The twelve categories

Every category PSI publishes, and the reference book each one sends you to.

The NASCLA exam blueprintPSI publishes twelve categories as raw question counts summing to 115. Procurement and Contracting Requirements is 31 and General Requirements is 25, …
Procurement and Contracting RequirementsThe largest category at 31 of 115 scored questions, covering bidding, contract types and precedence, bonds and insurance, changes and claims, payment …
General RequirementsThe second largest category at 25 of 115 scored questions, covering OSHA jurisdiction and recordkeeping, fall protection, scaffolds and ladders, perso…
Site ConstructionFifteen of 115 scored questions, covering excavation and protective systems, soils and compaction, stormwater and erosion control, site utilities and …
ConcreteSix of 115 scored questions covering formwork and shoring, reinforcing steel placement and cover, mixing and placing, and curing and weather concretin…
MetalsSix of 115 scored questions covering structural steel framing and connections, bolting and welding, steel decking and cold-formed framing, and erectio…
Mechanical and Plumbing SystemsSix of 115 scored questions covering plumbing rough-in and venting, water supply and backflow prevention, HVAC and ventilation, and fire protection an…
WoodFive of 115 scored questions covering framing members and load paths, fasteners and shear walls, and engineered wood, trusses and temporary bracing.
Thermal and Moisture ProtectionFive of 115 scored questions covering roofing systems and slope, flashing and waterproofing, insulation and vapor retarders, and sealants and envelope…
FinishesFive of 115 scored questions covering gypsum board and fire-rated assemblies, ceilings, flooring and tile, and painting and surface preparation.
MasonryFour of 115 scored questions covering units, mortar and grout, reinforcement and control joints, and cold and hot weather masonry. The limited access …
Doors, Windows and GlazingFour of 115 scored questions covering door types and hardware, fire-rated openings and egress hardware, and windows, curtain wall and glazing. Egress …
Electrical SystemsThree of 115 scored questions, the smallest category, covering temporary power, grounding and GFCI protection, and service and distribution coordinati…
OSHA 1926: what the exam asksThe exam asks for trigger heights, reporting deadlines, capacity multiples and which subpart governs an activity. Almost all of it is a lookup if the …
Fall protection trigger heightsSix feet in construction generally, ten feet on a scaffold, fifteen feet in steel erection. Three activities, three numbers, and questions are built o…
Guardrail dimensions and forcesA top rail at 42 inches plus or minus 3 inches, withstanding 200 pounds of downward force. A midrail withstanding 150 pounds. A toeboard of at least 3…
Personal fall arrest system numbersMaximum arresting force 1,800 pounds with a body harness, maximum free fall 6 feet, maximum deceleration distance 3.5 feet, and anchorage strength 5,0…
Scaffold capacity and platform rulesA scaffold must support four times the maximum intended load, and suspension ropes six times. Platforms are at least 18 inches wide, planks overhang b…
Ladder rules you must knowA ladder used for access must extend 3 feet above the landing. A portable ladder is set at a 4 to 1 ratio. A self-supporting ladder must support four …
Trench protective systems by soil typeA protective system is required at 5 feet unless the excavation is entirely in stable rock. Beyond 20 feet the system must be designed by a registered…
The competent person explainedA competent person is capable of identifying hazards and is authorized to take prompt corrective action. A qualified person has a degree, certificate …
The order of precedenceThe contract states its own order of precedence. Typically the agreement prevails over the general conditions, which prevail over the specifications, …
Bid, performance and payment bondsA bid bond guarantees the bidder will enter the contract if awarded. A performance bond guarantees completion. A payment bond guarantees payment to su…
Insurance a contractor must carryWorkers compensation covers employee injury on a no-fault basis. Commercial general liability covers bodily injury and property damage to third partie…
Change orders, claims and delaysA change order is a written amendment to price or time signed by both parties. A claim is an unresolved assertion of entitlement. Delays are excusable…
Retainage and progress paymentsRetainage is a percentage withheld from each progress payment, commonly 10 percent, released at or after completion. Progress payments follow a monthl…
Mechanics liens explainedA mechanics lien is a claim against the improved property securing payment for labor and materials. Deadlines for preliminary notice, filing and enfor…
Markup against marginMarkup is calculated on cost and margin on selling price. A 20 percent markup produces a margin of about 16.7 percent, and confusing them underprices …
Contract types comparedA lump sum fixes the price and puts overrun risk on the contractor. Cost plus reimburses cost and puts risk on the owner. A guaranteed maximum price c…
Estimating and quantity takeoffTakeoff questions ask for quantities in standard units - cubic yards of concrete, squares of roofing, board feet of lumber. The conversions are what g…
Overhead and break-evenOverhead is the cost of running the business that cannot be charged to any single job. Break-even is the revenue at which contribution covers fixed co…
Reading a financial statementThe balance sheet shows position at a point in time, the income statement shows performance over a period, and the cash flow statement shows money mov…
Business entity typesA sole proprietor has unlimited personal liability. A corporation is a separate legal entity limiting shareholder liability. An LLC combines limited l…
Employee or independent contractorClassification turns on the degree of control the business exercises, not on what the parties call the arrangement. Misclassification exposes the busi…
Soil classification explainedType A is 1.5 tons per square foot or greater, Type B above 0.5 and below 1.5, Type C at 0.5 or less. Maximum slopes are three quarters to one, one to…
Excavation atmospheric testingAtmospheric testing is required in an excavation more than 4 feet deep where a hazardous atmosphere could reasonably exist. Oxygen must be between 19.…
Crane power line clearancesTwenty feet is the default minimum clearance for crane assembly near lines up to 350 kilovolts. Ten feet applies to general work near lines up to 50 k…
Rigging and sling anglesAs the angle between a sling leg and the horizontal decreases, tension in the leg rises sharply. At 30 degrees from horizontal the tension is double t…
OSHA recordkeeping and reportingA fatality is reported within 8 hours. An inpatient hospitalization, amputation or loss of an eye within 24 hours. OSHA 300 logs are retained 5 years.…
Inspections, citations and abatementAn inspection runs from opening conference through walkaround to closing conference. Citations are classified from other-than-serious through serious …
Hazard communication and safety data sheetsA written hazard communication program, labels carrying six required elements, safety data sheets in a standard 16-section format, and training. The s…
Confined space entryA confined space is large enough to enter, has limited means of entry or exit, and is not designed for continuous occupancy. It becomes permit-require…
Formwork and shoringFormwork and shoring may only be removed when the concrete has gained sufficient strength, determined under a plan prepared by a qualified person, at …
Rebar cover and splicesConcrete cover is 3 inches where cast against and permanently exposed to earth, and 2 inches for formed surfaces exposed to earth or weather with larg…
Concrete testing and strengthCompressive strength is tested at 28 days on cylinders. The slump test measures workability, not strength. Air content, temperature and unit weight ar…
Cold and hot weather concretingCold weather provisions apply below 40 degrees Fahrenheit and hot weather precautions commonly at 90 degrees. Cold slows hydration and risks freezing;…
Mortar typesMortar types M, S, N and O run from highest to lowest compressive strength. Mortar should generally be weaker than the units so that cracking occurs i…
Masonry bracing and limited access zonesA limited access zone is required on the unscaffolded side of a masonry wall over 8 feet, equal to the wall height plus 4 feet. Bracing stays until pe…
Structural steel connectionsSteel connections are bolted or welded. Bolted connections may be snug-tight, pretensioned or slip-critical. Welds are inspected visually and by non-d…
Steel erection safetyFall protection in steel erection triggers at 15 feet rather than 6. Written notification of site readiness is required before erection begins, and co…
Wood framing and load pathsA load path carries force continuously from roof to foundation. Any interruption - an opening, a removed stud, a cantilever - must be carried by a mem…
Trusses and temporary bracingTrusses are designed to carry load in their own plane and are unstable laterally until braced. Temporary bracing during erection is the contractor's r…
Roofing slope and underlaymentRoof slope is expressed as rise over a 12 inch run. Three in 12 or less is generally low slope, which changes permitted systems and underlayment requi…
Flashing and waterproofingFlashing directs water away at every penetration and transition. Dampproofing resists moisture; waterproofing resists water under hydrostatic pressure…
Insulation, R-values and vapor retardersR-value measures resistance to heat flow and U-factor is its reciprocal. A vapor retarder goes on the warm side of the insulation in a heating climate…
Fire-rated assemblies and gypsumA fire rating belongs to a tested assembly, not to any component. Type X gypsum board is used in rated assemblies, usually at 0.625 inches, and every …
Egress doors and hardwareAn egress door needs 32 inches of clear width, measured with the door open. Interior accessible doors have a common maximum opening force of 5 pounds,…
GFCI and temporary powerGround fault circuit interrupter protection, or an assured equipment grounding conductor program, is required for temporary power on construction site…
Lockout and taggingControls that are to be de-energized must be tagged, and circuits locked out where possible, under 29 CFR 1926.417. Verification that the circuit is a…
PPE and hazard communicationThe employer assesses hazards, provides PPE and generally pays for it. PPE sits last in the hierarchy of controls, after elimination, substitution, en…
Fire prevention and emergency actionA fire prevention program, extinguishers provided by travel distance, hot work controls with a fire watch, and an emergency action plan covering evacu…
Plumbing drainage and ventingHorizontal drainage of small diameter commonly requires a quarter inch per foot of slope. Traps hold a water seal against sewer gas, and vents let air…
Backflow preventionA cross connection is any point where potable water could be contaminated by a non-potable source. An air gap prevents backflow physically; mechanical…
HVAC and ventilation basicsA general contractor coordinates rather than designs HVAC: equipment clearances, structural support, penetrations through rated assemblies, and the ou…
Fire sprinkler systemsWet pipe, dry pipe, pre-action and deluge are the four broad types. Design follows NFPA standards referenced by the code, and the general contractor c…
Reading plans and specificationsDrawings show location and dimension; specifications describe materials, quality and workmanship. Where they conflict, the contract order of precedenc…
Liquidated damages and substantial completionLiquidated damages are a pre-agreed daily sum for late completion, enforceable only as a genuine estimate of loss rather than a penalty. Substantial c…
Payroll taxes and workers compensationAn employer withholds income tax and the employee share of payroll taxes, pays a matching employer share, and carries workers compensation insurance r…
Earthwork quantities and compactionVolumes are calculated in cubic yards at 27 cubic feet each. Excavated soil swells when loose and shrinks when compacted, so bank, loose and compacted…
Stormwater and erosion controlConstruction sites disturbing land above a threshold need a stormwater permit and a pollution prevention plan, with control measures installed, inspec…
Site utilities and backfillA buried pipe is supported by its bedding and haunching rather than by its own strength. Backfill is placed in lifts and compacted, and locating exist…