Tennessee BC-B, C Combined Commercial/Industrial Contractor

Tennessee BC-B/C Commercial/Industrial Contractor Exam Study Brief

Key Concepts

Soil Classification (OSHA Appendix B to Subpart P) - Type A: Most stable — cohesive soils, unconfined compressive strength ≥1.5 tsf (clay, silty clay). Cannot be fissured or previously disturbed. - Type B: Cohesive soils with strength 0.5–1.5 tsf; previously disturbed soils; angular gravel; dry unstable rock. - Type C: Least stable — cohesive soils <0.5 tsf, granular soils, submerged soil, soil from which water is freely seeping. Always use most conservative slope.

Excavation Protective Systems (§1926.652) - Required for ALL excavations 5 feet or deeper (or shallower if a competent person determines a hazard exists). - Sloping ratios (Appendix B): - Stable Rock: Vertical (90°) - Type A: ¾:1 (H:V) = 53° angle - Type B: 1:1 (H:V) = 45° angle - Type C: 1½:1 (H:V) = 34° angle - Benching is not permitted in Type C soil. - Trench boxes (shields)…

Key Concepts

Basic Concrete Components

Concrete is a mixture of Portland cement, fine aggregate (sand), coarse aggregate (gravel/crushed stone), and water. Portland cement is hydraulic — it hardens through hydration, not drying. The water-cement (w/c) ratio is the single most critical factor controlling strength, durability, and watertightness: lower w/c ratio = higher strength and durability.

Concrete Mix Design & Proportioning

• Mix design must address strength (f'c), workability (slump), and exposure conditions
• Slump measures workability — not strength. High-slump concrete is more workable but weaker if excess water is added
• Fine aggregate volume measurement is inaccurate; weight measurement is preferred
• Use maximum allowable coarse aggregate particle size to reduce water demand and increase economy

Tennessee BC-B/C Combined Commercial/Industrial Contractor Exam

10 questions | 10% of exam weight

Key Concepts

Steel Joist Series (SJI Standards)

• K-Series: Short-span joists, spans up to 60 feet. Most common for light commercial roof/floor.
• LH-Series (Longspan): Spans 25–96 feet. Used for floors and roofs without intermediate supports.
• DLH-Series (Deep Longspan): Spans 89–144 feet. Heavy roof applications.
• CJ-Series (Composite Joists): Designed to act compositely with concrete slabs.
• Joist Girders: Primary structural members supporting K-, LH-, or DLH-Series joists; designated by depth, number of joist spaces, and factored load (e.g., 36G8N10K).

Erection Bridging & Hoisting Cable Release (OSHA §1926.757)

• Bridging must be installed and anchored before hoisting cables are released from joists — no exceptions unless the manufacturer's erection drawing specifies otherwise.
• Bolted diagonal bridging must be in place before releasing cables on joists with top chord lengths exceeding specific limits.
• A **bridging terminus…

Key Concepts

Masonry Materials

• Brick: Classified by grade (SW, MW, NW) based on weathering resistance. SW = severe weathering, used below grade or exposed to freezing.
• Concrete Masonry Units (CMU): Hollow or solid; strength varies by unit weight (lightweight, medium, normal weight). Minimum face-shell thickness governs.
• Mortar vs. Grout: Mortar bonds units together; grout fills cores/cavities of reinforced masonry. Grout must be fluid (high slump ~8–11 inches) to flow around rebar.

Mortar Types (ASTM C270)

Mortar type determines compressive strength and application:

Key Concepts

Lumber Grading & Quality Marks (IBC §2303.1.1) Sawn lumber used for load-supporting purposes must be identified by a grade mark from an approved lumber grading/inspection agency complying with DOC PS 20. A certificate of inspection may substitute for a grade mark on precut, remanufactured, or rough-sawn lumber, and for sizes larger than 3 inches nominal thickness. End-jointed lumber may be used interchangeably with solid-sawn members of the same species and grade; if used in a fire-resistance-rated assembly, the grade mark must include "HRA" (Heat Resistant Adhesive).

Wood Structural Panels (IBC §2303.1.5) Panels must conform to DOC PS 1, DOC PS 2, or ANSI/APA PRP 210 and be identified for grade, bond classification, and Performance Category by an approved agency trademark. Panels permanently exposed outdoors must be Exterior type, except roof sheathing exposed on the underside may be Exposure 1 type.

Tennessee BC-B, C – Commercial/Industrial Contractor Exam

Key Concepts

Fall Protection (29 CFR 1926 Subpart M)

• Fall protection required at 6 feet in construction (not 4 ft as in general industry)
• Guardrail systems: Top rail at 42 inches (±3 in.), mid-rail at 21 inches; top rail must withstand 200 lbs outward/downward force
• Safety nets: Must be installed as close as practicable, no more than 30 feet below working surface; drop-test required (400 lb bag of sand)
• Personal Fall Arrest Systems (PFAS): Must limit free fall to 6 feet, arrest force to 1,800 lbs; anchor must support 5,000 lbs per worker

Excavation & Trenching (29 CFR 1926 Subpart P)

• Competent person must classify soil and inspect daily and after rain
• Cave-in protection required for excavations 5 feet or deeper (or less if competent person determines hazard exists)
• Soil classifications: Type A (stable, cohesive) —…

Tennessee BC-B/C Commercial/Industrial Contractor Exam Study Brief

Key Concepts

Occupancy Classification & Building Height/Area (IBC Chapter 3 & 5) - IBC classifies occupancies as A, B, E, F, H, I, M, R, S, U — know which uses fall under each group. - Mixed occupancies may be treated as separated (fire-rated assemblies required) or nonseparated (most restrictive occupancy governs). - Building height and area limits are found in IBC Table 503 — modified by sprinklers (Section 504/506): fully sprinklered buildings gain unlimited area if meeting perimeter open space requirements (506.3).

Types of Construction & Fire-Resistance Ratings (IBC Chapter 6) - Five construction types: I-A, I-B (noncombustible, highest rated) → II, III, IV → V-A, V-B (combustible, least restrictive). - IBC Table 601 lists required fire-resistance ratings for structural elements by type. Example: Type I-A requires 3-hour columns, 2-hour floor assemblies. - Type IV (Heavy Timber): minimum 8"×8" columns, 6"×10" beams — no…

Tennessee BC-B/C Combined Commercial/Industrial Contractor Exam 10 questions | 10% of exam weight

Key Concepts

Gypsum Board Types & Limitations

• Standard wallboard (ASTM C1396): Available in 1/4″, 3/8″, 1/2″, 5/8″ thicknesses. Not for wet areas.
• Type X (Firecode): 5/8″ minimum for 1-hour rated assemblies; enhanced core with glass fibers. Required by IBC in many occupancy separations.
• Moisture-resistant (MR/green board): Not a substitute for cement board in wet/tile applications — it has moisture resistance, not immunity.
• Abuse-resistant panels: Higher surface hardness; used in corridors, schools, healthcare.
• Sag-resistant panels: Required for ceilings with framing spaced >16″ o.c.

Key Concepts

Roof Slope Measurement

• Slope is expressed as rise over run (e.g., 4:12 = 4" rise per 12" horizontal run)
• Low slope: less than 2:12; Steep slope: 4:12 and above; Moderate: 2:12–4:12
• Use a slope factor to convert horizontal (plan) area to actual roof area — multiply plan area by the appropriate slope factor (e.g., 6:12 slope = factor of 1.118)
• Roof area is measured in squares (1 square = 100 sq ft)

Asphalt Shingles

• UL Class A, B, C fire ratings — Class A is highest; commercial work typically requires Class A
• Three-tab shingles have 5" exposure on 12" shingles; architectural (laminated) shingles vary by manufacturer
• Minimum 4 fasteners per shingle strip; 6 fasteners in high-wind zones
• Deck must be solid; minimum ½" plywood or OSB for asphalt shingles
• Starter course required along eaves and rakes; overhangs eave edge ¼"–¾"…