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Electrical contractors are encountering seismic requirements in parts of the United States that previously were not considered earthquake prone. However, in these areas, the geological potential for earthquakes exists as much as the West Coast. The seismic requirements for electrical installations may be explicitly called out in the contract documents but also can be implicitly included by reference to the International Building Code (IBC), other industry codes and standards, or state and local requirements.
To further complicate matters for the electrical contracting firm, seismic requirements often are not included directly in the specifications for the power, communications and control systems, but instead are found in the general requirements for the project the electrical contracting firm’s installation must meet.
The electrical contracting firm must be aware of any seismic requirements pertaining to the projects on which it is bidding. Since most seismic requirements for nonstructural components are performance-based, the electrical contracting firm will need to have a plan for how to meet them, which usually will involve retaining a registered structural engineer. Seismic requirements can have a significant impact on the project cost, schedule and risk that needs to be addressed in the electrical contracting firm’s bid.
International Building Code
The International Code Council Inc. (ICC), which is primarily composed of the Building Officials and Code Administrators Inc. (BOCA), International Conference of Building Officials (ICBO) and Southern Building Code Congress International (SBCCI), publishes the IBC. The IBC is based on the BOCA National Building Code, ICBO’s Uniform Building Code and SBCCI’s Standard Building Code.
The purpose of the ICC is to provide the minimum requirements for protecting building occupants from fire and other hazards as well as to safeguard emergency personnel during emergency operations. The IBC is widely adopted throughout the United States and is currently in its 2006 edition.
IBC Section 1613 specifies earthquake requirements. The scope of Section 1613 includes structural systems as well as nonstructural building components, which includes installed electrical equipment. Section 1613 requires permanently attached electrical equipment, including attachments and support systems, to be designed and installed in accordance with the American Society of Civil Engineers’ (ASCE) Minimum Design Loads for Buildings and Other Structures, which is ASCE 7-05. Chapter 13 of ASCE 7-05 addresses the seismic requirements for electrical equipment.
Project seismic requirements
The project specifications typically will include the seismic requirements; they often are not indicated on the drawings. Furthermore, seismic requirements typically take the form of performance specifications rather than prescriptive specs that are common for electrical materials and equipment. Performance specifications state only how the system is to perform after installation, and the responsibility of meeting performance requirements falls onto the electrical contracting firm. With a performance specification, the electrical contracting firm is responsible for the performance of the installed system, which includes design, and the EC must guarantee the system will meet the owner’s stated performance criteria.
Performance specifications are used for a variety of reasons, such as when detailed design cannot be developed before bidding due to time constraints, unknown site conditions or the inability to know the exact installation requirements. These are the reasons the seismic requirements for an electrical installation are normally expressed as a performance spec. There are just too many variables on a typical project for the design team to provide detailed seismic anchoring and bracing specifications prior to construction. Each manufacturer’s equipment is different in terms of its construction, center of gravity and anchoring points, making it impossible for the design team to create seismic anchoring and restraints prior to the electrical contractor’s actual equipment procurement.
In addition, the installation of raceway, busway and other systems often depends on coordination with other trades. The allocation of space and the coordination of mechanical-electrical-plumbing (MEP) system installation takes place during construction, because actual field conditions often vary from those anticipated during design. Therefore, the actual support and seismic bracing of raceway and busway, duct and piping, and other systems cannot be determined until MEP systems have been coordinated.
Locating seismic requirements
Most commercial and institutional construction projects use the Construction Specifications Institute’s (CSI) MasterFormat as the basis for organizing the project specifications. Currently, the CSI MasterFormat is in its 2004 edition. However, due to the extensive changes made in the 2004 edition, the traditional 16-division 1995 edition still is in wide use in the construction industry today. The electrical contracting firm needs to be aware of the location of seismic requirements in both editions.
In the 1995 edition, seismic requirements may be found in Division 1/General Requirements, Division 13/Special Construction and Division 16/Electrical. Division 1 provides the general requirements for the entire project, including all of the specification sections that follow such as Division 16/Electrical. Division 1 usually includes a general listing of codes and standards that need to be met on the project as well as specific project requirements that apply universally to all specification divisions. The electrical contracting firm needs to review Division 1 to make sure there is not a general seismic requirement in Division 1 that the firm will be held to even though the requirement is not specifically referenced in Division 16.
Division 13/Special Construction includes Section 13080, which covers sound, vibration and seismic control. It would apply to the electrical contracting firm’s work if it is referenced in Division 16 as a requirement or specifically called out in the electrical contracting firm’s scope of work in its subcontract with the project’s prime contractor. The electrical contracting firm should review its assigned specification sections and subcontract to ensure it is not subject to any seismic requirements included in Division 13.
Seismic requirements also could be included in Division 16 either directly or by reference, even though the 1995 edition of the CSI MasterFormat does not have a specific section or subsection for electrical installation seismic requirements. When reviewing Division 16, the electrical contracting firm should check all references to other specifications sections to ensure that it knows about any seismic requirements to which the electrical installation will be subject.
Seismic requirements for nonstructural building systems, including MEP systems, are explicitly addressed in the 2004 edition of the CSI MasterFormat. For the electrical contracting firm, the seismic requirements for a project can be found in any or all of the following divisions:
- Division 01/General Requirements
- Division 25/Integrated Automation
- Division 26/Electrical
- Division 27/Communications
- Division 28/Electronic Safety & Security
Just like in the 1995 edition of the MasterFormat, Division 01 of the 2004 MasterFormat provides general requirements for the project that apply to all subsequent specification sections and might include seismic requirements that apply generally. Additionally, the following Level 3 sections are provided in Divisions 25, 26, 27 and 28 for seismic requirements:
25 05 48—Vibration & Seismic Controls For Integrated Automation
26 05 48—Vibration & Seismic Controls For Electrical Systems
27 05 48—Vibration & Seismic Controls For Communications
28 05 48—Vibration & Seismic Controls For Electronic Safety & Security
Division 13/Special Construction in the 2004 CSI MasterFormat contains seismic requirements like the previous 1995 edition. In the 2004 edition, Section 13 48 00, titled Sound, Vibration and Seismic Control, addresses manufactured seismic control components (13 48 53) and fabricated seismic control assemblies (13 48 63). In addition, Section 13 52 00 covers the procurement and installation of seismic instrumentation, and Subsection 13 01 52 specifies the operation and maintenance of seismic instrumentation.
Be advised that the CSI MasterFormat is only an advisory document, and there is no guarantee the design team will adhere to either edition’s numbering system when putting together the project specifications. Therefore, the electrical contracting firm needs to carefully review the project specifications to identify any seismic requirements to which it might be subject.
Taking seismic requirements into consideration
Incorporating seismic requirements into a bid estimate can be very difficult because the actual electrical materials and equipment have not been purchased, equipment layouts and locations have not been finalized and actual raceway and busway routing have not been determined. In addition, even if this information were available, there probably would not be time to design the necessary seismic bracing in order to include a detailed cost estimate for this work. Without previous experience and knowledge of exactly what will be required on a project, the electrical contracting firm will need to estimate the cost of seismic bracing using available information. This information can include typical details provided by the electrical contracting firm’s consulting structural engineer, typical seismic bracing information from equipment manufacturers, and any published standard details for raceway, cable tray, piping and duct systems seismic bracing that could be used in preparing the bid estimate.
Meeting seismic requirements for electrical equipment may also necessitate general construction work such as construction of equipment pads with special seismic detailing. The electrical contracting firm normally will not self-perform the general construction work associated with the seismic requirements. Therefore, it can either subcontract the work to an outside contractor or contract with the project construction team to perform the work. Either way, the electrical contracting firm needs to include an amount in its bid for the performance of general construction work.
Lastly, seismic requirements also will impact project overhead. The electrical contracting firm probably will need to retain a registered professional structural engineer to analyze the planned installation and equipment, design the appropriate anchoring and bracing systems, be available to answer questions during field installation, perform site visits to observe electrical material and equipment installation, and provide record drawings documenting any field changes to the original design details.
The engineering cost associated with the seismic design needs to be incorporated in the electrical contracting firm’s bid along with the cost of any additional insurance required. EC
This article is the result of a research project investigating the impact of seismic requirements on electrical installations that is being sponsored by ELECTRI International Inc. The authors would like to thank the EI for its support.
is an associate professor in the Department of Civil, Environmental and Architectural Engineering at the University of Kansas. He can be reached at 785.864.3435 or [email protected]
is an assistant professor in the Department of Construction Management at Florida International University. He can be reached at 305.348.3517 or [email protected]