WorksheetsDuctwork and Duct Materials Worksheet
Total questions: 31
Worksheet time: 16mins
Which class of manufactured duct has the lowest flame spread and smoke developed ratings?
Class 1
Class 2
Class 0
Ductwork does not burn
What are the two main types of duct-cleaning equipment being used?
Units that use brushes and vacuum and units that use ultrasonic particle precipitation
Large truck-mounted units and small portable units
Ultraviolet units and ultrasonic particle precipitators
Units that use high-velocity air and units that use sprayed cleaning compounds
When hanging flexible duct, the hanging material should be at least:
2 inches wide and spaced no further than every 5 ft.
2 inches wide and spaced no further than every 12 ft.
1 inch wide and spaced no further than every 12 ft.
1 inch wide and spaced no further than every 5 ft.
Which of the following is NOT a method used to insulate ducts?
Spray-on urethane foam
Bubble outer wrap or liner
Fiberglass liner
Fiberglass outerwrap with vapor barrier
Rectangular sheet metal ducts are sealed using:
S-locks and drives cleats
Mastic
Flanges and bolts
General purpose duct tape
When comparing duct materials, none have a lower friction rate or are as durable as:
Sheet metal
Flex duct
The majority of air leaks in sheet metal duct systems occur:
In the seams of adjustable elbows
At joints between ducts
Around takeoffs on supply and return plenums
Along the lengthwise seam in the duct
Hangers for fiberboard duct should be placed no further than every:
5 ft.
12 ft.
6 ft.
Fiberboard duct does not require hangers
Fiberboard duct is joined:
Using mechanically self-sealing joints formed on the end of the duct
With tape and mastic
With sheet metal screws and mastic
With staples and UL 181A tape
Organizations that provide duct installation standards and guidelines include:
ACCA and SMACNA
EPA and OSHA
AHRI and HVAC Excellence
Underwriters Laboratories and the NFPA
Rectangular sheet metal ducts are joined using:
Duct tape
S-locks and drives cleats
Flanges and bolts
Mastic
A major disadvantage of metal duct is that it:
Adds little resistance to airflow
Requires more support hangars
Requires insulation to be added during install
Is not durable
Which type of duct undergoes more rigorous testing before being labeled?
Galvanized sheet metal duct
Flexible duct
Flexible duct connector
Polycarbonate molded duct
Organizations that set safety standards for manufactured ductwork include:
Underwriters Laboratories and the NFPA
ACCA and RSES
AHRI and HVAC Excellence
EPA and OSHA
A duct blaster is used to:
Install duct runs quickly
Install takeoffs using percussive force
Clean ducts using high-velocity air
Measure air leakage in ducts
Hangers for metal duct should be placed no further than every:
6 ft.
12 ft.
5 ft.
Sheet metal duct does not require hangers
Two types of takeoff fittings available for sheet metal duct include:
Dove tail, adhesive-backed flanges
Trunk ducts with knock-outs
Dovetail, weld-on stubs
Weld-on stubs, preformed stubs
The maximum installed length of a flexible air connector is:
25 ft.
10 ft.
14 ft.
Unlimited
A manufactured duct meeting all 15 UL 181 tests is classified as:
A flexible air connector
A flexible air duct
Flexible air plenum
Either a flexible duct or connector
Duct leakage area calculates:
Area of leaks in duct systems
Correction factors by region
Duct leak category
Size of the hole if leaks were combined
A 1,600 sq ft house leaking 120 CFM has a leakage rate of:
7.5 CFM per 100 sq ft
1,600 ÷ 120 = 1,720 CFM
13 CFM per 100 sq ft
1,480 CFM
UL Standard 181 B covers:
All types of ducts
Flexible duct
A duct blaster measures leakage by:
Reflecting pressure waves
Measuring airflow to maintain pressure
Using a velocimeter
Measuring depressurization time
UL Standard 181 A covers:
All types of ducts
Flexible duct
Ductboard
Metal duct
For maximum efficiency, the duct system should be within the building's:
Mechanical room
Interior walls
Basement
Insulation envelope
Round sheet metal ductwork should be:
Sealed with mastic and screws
Sealed with duct tape
Fastened with mastic only
Fastened and sealed with duct tape
The National Air Duct Cleaners Association has established:
Standards and technician certifications
Large truck vacuums
Inspection tool standards
Specialized vacuums for duct cleaning
A system leaking 100 CFM with a 1,200 CFM design flow has a leakage rate of:
9%
8%
12%
11%
A _______ duct system uses large ducts branching into smaller ones.
Central plenum system
Perimeter loop system
Reducing radial duct system
Closed loop system
Fabric ductwork sections are connected by:
Mastic
Tape
Zippers
Staples
Which type of duct should NOT pass through fire-rated walls?
Flexible duct
Galvanized sheet metal
Flexible duct connector
Ductboard
