What are the criteria for determining whether a building requires seismic support brackets?
What are the criteria for determining whether a building requires seismic support brackets?
Simply put, the core criteria for determining whether a building requires seismic support brackets are the mandatory engineering construction codes and technical standards issued by national and local authorities, as well as the specific characteristics of the building itself. This is not a matter that can be decided arbitrarily based on intuition or experience, but rather one defined by a series of clear, scientific, and legally mandated conditions. The fundamental purpose of installing seismic support brackets is to ensure that, in the event of an earthquake, the building’s mechanical and electrical pipeline systems (such as fire protection, plumbing, ventilation and air conditioning, and electrical systems) remain secure. This prevents secondary disasters—such as fires, flooding, electric shocks, or obstructed escape routes—caused by falling, ruptured, or displaced pipelines, thereby safeguarding lives and property and maintaining the post-earthquake operational functionality of critical systems.
So, what specific criteria play a decisive role? We can gain a clear understanding by examining the following aspects. The primary and most authoritative basis is national laws, regulations, and design standards. Since the full implementation of the new edition of the “Code for Seismic Design of Building Mechanical and Electrical Engineering” (GB 50981-2014) in 2015, this code has served as the cornerstone for such determinations. The code explicitly stipulates that building mechanical and electrical engineering facilities in regions with seismic fortification intensity of 6 or higher must undergo seismic design. This means that as long as the seismic fortification intensity of a building project’s location reaches or exceeds 6, its mechanical and electrical piping systems must, in principle, incorporate seismic supports. This represents a mandatory baseline established by the state from a macro perspective of disaster prevention and mitigation.
Second, the specific type and functional attributes of a building are key determining factors. Buildings with different uses have varying safety levels and importance, resulting in distinct requirements. For example, public spaces with high concentrations of people—such as schools, hospitals, theaters, shopping malls, and sports venues—typically have stricter seismic requirements. Critical lifeline facilities, such as fire stations, emergency command centers, communication hubs, and major transportation hubs, must strictly adhere to the highest standards due to the vital importance of their post-earthquake functions. Additionally, high-rise buildings and structures with large-span spatial configurations require higher stability for their piping systems due to their complex dynamic responses. For these structures, seismic support systems are typically explicitly incorporated into the design regardless of the seismic zone in which they are located.
Third, the inherent characteristics and layout of the building’s mechanical and electrical piping systems serve as the direct technical basis. Not all piping requires supports; the code primarily targets those systems whose damage could cause serious harm or disrupt critical functions. Specifically, these include: pipes exceeding certain weight limits (such as large-diameter water supply and HVAC water pipes); critical lifeline pipes (such as fire sprinkler pipes, fire hydrant pipes, and gas pipelines); electrical conduits with an internal diameter of no less than 60 millimeters; ventilation and air conditioning ducts with a rectangular cross-sectional area of 0.38 square meters or greater, or a circular diameter of 0.7 meters or greater; and suspension rods used to support equipment. The horizontal and vertical fixation of these systems must be achieved through seismic support systems (such as lateral supports, longitudinal supports, or bidirectional supports) to provide sufficient seismic load-bearing capacity.
Fourth, specific project design documents serve as the direct basis for implementation. Provided that national standards are met, the final determination of whether seismic supports are required, where they should be installed, and what types should be used is established by the project’s construction drawings (including the specialized seismic design). The design firm will conduct detailed seismic calculations and design based on factors such as structural analysis, the comprehensive layout of piping and ductwork, specific seismic design intensity, and site classification, and will clearly indicate these in the drawings. Therefore, both construction and acceptance must strictly adhere to the design drawings that have passed review. Finally, local regulations and special requirements are also critical factors that cannot be overlooked. In certain areas designated as key earthquake monitoring and defense zones or regions with a history of specific disasters, local governments may issue stricter or more specific regulations. Additionally, some building owners, driven by exceptionally high standards for building safety and reliability, may request additional seismic measures beyond the standard requirements.
In summary, determining whether a building requires the installation of seismic supports is a comprehensive technical decision-making process. It is guided by the national mandatory standard (GB 50981) as the overarching framework, uses the seismic fortification intensity of the building’s location as the basic threshold, considers the building’s importance and function as key factors, takes the specific parameters of mechanical and electrical piping and ductwork as the technical focus, and relies on the final legally binding design drawings as the implementation documents. The fundamental logic lies in minimizing the potential secondary hazards caused by earthquakes through scientific, systematic, and mandatory engineering measures, thereby providing an additional layer of safety for both the building and its occupants. Therefore, in construction projects, strict adherence to these guidelines is by no means an optional choice, but rather an essential requirement for modern buildings to withstand natural disasters and uphold the principle of prioritizing human life.