duct takeoffs

Question 1

Duct takeoff is required when you want to split the main trunk to move a large volume of air to another zone of the building ,it replaces the

Answer 1

“Y” branch

Question 2

The duct take off needs to be larger at the cross section where its attached to the main duct for

Answer 2

easy air flow

Question 3

Two types of duct take offs are

Answer 3

,flat wrapper and curved wrapper

Question 4

4. Flat wrapper is easier to develop then the curved wrapper

Answer 4

true

Question 5

Flat wrappers are recommended to have a

Answer 5

45 or 1/4 width of the duct going upstream ,this gives about 25 % of a opening

Question 6

6. Curved duct dose not have specific cross section because the air flow has a smoother flow

Answer 6

true

Question 7

Pto is the take off that”s installed on the plenium and is

Answer 7

50% bigger on the cheeks

Question 8

8. Two types of take offs are flat and a rise takeoff ,4 inch rise is common in residential it helps for air flow to the main duct

Answer 8

true

Question 9

Furnace installations require a “1 inch clearance from combustibles

Answer 9

( floor joist)

Question 10

10. Parallel top take off cheek can have the same opening as the duct opening , the lenght should equal or greater then the width of the cheek

Answer 10

true

Question 11

When notching is being done to the Pittsburgh lock , the notches go to

Answer 11

the net line

Question 12

14. Plenium take off is different as to others because it comes off the main plenium with a hammerlock and increases in size at the cross section

Answer 12

true

Question 13

15. Couple things to determine is to make sure the width of the plenium and the pto will fit on it using a simple layout to develope it

Answer 13

true

Question 14

If the duct is bigger then the plenium you will need to use

Answer 14

triangulation developement

Question 15

When attaching duct connections reduce 1/2 to the net for

Answer 15

the slip and drive connection

Question 16

19. To develope the top take off draw a base line and a perpendicular line and then the length , now you can mark the opening with 1.5 added on the pto side of rising pto

Answer 16

true

Question 17

Wrappers are measured by Pythagorean theorem ,to determine this you will do lenght of the plenium opening by squared and the offset of the riser by squared ,add them and then square that number and round to lowest fraction

Answer 17

true

Question 18

Clinchlock is also known as a

Answer 18

hammerlock

Question 19

22. Hammer lock on straight and sweep uses the transition lock with notches with perpendicular notches to the net line and 30 angle on the ends

Answer 19

true

Question 20

23. Notching of a rising pto is the same as the sweep take off

Answer 20

true

Question 21

You use a duct connection when ?

Answer 21

No “Y” branch , unsure of location , adding to branch run , change of sides is needed in both directions

Question 22

Duct takeoff has to be built with curved and heel true or false

Answer 22

false

Question 23

Whats the size of the plenium takeoff connection at the cross section area ?

Answer 23

150% greater

Question 24

A flat top take is not used often because ?

Answer 24

It cannot get close enough to the joist

Question 25

Wrapper lengths can only be done by adding

Answer 25

False

Question 26

Hammer lock on a break with inside facing up ?

Answer 26

DN UP DN