic testing methods for general electronics, ICC-ES AC156 remains the definitive global standard for the broader spectrum of non-structural components.

Developed in the United States to support the International Building Code (the foundational model building code in the US), AC156 details specific verification procedures using a shake table test. Due to its technical rigour, this criteria is heavily utilised across the UK and mainland Europe. Multinational manufacturing organisations routinely implement it to certify equipment destined for high-consequence infrastructure projects in seismically active zones worldwide.

Key Changes Introduced by the New AC156 Edition

The latest revision delivers a profound structural alignment with the newest generation of American engineering codes: the 2024 International Building Code and the ASCE/SEI 7-22 standard (Minimum Design Loads and Associated Criteria for Buildings and Other Structures).

This regulatory shift alters the certification landscape in two primary ways:

1. Revised Seismic Input Motion

The core modification dictates how the reference seismic demand—the actual shaking force applied to the test specimen—is calculated. The update incorporates newly refined mathematical parameters and modernised seismic hazard maps. For manufacturing businesses, this translates to an altered baseline when establishing the peak spectral acceleration and displacement required during laboratory testing.

2. Streamlined Multi-Market Testing

Crucially for project timelines, the actual execution mechanics of the physical tests and the structural acceptance criteria remain unaltered. Furthermore, the new framework allows engineers to design a single, integrated experimental test programme that satisfies both the historical and updated code parameters simultaneously. This mitigation prevents redundant testing cycles, drastically reducing time-to-market and operational expenditure for firms targeting multiple geographic jurisdictions.

Optimising the Certification Path with Eucentre

Navigating complex international compliance mandates requires specialised engineering expertise and elite laboratory infrastructure. The Eucentre Foundation, equipped with internationally accredited testing facilities and a high-performance 6-degrees-of-freedom (6 DoF) shake table, serves as a premier technical partner for global manufacturers.

Working in seamless synergy with prominent American certification bodies, Eucentre guides organisations through every phase of the validation lifecycle. From interpreting the precise response spectra required by the ASCE/SEI 7-22 code to executing final shake-table testing, Eucentre guarantees absolute compliance with the revised AC156 criteria, enhancing product safety and market access.