CID key terms

A written statement of a client's needs, goals, and requirements for a project, covering spaces, sizes, relationships, and performance criteria. It guides design decisions before and during schematic work.

A grid that rates how strongly each pair of spaces should be near or connected to one another. Planners use it to test and document functional relationships before drawing floor plans.

A loose diagram of circles or blocks representing spaces, joined by lines that show required relationships. It explores organization and circulation without committing to dimensions or wall locations.

A vertical section-style diagram that assigns departments or uses to building floors, showing how they relate by elevator, stair, and service core. It resolves vertical organization before floor plans are drawn.

The floor area of spaces actually usable for a program's functions, excluding corridors, walls, mechanical rooms, and other support space. It is compared with gross area to test planning efficiency.

Net assignable area divided by gross floor area, expressed as a percentage. It measures how much of a building serves program versus circulation, structure, and building systems, and varies by building type.

The total enclosed floor area of a building measured to the outside faces of exterior walls, including corridors, mechanical rooms, and structure. Codes and zoning use it for limits and calculations.

The number of people a space or building is expected to hold, computed by dividing floor area by a code-specified factor or by counting fixed seats. It sets egress width, exits, and plumbing fixture counts.

The clear width of exits, corridors, and stairs required to move the occupant load out safely, calculated from code tables based on occupant load. It must remain unobstructed at all points.

The measured path length from the most remote point in a space to an exit or exit access doorway. Codes cap it by occupancy and sprinkler protection to limit exposure during evacuation.

The portion of the means of egress that leads from any occupied point to an exit, such as a room, aisle, or corridor. It differs from the exit itself and from exit discharge.

The continuous and unobstructed path from any point in a building to a public way, made up of exit access, exit, and exit discharge. Codes regulate each component's width, enclosure, and protection.

A continuous, unobstructed path connecting accessible elements and spaces, meeting limits on slope, width, and surface. It must connect site arrival points, entrances, and all accessible features inside.

The unobstructed area required for a single wheelchair to approach and use a fixture, control, or element, typically a defined rectangle. It must be positioned to allow forward or side approach as required.

The circular clear area a wheelchair needs to reverse direction, commonly specified as a diameter in accessibility standards. It governs the size of toilet rooms, vestibules, and tight corners.

The ratio of a building's total floor area to the area of its lot, used by zoning to control density and bulk. A higher ratio permits more building mass on the same parcel.

The minimum distance a building must be held back from a lot line, street, or other reference line under zoning. Setbacks shape massing, daylight access, and the public edge of the site.

The category assigned to a building or space based on its use and hazard, such as assembly, business, or residential. The classification drives allowable height, area, egress, and fire protection requirements.

The period, in hours, that an assembly or building element resists fire under standardized test conditions. Ratings are assigned to walls, floors, shafts, and structural members based on occupancy and height.

A written project document that sets quality, products, materials, execution, and performance requirements for work not fully described on drawings. It is coordinated with drawings and forms part of the contract documents.

A standardized numbering system that organizes construction specifications and cost information into divisions by work type. It gives owners, designers, and contractors a common structure for bidding and administration.

A document such as a shop drawing, product data sheet, or sample that a contractor sends to the design team for review and approval before installation. It verifies that materials meet the specification.

A detailed fabrication or installation drawing prepared by a contractor, fabricator, or supplier from the design drawings. It shows how a component will actually be built and is reviewed for design intent.

A drawing revised during construction to record the actual installed conditions, dimensions, and locations. It becomes a record document for the owner's future operation and renovation work.

A formal written question from the contractor asking the design team to clarify drawings, specifications, or site conditions. Responses become part of the project record and may lead to change orders.

A written modification to the contract that adjusts scope, cost, or schedule, signed by the owner and contractor. It is the formal mechanism for authorizing work outside the original agreement.

The contract provisions defining the rights, duties, and procedures of the owner, contractor, and design professional, including payment, changes, and dispute handling. They are often a standard published document incorporated by reference.

A calculation that estimates the average illuminance in a room from lamp lumens, fixture count, and utilization and maintenance factors. It is used for uniform general lighting layouts rather than accent or task lighting.

The amount of light arriving at a surface, measured in lux or footcandles. Design targets for illuminance vary by task and are published in lighting references and energy standards.

A unit of illuminance equal to one lumen per square foot. It is the customary unit in United States lighting design practice and appears in task illuminance recommendations.

A scale from zero to one hundred describing how faithfully a light source renders object colors compared with a reference source. Higher values suit tasks where color judgment matters.

A measure in kelvin of the apparent warmth or coolness of white light, from warm tones near 2700 K to cool tones above 5000 K. It sets the mood and is specified alongside color rendering.

The equipment and distribution that heats, ventilates, and air-conditions a building, including air handling units, ducts, piping, and terminal devices. Its space needs shape ceiling heights and mechanical rooms.

A space used to distribute or return air, often the cavity between a suspended ceiling and the structure above. It may also house wiring and piping, subject to code limits on combustible materials.

A vertical enclosed space that carries ducts, pipes, or wiring between floors. It must be sized early in planning and coordinated with structural and egress layout.

The centralized zone of a building containing elevators, stairs, restrooms, shafts, and mechanical space. Its size and position drive floor plate efficiency, structural grid, and egress strategy.

A drawing viewed as if looking up at the ceiling from below, showing ceiling heights, light fixtures, diffusers, sprinklers, and other ceiling-mounted items. It coordinates trades that share the ceiling plane.

A composite drawing that overlays structural, mechanical, electrical, and plumbing elements to reveal clashes and confirm clearances. It is used during design and construction to resolve conflicts before installation.

The process of comparing building models or drawings from different disciplines to find physical conflicts, such as a duct crossing a beam. It is a core use of building information modeling.

A digital, object-based model of a building that carries geometry and data used for design, coordination, quantity takeoff, and facility management. Models are shared and federated across disciplines.

The early project phase that establishes concept, program fit, massing, and approximate cost, ending in client review and approval. It precedes design development and typically involves limited documentation.

The phase after schematic design in which the design is refined, major systems are selected, and drawings and outline specifications become more detailed. It concludes with an updated cost estimate and client approval.

The final drawings and specifications that define the work for bidding and construction, forming part of the contract. They must be coordinated, complete, and clear enough for contractors to price and build.

A drawing submitted by the contractor marking changes made during construction, which the design professional may use to prepare as-builts. It documents deviations from the contract documents.

Design that reduces environmental impact through energy efficiency, material selection, water use, site strategy, and occupant health. Goals are often verified against third-party rating systems and energy codes.

The total cost of a building element or system over its useful life, including first cost, operation, maintenance, and replacement. It supports decisions where a higher initial cost yields long-term savings.

A structured review that seeks equivalent function at lower cost by substituting materials, systems, or details. It should preserve design intent and is best performed with the design team involved.