Trade Skills Print Reading and Ductwork

2 Drawings are a useful tool in manufacturing and construction because most people find it difficult to explain in words how an object is to be built. A drawing can illustrate, step by step, the process to follow in the construction of any type of part or item. Drawings are a useful tool in manufacturing and construction because most people find it difficult to explain in words how an object is to be built. A drawing can illustrate, step by step, the process to follow in the construction of any type of part or item.

3 Prints Prints are original, detailed drawings that illustrate how an object is to be built. Because prints are the original set of drawings, copies, which are referred to as “working drawings”, are made for use on the job site or shop. Prints are original, detailed drawings that illustrate how an object is to be built. Because prints are the original set of drawings, copies, which are referred to as “working drawings”, are made for use on the job site or shop.

4 A set of working drawings include all drawings needed to complete a job. –Some construction jobs can have drawings in the hundreds. A standard set of working drawings can include: –A title sheet –A set of civil drawings –Architectural drawings –Structural drawings –Plumbing, mechanical and electrical drawings A set of working drawings include all drawings needed to complete a job. –Some construction jobs can have drawings in the hundreds. A standard set of working drawings can include: –A title sheet –A set of civil drawings –Architectural drawings –Structural drawings –Plumbing, mechanical and electrical drawings

5 Working drawings are created either manually or using computer aided drafting software (CAD) Architects do not always have time to prepare a complete set of drawings for a room or area. –They sketch the requirements for the space The sketch is then given to the sheet metal worker who will then determine the types of ducts and joints needed to do the job. Working drawings are created either manually or using computer aided drafting software (CAD) Architects do not always have time to prepare a complete set of drawings for a room or area. –They sketch the requirements for the space The sketch is then given to the sheet metal worker who will then determine the types of ducts and joints needed to do the job.

6 Air Duct Systems HVAC systems are composed of an arrangement of pipes, ducts and other special devices. The system is used to circulate conditioned air throughout a building. A properly designed system will operate economically, efficiently, safely, and quietly. –The correct amount of air will be delivered to the correct areas. HVAC systems are composed of an arrangement of pipes, ducts and other special devices. The system is used to circulate conditioned air throughout a building. A properly designed system will operate economically, efficiently, safely, and quietly. –The correct amount of air will be delivered to the correct areas.

7 Testing and diagnosing duct systems Visual inspection can reveal some flaws, but many poorly performing systems may look just fine. The need for quantitative testing must be recognized, but with a practical view to the limited time that a builder or contractor can profitably spend on such detective work. Visual inspection can reveal some flaws, but many poorly performing systems may look just fine. The need for quantitative testing must be recognized, but with a practical view to the limited time that a builder or contractor can profitably spend on such detective work.

8 Steps to diagnosing duct work There are several steps to properly diagnosing duct systems. –Inspect the duct system –Test for duct leakage –Measure the system air flow rate –Determine what actions to take There are several steps to properly diagnosing duct systems. –Inspect the duct system –Test for duct leakage –Measure the system air flow rate –Determine what actions to take

9 Visual inspection For a contractor, time is money. It is essential that he have some quick methods of assessing whether or not a piece of duct needs repair or an upgrade. The quickest thing a sheet metal or service mechanic can do to evaluate duct work systems is simply look at it.. For a contractor, time is money. It is essential that he have some quick methods of assessing whether or not a piece of duct needs repair or an upgrade. The quickest thing a sheet metal or service mechanic can do to evaluate duct work systems is simply look at it..

10 General appearance of the duct system The first thing to note is the general appearance of the duct system. –A good system might still have unacceptable air leakage that may not be seen with the naked eye. –It may be badly damaged or falling apart. –A system may be working properly but was damaged later on. Even if the duct sections are in good condition, they may be disconnected in places. –Example: flexible duct connections. The first thing to note is the general appearance of the duct system. –A good system might still have unacceptable air leakage that may not be seen with the naked eye. –It may be badly damaged or falling apart. –A system may be working properly but was damaged later on. Even if the duct sections are in good condition, they may be disconnected in places. –Example: flexible duct connections.

11 Location of the duct system The location of the duct system is also important to the general appearance of the entire system. Location means what kind of space is the duct work located in. –Attic –Crawl space –Slab –Basement, etc.. The location of the duct system is also important to the general appearance of the entire system. Location means what kind of space is the duct work located in. –Attic –Crawl space –Slab –Basement, etc..

12 Duct work located in attic spaces are highly prone to high energy loss because it is located in an area that is very seldomly conditioned. Duct work in this location is subject to hot, humid climates along with cold, fridged climates. Duct work located in attic spaces are highly prone to high energy loss because it is located in an area that is very seldomly conditioned. Duct work in this location is subject to hot, humid climates along with cold, fridged climates.

13 Leaky return air ducts can cause, hot moist air to drawn into the system, placing an extra load on the system, thus making it run longer. –Same principle applies for heating loads. Basements are usually better locations for ducts than either attics or crawl spaces, because they are not exposed to the harshest temperatures. –Plus, any duct leakage is effectively regained as the system runs. Leaky return air ducts can cause, hot moist air to drawn into the system, placing an extra load on the system, thus making it run longer. –Same principle applies for heating loads. Basements are usually better locations for ducts than either attics or crawl spaces, because they are not exposed to the harshest temperatures. –Plus, any duct leakage is effectively regained as the system runs.

14 Heat lost into the basement tends to warm it. –This slows down further heat conduction from the duct and it reduces the rate of heat loss from the house through the basement ceiling. Since ducts installed in a basement have a slight advantage than ducts installed in an attic or crawl space, they are more often left un-insulated. Heat lost into the basement tends to warm it. –This slows down further heat conduction from the duct and it reduces the rate of heat loss from the house through the basement ceiling. Since ducts installed in a basement have a slight advantage than ducts installed in an attic or crawl space, they are more often left un-insulated.

15 However, the best location for ductwork is simply within the conditioned space. –Any heat or cooling that leaks to the living space is still useful, and lost at all. Energy savings of up to 40% have been demonstrated by simply ductwork into the conditioned space. However, the best location for ductwork is simply within the conditioned space. –Any heat or cooling that leaks to the living space is still useful, and lost at all. Energy savings of up to 40% have been demonstrated by simply ductwork into the conditioned space.

16 People may ask whether or not a basement is considered part of the conditioned space. –If the basement is used for human activities and not just storage, and if there are air registers in the basement, then it is part of the living space. If this is the case, the basement walls should be insulated. People may ask whether or not a basement is considered part of the conditioned space. –If the basement is used for human activities and not just storage, and if there are air registers in the basement, then it is part of the living space. If this is the case, the basement walls should be insulated.