AZ ROC A (KA) Dual Engineering key terms

A written statement, usually signed by a subcontractor or supplier, giving up the right to file a mechanics lien for work or materials already furnished, often exchanged for progress or final payment.

A statutory claim against real property that secures payment for labor, services, or materials provided to improve it. Contractors and suppliers must follow strict notice and filing deadlines to preserve it.

A formal written warning, required in some states, telling a property owner that a party supplying labor or materials may later claim a mechanics lien if it is not paid.

A percentage of each progress payment withheld by the owner or general contractor until the work is substantially or fully complete, protecting against incomplete or defective work and unpaid lower-tier parties.

The stage when the work is sufficiently finished that the owner can use the project for its intended purpose, even though minor punch-list items remain. It often starts warranty periods and releases retainage.

A written, signed amendment to the contract that modifies scope, price, or schedule. Without written authorization, extra work may not be compensable.

A line-item breakdown of the contract sum allocated to portions of the work, used as the basis for progress payment requests and for tracking earned value against completed work.

A compiled record of incomplete or defective items identified during a walkthrough near project closeout, which the contractor must correct before final acceptance and final payment.

A subsurface or latent physical condition at the site that differs materially from what the contract documents indicated, potentially entitling the contractor to extra time or money.

A fixed reference point of known elevation or horizontal position used to establish and check grades and alignments during surveying and construction layout.

The earthwork process of removing soil from high areas (cut) and placing it in low areas (fill) to reach a desired grade, ideally balancing volumes on site to minimize hauling.

The percentage by which a soil's volume increases when excavated and loosened compared with its compacted in-place volume, used to convert truck loads and stockpile quantities.

Mechanical densification of soil by removing air voids, usually measured as a percentage of maximum dry density and verified in the field with a nuclear gauge or sand cone test.

A system of hydraulic jacks, plates, or sloping used to protect workers from cave-ins while working in excavations, required once a trench reaches five feet deep unless a competent person deems otherwise.

An individual capable of identifying existing and predictable hazards and authorized to take prompt corrective action, such as inspecting excavations and fall protection systems before work begins.

Written authorization from a local authority to dig, including requirements to notify utility locating services and confirm no buried lines will be struck before breaking ground.

The ratio of the mass of water to the mass of cementitious material in a concrete mix; lower ratios generally increase strength and durability but reduce workability.

A field test measuring how far a fresh concrete sample settles when a standard cone is lifted, giving a quick indication of consistency and workability before placement.

Maintaining adequate moisture and temperature in placed concrete so cement hydration can continue, allowing the mix to develop its designed strength and durability over time.

Temporary molds and supporting falsework that hold fresh concrete in the required shape and position until it hardens enough to support itself.

The thickness of concrete between the outer surface of embedded reinforcing steel and the nearest concrete face, protecting the steel from corrosion and providing fire resistance.

A factory-made grid of crossing wires electrically welded at intersections, used in slabs and walls to control cracking and distribute loads.

A systematic determination of heating and cooling loads for a building based on envelope, occupancy, and climate data, used to size HVAC equipment correctly rather than by rule of thumb.

A network of sheet-metal or flexible conduits that distributes conditioned air from HVAC equipment to occupied spaces and returns air to the unit.

A movable plate inside ductwork or a flue that regulates airflow, used for balancing air distribution or for fire and smoke control in life-safety systems.

The reduction in voltage along a conductor caused by its resistance and the current flowing through it, which must be limited so equipment receives adequate operating voltage.

Connecting electrical equipment and systems to earth through a low-resistance path, providing a safe route for fault current and reducing shock and fire hazards.

A physical separation between a potable water supply outlet and the flood level of a receiving fixture or vessel, the most reliable form of backflow prevention.

A device or assembly installed in a piping system to stop contaminated water from reversing flow into the potable supply, selected according to the degree of hazard present.

A dimensionless measure of the probable water demand or drainage load of a plumbing fixture, used to size supply and drain piping for a building.

A written document giving the detailed welding parameters, materials, and techniques qualified by testing for a particular joint, so welders produce consistent, code-compliant results.

Testing of an individual welder's ability to produce acceptable welds on a specific process and joint configuration, documented to show the welder is certified for that work.

Inspection methods such as ultrasonic, radiographic, magnetic particle, or dye penetrant testing that reveal internal or surface weld defects without damaging the completed weldment.

A standard graphical notation on drawings that specifies weld type, size, length, spacing, and location relative to the joint reference line.

The written portion of the contract documents describing materials, workmanship, quality standards, and execution requirements that supplement the drawings.

A written modification to the bidding or contract documents issued before bid opening to clarify, correct, or change the drawings or specifications.

The process of measuring and listing materials and labor from the drawings and specifications to price a project and prepare a bid.

Systems and practices, such as guardrails, personal fall arrest, or safety nets, used to prevent or arrest falls from elevations, generally required at six feet or more in construction.

The OSHA-required program of labeling, safety data sheets, and employee training that informs workers about hazardous chemicals present on the job site.

A site-specific plan required under clean water regulations that identifies erosion and sediment controls and best management practices to keep construction runoff from polluting waterways.