Transitional Fittings And Pipe Tees

Question 1

How are pipe tees identified

Answer 1

By the angle and diameter of the stub and the diameter of the body

Question 2

How is the type of seam determined

Answer 2

By the pressure class and material thickness of the ducting system

Question 3

What is the formula to calculate the stretch out of the cylinder

Answer 3

3.14xdiameter of the cylinder

Question 4

Why is it necessary to number the plan views and patterns properly

Answer 4

Miter line may turn out not correct

Question 5

What methods can be used to divide the stretch out on the round stub

Answer 5

Dividers
Slope line method
Mathematically

Question 6

Why is it important to lay out all patterns as inside patterns

Answer 6

Inside patterns will place all the scribe lines inside the fitting

Question 7

Why is notching necessary

Answer 7

For ease of assembly and equiptment may be damaged do to layers of metal not being removed

Question 8

Why is it a good idea to start spot welding at the center of the lap seam

Answer 8

Eliminate buldging or buckling between spot welds

Question 9

What should you do to the metal of the body before folding the hooks for a grooved seam

Answer 9

Ends of material should be rolled slightly to reduce flat spots at the seam

Question 10

When cutting the hole in the body you should cut directly on the line

T or F

Answer 10

False

Question 11

Why is it useful to know the fabrication technique when measuring a fitting to be installed

Answer 11

To know if a given fitting is practical or not

Question 12

When fabricating a transitional fitting which type of lock is commonly used

Answer 12

Pittsburg is the most common

Question 13

What type of fitting is needed if a duct changes size in both dimensions and sometimes also changes direction

Answer 13

Transition/transitional fitting is needed

Question 14

List three places where transitional duct fittings could be used

Answer 14

Reduced airflow
Increased airflow
Accommodate architectural requirements

Question 15

Which rectangular duct ratio of width to depth moves air most efficiently

Answer 15

1:1

Question 16

Which duct size ratio should be maintained to optimize airflow

Answer 16

1:1

Question 17

What should be done to a duct that is approaching 4:1 width to depth ratio

Answer 17

Should be transitioned back to square or round ASAP

Question 18

List two factors that may make transitional fitting fabrication impractical

Answer 18

Layout skills
Cost of fitting

Question 19

What knowledge is required when developing patterns for a transitional fitting

Answer 19

Triangulation and how to develop patterns

Question 20

What affects the overall cost of developing patterns for a transitional fitting

Answer 20

Labour and layout costs

Question 21

List two options that can be used to avoid a complex transitional fitting

Answer 21

Change duct sizes to something that does not require a transitional fitting

Transition done in two fittings

Question 22

Why is it not recommended to use multiple fittings connected together in a medium to high pressure duct system

Answer 22

Cause turbulence, noise and pressure loss in airstream

Question 23

When would we used the specialized term flat on back/ flat on top

Answer 23

A transitional fitting that shows flat on one of the cheeks

Question 24

When would we used the specialized term “on center “

Answer 24

When A transitional fitting that has equal amounts of change on both sides

Question 25

What is the allowance for a raw edge duct connection

Answer 25

No allowance is added to the completed pattern

Question 26

list two scenarios where we would use a raw edge duct connection

Answer 26

The duct or fittings are welded When manufactured duct connectors are applied to the end of the duct or fitting

Question 27

Where would we most commonly use a slip and drive duct connection and what is the allowance added to the end of the duct

Answer 27

Square duct, 1/2” allowance

Question 28

What is the technical term used for cp connection

Answer 28

Standing drive

Question 29

Why is cp connection primarily used on a larger duct

Answer 29

Adds strength and rigidity

Question 30

Where do we primarily use a hammerlock connection

Answer 30

Joining a smaller piece of duct to a larger piece of duct

Question 31

What is the allowance added to the edge of a duct to accept a hammerlock connection

Answer 31

3X width of the seam

Question 32

List three fittings that hammerlock connections are sometimes used on

Answer 32

Duct connection collars Plenum take off Tee branches

Question 33

List three things that can be done to a slip joint to stiffen long/wide duct connections

Answer 33

Extra folds Flat iron Angle iron

Question 34

What adjustments need to be made to the end of a duct fitting that is to be fabricated with either a standing drive cp or a hammerlock seam

Answer 34

No adjustments

Question 35

Other than the slip and drive connection S plus D list one more transverse duct connection that requires an adjustment to the net pattern

Answer 35

Proprietary connection

Question 36

When fabricating a transitional duct fitting that has a proprietary duct connection what determines the amount we need to shorten the net pattern for development of the fitting

Answer 36

Size of slelected proprietary flange

Question 37

How are fittings drawn on blueprints by engineers

Answer 37

Net patterns

Question 38

What standards do most prints or job specifications state that all ductwork must be constructed meet

Answer 38

SMACNA

Question 39

When developing patterns why do we thrive to keep all of the layout lines on the inside of the fitting

Answer 39

Taking Pride in the work

Question 40

List two ways we can add the allowances used to join ducts together on our change cheek

Answer 40

Measure allowance perpendicular to the net pattern line Use a compass to scribe arcs on either end

Question 41

Why is it recommended to calculate and pre cut the wrappers when developing the fitting

Answer 41

Saves time

Question 42

When fabricating a transitional duct fitting, why do we use an angle transfer notch on some of the angled sides

Answer 42

Removes material that will interfere with the duct connection

Question 43

What formula can be used to find the sloped side of a triangle

Answer 43

Pythagorean theorem

Question 44

What strategy can be used in a shop to eliminate much of the triangulation work associated with developing patterns for a flat sided transition

Answer 44

Cut lists, calculations done before metal is cut, to determine cut lengths