California CSLB C-43 Sheet Metal Examination

A rectangular sheet metal duct measuring 24 inches wide by 12 inches high handles an airflow rate of 2,400 CFM. What is the average air velocity inside the duct in feet per minute (FPM)?

• A1,200 feet per minute average velocity
• B1,400 feet per minute average velocity
• C1,600 feet per minute average velocity
• D1,800 feet per minute average velocity

A sheet metal estimator calculates that a duct system requires 150 square feet of 24-gauge galvanized steel sheet. If 24-gauge steel weighs 1.156 pounds per square foot, what is the net weight of the sheet metal required?

• A161.2 pounds of galvanized sheet steel
• B173.4 pounds of galvanized sheet steel
• C185.6 pounds of galvanized sheet steel
• D197.8 pounds of galvanized sheet steel

Under California Contractors State License Board (CSLB) contracting rules, what is the maximum down payment a sheet metal contractor may legally collect on a home improvement contract?

• A$1,500 or 15% of contract price, whichever is lower
• B$2,000 or 20% of contract price, whichever is lower
• C$1,000 or 10% of contract price, whichever is lower
• D$5,000 or 25% of contract price, whichever is lower

What is the net surface area of sheet metal required to fabricate a straight 20-foot rectangular duct section measuring 18 inches wide by 12 inches high (excluding seams and overlaps)?

• A80 square feet of total sheet metal only
• B90 square feet of total sheet metal
• C95 square feet of total sheet metal
• D100 square feet of total sheet metal

According to California Title 24, Part 6 energy efficiency standards, what is the maximum allowable total duct leakage rate for new residential HVAC duct installations during field verification testing?

• A5 percent of total system airflow rating
• B10 percent of total system airflow rating
• C15 percent of total system airflow rating
• D20 percent of total system airflow rating

On a mechanical blueprint drawn to a scale of 1/4 inch = 1 foot, a straight duct run measures 5.5 inches long on the plan. What is the actual installed length of the duct section?

• A18.0 feet in actual installed length
• B22.0 feet in actual installed length
• C24.5 feet in actual installed length
• D26.0 feet in actual installed length

When estimating raw sheet metal material quantities for complex rectangular fittings (elbows, transitions, and offsets), what waste factor percentage is standardly added to net square footage?

• A3 percent to 5 percent material waste
• B6 percent to 8 percent material waste
• C15 percent to 20 percent material waste
• D25 percent to 30 percent material waste

A 12-inch diameter round supply duct carries an airflow volume of 1,100 CFM. What is the approximate air velocity inside the duct in feet per minute (FPM)?

• A1,050 feet per minute air velocity
• B1,200 feet per minute air velocity
• C1,320 feet per minute air velocity
• D1,400 feet per minute air velocity

Which of the following U.S. Standard Galvanized Sheet Steel gauges represents the thickest sheet metal material?

• A16-gauge galvanized steel sheet
• B18-gauge galvanized steel sheet
• C22-gauge galvanized steel sheet
• D26-gauge galvanized steel sheet

To preserve mechanics lien rights on a private commercial sheet metal installation project in California, within how many days of first providing labor or materials must a contractor serve a Preliminary Notice?

• A10 days after starting project work
• B20 days after starting project work
• C30 days after starting project work
• D45 days after starting project work

When estimating duct sealing materials for a commercial HVAC duct system operating at +4.0 inches water gauge (w.g.) static pressure, what SMACNA Seal Class is required?

• ASMACNA Seal Class C with unsealed joints
• BSMACNA Seal Class B with transverse sealing
• CSMACNA Seal Class A with full duct sealing
• DSMACNA Unsealed Class with slip connections

When substituting rectangular ductwork for round pipe during planning, which rectangular duct size provides approximately the same cross-sectional area as a 14-inch diameter round duct (153.9 sq in)?

• A10 inches wide by 10 inches deep duct
• B12 inches wide by 10 inches deep duct
• C14 inches wide by 10 inches deep duct
• D14 inches wide by 11 inches deep duct

Architectural copper sheet specified as 16-ounce copper has what nominal weight per square foot when estimating roofing material quantities?

• A1.00 pound per square foot sheet
• B1.25 pounds per square foot sheet
• C1.50 pounds per square foot sheet
• D2.00 pounds per square foot sheet

According to SMACNA duct design principles, what happens to friction loss per 100 feet of ductwork if air velocity is doubled while duct dimensions remain constant?

• AFriction loss increases by two times value only
• BFriction loss increases by four times value
• CFriction loss remains completely unchanged
• DFriction loss decreases by one half value

If an estimator allocates 1.5 labor hours to lay out, pattern, shear, brake, and assemble one complex rectangular transition fitting, how many total labor hours are needed for 16 identical fittings?

• A16.0 labor hours for fitting job
• B20.0 labor hours for fitting job
• C24.0 labor hours for fitting job
• D28.0 labor hours for fitting job

Under California mechanics lien law, if the project owner records a valid Notice of Completion, how many days does a prime sheet metal contractor have to record a mechanics lien?

• A15 days from recording date notice
• B30 days from recording date notice
• C45 days from recording date notice
• D60 days from recording date notice

What is the maximum recommended aspect ratio (width-to-height ratio) for rectangular ductwork per SMACNA duct design standards to ensure efficient airflow and material economy?

• A4 to 1 maximum recommended ratio
• B6 to 1 maximum recommended ratio
• C8 to 1 maximum recommended ratio
• D10 to 1 maximum recommended ratio

Aluminum sheet metal has a density of approximately 0.098 lbs per cubic inch. What is the approximate weight of a 4 ft by 8 ft sheet of 0.050-inch thick aluminum?

• A18.2 pounds per aluminum sheet
• B22.6 pounds per aluminum sheet
• C28.4 pounds per aluminum sheet
• D34.1 pounds per aluminum sheet

According to the California Building Standards Code (Title 24), exterior sheet metal window and door head flashings must be designed to integrate directly with what building envelope component?

• AInterior gypsum drywall board finish only
• BStructural floor slab edge rebar
• CWater-resistive barrier drainage plane
• DRoofing insulation vapour retarder

A pitot tube traverse measurement inside a 20-inch by 10-inch rectangular main supply duct indicates an average air velocity of 1,500 FPM. What is the total airflow rate in CFM?

• A1,450 CFM total system airflow
• B1,600 CFM total system airflow
• C1,850 CFM total system airflow
• D2,083 CFM total system airflow

Under California Contractors License Law (B&P Code §7059), a C-43 Sheet Metal contractor may accept a prime contract that includes other trade work only if what condition is met?

• ASheet metal work forms the principal part of contract
• BContractor holds a general engineering A license type
• CSubcontractors perform all electrical wiring operations
• DTotal contract value is under twenty-five thousand

Calculate the Bend Allowance (BA) for a 90-degree bend in 20-gauge steel sheet (thickness T = 0.036 in) using an inside radius R = 0.125 in and neutral axis K-factor of 0.40. Formula: BA = 1.5708 x (R + K x T).

• A0.185 inches bend allowance value
• B0.219 inches bend allowance value
• C0.252 inches bend allowance value
• D0.284 inches bend allowance value

Which pattern development layout method is used primarily for three-dimensional sheet metal shapes that have parallel element lines, such as round pipe elbows, tees, and rectangular duct fittings?

• ATriangulation pattern development
• BRadial line pattern development
• CParallel line pattern development
• DOverlay grid pattern development

Which sheet metal pattern layout method must be used to develop flat templates for complex transitions, such as a square-to-round duct fitting where element lines are neither parallel nor convergent at a single point?

• AParallel line pattern development
• BRadial line pattern development
• CTrue length projection method
• DTriangulation pattern layout

Which pattern development method is specified for laying out tapered sheet metal shapes that converge at a central apex, such as right cones, frustums, and pyramid caps?

• ARadial line pattern development
• BParallel line pattern development
• CTriangulation pattern layout
• DBraking grid offset development

In sheet metal layout and braking operations, what is the formula for calculating Set-Back (SB) for a standard 90-degree bend given inside bend radius R and material thickness T?

• ASet-back equals radius divided by thickness value
• BSet-back equals inside radius plus thickness
• CSet-back equals radius minus thickness value
• DSet-back equals radius times thickness value

When fabricating a standard female Pittsburgh lock seam on 24-gauge rectangular HVAC ductwork, how much total material allowance is added to the pattern edge for the female pocket?

• A0.25 inch total seam allowance
• B0.50 inch total seam allowance
• C1.00 inch total seam allowance
• D1.25 inch total seam allowance

Calculate the exact stretchout flat pattern length required to fabricate a 10-inch inside diameter round pipe from 24-gauge steel (T = 0.024 in) using the mean neutral axis diameter formula D_mean = D_inside + T.

• A30.56 inches total stretchout
• B31.00 inches total stretchout
• C31.42 inches total stretchout
• D31.49 inches total stretchout

Which soldering flux is standard and required when hand-soldering galvanized sheet steel seams to strip zinc oxide and ensure proper tin-lead solder adhesion?

• AMuriatic acid killed with zinc drops
• BRosin core non-corrosive flux paste only
• CPure nitric acid cleaning solution
• DPetroleum jelly flux base compound

According to SMACNA HVAC Duct Construction Standards, standing seam transverse joint connections on rectangular ductwork serve what primary structural function?

• AVibration isolation and sound attenuation too
• BJoint sealing and structural reinforcement
• CThermal expansion and seismic anchoring
• DAirflow deflection and pressure balancing

When resistance spot welding galvanized sheet steel compared to uncoated mild steel, how must welding current and dwell time settings be adjusted?

• ALower current and shorter dwell time are required
• BEqual current and equal dwell time are required
• CHigher current and longer dwell time are required
• DPulsed current with zero dwell time is required

In standard rectangular HVAC duct assembly, on which sides of the duct joints are drive cleats installed, and on which sides are S-cleats installed?

• ADrive cleats on long sides and S-cleats on short sides
• BDrive cleats on top side and S-cleats on bottom side
• CDrive cleats on all four sides of high pressure ducts
• DDrive cleats on short sides and S-cleats on long sides

When air bending sheet metal on a hydraulic press brake, what is the standard recommended V-die opening width relative to material thickness (T)?

• A8 times material thickness value
• B4 times material thickness value
• C12 times material thickness value
• D16 times material thickness value

When setting blade clearance on a power squaring shear for cutting 16-gauge mild steel (T = 0.060 in), what is the recommended blade clearance setting as a percentage of material thickness?

• A2 percent of material thickness
• B7 percent of material thickness
• C15 percent of material thickness
• D25 percent of material thickness

During sheet metal bending operations, where is the neutral axis (the plane where metal neither stretches nor compresses) located within the sheet thickness?

• AAt the exact outside surface of bend radius
• BAt the exact inside surface of bend radius
• CInside the sheet between 30% and 50% depth
• DOutside the sheet thickness profile plane

What type of mechanical lock seam is standard on factory-fabricated spiral round metal ductwork?

• AStanding button punch lock seam
• BGrooved flat lock longitudinal seam
• CStandard female Pittsburgh seam
• DContinuous four-ply spiral lockseam

When hand-soldering 304 stainless steel architectural flashing, what surface preparation and flux are required before applying 50/50 tin-lead solder?

• APhosphoric acid flux with mechanical roughening
• BRosin core flux paste with solvent degreasing only
• CZinc chloride acid flux with smooth polishing
• DPetroleum flux jelly with water flame heating

For a 48-inch wide by 24-inch high rectangular duct made from 22-gauge steel operating at 2.0 inches w.g. static pressure, SMACNA tables specify adding intermediate structural stiffeners at what maximum spacing?

• A2.5 feet maximum angle spacing
• B5.0 feet maximum angle spacing
• C8.0 feet maximum angle spacing
• D10.0 feet maximum angle spacing

When programming CNC plasma cutting machines to cut sheet metal patterns for architectural wall panels, what typical cut kerf width allowance is factored into CAD/CAM software?

• A0.015 inches plasma kerf width
• B0.030 inches plasma kerf width
• C0.060 inches plasma kerf width
• D0.125 inches plasma kerf width

When laying out corner notches on a sheet metal fitting pattern designed for a 1-inch broadway flange bend, what notch angle is cut at corner bend line intersections?

• A30-degree corner angle notch
• B45-degree corner angle notch
• C60-degree corner angle notch
• D90-degree corner angle notch

Unlike galvanized steel sheet which is specified by gauge number, architectural sheet copper thickness is standardly designated in what units?

• AOunces per square foot of material
• BGrams per square meter of surface
• CDecimals of an inch thickness gauge
• DPounds per linear yard of material

Button punch snap lock seams are restricted by SMACNA HVAC Duct Construction Standards to ductwork operating up to what maximum static pressure rating?

• A1.0 inch water gauge static rating
• B2.0 inches water gauge static rating
• C4.0 inches water gauge static rating
• D10.0 inches water gauge static rating

What is the primary fabrication purpose of folding a 1/2-inch single or double hem along the exposed raw edge of a sheet metal hood or access door?

• ATo increase thermal conductivity of panel only
• BTo reduce air turbulence inside duct hood
• CTo eliminate sharp edges and stiffen material
• DTo allow expansion during thermal cycling

When locking a grooved lock seam with a hand groover and mallet on round sheet metal pipe, what is the operational purpose of the recessed groove in the tool head?

• ATo punch rivet holes along seam overlap line
• BTo shear off excess metal overlap material
• CTo crimp the end of round pipe for fitting
• DTo compress and lock folded seams together

According to SMACNA HVAC Duct Construction Standards, what is the maximum horizontal hanger spacing for rigid rectangular sheet metal ductwork?

• A10 feet maximum hanger spacing
• B12 feet maximum hanger spacing
• C14 feet maximum hanger spacing
• D16 feet maximum hanger spacing

Per SMACNA and California Mechanical Code (CMC) standards, flexible air ducts must be supported at maximum intervals of how many feet, and with what maximum allowable sag per foot?

• ASupported at 6 feet with max 1 inch sag per foot
• BSupported at 4 feet with max 1/2 inch sag per foot
• CSupported at 5 feet with max 3/4 inch sag per foot
• DSupported at 8 feet with max 1/4 inch sag per foot