IBC Seismic Code Standards and Installation Requirements

Today’s Seismic Standards

What Is The IBC?

 It is the first model building code to specifically address the differences in seismic hazard based on soil type.

 It can significantly impact the cost of installing suspended ceilings in areas that have not historically required seismic installations – 2 –

Today’s Seismic Standards

How Big Is The Risk?

 Currently 45 states use the International Building Code   66% of the U.S. is now at some level of risk 25 – 40% chance for a major quake in the Midwest – 3 –

Today’s Seismic Standards

This is a complicated issue !

 Three variables determine a Seismic Design Category  Interpretation of installation practices by contractors and code officials  Integration of seismic information into plans and specifications – 4 –

Today’s Seismic Standards

According to the International Building Code [IBC], a

Seismic Design Category

must be established for

each construction project

based on

three variables

:  anticipated ground motion  type of soil in a specific geographic area  seismic [building] use group designation In the former CISCA zone classification, an entire geographical area determined construction methods. The IBC ‘project by project’ analysis is a major change!

The design team is responsible for the analysis required to assign a Seismic Design Category to a project.

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Seismic Design Category – Variable 1

Determine Maximum Ground Motion

 Ground acceleration is evaluated by location on hazards maps  Two maps are used to list ground motion at 0.2 and 1 second periods  Ground motion is presented as a percentage of the acceleration of gravity – 6 –

Seismic Design Category – Variable 2

Determine [Soil] Site Class

 Soil type is evaluated to a depth of 100'  The “Site Class” is rated A through F, where A is hard rock and F is more unstable soil types  Site Class D is used when specific data is not available unless class E or F soil types are likely – 7 –

Seismic Design Category – Variable 3

Determine Seismic Use Group

A risk factor is assigned based on the occupancy of the structure and how critical the operability of the facility is in the event of a disaster, such as an earthquake.

 Seismic Use Group I – normal occupancy Examples: everything not assigned to another group  Seismic Use Group II – high occupancy Examples: schools, large office buildings and utilities  Seismic Use Group III – essential use Examples: police and fire stations; medical facilities – 8 –

What About Specifications?

Seismic Information in Construction Documents

This may vary by location, but: 1. A Seismic Design Category [SDC] tells the construction team what level of performance the building and its systems must achieve 2. SDC is to be listed in the construction documents 3. While exact location in the CDs may vary by jurisdiction, most likely it will be in the general conditions section of the specification, and in of structural drawings general notes on the first page – 9 –

Today’s Seismic Standards

Non-Structural Systems Get A Closer Look

 Before IBC: Suspended ceilings could fail and render a space unusable  After IBC: Suspended ceilings – designed and installed to meet IBC Seismic Design Categories – can survive intact – 10 –

Today’s Seismic Standards

IBC Installation Requirements for Suspended Ceilings

 Provide a suspension system strong enough to resist lateral forces imposed upon it without failing  Prevent border panels from falling from the ceiling plane Perimeter Wires – Categories D, E, and F – 11 –

Seismic Code Compliance

“Old” and “New” Code Comparison: Seismic Design Category A and B

IBC Category CISCA Zone A, B 0-1 Installation Requirement Ceiling installations should conform to basic minimums established in ASTM C 636.

The IBC does not require any special ceiling installation considerations in these categories

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Seismic Code Compliance

“Old” and “New” Code Comparison: Seismic Design Category C

IBC Category C CISCA Zone 2 Installation Requirement To be installed to CISCA recommendations for areas subject to

light-to-moderate

seismic activity:       Minimum

7/8”

wall molding Grid

must not be attached

to the wall molding 3/8” clearance on all sides 3/8” overlap of the grid on the wall molding Ends of main beams and cross tees must be tied together to prevent their spreading No perimeter wires The IBC installation requirements for Seismic Design Category [SDC] C exempts ceilings in most one and two story buildings unless they are Seismic Use Group III [essential facilities].

The objective of this standard is to create an unrestrained ceiling.

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Seismic Code Compliance

The “unrestrained ceiling” Seismic Design Category C

 The notion of a free-floating ceiling is new, and will impact the installed cost  Ceilings that cannot touch the walls are more expensive to install, because it is harder to keep them straight and square  Estimated cost increase per SF is 10-15% Seismic Installation – Braced Perimeter Soffit – 14 –

Seismic Code Compliance

“Old” and “New” Code Comparison: Seismic Design Categories D, E, and F

IBC Category D, E, F CISCA Zone 3-4            Installation Requirement To be installed to CISCA recommendations for areas subject to

severe

seismic activity. IBC

categories D, E, and F

must also meet these additional requirements:

Minimum 2” wall molding Grid must be attached to two adjacent walls

¾” clearance – opposite walls must have a Ends of main beams and cross tees must be tied together to prevent their spreading Perimeter support wires Heavy-duty grid system Ceiling areas over 1,000 SF must have horizontal restraint wire or rigid bracing Ceiling areas over 2,500 SF must have seismic separation joints or full height partitions Ceilings without rigid bracing must have 2” oversized trim rings for sprinklers and other partitions Changes in ceiling plane must have positive bracing Cable trays and electrical conduits must be independently supported and braced Suspended ceilings will be subject to special inspection

This practice creates a restrained ceiling.

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Seismic Code Compliance

Seismic Design Categories D, E, and F

Meeting the most rigorous code guidelines costs 50% more than Seismic Design Category A or B [standard suspended ceiling installation practices] The cost increase is associated with the labor and materials to install the suspension system and perimeter components Note the use of 2” wall molding in this photo.

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Alternative Designs and Methods

Code officials may approve other

installation designs based upon the following:

 IBC Section 104.11 Alternative materials, design and methods of construction and equipment. The provisions are not intended to prevent the installation of any material … providing that alternatives are approved.

 IBC Section 101.11.1 Tests. Whenever code compliance is questionable … the building official can require tests as evidence of compliance.

Armstrong has conducted full scale seismic tests.

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Alternative Designs and Methods



IBC Seismic Design Category C Alternative Installation Test:

Tested Prelude XL  intermediate-duty main beams [7300] and cross tees [XL7342 and XL7328] and 7/8” wall molding. The system was installed according to the IBC Category C with the following exceptions: 1. Used BERC clip to eliminate stabilizer bars 2. Installed grid tight to two adjacent walls - and less than ¼” clearance on the opposite walls  Verified that the system meets required code performance.

The result: a ceiling that is easier to square at the perimeter .

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Alternative Designs and Methods

Another Approach to Seismic Design Category C

One of our suspension system accessories, the BERC clip, offers an alternate method to prevent grid from spreading The BERC costs less than stabilizer bars and does not interfere as much with placement and removal of border panels Arrow indicates stabilizer bar at perimeter – 19 –

Alternative Designs and Methods



IBC Seismic Design Category D, E, F Alternative Installation Test:

Tested Prelude XL exceptions:  with heavy-duty main beams [7301] and cross tees [XL7348 and XL7328]. The system was installed according to CISCA guidelines for seismic restraint, and the IBC, with the following 1.

Used 7/8” wall molding [7800] instead of 2” wall molding 2.

Used 2” BERC clips [BERC2] and eliminated the need for stabilizer bars  This test verified that the system meets code performance requirements.

Special note: only heavy-duty grid options are acceptable .

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Heavy-Duty Grid Options

Design Options are Limited in Seismic Design Category D, E, F

Suspension Systems – General Applications 1.

Prelude 15/16” t-bar 2.

Suprafine 9/16” t-bar 3.

Silhouette 9/16” t-bar Suspension Systems – Special Applications 1. Clean Room 1 1/2” t-bar 2.

Prelude Plus 15/16” t-bar – 21 –

Additional Armstrong Testing

Over 70 tests performed!

 Code officials must approve all drawings of public buildings before bidding  Liability can be a major issue if products vary from the IBC code  Specialty ceilings, like wood or metal, can be a concern for code officials. Armstrong can provide test results for products you may want to specify for signature spaces.

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Additional Armstrong Testing



We’ve also tested “specialty” and “floating” systems!

Armstrong has performed extensive testing on standard, specialty, and floating ceiling solutions  Testing was performed at the State University of New York at Buffalo – Armstrong is a premier Multidisciplinary Center for Earthquake Engineering Research [MCEER] partner Shake Table Test - Infusions  You can specify non-standard ceilings confident that they have been tested to meet IBC requirements [Serpentina, Infusions, Axiom, WoodWorks, and Metalworks]!

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Other Seismic Support Tools For Seismic Information on the Web: www.armstrong.com/seismic

 Latest product and solution news  Seismic Test Summaries  Seismic Design Solution CAD renderings   Seismic FAQs IBC Guide Specification – 24 –

Other Seismic Web sites For More Seismic Information on the Web Visit These Code Related sites Name of the Organization American Society for Testing and Materials [ASTM] Building Seismic Safety Council [BSSC] Federal Emergency Management Agency [FEMA] International Code Council [ICC] United States Geological Survey [USGS] Web site

www.astm.org

www.nibs.org

www.fema.gov

www.iccsafe.org

geohazards.cr.usgs.gov

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Additional Resources and References

1. The 2004 Armstrong catalog references Seismic performance [note the new icons].

2. Need guide specs, samples, or additional technical assistance? We can help you meet Seismic code requirements on your projects. Call TechLine for all your Seismic needs.

3. Need AIA CES credits? We can deliver an AIA approved program worth one learning unit [LU]. This course meets health, life safety, and welfare guidelines! – 26 –