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SMACNA Seismic Restraint Manual

SMACNA Seismic Restraint Manual. Mark Terzigni Project Manager SMACNA Technical Resources. History. 1976 – Guidelines for Seismic Restraint of Mechanical Systems (Sheet Metal Industry Fund of Los Angeles)

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SMACNA Seismic Restraint Manual

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  1. SMACNA Seismic Restraint Manual Mark Terzigni Project Manager SMACNA Technical Resources

  2. 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.)

  3. History • 1991 – 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

  4. History • 1998 – Second Edition • 2000 – ANSI Approval • 2000 – Addendum #1

  5. QUESTION?? What is the Issue?

  6. ANSWER Physics!!

  7. PHYSICS F = Ma

  8. Code Considerations OLDER CODES • BOCA Fp = AvCcPacWc • SBCCI Fp = AvCcPacWc • ICBO Fp = ZIpCpWp

  9. 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

  10. 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

  11. The Form is the Same IBC 0.4 apSDS is a measure of acceleration Rp/Ip UBC apCaIp is a measure of acceleration Rp

  12. Simplifying IBC Fp = CsWp (1 +2Z/h) UBC Fp = Cs(1 + 3hx/hr)Wp

  13. The Components IBC (1 + 2Z/h) and UBC (1 + 3hx/hr) Are Adjustments for the Anticipated Force Levels Depending on Location in the Building

  14. Basic Equation Fp = CsWp Where Cs includes the Location Adjustment Factors

  15. Rearranging the Equation

  16. The SMACNA Seismic Restraint Manual has Tables for Four Values of Cs These Tables are Identified as Seismic Hazard Level (SHL)

  17. SMACNA SHL Values SHL A = Cs = 1.0 SHL B = Cs = 0.75 SHL C = Cs = 0.50 SHL D = Cs = 0.25

  18. The Design Professional Should • Calculate Cs from the Information in the Applicable Local Building Code • Calculate the Values of Cs at the Various Attachment Locations in the Building • Indicate the Required SMACNA SHL Tables to be Used at the Different Attachment Locations

  19. Terms • Occupancy Category • I – IV Table 1-1 ASCE-7 05 • Seismic Design Category • Section 11.6 ASCE-7 05 • Seismic Hazard Level • A-D based on seismic acceleration SMACNA

  20. ASCE-7 05

  21. General Requirements • Details provide lateral bracing system. Typical vertical supports per local building code must be used. • Thermal expansion not given but must be considered. • Duct construction to conform to the appropriate SMACNA publications.

  22. General Requirements • Pipes will conform to ANSI/ASME B 31.9 Building Services Piping Code. • Brace in-line equipment independently of ducts and pipes. • 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)

  23. General Requirements • Hot rolled shapes and plates to conform to ASTM A36. Pipes used as braces to conform to ASTM A120 or A53. • Cables to have minimum breaking strength. Per Table 3-2.

  24. General Requirements • Bolts to conform to ASTM A307. • Expansion anchors per Table 3-3. Proprietary connectors may be used where values are greater. • Welding to conform to AWS D1.1 using shielded or submerged ARC method. • Brace conduit same as equivalent weight of pipe.

  25. General Requirements • Do not mix solid and cable bracing. • Bracing for equipment NOT included. • All runs will have a minimum of two transverse and one longitudinal braces. • A run is defined as any change in direction except as allowed by offsets.

  26. Bracing of Ducts Seismic supports are not required for HVAC ductwork when the Ip = 1.0 if either of the following conditions is met for the entire duct run: • Ducts are suspended from hangers 12 in. or less as measured from the top of the duct to the bottom of the support where

  27. Bracing of Ducts the hanger is attached. Hangers must be positively attached to the duct within 2 in. of the top of the duct with a minimum of two #10 sheet metal screws. Lateral motion will not cause damaging impact with other systems. Lateral motion will not cause loss of vertical support. • Ducts have a cross-sectional area of 6 ft2 or less.

  28. Bracing of Ducts • Transverse and longitudinal bracing per tables (Chapters 5, 6, 7 and 8). • Ducts may be grouped. Select bracing requirements based on combined weight. Minimum of two sides to be attached to horizontal or vertical angles.

  29. Bracing of Ducts • Wall penetrations may replace transverse brace. Solid blocking required.

  30. Bracing of Pipes or Conduit • Brace fuel oil, and gas (such as, fuel gas, medical gas, and compressed air) as per local codes. • Brace all pipes 3 inch nominal diameter or larger.

  31. Bracing of Pipes - Conduit • Transverse and longitudinal bracing as per tables (Chapters 5, 6, 7 and 8). • 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.

  32. Bracing of Pipes - Conduit • Seismic supports are not required for piping systems where one of the following conditions is met: • Piping is supported by rod hangers; hangers in the pipe run are 12 in. (305 mm) or less in length from the top of the pipe to the supporting structure;

  33. Bracing of Pipes - Conduit • hangers are detailed to avoid bending of the hangers and their attachments; and provisions are made for piping to accommodate expected deflections. • High-deformability piping is used; provisions are made to avoid impact with larger piping or mechanical

  34. Bracing of Pipes - Conduit • components or to protect the piping in the event of such impact; and the following requirements are satisfied: • For Seismic Design Categories D, E or F where Ip is greater than 1.0, the nominal pipe size shall be 1 in. (25 mm) or less.

  35. Bracing of Pipes - Conduit • For Seismic Design Category C, where Ip is greater than 1.0, the nominal pipe size shall be 2 in. (51 mm) or less. • For Seismic Design Category D, E or F where Ip is equal to 1.0, the nominal pipe size shall be 3 in. (76 mm) or less.

  36. Vertical risers not specifically engineered will be laterally supported with a riser clamp at each floor.

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

  38. 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

  39. Elements of a Seismic Restraint • Brace • Attachment to the Component • Attachment to the Structure

  40. RIGID Angles Pipes Strut Channels NON-RIGID Cables Bracing Members

  41. Connection to the Element • Ducts • Pipes

  42. Connections to Ducts • The SMACNA Seismic Restraint Manual Contains 12 Different Details for Connecting to Ductwork, Rectangular and Round

  43. FIGURE 4-2 SIDE BRACING FOR RECTANGULAR DUCTS

  44. FIGURE 4-3 SIDE BRACING FOR RECTANGULAR DUCTS

  45. FIGURE 4-4 CABLE SIDE BRACING FOR RECTANGULAR DUCTS

  46. FIGURE 4-5 SIDE BRACING FOR RECTANGULAR DUCTS

  47. FIGURE 4-6 CENTER BRACING FOR RECTANGULAR DUCTS

  48. FIGURE 4-7 CABLE CENTER BRACING FOR RECTANGULAR DUCTS

  49. FIGURE 4-8 FLOOR SUPPORTED DUCT

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

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