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Hvac duct construction wasilewski

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Iyan Gutierrez
Iyan Gutierrez

This document summarizes the key changes between the first and second editions of the SMACNA HVAC Duct Construction Standards (HVAC-DCS). Some major changes include more specific construction requirements for volume dampers, addition of metrics, and expanded reinforcement schedules and pressure classes for rectangular ducts. It also reviews the standards and considerations for proper duct system design and construction for transporting air in HVAC and exhaust systems according to the SMACNA HVAC-DCS.

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HVAC Duct Construction Bob Wasilewski Project Manager, Technical Resources SMACNA
HVAC Duct Construction Standards WHAT? WHY? HOW?
Today's Program 1st – 2nd Edition HVAC-DCS Review Joints and Limitations Transverse Joints & Reinforcements Use of the Pressure Class Tables Tie Rod Addendum
Documents Preceding 2nd Edition HVAC-DCS Low Velocity Systems Duct Manual – First Edition 1959 – Second Edition 1963 – Third Edition 1967 Low Velocity Duct Construction Standard – 1969
Documents Preceding 2nd Edition HVAC-DCS Low Pressure Duct Construction Standard – Fifth Edition 1976 High Velocity Duct Systems Manual – First Edition 1965 High Velocity Duct Construction Standards – Second Edition 1969
Documents Preceding 2nd Edition HVAC-DCS High Pressure Duct Construction Standards – Third Edition 1975 Duct Liner Application Standard – First Edition 1971 – Second Edition 1975
Documents Preceding 2nd Edition HVAC-DCS Flexible Duct Installation Standards – First Edition 1979 – Second Edition 1980 HVAC Duct Construction Standards -- Metal and Flexible – First Edition 1985
Major Changes from First Edition GENERAL Text edited to be more reader-friendly Reading aids added Static pressure only as the basis for duct construction classification -- velocity levels deleted (Table 1-1)
Major Changes from First Edition Chapter 7 revised to facilitate use for equivalent and comparable tests and ratings Model project specification added Reminders to designers to show all required fire, smoke, radiation and volume control dampers on contract drawings are accented
Major Changes from First Edition Boiler breeching omitted Volume damper construction is more specific Lead radiation shielding added Metrics are included Air terminal runouts and supports are revised
Major Changes from First Edition RECTANGULAR DUCT REVISIONS Negative pressure construction given for 4", 6", and 10" w.g. Six feet reinforcement schedules added Reinforcement schedules extended to 120" width
Major Changes from First Edition Tie rod alternatives expanded for both positive and negative pressures TDC and TDF joint systems included and rated as T-25a and T-25b joints T-24a joint added as a modification of T-24
Major Changes from First Edition Use of 26 gage added for 4", 6" and 10" pressures Trapeze hanger tables expanded to cover the 120" width range Duct liner pin schedule adjusted Infrequently used joints (T-4, 8, 17, 18, 19, 20 and 23) omitted
Major Changes from First Edition Round, Flexible and Oval Duct Revisions Duct pressure classes revised to be positive and negative at 2", 4" and 10" w.g. Crimped joint connection length changed from 1" to 2" Rectangular branch taps into round added for straight or 45 degree lead-in-entry
Major Changes from First Edition Type 1 reinforcement of oval duct now has an internal tie rod (based on ASHRAE test program) Maximum support spacing for round flexible duct and connector changed from 10 feet to 5 feet Additional riser support details are provided
DUCT SYSTEMS SIZINGS FIRE/SMOKE CODE FITTINGS, ETC. PROTECTION COMPLIANCE CODE DUCT COMPLIANCE CONSTRUCTION SMACNA HVAC-DCS 2ND ED. 1995 INSPECTION CODE COMPLIANCE
DUCT SYSTEMS ENGINEER CONTRACTOR Design Considerations: Construction Considerations: CFM Panel Thickness (Gage) Static Pressure Pressure Class (as specified) Duct Size Panel Width/Height Fitting Type Joint Type/Spacing Construction Pressure Intermediate Reinforcement Class Type/Spacing
DEPENDENT VARIABLES
REGULAR DUCTS Maximum Deflection Maximum Test Pressure Joint and Reinf. Sheet: Lab: 1/4" on 48" w. 3/8" on 12" Dn. Class Rating + 50% W/200 on 1/2" on 13"-18" 49"-120" 5/8"on 19"-24" Field: 3/4" on 25"-84" Class Rating + 25% 1" on 85"-120" Tolerance: Tolerance: +7.5% +10%
Duct Systems Used for the movement of air in HVAC/Exhaust systems Ducts are classified based on maximum operating pressure – 0.5" w.g. positive or negative – 1.0" w.g. positive or negative – 2.0" w.g. positive or negative
Duct Systems (Continued) Ducts are classified based on maximum operating pressure – 3.0" w.g. positive or negative – 4.0" w.g. positive or negative – 6.0" w.g. positive or negative – 10.0" w.g. positive or negative
Hvac duct construction wasilewski
TABLE 1-2 STANDARD DUCT SEALING REQUIREMENTS
Hvac duct construction wasilewski
Hvac duct construction wasilewski
Hvac duct construction wasilewski
Hvac duct construction wasilewski
Hvac duct construction wasilewski
Hvac duct construction wasilewski
Hvac duct construction wasilewski
Hvac duct construction wasilewski
Hvac duct construction wasilewski
Hvac duct construction wasilewski
Hvac duct construction wasilewski
Hvac duct construction wasilewski
Hvac duct construction wasilewski
EXAMPLE 1 Duct Size 24" x 24" Pressure Class 2" w.g. Sheet Stock Joints/Reinforcements 8 ft / 4 ft Standing S
Hvac duct construction wasilewski
Hvac duct construction wasilewski
EXAMPLE 2 Duct Size 42" x 24" Pressure Class 3" w.g. 5 ft Coil Line Joints/Reinforcements 5 ft / 2 ½ ft TDC or TDF
Hvac duct construction wasilewski
Hvac duct construction wasilewski
Hvac duct construction wasilewski
MIDPANEL TIE ROD (MPT) ½" w.g. - 6" w.g. 37" - 96" Duct Dimension Rectangular Duct
Mid Panel Tie Rod Addendum Joints – All Tie Rods – Threaded Rod or Tubing/Conduit with Threaded Insert Additional Application Tables, Qualifications and Reader Aids Included
Hvac duct construction wasilewski
Hvac duct construction wasilewski
Hvac duct construction wasilewski
Hvac duct construction wasilewski
Hvac duct construction wasilewski
FIGURE 1-3 TIE ROD ATTACHMENTS
FIGURE 1-4 TRANSVERSE (GIRTH) JOINTS
FIGURE 1-4 TRANSVERSE (GIRTH) JOINTS
FIGURE 1-4A SPECIAL JOINT PROFILES
FIGURE 1-5 LONGITUDINAL SEAMS – RECTANGULAR DUCT
TABLE 1-24 UNREINFORCED DUCT (WALL THICKNESS)
TABLE 1-25 T-1 FLAT DRIVE ACCEPTED AS REINFORCEMENT
FIGURE 1-7 UNREINFORCED DUCT
FIGURE 1-8 CROSSBROKEN DUCT & BEADED DUCT
FIGURE 1-9 DUCT REINFORCED ON TWO SIDES
FIGURE 1-10 DUCT REINFORCED ON ALL SIDES
FIGURE 1-12 DUCT OVER 120" (3048 MM) WIDE
FIGURE 1-15 CORNER CLOSURES - FLANGES
FIGURE 2-22 DUCT LINER INTERRUPTION
TABLE 3-2A ROUND DUCT GAGE UNREINFORCED POSITIVE PRESSURE
TABLE 3-2B ROUND DUCT GAGE NEGATIVE PRESSURE
FIGURE 3-1 SEAMS – ROUND DUCT AND FITTINGS
FIG. 3-2 TRANSVERSE JOINTS – ROUND DUCT
FIGURE 3-6 FLAT OVAL DUCTS
FIGURE 3-9 FLEXIBLE DUCT SUPPORTS
FIGURE 3-10 FLEXIBLE DUCT SUPPORTS
TABLE 4-1 RECTANGULAR DUCT HANGERS MIN. SIZE
TABLE 4-2 MINIMUM HANGER SIZES FOR ROUND DUCT
FIGURE 4-4 LOWER HANGER ATTACHMENTS
Questions & Answers

More Related Content

Hvac duct construction wasilewski

  • 1. HVAC Duct Construction Bob Wasilewski Project Manager, Technical Resources SMACNA
  • 2. HVAC Duct Construction Standards WHAT? WHY? HOW?
  • 3. Today's Program 1st – 2nd Edition HVAC-DCS Review Joints and Limitations Transverse Joints & Reinforcements Use of the Pressure Class Tables Tie Rod Addendum
  • 4. Documents Preceding 2nd Edition HVAC-DCS Low Velocity Systems Duct Manual – First Edition 1959 – Second Edition 1963 – Third Edition 1967 Low Velocity Duct Construction Standard – 1969
  • 5. Documents Preceding 2nd Edition HVAC-DCS Low Pressure Duct Construction Standard – Fifth Edition 1976 High Velocity Duct Systems Manual – First Edition 1965 High Velocity Duct Construction Standards – Second Edition 1969
  • 6. Documents Preceding 2nd Edition HVAC-DCS High Pressure Duct Construction Standards – Third Edition 1975 Duct Liner Application Standard – First Edition 1971 – Second Edition 1975
  • 7. Documents Preceding 2nd Edition HVAC-DCS Flexible Duct Installation Standards – First Edition 1979 – Second Edition 1980 HVAC Duct Construction Standards -- Metal and Flexible – First Edition 1985
  • 8. Major Changes from First Edition GENERAL Text edited to be more reader-friendly Reading aids added Static pressure only as the basis for duct construction classification -- velocity levels deleted (Table 1-1)
  • 9. Major Changes from First Edition Chapter 7 revised to facilitate use for equivalent and comparable tests and ratings Model project specification added Reminders to designers to show all required fire, smoke, radiation and volume control dampers on contract drawings are accented
  • 10. Major Changes from First Edition Boiler breeching omitted Volume damper construction is more specific Lead radiation shielding added Metrics are included Air terminal runouts and supports are revised
  • 11. Major Changes from First Edition RECTANGULAR DUCT REVISIONS Negative pressure construction given for 4", 6", and 10" w.g. Six feet reinforcement schedules added Reinforcement schedules extended to 120" width
  • 12. Major Changes from First Edition Tie rod alternatives expanded for both positive and negative pressures TDC and TDF joint systems included and rated as T-25a and T-25b joints T-24a joint added as a modification of T-24
  • 13. Major Changes from First Edition Use of 26 gage added for 4", 6" and 10" pressures Trapeze hanger tables expanded to cover the 120" width range Duct liner pin schedule adjusted Infrequently used joints (T-4, 8, 17, 18, 19, 20 and 23) omitted
  • 14. Major Changes from First Edition Round, Flexible and Oval Duct Revisions Duct pressure classes revised to be positive and negative at 2", 4" and 10" w.g. Crimped joint connection length changed from 1" to 2" Rectangular branch taps into round added for straight or 45 degree lead-in-entry
  • 15. Major Changes from First Edition Type 1 reinforcement of oval duct now has an internal tie rod (based on ASHRAE test program) Maximum support spacing for round flexible duct and connector changed from 10 feet to 5 feet Additional riser support details are provided
  • 16. DUCT SYSTEMS SIZINGS FIRE/SMOKE CODE FITTINGS, ETC. PROTECTION COMPLIANCE CODE DUCT COMPLIANCE CONSTRUCTION SMACNA HVAC-DCS 2ND ED. 1995 INSPECTION CODE COMPLIANCE
  • 17. DUCT SYSTEMS ENGINEER CONTRACTOR Design Considerations: Construction Considerations: CFM Panel Thickness (Gage) Static Pressure Pressure Class (as specified) Duct Size Panel Width/Height Fitting Type Joint Type/Spacing Construction Pressure Intermediate Reinforcement Class Type/Spacing
  • 19. REGULAR DUCTS Maximum Deflection Maximum Test Pressure Joint and Reinf. Sheet: Lab: 1/4" on 48" w. 3/8" on 12" Dn. Class Rating + 50% W/200 on 1/2" on 13"-18" 49"-120" 5/8"on 19"-24" Field: 3/4" on 25"-84" Class Rating + 25% 1" on 85"-120" Tolerance: Tolerance: +7.5% +10%
  • 20. Duct Systems Used for the movement of air in HVAC/Exhaust systems Ducts are classified based on maximum operating pressure – 0.5" w.g. positive or negative – 1.0" w.g. positive or negative – 2.0" w.g. positive or negative
  • 21. Duct Systems (Continued) Ducts are classified based on maximum operating pressure – 3.0" w.g. positive or negative – 4.0" w.g. positive or negative – 6.0" w.g. positive or negative – 10.0" w.g. positive or negative
  • 23. TABLE 1-2 STANDARD DUCT SEALING REQUIREMENTS
  • 37. EXAMPLE 1 Duct Size 24" x 24" Pressure Class 2" w.g. Sheet Stock Joints/Reinforcements 8 ft / 4 ft Standing S
  • 40. EXAMPLE 2 Duct Size 42" x 24" Pressure Class 3" w.g. 5 ft Coil Line Joints/Reinforcements 5 ft / 2 ½ ft TDC or TDF
  • 44. MIDPANEL TIE ROD (MPT) ½" w.g. - 6" w.g. 37" - 96" Duct Dimension Rectangular Duct
  • 45. Mid Panel Tie Rod Addendum Joints – All Tie Rods – Threaded Rod or Tubing/Conduit with Threaded Insert Additional Application Tables, Qualifications and Reader Aids Included
  • 51. FIGURE 1-3 TIE ROD ATTACHMENTS
  • 52. FIGURE 1-4 TRANSVERSE (GIRTH) JOINTS
  • 53. FIGURE 1-4 TRANSVERSE (GIRTH) JOINTS
  • 54. FIGURE 1-4A SPECIAL JOINT PROFILES
  • 55. FIGURE 1-5 LONGITUDINAL SEAMS – RECTANGULAR DUCT
  • 56. TABLE 1-24 UNREINFORCED DUCT (WALL THICKNESS)
  • 57. TABLE 1-25 T-1 FLAT DRIVE ACCEPTED AS REINFORCEMENT
  • 59. FIGURE 1-8 CROSSBROKEN DUCT & BEADED DUCT
  • 60. FIGURE 1-9 DUCT REINFORCED ON TWO SIDES
  • 61. FIGURE 1-10 DUCT REINFORCED ON ALL SIDES
  • 62. FIGURE 1-12 DUCT OVER 120" (3048 MM) WIDE
  • 63. FIGURE 1-15 CORNER CLOSURES - FLANGES
  • 64. FIGURE 2-22 DUCT LINER INTERRUPTION
  • 65. TABLE 3-2A ROUND DUCT GAGE UNREINFORCED POSITIVE PRESSURE
  • 66. TABLE 3-2B ROUND DUCT GAGE NEGATIVE PRESSURE
  • 67. FIGURE 3-1 SEAMS – ROUND DUCT AND FITTINGS
  • 68. FIG. 3-2 TRANSVERSE JOINTS – ROUND DUCT
  • 69. FIGURE 3-6 FLAT OVAL DUCTS
  • 70. FIGURE 3-9 FLEXIBLE DUCT SUPPORTS
  • 71. FIGURE 3-10 FLEXIBLE DUCT SUPPORTS
  • 72. TABLE 4-1 RECTANGULAR DUCT HANGERS MIN. SIZE
  • 73. TABLE 4-2 MINIMUM HANGER SIZES FOR ROUND DUCT
  • 74. FIGURE 4-4 LOWER HANGER ATTACHMENTS
  • 75. Questions & Answers