smacna seismic restraint manual

SMACNA Seismic Restraint Manual

Bob WasilewskiProject Manager, Technical Resources

SMACNA

ANSI/SMACNA 001-2000Approved by ANSI July 31, 2000

History

1976 – Guidelines for Seismic Restraint of Mechanical Systems(Sheet Metal Industry Fund of Los Angeles)

1982 – Guidelines for Seismic Restraints of Mechanical Systems and Plumbing Piping Systems(Sheet Metal Industry Fund of Los Angeles and The Plumbing and Piping Industry Council , Inc.)

History1991 – Seismic Restraint Manual –Guidelines for Mechanical Systems(SMACNA)– Included larger ducts– Included conduit– Created Seismic Hazard Level (SHL)

1993 – Appendix E– Corrections and Clarifications– Specific Requirements for OSHPD– OSHPD Approval

History

1998 – Second Edition

2000 – ANSI Approval

2000 – Addendum #1

QUESTION??

What is the Issue?

ANSWER

Physics!!

PHYSICS

F = Ma

Code Considerations

OLDER CODES1. BOCA

Fp = AvCcPacWc

2. SBCCIFp = AvCcPacWc

3. ICBOFp = ZIpCpWp

All Codes Take the Form of

Fp = Cs Wp

Where Cs = A series of constants given in the building code

Cs is a measure of acceleration

Current Codes

International Building Code (IBC) 2000-2003

Fp = 0.4ap SDS Wp (1 + 2Z/h)Rp/Ip

Uniform Building Code (UBC) 1997

Fp = apCaIp (1 + 3hx/hr) Wp

Rp

The Form is the Same

IBC0.4 apSDS is a measure of acceleration

Rp/Ip

UBCapCaIp is a measure of acceleration

Rp

Simplifying

IBC

Fp = CsWp (1 +2Z/h)

UBC

Fp = Cs(1 + 3hx/hr)Wp

The Components

IBC (1 + 2Z/h)and

UBC (1 + 3hx/hr)

Are Adjustments for the Anticipated Force Levels Depending on Location in the Building

Basic Equation

Fp = CsWp

Where Cs includes the Location Adjustment Factors

Rearranging the Equation

=Wp

Cs

Fp

The SMACNA Seismic Restraint Manual has Tables for Four Values

of Cs

These Tables are Identified as Seismic Hazard Level (SHL)

SMACNA SHL Values

SHL C = Cs = .21

SHL B = Cs = .42

SHL A = Cs = .67

SHL AA = Cs = 1.0

The Design Professional Should

1. Calculate Cs from the Information in the Applicable Local Building Code

2. Calculate the Values of Cs at the Various Attachment Locations in the Building

3. Indicate the Required SMACNA SHL Tables to be Used at the Different Attachment Locations

General Requirements

1. Details provide lateral bracing system. Typical vertical supports per local building code must be used.

2. Thermal expansion not given but must be considered.

3. Duct construction to conform to the appropriate SMACNA publications.


4. Pipes will conform to ANSI/ASME B 31.9 Building Services Piping Code.

5. Brace in-line equipment independently of ducts and pipes.

6. Cold formed angles to conform to the requirements of the latest "Specifications for the Design of Cold-Formed Steel Structural Members" (AISI) (FY = 33 KSI)


7. Hot rolled shapes and plates to conform to ASTM A36. Pipes used as braces to conform to ASTM A120 or A53.

8. Cables to have minimum breaking strength. Per Table 3-2.

FS = 2.0FS = 5.0

General Requirements9. Bolts to conform to ASTM A307.10. Expansion anchors per Table 3.3.

Proprietary connectors may be used where values are greater.

11. Welding to conform to AWS D1.1 using shielded or submerged ARC method.

12. Brace conduit same as equivalent weight of pipe.


13. Do not mix solid and cable bracing. 14. Bracing for equipment NOT included.15. All runs will have a minimum of two

transverse and one longitudinal braces. 16. A run is defined as any change in

direction except as allowed by offsets.

Bracing of Ducts1. Brace all ducts with a cross sectional area

of 6 square feet or larger. Brace flat oval ducts the same as rectangular ducts.

2. Exception - Hangars 12" in length or less as measured from the top of the duct to the supporting structure. Hangars must be positively attached to the duct within two inches of the top with a minimum of two No. 10 sheet metal screws.

Bracing of Ducts

3. Transverse and longitudinal bracing per tables (Chapters 5, 6 and 7).

4. Ducts may be grouped. Select bracing requirements based on combined weight. Minimum of two sides to be attached to horizontal or vertical angles.

Bracing of Ducts

5. Wall penetrations may replace transverse brace. Solid blocking required.

Bracing of Pipes - Conduit

1. Brace fuel oil, gas (such as, fuel gas) medical gas and compressed air as per local codes.

2. Brace piping in boiler, mechanical equipment and refrigeration mechanical rooms 1 ¼" inch or larger.

Bracing of Pipes - Conduit3. Brace all pipes 2 ½ inch nominal diameter or

larger.4. Exception - Pipes suspended from individual

hangers 12" or less as measured from the top of the pipe to the supporting structure. For pipes on a trapeze, the 12" exception is measured from the upper face of the horizontal trapeze member or the bottom of the pipe.


5. Transverse and longitudinal bracing as per tables (Chapters 5, 6 and 7).

6. Provide joints/connections capable of accommodating seismic displacements where pipes pass through building seismic or expansion joints or where pipes connect to equipment with vibration isolators.


7. Branch lines may not be used to brace main lines.

Vertical risers not specifically

engineered will be laterally

supported with a riser clamp at each

floor.

DEFINITIONS

TRANSVERSE BRACE - those designed and installed to restrain movement in the direction perpendicular to the piping or duct run

DEFINITIONS

LONGITUDINAL BRACE - those designed and installed to restrain movement in the direction parallel to the piping or duct run

RUN (Piping or Duct) - a straight length with no changes in direction except as allowed by offsets

Elements of a Seismic Restraint

Brace

Attachment to the Component

Attachment to the Structure

Bracing Members

RIGIDAnglesPipesStrut Channels

NON-RIGIDCables

Connection to the Element

Ducts

Pipes

FIGURE 4-2 SIDE BRACING FOR RECTANGULAR DUCTS

FIGURE 4-4 CABLE SIDE BRACING FOR RECTANGULAR DUCTS

FIGURE 4-6 CENTER BRACING FOR RECTANGULAR DUCTS

FIGURE 4-7 CABLE CENTER BRACING FOR RECTANGULAR DUCTS

FIGURE 4-8 FLOOR SUPPORTED DUCT

FIGURE 4-9 SINGLE HANGER SPACING FOR ROUND DUCTS33-36 INCHES (838-900 MM)

FIGURE 4-10 SINGLE HANGER CABLE BRACING FOR ROUND DUCTS33-36 INCHES (838-900 MM)

FIGURE 4-13 TRANSVERSE BRACING FOR PIPES

FIGURE 4-14 STRUT BRACING FOR PIPES

FIGURE 4-16 LONGITUDINAL BRACING FOR PIPES

FIGURE 4-18 CABLE BRACING FOR PIPES

FIGURE 4-20 STRUT BRACING FOR PIPE TRAPEZE

FIGURE 4-21 CABLE BRACING FOR PIPE TRAPEZE

FIGURE 4-22 FLOOR SUPPORTED PIPES

Tables

TABLE 5-1 SIDE BRACING FOR RECTANGULAR DUCTS, SHL A, L=2' 8" (MAX.)

TABLE 5-2 SIDE BRACING FOR RECTANGULAR DUCTS WITH ROD HANGERS, SHL A

TABLE 5-6 BRACING FOR ROUND DUCTS, SHL A

TABLE 5-7 SCHEDULE FOR BRACING PIPES AND CONDUIT, SHL A

TABLE 5-8 SCHEDULE FOR BRACING PIPES ON TRAPEZE, SHL A

Connection to the Structure

FIGURE 8-1 CONNECTIONS TO CONCRETE

TABLE 8-1 SCHEDULE FOR TYPICAL CONNECTIONS TO STRUCTURAL SUPPORTING MEMBERS

Miscellaneous Connections

FIGURE 8-2 ADJUSTABLE CONNECTIONS TO CONCRETE

FIGURE 8-4 ALTERNATE CONNECTIONS TO CONCRETE

FIGURE 8-6 CONNECTIONS TO CONCRETE FILL ON STEEL DECK

FIGURE 8-12 CONNECTIONS TO STEEL

FIGURE 9-5 CABLE END CONNECTION

FIGURE 9-10 RISER BRACING FOR HUBLESS PIPES

FIGURE 9-17 WELDED TABS

FIGURE 9-20 288-POUND (MAX.) VARIABLE AIR VOLUME TERMINAL

SMACNA Guidelines/ConsultantSEISMIC SOURCES:

Contractor/ConsultantSEISMIC DESIGN (Mechanical):

10.0 Richter EarthquakeSEISMIC REQUIREMENTS:

3 MillionSEISMIC RESTRAINT COST:

30 Million (No Equipment)PIPING/SHEET METAL:

4350 Tons Cooling - Central PlantMECHANICAL:

Start 1989, (1992), Complete 1997TIME:

1 BillionCOST:

6 Buildings, 110 Acres, 100 Year Life, 945,000 SFSIZE:

Getty Center - Brentwood, CaliforniaPROJECT:

Other Resources

ASHRAE –

A Practical Guide to Seismic Restraint

Other Resources

FEMA1. 2000 Provisions (FEMA 368)2. 2000 Commentary (FEMA 369)3. Installing Seismic Restraints For

Mechanical Equipment (FEMA 412)4. Installing Seismic Restraints For Duct &

Pipe (FEMA 414)

FEMA Distribution Center 1-800-480-2520

smacna seismic restraint manual

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