Ductwork takeoff is an important step in the estimating process. It impacts materials costs, labor requirements and project timelines.
Several styles of takeoffs are used in duct system installations. Each type has different effects on airflow.
When pressurized air encounters a restrictive duct fitting like a takeoff, it loses its turbulent flow. Choosing the right takeoff will help prevent this.
Matching Equipment to Ductwork
Furnaces and air conditioners need a certain amount of air flow to work properly. The ideal ductwork system delivers this airflow to the equipment without restricting it or limiting its efficiency. Problems like stuffy rooms, drafts, uneven temperatures, high energy costs and shortened unit lifespan are often linked to bad duct design.
The physics of airflow determines how much capacity each run of duct should have, as well as the type of fittings and materials used to create the system. In most cases, the load calculations determined during Manual J will inform the size of each piece of ductwork and where it should be placed in the house.
Once the load is determined & the units sized the next step in the process is to take the manual d or mechanical drawing and create an elevation view of the supply, return & exhaust systems. It is very difficult to know how much vertical rise the ductwork makes without an elevation view.
The most common ductwork material is galvanized steel. It is durable, resists corrosion from harsh chemicals and saline solutions and works well indoors or out. Stainless steel is also available and offers added strength and durability, but may be more expensive than galvanized steel. Aluminum is another popular option and is suitable for both indoor and outdoor use, but can be less durable than stainless steel and is prone to oxidation over time.
Choosing the Right Type of Take-Off
Ducts that don’t transfer air effectively cause a variety of problems, including drafts and hot or cold spots in buildings. They can also shorten the lifespan of equipment and expose building occupants to high levels of dust, pollen and odors.
Choosing the right type of takeoff makes all the difference in how efficiently and easily a duct system works. Several styles are used in commercial ductwork installations, but not all of them have the same effect on airflow. There is a wide range of commercial takeoffs available, from those with metal tabs that snap in place to those designed to be slipped over a reducer collar instead of being mounted to the duct. The most common type of commercial takeoff is the circular takeoff, which can be found in a wide range of sizes.
Other types of commercial takeoffs include the Conical and Bellmouth. These are wider at the base and narrower at the branching size, which makes them more efficient than the standard Round takeoff. There are also directional takeoffs, which have some form of metal scoop or extractor fitting that protrudes into the airstream. Directional takeoffs are not as efficient as the HETO, but they are less expensive.
Contractors need to consider raw materials and manufactured fixtures when estimating construction projects. They need to know how much these different elements will cost so that they can pass along accurate prices to their clients.
Streamlining the Process
Takeoffs aren’t exactly a glamorous part of the construction process, but they do have the potential to significantly impact your final estimates. Streamlining the process with construction estimating software, accurate measurements and values, a checklist and up-to-date plans can help you build more accurate estimates in less time.
The first step in creating a ductwork takeoff is to consult the construction documents. This will let you know which type of materials are required for the project and which sizes are best suited to each area in the building. Once you’ve determined which size equipment and ductwork to use, you can begin to calculate the number of pieces needed to cover all the spaces that require heating or cooling.
It’s also important to keep in mind that certain design elements can affect air flow and performance. For instance, sharp turns or ducts that are too long can create turbulence and reduce air flow. This can lead to drafts, hot or cold spots and higher energy costs, not to mention shortening the lifespan of your HVAC system.
One of the best ways to minimize turbulence is by adding turning vanes to your ductwork. These can be fabricated in any sheet metal shop and will help smooth out the change in direction and increase air flow downstream. You should also try to choose rectangular ductwork whenever possible, which will allow for more air volume at each end of the duct and is easier to balance.
Using Online Estimating Software
Using a digital takeoff and estimating solution is an effective way to streamline the process and save time. The software will quickly and accurately generate the necessary information for a precise estimate and subsequently help you develop and submit a competitive bid. It will also provide accurate itemized breakdowns of quantities, ensuring that you don’t overlook any costs.
It’s important to choose the right software tool, and one that fits your business needs. The best estimating software solutions are flexible enough to accommodate any type of construction project and are easy to use, so that you can quickly get estimates completed and turned into polished bid documents. It’s also a good idea to consider how well the software integrates with any existing systems your business uses, such as accounting and project management tools, in order to reduce duplication of effort and ensure consistent data across all functions.
One leading estimating software program, Buildertrend, offers a number of standard features that you would expect from an estimating application, including a regularly-updated cost database, pre-built templates and assemblies, and a robust feature set. However, what sets Buildertrend apart is its tight integration with other features, such as BIM, project management and scheduling, and construction accounting, which enables users to begin with a takeoff, then easily generate an estimate, and then turn that into a proposal for the client.