AZ ROC A (KA) Dual Engineering cheat sheet

Arizona contractor licenses are issued by the Registrar of Contractors (ROC) under A.R.S. Title 32, Chapter 10; a license is required before advertising or bidding work.

License classifications: A = general engineering, B = general building, and specialty (C) classifications; a dual A/B license allows both engineering and building scope.

Change orders must be in writing and signed by the owner before the extra work proceeds to preserve the right to payment.

Prompt payment: on private work the owner must pay the contractor within 7 days after the contractor's billing period ends unless contract terms state otherwise (A.R.S. § 32-1129 series).

Retainage on private construction is limited to 10 percent of the amount due and must be released within 60 days after substantial completion.

Contractor license must remain active; a suspended or expired license bars the contractor from filing suit to collect for work performed while unlicensed.

Mechanics' liens must be recorded within 120 days after completion of the project (A.R.S. § 33-993); a 20-day preliminary notice is required from parties without a direct contract with the owner.

Arizona has no state prevailing wage law for private work; federal Davis-Bacon rates apply only to federally funded projects.

Contractor must provide the ROC with a current residential address and notify the Registrar within 30 days of any change.

Swell factor = (loose volume − bank volume) / bank volume; shrinkage is the opposite and applies to compacted fill from bank material.

1 cubic yard = 27 cubic feet; earthwork quantities are usually computed in bank cubic yards (BCY) and converted to loose (LCY) with the swell factor.

Slope ratio 2:1 (horizontal:vertical) is the typical maximum for stable temporary excavations in ordinary soil; OSHA requires 1.5:1 or flatter in Type C soil.

Soil classification (OSHA): Type A cohesive ≥ 1.5 tsf unconfined compressive strength; Type B 0.5–1.5 tsf; Type C < 0.5 tsf or granular/loose.

Trench spoil must be kept at least 2 feet back from the excavation edge to prevent surcharge loading and raveling.

Compaction is verified by field density tests; standard Proctor (ASTM D698) vs modified Proctor (ASTM D1557) - most structural fills specify 95% of modified Proctor.

Cut and fill balance: net earthwork = Σ cut − Σ fill; a positive value means export is required, negative means import.

Excavation deeper than 5 feet requires a protective system (sloping, benching, shoring, or trench box) unless the excavation is entirely in stable rock.

Concrete mix design: absolute volume method - 1 cubic yard = 27 ft³ divided among cement, water, fine aggregate, coarse aggregate, and entrained air.

Water-cement ratio (w/c) controls strength and durability; typical structural concrete w/c = 0.40–0.50, and strength decreases as w/c increases.

ACI 318 minimum cover over reinforcement: 3 inches for concrete cast against earth, 1.5 inches for beams/slabs exposed to weather, 0.75 inch for interior slabs.

Standard concrete cylinder size is 6 in. × 12 in.; compressive strength is tested at 28 days and must reach f'c specified.

Slump test (ASTM C143) measures workability; typical structural slump is 3–5 inches.

Rebar lap splice length for #4 through #6 bars in tension is typically 40 bar diameters when using Grade 60 steel in normal-weight concrete.

Curing: moist curing for at least 7 days (Type I cement) is required to develop design strength; cold-weather protection is required when ambient temperature falls below 40°F.

Formwork removal: sides of beams and columns may be removed after 24 hours; soffits of slabs and beams require 7–14 days depending on member and temperature.

Ohm's law: V = I × R; power P = V × I = I²R; single-phase kW = (V × I × PF) / 1000.

Three-phase power: kW = (√3 × V × I × PF) / 1000; use line-to-line voltage and line current.

NEC conductor ampacity is adjusted for ambient temperature and conduit fill; more than 3 current-carrying conductors in a raceway requires derating per Table 310.15(C).

Voltage drop on a branch circuit should not exceed 3 percent; total feeder plus branch should not exceed 5 percent.

HVAC: 1 ton of refrigeration = 12,000 BTU/hr; airflow rule of thumb is 400 CFM per ton.

Sensible heat equation: BTU/hr = 1.08 × CFM × ΔT; latent heat: BTU/hr = 0.68 × CFM × Δgrains.

Duct sizing by equal friction method uses 0.08–0.10 in. w.g. per 100 ft of duct for low-velocity systems.

GFCI protection is required in bathrooms, kitchens, outdoors, and within 6 feet of a sink; AFCI is required in dwelling bedrooms and living areas.

Slope of horizontal drain pipe: 1/4 inch per foot for pipe 2½ inches and smaller; 1/8 inch per foot for 3 inches and larger.

Fixture units (FU): a water closet = 3 FU (private) and a lavatory = 1 FU; total FU determines drain and supply pipe sizing.

Minimum size of a building sewer is 4 inches; minimum size of a soil stack is 3 inches.

Vent stack must extend at least 6 inches above the roof and be at least 12 inches above any opening within 10 feet.

Water service pressure should be 45–80 psi; a pressure-reducing valve is required above 80 psi.

Water supply fixture units convert to gpm using the Hunter curves; a 1-inch service typically supports about 250 total fixture units.

Backflow prevention: an air gap is the only acceptable protection against a health hazard; RPZ devices are required for cross-connections to potable water.

A trap arm length is limited to the developed length equal to the pipe diameter in inches × 2 feet (per UPC) to prevent siphonage.

AISC standard bolt hole diameter is 1/16 inch larger than the bolt diameter for bolts up to 1 inch; 1/8 inch larger for bolts over 1 inch.

Minimum edge distance for a bolt is 1.5 × bolt diameter measured from the center of the hole to the edge of the plate.

Fillet weld throat = 0.707 × weld size; capacity = throat × length × allowable stress.

AWS D1.1 prequalified fillet welds: minimum size is 1/8 inch for material up to 1/4 inch thick; single-pass maximum is 5/16 inch.

Common electrode E70XX: minimum tensile strength 70 ksi; the first two digits are tensile strength in ksi.

Shop drawings must be approved by the EOR before fabrication; mill test reports (MTRs) verify steel chemistry and strength.

High-strength bolts A325 (now F3125 Grade A325) are tensioned by turn-of-nut, calibrated wrench, or direct tension indicator.

Steel weighs 490 lb/ft³; use this to compute member weights - e.g., W-shape weight per foot is given in the designation (W14×90 = 90 lb/ft).

CSI MasterFormat divides specifications into 50 Divisions; Division 01 is General Requirements, Division 02 is Existing Conditions, Division 03 is Concrete, Division 05 is Metals.

Drawing scale: measured length × scale factor = actual length; verify by a known dimension on the sheet before scaling.

Quantity takeoff: length × width × depth = volume in cubic feet; divide by 27 for cubic yards.

Contingency in an estimate typically runs 5–10 percent for design-bid-build and 10–20 percent for conceptual budgets.

Overhead and profit (O&P) are typically added as a percentage on top of direct cost; direct cost + indirect cost = total cost.

Bid documents priority order: written specifications govern over drawings; large-scale drawings govern over small-scale; dimensions govern over scaled measurements.

The critical path is the longest duration path through the network; any delay on it delays the project completion.

Unit price contracts pay by measured quantity; lump-sum contracts pay a fixed amount regardless of quantity variance.

OSHA 1926 Subpart M: fall protection is required at 6 feet in construction; guardrails, safety nets, or personal fall arrest systems are acceptable.

Scaffold top rail height is 38–45 inches; midrail is approximately 21 inches; toe boards are 3½ inches high.

Hard hats, safety glasses, and high-visibility vests are minimum PPE on most construction sites; hearing protection is required above 85 dBA TWA.

Arizona OSHA (ADOSH) enforces federal standards through a state plan; recordable injuries must be logged on OSHA Form 300 within 7 days.

Environmental: NPDES Construction General Permit requires a Stormwater Pollution Prevention Plan (SWPPP) for sites disturbing 1 acre or more.

Asbestos and lead: pre-renovation surveys are required before demolition of pre-1980 buildings; RRP Rule applies to pre-1978 residential work.

Hazard Communication (HazCom) requires a written program, SDS on site, and training for every employee exposed to chemicals.

Arizona fire code: fire extinguishers must be tagged annually and mounted within 75 feet of travel distance for Class A hazards.