Electrical boxes (e.g., terminal boxes and pullboxes).
This design manual is part of a two-volume set produced by International Seismic Application Technology (ISAT), which is a global provider of engineering services, consulting services, and restraint system components for nonstructural seismic bracing. The two volume series provides guidelines for the design and installation of engineered seismic restraint systems for suspended utilities.
ISAT installation details and engineered bracing tables are suitable for use under the following codes and standards:
2006 International Building Code.
ASCE 7-05, Minimum Design Loads For Building and Other Structures.
FEMA 450-03, NEHRP Recommended Provisions for Seismic Regulations for New Buildings and Other Structures.
TI-809-04 Seismic Design For Buildings, US Army Corp of Engineers Department of Defense, Unified Facilities Criteria 3-310-04 (6/07), Seismic Design for Buildings.
NFPA 5000, Building Construction and Safety Code.
American Concrete Institute (ACI) 318-02, Appendix D.
Seismic Force Formulas
The ISAT Applications and Design Manual provides seismic restraint requirements engineered for use within a broad range of horizontal accelerations. Information required at the beginning of the process includes project type, location, seismic force variables (below), and the seismic design specifications or performance criteria. Once these parameters have been determined and certain basic calculations have been performed, ISAT’s Engineered Bracing Tables and Detail Drawings are used to define the seismic bracing requirements for the suspended utilities.
ASCE 7-05, Section 13.1. requires design of the seismic restraints for nonstructural components. The resultant construction documents are to be prepared by a registered design professional.
Seismic Design Force for the component, Fp, is calculated per ASCE 7-05 Equations 13.3-1 thru 13.3-3. In order to perform these calculations it is first necessary that the project specific SDS value, defined below, be provided by the Engineer of Record or the Project Architect. The SDS value should commonly be identified on the structural plans or within the construction documents.
Variables used to determine the Seismic Design Force include:
Spectral Response Acceleration at Short Periods, SDS.
Component Amplification Factor, ap.
Component Response Modification Factor, Rp.
Component Importance Factor, Ip.
Component Operating Weight, Wp.
Height in Structure, Point of Component Attachment, z.
Average Roof Height With Respect To Base, h.
The ISAT Project Worksheet at the back of the Manual will help you efficiently gather the required information for accurate calculations. The ISAT Manual also provides you with contact numbers to obtain project worksheets for use with other codes.
ISAT Engineered Bracing Tables
The cumulative result of applying the seismic demand formulas is the need to provide engineered seismic restraint systems covering a substantial range of possible horizontal accelerations. For simplicity, the worst case horizontal acceleration can be calculated at the underside of the roof deck and then used for all floors of the structure. However, to achieve economy of installation, the horizontal acceleration for each floor can be computed separately and used in conjunction with the ISAT bracing tables.
In response to this need ISAT has generated concise tables of the minimum restraint requirements for a broad array of component accelerations applied to commonly used suspended utilities.
Quality Assurance Provisions and Special Inspection
Per Sections 1705 and Section 1707 of the 2003 IBC quality assurance and special inspection is required of certain mechanical, electrical and plumbing systems within facilities assigned to Seismic Design Categories C, D, E or F. The registered design professional in responsible charge may utilize ISAT documentation as the basis for submitting a Code required “special inspection plan” for these items.
Along with the need for special inspection of specific components as referenced above, contractor’s are required by Codes to submit “a written statement of responsibility” prior to installation of the system or components.
A definition of what systems and components require special inspection is provided within the Manual under the Application Notes section specific to each trade.
Blast Protection and Operational Resiliency
Seismic bracing can also be used to enhance the resiliency of utility systems within critical facilities where it has been deemed necessary to mitigate against the potential of a bomb blast. ISAT's bracing system can be applied on projects where blast loads are defined.
Author: International Seismic Application Technology Format: Looseleaf with custom binder Copyright: 2006
No, these tips aren't free material from the standards. They are tips to help you avoid problems in applying the standards.
Examine the plans and identify the building structure and non-building structure items that need attention for seismic protection purposes. Obtain the relevant ISAT books for the non-building structure items and the relevant ICC codes for the building structure items.
Review the contract for specifications arising from seismic requirements. Note that these may be incorrect, insufficient, or missing. Sometimes the design firm makes assumptions, instead of determinations, about seismic location. Identify the needed changes and additions, based on what the codes and standards say.
Understand that seismic guidelines and standards are based on approximations and risk acceptance. There's nothing stopping you from exceeding the standards for a given area, other than implementation cost. It might be prudent to accept a higher cost and lower risk. Examine these factors with the client, rather than simply going with the minimum requirements. Discuss proposed changes with the insurer, with an eye to a rate discount.
Construction and testing methods can easily defeat seismic standards. Ensure fasteners are not re-used (a mistake made when test technicians unbolt something, such as a pressure transmitter, then bolt it back on with bolts that no longer have the same clamping power). Ensure all fasteners, including screws, are tightened to the correct torque value using the correct lubricant (if any) and correct torque measuring tool, with the correct torquing pattern. Ensure all torque measurement tools are correctly calibrated, stored, and used. Typically, all three of these are done wrong.
Communicate. Many people are not accustomed to implementing seismic standards. A work order or job instruction may say to use a calibrated torque wrench, but that doesn't mean the craft technician will use one. Talk to people. Hold training. Walk around and see what people are doing. Don't just expect things to be automatically done according to plan.
Review each phase of the project on a continuous basis. Just because something is in the specifications when the crews show up to start building or installing doesn't mean it's a done deal. People can change drawings (perhaps due to schedule pressures or budget pressures, but sometimes just out of ignorance) or simply ignore them and do things the "regular way."
No More Confusion
Two general areas of confusion arise in regard to these standards. One is the way jobs are sometimes specified or put out for bid. The developer may have overlooked certain requirements, allowing an unscrupulous competitor to bid on that job while you would have done it the right way from the start. By having the codes on hand and referencing specific parts of your bid to specific codes, you force everyone to bid on the same job you're bidding on--not a cheaper job that naturally results in your being underbid.
Another area of confusion is what exactly the construction and renovation code requirements are, and which apply to your particular project. Ask 10 different project managers, and you're likely to get a dozen different answers. Thesolution is to obtain and study the codes relevant to your project. This is much more efficient than trying to argue with an inspector or attorney after you've already completed work that violates one or more code provisions.
ISAT stands for International Seismic Application Technology. It differs from a standards assocation mainly in the fact that it's not a standards association but is instead a single company. ISAT produces seismic bracing products and and provides related services for all non-structural building utility systems. It's really a narrow niche, and it's one they "own" due to their focus in this niche for so long. So the company has developed a set of standards to help people protect these systems from seismic events.
Of course, ISAT would also like to sell products and services. But the manuals are written as separate products (which is why we sell them), not sales brochures. And that approach is also why ISAT manuals have such wide-ranging acceptance among engineers.
From ISAT's company profile:
Since ISAT’s sole discipline is the design of non-structural seismic restraints, we have gained a tremendous amount of experience and expertise, complimented by streamlined execution efficiencies. We are constantly upgrading our products and services based on changing building codes, changing industry standards and feedback from the installing contractors. In order to streamline our services, ISAT archives our engineering, details and solutions for easy recall.
This is the backbone of ISAT’S Design, Installation and Inspection Manuals. Each manual is approximately 600 hundred pages and is a comprehensive library of code specific seismic bracing solutions, engineering design tables, code clarifications, in depth installation details and inspection criteria. These design manuals are trade specific to each MEP & F trades. The ISAT approach removes the redundancy of engineering the most common conditions, and has become the standard for engineers that deal with requirements pertaining to the International Building Code and/or California hospitals under the jurisdiction of OSHPD.
From ISAT's Website:
International Seismic Application Technology (ISAT) is dedicated to assisting contractors, engineers, facility owners and project teams achieve code compliance in a cost effective manner. It is easy to see why the nation's largest contractors use ISAT for their most complicated projects. Find out why the industry's leading contractors, engineers, inspectors, and facility owners rely on the ISAT approach for stream-lined seismic code compliance. Take the fear out of seismic bracing and put ISAT on your jobsite.
The seismic restraint of suspended HVAC ducts, fire protection piping, electrical utilities and plumbing/piping systems for hospital construction projects has been a daily function of ISAT for many years. Although we have a broad range of project types under our belt, we are extremely proud of our hospital experience.
If you are involved in healthcare construction, you are familiar with the issues that compound the process. Highly congested hospital corridors, more stringent code requirements and ambiguous inspection influences all complicate an already tricky construction project. Past experience has proven a solid understanding of inherent issues and a good base knowledge of the seismic bracing code requirements by the entire construction and design team, can drastically streamline issues surrounding seismic bracing code compliance.