By / Peter Boileau, Chairperson, SMACNA-Western Washington Code & Technical Committee
Our SMACNA technical committee partners at the national level have been busy this year developing updates to a number of different tools, manuals, and guidelines, both previously published and in one case a new manual that addresses a new industry needing our expertise and guidance. Below is a summary of what’s “coming down the duct” to assist and change your business in the near future.
SMACNA will be releasing its completed Ductulator tool for use on both IOS and Android operating systems. This powerful application can be downloaded from the SMACNA national website later this year onto your mobile device to develop quicker and more accurate designs. The tool can store multiple projects as well as design alternates within projects for comparison purposes. It has the ability to design based on friction loss, velocity, or both together based on your parameters, to assist in selecting the most efficient size and configuration of ductwork for your customers. It includes a user selected air compression percentage (10% compression recommended) to accurately account for real world compression that occurs in our duct systems. It also includes a user selection menu for a wide variety of duct materials/roughness factors to assist in selecting the right combination of materials and associated pressure loss/fan horsepower required in any system you design.
During our last Western Washington ICC Code/Technical Advisory meeting we reviewed a number of new SMACNA Technical Resource Bulletins, including rooftop ductwork applications and installation recommendations, recommendations for using tie-rods for duct reinforcement, and grease duct reinforcement standards. These technical bulletins are primarily tools to guide designers in the above subjects, although the tie-rod recommendations are meant to provide additional guidance for proper duct fabrication. As the committee reviewed these tie-rod recommendations, we were at times uncertain about how tie rod sizes and placement are calculated from this guide. It appears that we were not alone, as SMACNA national has just released an additional tie-rod clarification guide. This new guide is meant to eliminate confusion on how to size and place internal tie-rods, specifically to clarify how to size and place rods in positive pressure ductwork versus negative pressure duct. It includes a new worksheet to assist us in calculating duct loads in negative pressure duct systems, which have much larger loads than positive pressure systems. This clarifications bulletin indicates that negative pressure systems 2” water gauge and higher need to use ¾” diameter conduit instead of ½” and limit mid-panel tie rods to ductwork widths 96 inches and less (larger than this width require external reinforcement). In addition, they limit the use of internal tie-rods to ducts with velocities of 2,500 feet per minute and more.
The long-anticipated release of the SMACNA Seismic Restraint Manual: Guidelines for Mechanical Systems 4th edition will be available in early 2023. This update to the 3rd edition published in 2008 includes significant changes to the way we currently brace our mechanical systems. The 4th edition will require bracing systems to align with the State of California’s Office of Statewide Health Planning and Development (OSHPD) requirements. This will change the way we currently calculate anchorage requirements and potentially how we size and select anchors. The new edition will limit the use of cable systems and increases the allowable type and size of steel angles if used to brace our work. The new manual will also include new bracing schedules, examples, and details to assist us in understanding how these new bracing requirements will apply. For the first time many of the details in the manual will be available in Revit format. Although the changes are significant, the authors of the 4th edition of this manual have stated that the approach used is more simplified and intuitive than in previous editions, and I think we all would welcome a more straightforward process to select, fabricate or purchase, and install our seismic bracing systems.
A new, 6th edition of the Fire, Smoke and Radiation Damper Installation Guide for HVAC is coming our way in 2023. It will include a very useful code comparison matrix to match types of fire separation walls, ceilings, and shafts (as defined in the International Building Code) to duct and damper requirements. This will greatly simplify both plan review and field inspection interpretations of these conditions. The new edition also has expanded guidelines for testing of smoke/fire dampers and has updates on breakaway duct connections and fire/smoke dampers.
For those of us who fabricate and install large rectangular duct systems (widths exceeding 10 feet) a new, 3rd edition of the SMACNA Rectangular Industrial Duct Construction Standards will be available next year. This new edition includes construction standards for fabricating rectangular duct with panel widths from 12 to 16 feet wide. It also has new tables for 2.5-foot external stiffener spacing for various pressure classifications, and revised duct loading tables for exterior ductwork subject to snow, ice, and wind loads. It includes guidelines on the use of stainless-steel material to include Class 2, 3 and 4 constructions, and stainless-steel duct systems operating/carrying air and particulates at up to 500 degrees Fahrenheit.
Another pair of updated technical manuals coming our way next year is the 4th edition of the HVAC Systems Testing, Adjusting & Balancing Guide and the 5th edition of the Duct Design Manual. The new edition of the balancing guide replaces the 3rd edition published in 2002, and the new edition of the design manual replaces the 4th edition published in 2006. These two manuals have been developed simultaneously to ensure that ductwork systems are properly designed so that they properly work to eliminate problems requiring rework of installed systems discovered during testing and balancing.
And finally, SMACNA national is busy updating its Kitchen Ventilation Systems and Food Service Equipment Fabrication and Installation Guidelines, first published in 2001, and they are starting work on a new Grow House “Cannabis” Ventilation Systems technical manual, which will address multiple, unique issues involved with this new industry. Stay tuned for more information on these guidelines as we receive updates. ■
