Pattern Development Flashcards
What are the most common triangulated fittings?
Top Takeoff, End Boot and Garbage Chute
When is a face line used ?
When triangulating a transitional Y-Branch
What is a foreshortened line?
A line that appears shorter than it actually is.
When determining the VH (vertical height) for a pattern all seams and allowances must be _________.
Subtracted.
How much of the pattern of an on centre both ways square to round needs to be developed ?
1/4 pattern
What view is necessary to develop a square or rectangular to round fitting ?
Plan view.
Transitional elbows are most commonly found in __________ installations.
Commercial
What are the benefits of transitional elbows ?
direction, dimension and elevation can be changed with one fitting
In transitional ogee offsets the vertical height of the sloped pattern is obtained from the sloped length of the ________
Runners
Why are transitions necessary ?
Transitions are necessary to change the size and or position of the main trunk to maintain the required amount of airflow
Twists serve the same purpose as ________
Transitions.
The vertical height of transitions and twists is the height of he fitting minus any ________ and ________.
Collars and Allowances
Cheek patterns for transitional y-branches are developed from the _________ view.
Elevation view
Multiple branch fittings are typically used in _______ systems
Blowpipe systems
How are 3 way branches triangulated ?
Chord offsets
What is the simplest form of triangulation?
Triangulation from plan view
The round collar pattern must be developed ______in order to determine the distance from point to point as you work your way around the round opening
First
Rectangle to round on patch fittings are found on what type of roofs ?
Pitch roofs only
What is an advantage of rectangle to round offsets ?
Combine 2 fittings into 1
Triangulation from elevation uses what views ?
Elevation and Plan View
When the fitting is on Centre the work line is always located ______ the depth of the rectangular opening as seen in the plan view.
1/2
Where are garbage chutes found ?
Older apartment buildings or small apartment blocks
Where is rectangle to round used in residential?
End boots
If the work line falls within the plan view you continue the ______ development
Pattern
What is a chord offset ?
A chord offset can be described as a distance between a point on the collar opening and a point on the plan view perpendicular to the collars opening
Developing a pattern for a round reducing elbow uses __________ and _______ _____ development
Triangulation and parallel line development
On a round reducing elbow when subtracting once chord offset from another you must always work from the __________ in
Outside
When do the collars need to be developed on a round reducing offset ?
The collars need to be developed first
On round reducing offsets the collars must be developed ______
First
Round reducing y branches are typically found in _____ _______ systems
Dust collection
How much of the pattern must be developed for an on Centre round reducing y branch ?
1/2 pattern
How is the crotch mitre plan view developed ?
From the major and minor axis
How is the ellipse developed in a round reducing y branch ?
With a minor and major axis
Where are boots most commonly found ?
Residential duct systems
Where are right angle boots commonly found ?
Above and below windows
How many work lines are required for on Centre boots ?
One work line
How many work lines are required for off Centre boots ?
Two work lines
What is an advantage of top take offs ?
Top take offs allow branch lines and run within joists
What view is used to triangulate end or right angle boots ?
Elevation view
It is acceptable to use boot configurations when developing a _________
Wall stack
The work line of a boot is found by measuring the centre of the ______ opening to the outside of the _____ opening
Round . Rectangular
What types of pattern development are used on bull head tees ?
Line to line and triangulation
What type of installations are bull head tees used in?
Blow pipe installations
How many side of the triangle need to be triangulated in bull head tees ?
2 sides
One foot of water equals ____ PSI
0.433 PSI
