NCIDQ IDFX key terms

A written and graphic statement of a client's needs, goals, and constraints, listing required spaces, sizes, adjacencies, and performance criteria that guide design decisions.

A grid that rates how closely each pair of required spaces should be located, using symbols or numbers to show strong, weak, or undesirable relationships during programming and blocking.

A loose schematic drawing of circles or blobs representing spaces, connected by lines that show required relationships, used to test zoning and circulation before dimensions are fixed.

The floor area actually usable for a stated function, excluding walls, columns, corridors, mechanical rooms, and other nonassignable space; the basis for comparing program requirements to available area.

Total floor area measured to the outside face of exterior walls, including corridors, partitions, structure, and service space; used for cost estimating, code occupancy, and lease calculations.

Net assignable area divided by gross area, expressed as a percentage; a planning metric showing how much of a building actually serves occupants rather than circulation and services.

A scaled diagram of furniture, fixtures, and equipment placed within a space to test clearances, circulation, and functional fit before detailed design or documentation.

The unobstructed dimension between the closest projecting surfaces along a path of travel, measured at and below specified heights; governs accessibility, egress, and furniture spacing checks.

Designing environments usable by the widest range of people regardless of age, ability, or stature, through equitable use, flexibility, simple operation, perceptible information, tolerance for error, low physical effort, and appropriate size and space.

A continuous, unobstructed path connecting accessible elements and spaces within a site or building that meets minimum width, slope, surface, and turning-space criteria so people with disabilities can travel independently.

A clear floor area, commonly a 60-inch diameter circle or T-shaped configuration, provided so a wheelchair or mobility device can reverse direction within a confined space such as a toilet room.

The continuous and unobstructed path of travel from any point in a building to a public way, composed of exit access, the exit, and exit discharge.

The number of people a space or building is calculated to hold, derived from floor area divided by a code-specified area per occupant based on use; it drives egress width, exits, and plumbing fixture counts.

The measured length along the path of egress travel from the most remote point in a space to the nearest exit or exit-access doorway, limited by occupancy group and whether the building is sprinklered.

A fire-resistance-rated stairway or ramp enclosure that protects the exit component of the egress system from fire and smoke, with opening protectives and limited penetrations.

The period, in hours or fractions of an hour, that an assembly withstands a standardized fire test while maintaining its structural integrity and limiting heat transmission; shown in ratings such as 1-hour or 2-hour.

A rated wall, floor, or assembly that divides a building into areas of limited size or separates occupancies, restricting fire spread for a specified time period.

The most fire-resistive building type, with structural members of noncombustible materials having high fire-resistance ratings, typically used for high-rise and large-area buildings.

The least restrictive building type, permitting combustible structural elements such as wood-frame walls and floors; ratings and allowable height and area are correspondingly limited.

The number of plumbing fixtures such as water closets, lavatories, and drinking fountains required by code, calculated from occupant load and occupancy classification, with accessibility and gender-distribution rules applied.

Dividing a building into separately controlled thermal zones so that heating, cooling, and ventilation can respond to differing loads, exposures, occupancy schedules, and equipment capacity.

An HVAC approach that delivers a constant supply-air temperature while modulating airflow to each zone, saving fan energy at part load compared with constant-volume systems.

An air-handling space or duct that distributes conditioned or return air; the ceiling cavity above a suspended ceiling is often used as a return-air plenum, which affects material flammability and smoke requirements.

Air drawn from conditioned spaces back to the air-handling unit for filtering, tempering, and redistribution; its path affects ceiling design, door undercuts, and transfer grilles.

A numerical rating from standardized surface-burning tests describing how quickly a material propagates flame across its surface, used with smoke-developed index to classify interior finishes.

The most restrictive interior finish classification, generally requiring flame-spread index of 25 or less and smoke-developed index of 450 or less, applied in exits and other high-risk locations.

A numerical rating from standardized tests indicating how much smoke a material produces when burning; code limits apply to wall and ceiling finishes, especially along egress paths.

Carbon-based chemicals that vaporize at room temperature from paints, adhesives, sealants, carpets, and composite wood; low-emitting selections support indoor air quality and green certification credits.

The release of airborne chemicals from new materials, finishes, and furnishings over time, strongest when products are new; ventilation and product selection reduce occupant exposure.

The condition of air inside a building as it affects occupant health and comfort, influenced by ventilation rates, pollutant sources, moisture control, filtration, and maintenance practices.

The ratio of interior illuminance at a point to simultaneous exterior horizontal illuminance under an overcast sky, expressed as a percentage; used to predict daylight availability independent of orientation and time.

A unit of illuminance equal to one lumen per square foot, describing the amount of light arriving at a surface; used in task illuminance recommendations and lighting power calculations.

The amount of light leaving or reflecting from a surface in a given direction, measured in candelas per square meter; it determines perceived brightness and glare potential.

A single-number rating from 0 to 1 describing how much sound energy a material absorbs on average across speech frequencies; higher values indicate more absorption and less reverberation.

A single-number rating of how well a wall, floor, or door assembly blocks airborne sound; higher ratings mean more isolation between adjacent spaces.

The time in seconds for sound pressure level in a room to decay by 60 decibels after the source stops; it depends on room volume and total sound absorption.

A drawing viewed as if looking up at the ceiling from the floor, showing ceiling heights, light fixtures, diffusers, sprinklers, and other overhead items in their plan positions.

The coordinated drawings, schedules, and specifications that convey the design for bidding and construction, including plans, elevations, sections, details, and general and technical requirements.

Written requirements describing materials, products, workmanship, and execution, organized by standardized division or section formats and complementary to the drawings.

The process of resolving conflicts among architectural, structural, mechanical, electrical, and plumbing work so that clearances, penetrations, and dimensions agree across drawings and specifications.

A review, often using a building information model, that identifies physical conflicts between building elements such as ducts, beams, and ceilings before construction begins.

A documented list of incomplete or defective work identified near substantial completion, which the contractor must correct before final payment and closeout.

A formal written question from the contractor to the design team seeking clarification or interpretation of contract documents; responses become part of the project record.

A solicitation asking consultants or contractors to submit qualifications, approach, schedule, and fees for described scope; used to select design services or negotiate work.

The written statement of work a design professional will perform, including phases, deliverables, exclusions, and assumptions; it defines the basis for fees and liability.

The standard design phases and deliverables customarily provided under a professional services agreement, typically schematic design, design development, construction documents, bidding, and construction administration.

A legal claim against property securing payment for labor, materials, or services; contractors and suppliers may file liens, and owners often require lien waivers with progress payments.