When you work in HVAC, a sizable part of your daily tasks will involve working with ductwork. From installing entire ductwork systems to troubleshooting leaks, having experience in this area is a must. And it should come as no surprise that those technicians who are capable of fabricating ducts are among the most in-demand techs in the field.
The reason is because ductwork is a critical aspect of heating, ventilation, and air conditioning systems. Properly fabricated ductwork ensures efficient airflow, reduces energy consumption, and maintains continuous indoor air quality. But when fabrication projects encounter issues or the ducts are fabricated by a tech with inadequate training, the ducts will compromise system performance. Identifying and avoiding common mistakes are therefore essential to saving time, reducing costs, and improving the longevity of the system. Below, we share some of the most common errors in HVAC duct fabrication and provide practical solutions that will help you address and/or avoid them.
1. Inaccurate Measurements
One of the most common mistakes in HVAC duct fabrication is incorrect measurements. Ducts that are too small or too large for the system or the home will lead to airflow restrictions, energy inefficiencies, and increased noise levels.
To avoid this problem, you should always double-check your measurements before cutting any materials. Follow the old adage, “measure twice and cut once.” To help make precise cuts, use tools such as laser measuring devices or CAD software. It is also important to remember to account for fittings, bends, and other components when calculating dimensions.
2. Wrong Material Selection
Choosing the wrong materials for duct fabrication can result in structural weakness, corrosion, or inefficiencies in temperature regulation. For instance, using thin or low-grade materials may lead to leaks or damage over time.
You should always match the material type to the application. For example, galvanized steel is ideal for durability, while aluminum is lightweight and corrosion-resistant. Before designing your duct network, consider the operating environment, such as humidity levels and temperature ranges. Consulting industry standards like SMACNA (Sheet Metal and Air Conditioning Contractors' National Association) guidelines will help you make proper material decisions and specifications.
3. Improper Sealing
Leaky ducts are a significant source of energy loss in HVAC systems. Gaps, poorly applied sealants, or insufficient fastening can cause air to escape, leading to reduced efficiency and increased energy costs.
When installing or repairing ductwork, use only high-quality sealants and tapes rated for HVAC applications. Inspect all joints, seams, and connections for proper sealing during and after installation. Never assume that your project is perfect; conduct pressure testing to identify and correct any leaks.
4. Ignoring Airflow Design Principles
A properly designed HVAC system follows certain airflow principles to ensure optimum operational efficiency. Neglecting these basic airflow principles will lead to issues such as uneven heating or cooling, increased static pressure, and noisy operation. Common design flaws in this area can range from sharp bends and excessive lengths to undersized ducts.
Established duct design principles are there for a reason. Learn them so you can fabricate duct networks that enhance the system’s performance. Things to keep in mind include minimizing bends, keeping runs as short as possible, and using gradual transitions instead of sharp changes in duct size. Always perform airflow calculations to help ensure the ductwork can handle the required volume.
5. Lack of Insulation
Uninsulated or poorly insulated ducts can result in energy loss and temperature fluctuations. This is particularly problematic in ducts running through unconditioned spaces, such as attics, garages, or basements.
Using appropriate insulation materials, such as fiberglass or foam board, will help prevent heat loss or gain. When installing insulation, make sure it is applied uniformly, with no gaps or compressed sections. It is also vital to choose insulation with the correct R-value for your specific climate and application to achieve the desired results.
6. Overlooking Noise Control
When ductwork is improperly fabricated, the end result can generate noise due to airflow turbulence, vibration, or poorly secured components. This can lead to complaints from clients and making the required adjustments to solve the issue will almost always be expensive.
To help minimize noise, use flexible duct connectors and vibration isolators as these pieces are specifically designed to reduce noise transmission in an HVAC system. You should also secure all components firmly to prevent rattling and avoid abrupt changes in duct size or direction because they can create unwanted turbulence. In extreme cases, you may need to take extra steps by incorporating sound-absorbing materials where necessary.
7. Failing to Account for Thermal Expansion of Ducts
Ducts expand and contract with temperature changes. Failing to accommodate for this movement can cause structural stress, leading to cracks, leaks, or misaligned sections.
When designing any ductwork system, always allow for thermal expansion by including flexible joints or expansion gaps in the design. Use materials that are capable of handling temperature fluctuations without deforming. Additionally, when performing maintenance on systems, regularly inspect the ducts for signs of stress or misalignment.
8. Inadequate Documentation and Communication
Miscommunication between teams or lack of detailed documentation are easily avoidable, but they unfortunately do occur and they can lead to errors in fabrication and installation. This often results in rework, delays, and increased costs.
To help avoid these costly problems, be sure to use detailed blueprints and fabrication specifications. Maintain clear communication between design, fabrication, and installation teams. Implement project management tools to track progress and address issues promptly and conduct regular meetings to ensure everyone is aligned on project goals and updates.
9. Neglecting Quality Control
When pressed for time, a tech may be tempted to skip the quality control checks, but this will almost always result in substandard ductwork making its way into the final system. Making matters even worse is that the poorly fabricated ducts will lead to inefficiencies, safety hazards, and costly repairs.
A professional HVAC tech is one who will develop a system that includes a robust sequence of quality control processes, including detailed inspections at each stage of fabrication and installation. This commitment will help you recognize potential issues, so you can address them immediately.
10. Not Enrolling in a Ductwork Fabrication Workshop
Mistakes in HVAC duct fabrication can have far-reaching consequences, affecting system efficiency, cost, and occupant comfort. But all this can be avoided simply by gaining a better understanding of good ductwork fabrication practices. Investing in proper training, tools, and processes not only prevents errors but also builds a reputation for excellence in the HVAC industry.
At BTrained, our ductwork fabrication workshop will provide you with a solid foundation in this particular skill. If you want to become an in-demand professional in this field, then our comprehensive workshops in Huntsville, AL are specially designed to help you gain the skills, confidence, and experience you will need to succeed. We intentionally keep our workshop sizes small, so you can enjoy one-on-one instruction from our highly experienced instructors.
At BTrained, our workshops allow you to gain practical hands-on experience in designing, cutting, and fabricating ductwork. Once complete, you will have a newfound relationship with ductwork and enhanced skills that will help elevate your value. So, if you want to get the training you need to become a skilled HVAC technician, then it’s recommended that you claim your spot early. Enroll today and secure your spot in one of our upcoming ductwork design and fabrication workshop in Huntsville, AL!