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Sheet Metal 101: The Fundamentals of Commercial Ductwork

Commercial Ductwork (Exposed)

The Fundamentals of Ductwork

Placement of duct components

There are a variety of different parts that make up ductwork from rectangular/square /cylindrical ducts, elbows, grilles, registers and insulating materials. These components should come together with as little as distance as possible from the heating or cooling source to the occupied area in need of conditioned air.  Exposed ductwork is popular in modern construction and this promotes efficiency while facilitating post-installation inspection and maintenance as well.  Here at JDC Mechanical we can recommend a variety of duct configurations along with grilles and registers to enhance system performance and improve hassle free operation.

Fastening and thermal protection

All joints should be securely fastened.  Anything from mesh to modern metallic duct tape will be used as an effective seal.  Collars that are adjustable can also be used to lock the ductwork together, these are the most reliable and generally do not dislodge over time or with vibration. It’s important to inspect all fasteners throughout your ductwork on a routine basis.  Areas of weakness when fastening registers and grilles are bolts and screws, these can loosen over time.

Thermal protection or insulation is generally installed on the exterior of the ductwork to keep the air at optimal temperature as it moves to the occupied space.  There are vast choices for insulation, we can provide options and assist with selection in the design process.

Air movement

Precisely directed air supply then subsequent return and blending is critical for sustaining even air pressure throughout your building. Imbalanced air pressure can influence air exchange between indoor and outdoor environments, strain your HVAC equipment, and skyrocket utility costs. Our technicians can assess your ductwork and suggest economical additions to increase your control over the air flow.

Our in depth look on why your ductwork design is of the greatest importance

Some will neglect the importance of ductwork for HVAC system function but it could not be more paramount.  Often, we will see ductwork that is faulty, with inefficient design and even manufacturing deficiencies that are impact system operation through poor installation. Ductwork carries the conditioned air throughout your building for even heating and cooling, this is perhaps the greatest purpose of your entire system.

Ductwork acts much like the circulatory system does, it transports air from your heating and cooling equipment through a supply duct. This forced air that is heated or cooled fills each room, creating positive pressure and ventilation or return of the air is promoted through an outlet, then back into the ductwork infrastructure for blending, exhaust or re-circulation.

Free air flow in a building is crucial for optimal air quality along with the appropriate air movement.  Air avoids stagnation by essentially being forced into the return air duct, if there are inefficiencies the pressurized air will be forced out of any windows, doors or even electrical plug/switch covers that are not properly insulated.  Any over-pressurization and of course the air loss will cause premature HVAC equipment failure due to stress from over operation.

The opposite of this is not enough pressurized air flowing into rooms and the result is imbalanced heating or cooling.  It allows air to flow into rooms from windows, doors and other cracks that are not properly sealed.  Low pressure air can result from poorly installed ductwork or even misalignment.

In either event, we can assist in the identification of ductwork system failures and adjust, repair or re-design accordingly. 

Ductwork design: do it right from the beginning

There are many benefits to effective ductwork design from eco-efficiency, comfort and lower monthly energy bills.  Engineered ductwork will promote air distribution according to your building requirements.  Most ductwork will be manufactured to meet engineering specifications away from your building then assembled and installed on-site.  We treat each of our projects as unique and offer totally custom sheet metal design for large to small commercial clients.

Assessment is critical in the design process and duct sizing estimates can prevent air flow issues or complete retrofit should there be an error in the estimation and design process.  Faulty or uncertified installation can also be a factor in ductwork failure, not to mention, keep your energy costs balanced. 

You may notice cold or hot spots in your property that will cause stress and discomfort for occupants.  These result in complaints to building operations and as such, temperatures are varied which may cause unnecessary overload of your HVAC equipment and errors in your building management system.

Our red seal, journeyman sheet metal technicians offer estimation, design, installation, maintenance and of course, emergency service for your project.

Is your building’s ductwork in need of retrofit?

Original ductwork installed during initial construction can easily compromise your system’s efficiency, occupant comfort and air quality.  During evaluation, watch for these indicators that retrofit or replacement is required.

When was the original ductwork installed?  Has it been replaced?

As building efficiency standards have changed greatly over the last three decades, not much thought may have been given to green building standards but instead focused on cost alone.  Aging ductwork was not designed for longevity either. Deterioration of materials used, often around the 10-year mark is common as well.

Is airflow balanced?  Are there complaints from occupants?

Reduced air flow rates can be indications of ductwork that is blocked by particulate, debris or dust, disconnected or even damaged.  Complaints of temperature variations all point towards air loss from the ductwork infrastructure.  A complete assessment including a duct blower test and full visual investigation with duct scope/camera should be performed.

Are there any errors in your building management system?  Maintenance overlooked by building operators? 

Your building management system can often pinpoint the exact location of any duct failure and encourage visual inspection of the area.  Maintenance or routine inspection can be overlooked by building operators and it may take a trained eye to rapidly identify problems.  We specialize in all types of commercial HVAC ductwork and can diagnose issues that plague your system.  We are the trusted choice of many building managers throughout Calgary.

Property owners in Calgary are seeking economical, qualified, reliable and honest HVAC service. JDC Mechanical is not only red seal certified we also have over 25 years of experience to handle all of your commercial HVAC equipment installation and service needs.