Basic Architectural & Building Engineering interview questions

150 questions with answers (ARC-001 to ARC-150). Try each one aloud before reading the answer.

Architectural Design Principles

ARC-001 · What are Vitruvius's three principles of architecture?

Firmitas (durability), utilitas (usefulness) and venustas (beauty), set out in *De Architectura*. They are still used as a test of good design: a building must stand up, work for its users and delight them.

ARC-002 · What is the difference between scale and proportion?

Scale is the size of a building or element relative to the human body or its surroundings. Proportion is the ratio of parts to each other and to the whole, such as the height-to-width ratio of a window or façade.

ARC-003 · What is the golden ratio in architecture?

The ratio φ = (1 + √5)/2 ≈ 1.618, where the whole is to the larger part as the larger part is to the smaller. Designers use it to set pleasing proportions of façades, plans and openings.

ARC-004 · What is Le Corbusier's Modulor?

A proportioning system based on a 1.83 m human figure and the golden ratio, producing two Fibonacci-like series of dimensions. It links building dimensions to human stature and was used at Chandigarh and the Unité d'Habitation.

ARC-005 · What does "form follows function" mean?

Louis Sullivan's principle that a building's shape should arise from its purpose and use, not from applied decoration. It underpins modernist architecture and functional planning.

ARC-006 · What is circulation in building design?

The movement paths of people, goods and services through a building: corridors, lobbies, stairs, ramps and lifts. Good circulation is short, legible, separates conflicting flows and supports fire escape.

ARC-007 · What is a bubble diagram?

An early-stage sketch where spaces are drawn as circles sized roughly by area and linked by lines showing adjacency or relationships. It helps organise functions before drawing a scaled plan.

ARC-008 · What is anthropometry and why does it matter to architects?

The measurement of human body dimensions and reach. It sets sizes such as door widths, stair risers, counter heights, seating and clearances so spaces fit their users, including children, the elderly and wheelchair users.

ARC-009 · What is universal (barrier-free) design?

Design that lets all people, including those with disabilities, use a building without adaptation: step-free access, ramps, accessible toilets, tactile paving, lifts and clear signage. In India, NBC 2016 and the Harmonised Guidelines on universal accessibility govern it.

ARC-010 · What is the difference between carpet area, built-up area and super built-up area?

Carpet area is the net usable floor area inside the walls. Built-up area adds wall thickness and balconies. Super built-up area adds a proportionate share of common areas such as lobbies, stairs and lifts. RERA requires apartments to be sold on carpet area.

ARC-011 · Why is orientation important in building design?

Orientation controls solar gain, daylight, wind and views. In most of India, long façades facing north and south with short east and west walls reduce heat gain, since low east and west sun is hard to shade.

ARC-012 · What is site analysis?

A study of a site before design: topography, soil, climate, sun path, wind, drainage, vegetation, access, utilities, neighbouring buildings, views and bye-law constraints. It drives building placement and massing.

ARC-013 · What is functional zoning within a building?

Grouping spaces by use and privacy, such as public, semi-private, private and service zones. A house separates living areas from bedrooms; a hospital separates outpatient, inpatient, clinical and service zones.

Building Materials

ARC-014 · What is the standard size of a modular brick in India?

The modular brick is 190 × 90 × 90 mm, giving a nominal 200 × 100 × 100 mm with a 10 mm mortar joint. Traditional non-modular bricks are about 230 × 115 × 75 mm.

ARC-015 · What are the grades of Ordinary Portland Cement?

OPC is made in 33, 43 and 53 grades, where the number is the minimum 28-day compressive strength in MPa of standard cement mortar cubes. 53 grade gains strength faster but generates more heat of hydration.

ARC-016 · How does Portland Pozzolana Cement differ from OPC?

PPC blends OPC clinker with pozzolana, usually fly ash. It gains strength more slowly but has lower heat of hydration, better long-term durability and lower embodied carbon. OPC gives faster early strength.

ARC-017 · What is the water–cement ratio?

The mass of water divided by the mass of cement in a concrete mix. A lower ratio gives higher strength and lower permeability, but reduces workability unless a plasticiser is added. Abrams' law relates strength inversely to this ratio.

ARC-018 · What is autoclaved aerated concrete (AAC) block?

A lightweight masonry unit made from cement, lime, fly ash or sand and aluminium powder, which creates gas bubbles, then cured under high-pressure steam. It is far lighter than clay brick and insulates better.

ARC-019 · What is the difference between lime mortar and cement mortar?

Lime mortar sets slowly by carbonation, stays flexible and breathable, and suits heritage masonry. Cement mortar sets quickly by hydration and is stronger and harder but more brittle and less vapour-permeable.

ARC-020 · What is seasoning of timber?

Drying timber to reduce its moisture content to suit its use. This improves strength, stability and resistance to decay and insects. Methods are air seasoning and kiln seasoning.

ARC-021 · What is the difference between toughened and laminated glass?

Toughened glass is heat-treated to be about four to five times stronger than annealed glass and breaks into small blunt pieces. Laminated glass bonds layers with a PVB or similar interlayer that holds fragments in place when broken.

ARC-022 · What is gypsum board used for?

Gypsum plasterboard is a gypsum core faced with paper. It is used for dry-lining, partitions and false ceilings. It is quick to install, smooth to finish, and the water of crystallisation in gypsum gives some fire resistance.

ARC-023 · What is thermal conductivity of a material?

The rate of heat flow through a unit thickness of material per unit area per unit temperature difference, k in W/m·K. Insulants such as mineral wool or EPS have k around 0.03–0.04 W/m·K; dense concrete is above 1 W/m·K.

ARC-024 · What is an aluminium composite panel (ACP)?

Two thin aluminium skins bonded to a core, used for façade cladding. Polyethylene cores are combustible and have spread fires on tall buildings, so fire-retardant or non-combustible cores are required for high-rise use.

ARC-025 · How do vitrified tiles differ from ceramic tiles?

Vitrified tiles are fired at a higher temperature with more silica and feldspar, so the body fuses into a glassy, dense mass with very low water absorption. Ceramic tiles are more porous, softer and better suited to walls.

ARC-026 · Why is bamboo considered a sustainable building material?

Bamboo grows fast, sequesters carbon and has high tensile strength for its weight. It needs treatment against insects and fungi and careful jointing, and is used for frames, roofs, scaffolding and engineered panels.

Building Construction Techniques

ARC-027 · What are the main components of a building?

Foundation, plinth, walls and columns, floors, roof, doors and windows, stairs and lifts, plus finishes and building services. The substructure is below plinth level and the superstructure above it.

ARC-028 · What is a damp-proof course (DPC)?

A continuous impervious layer, such as cement concrete with waterproofing compound, bitumen or a membrane, laid at plinth level in walls. It stops ground moisture rising into the wall by capillary action.

ARC-029 · What is a plinth and a plinth beam?

The plinth is the part of the building between ground level and ground-floor level. A plinth beam is an RC beam at this level that ties the walls or columns, spreads load and reduces differential settlement and cracking.

ARC-030 · What is the difference between English bond and Flemish bond?

English bond has alternate courses of headers and stretchers and is strongest for load-bearing walls. Flemish bond has headers and stretchers alternating within each course; it looks better but is slightly weaker.

ARC-031 · What is curing of concrete and how long is it done?

Keeping concrete moist and at a suitable temperature so cement hydrates fully. IS 456 calls for at least 7 days for OPC concrete and at least 10 days when mineral admixtures or blended cements are used, with longer periods in hot, dry weather.

ARC-032 · What is formwork?

A temporary mould, of timber, plywood, steel or aluminium, that holds fresh concrete to shape until it gains enough strength. It must be rigid, leak-tight and safe to strip without damaging the concrete.

ARC-033 · What is the difference between a lintel and a sill?

A lintel is a horizontal member over a door or window opening that carries the wall above. A sill is the horizontal bottom member or ledge of a window opening that sheds water away from the wall.

ARC-034 · What is precast construction?

Making building elements such as slabs, walls, beams and stairs in a factory or yard, then transporting and assembling them on site. It gives faster construction, better quality control and less site waste, but needs cranes and careful joint design.

ARC-035 · What is the difference between shallow and deep foundations?

Shallow foundations, such as isolated, strip and raft footings, transfer load to soil near the surface. Deep foundations, such as piles and caissons, transfer load to deeper, stronger strata when surface soil is weak.

ARC-036 · What is plastering and what are typical thicknesses?

A thin coat of cement or lime mortar, or gypsum, applied to walls and ceilings to give a smooth, durable, weather-resistant surface. Typical cement plaster is about 12 mm internally and 15–20 mm externally, often in two coats.

ARC-037 · What is anti-termite treatment?

Pre-construction chemical treatment of the soil under foundations, plinth filling and along walls to form a barrier against subterranean termites. Post-construction treatment is done by drilling and injecting chemicals.

ARC-038 · What are common methods of waterproofing a flat roof?

Brick-bat coba, bituminous membranes, APP or SBS modified bitumen sheets, liquid-applied polyurethane or acrylic coatings, and cementitious systems. Each needs a proper slope to drains and careful detailing at parapets and outlets.

ARC-039 · What is a cavity wall?

A wall of two leaves of masonry separated by an air gap and tied with metal ties. The cavity stops rain penetration and improves thermal insulation, especially when partly filled with insulation.

Structural Systems for Buildings

ARC-040 · What is the difference between a load-bearing and a framed structure?

In a load-bearing structure, walls carry all loads to the foundation. In a framed structure, a beam–column frame carries the loads and walls are only infill partitions, allowing open plans and more storeys.

ARC-041 · What is a flat slab?

A reinforced concrete slab supported directly on columns without beams, sometimes with drop panels or column heads. It gives a flat soffit, lower floor-to-floor height and easier service routing, but needs checks for punching shear.

ARC-042 · What is the difference between a one-way and a two-way slab?

A one-way slab bends mainly in one direction because it is supported on two opposite sides or has long span ÷ short span > 2. A two-way slab is supported on all four sides with a ratio ≤ 2 and bends in both directions.

ARC-043 · What is a shear wall?

A stiff vertical wall, usually reinforced concrete, that resists lateral loads from wind and earthquakes by in-plane shear and bending. It greatly reduces sway in multi-storey buildings.

ARC-044 · What is a truss?

A framework of straight members joined at nodes to form triangles, so members carry mainly axial tension or compression. Trusses are used for long-span roofs, such as Howe, Pratt and Fink types.

ARC-045 · What is a space frame?

A three-dimensional truss of linear members arranged in repeating geometric units. It spans large column-free areas such as airports, exhibition halls and stadium roofs with light members.

ARC-046 · What is a cantilever?

A member fixed at one end and free at the other, such as a balcony, chajja or canopy. It produces hogging moment and needs top reinforcement and adequate back-span anchorage.

ARC-047 · What is the difference between dead load and live load?

Dead load is the permanent self-weight of structure, finishes and fixed services. Live or imposed load comes from occupants, furniture and movable items. In India, IS 875 Part 1 and Part 2 give these values; residential floors use about 2 kN/m².

ARC-048 · What is an expansion joint in a building?

A gap that separates a long building into independent blocks so they can expand and contract with temperature, shrinkage and movement without cracking. Joints are sealed with compressible fillers and covers.

ARC-049 · What is a shell roof?

A thin curved structural surface, such as a dome, barrel vault or hyperbolic paraboloid, that carries load mainly by membrane action. Shells span large areas with very little material.

ARC-050 · What is a tensile membrane structure?

A structure where a fabric such as PTFE-coated glass fibre or PVC-coated polyester is pre-tensioned between masts, cables and edge members. It carries load only in tension and is used for canopies and stadium roofs.

ARC-051 · What is a soft storey?

A storey that is much less stiff than those above, often an open ground floor used for parking. It concentrates seismic deformation and is a common cause of collapse in earthquakes.

Plumbing & Electrical Services

ARC-052 · What is a trap and a water seal?

A trap is a U-, P- or S-shaped bend in a drain that holds water. The water seal, typically around 50 mm deep, stops sewer gases and insects entering the building while letting waste flow through.

ARC-053 · What is the difference between one-pipe and two-pipe drainage systems?

A two-pipe system has separate stacks for soil waste from WCs and sullage from basins and sinks, each with vent pipes. A one-pipe system uses a single stack for both, with trap vents. The single-stack system eliminates separate venting.

ARC-054 · What is the purpose of a vent pipe in drainage?

It lets air into and out of the drainage system, keeping pressure near atmospheric. This prevents siphonage and back-pressure from breaking trap seals, and releases sewer gases above roof level.

ARC-055 · What is the per capita water demand for Indian residential buildings?

A commonly used design figure is 135 litres per capita per day for residences with full flushing, with higher values for large cities. Flushing typically accounts for about a third of this.

ARC-056 · Why do buildings have both an underground sump and an overhead tank?

The sump stores water from the municipal supply, which often has low pressure or runs intermittently. Pumps lift water to the overhead tank, which then supplies fixtures by gravity at steady pressure.

ARC-057 · What is rainwater harvesting?

Collecting rainwater from roofs and paved areas for storage and reuse, or for recharging groundwater through pits, trenches or wells. Many Indian bye-laws make it mandatory above a specified plot size.

ARC-058 · What is a septic tank?

An underground watertight chamber that receives sewage where no public sewer exists. Solids settle and are digested anaerobically, while partly treated effluent flows to a soak pit or drain field.

ARC-059 · What is an inspection chamber or manhole?

An access chamber built on a drain at changes in direction, gradient or junctions, and at regular intervals. It allows inspection, rodding and cleaning of the drainage line.

ARC-060 · What is the difference between an MCB and an RCCB?

An MCB trips on overcurrent from overload or short circuit to protect cables. An RCCB trips on earth-leakage current, the imbalance between phase and neutral, typically at 30 mA for protection against electric shock.

ARC-061 · What is earthing and why is it needed?

Connecting exposed metal parts of equipment and the electrical system to the general mass of earth through a low-resistance path. It makes protective devices trip during faults and keeps touch voltages safe.

ARC-062 · What is a distribution board?

An enclosure that divides incoming supply into final circuits, each protected by MCBs, RCCBs or fuses. Buildings use a main distribution board and floor or flat-level distribution boards.

ARC-063 · What is a rising main or bus duct?

A vertical busbar system in an enclosed shaft that carries power up a multi-storey building, with tap-off units at each floor. It replaces many individual cables in high-rise buildings.

HVAC & Mechanical Services

ARC-064 · What does HVAC stand for and what does it do?

Heating, Ventilation and Air Conditioning. It controls indoor temperature, humidity, air quality and air movement for thermal comfort and health, or to suit process needs.

ARC-065 · What is a ton of refrigeration?

A unit of cooling capacity equal to 12,000 BTU/h, or about 3.517 kW. It comes from the heat needed to melt one short ton of ice in 24 hours.

ARC-066 · What is the difference between sensible and latent heat load?

Sensible heat changes air temperature and is read on a dry-bulb thermometer. Latent heat is linked to moisture: adding or removing water vapour changes humidity without changing temperature. Occupants, cooking and infiltration add both.

ARC-067 · What is relative humidity?

The ratio of the actual partial pressure of water vapour in air to the saturation pressure at the same temperature, as a percentage. Comfort is usually best between about 30% and 60% RH.

ARC-068 · What are dry-bulb, wet-bulb and dew-point temperatures?

Dry-bulb is the air temperature on an ordinary thermometer. Wet-bulb is read on a thermometer with a wetted wick and reflects evaporative cooling. Dew point is the temperature at which air becomes saturated and condensation starts.

ARC-069 · What is a psychrometric chart?

A chart of moist-air properties showing dry-bulb temperature, humidity ratio, relative humidity, wet-bulb temperature, enthalpy and specific volume. It is used to plot and size HVAC processes such as cooling, dehumidification and mixing.

ARC-070 · What is the difference between a split AC and a VRF system?

A split AC links one outdoor unit to one, or a few, indoor units. A VRF (variable refrigerant flow) system links many indoor units to one or more outdoor units with inverter compressors, varying refrigerant flow to each zone.

ARC-071 · What is the difference between an AHU and an FCU?

An air handling unit (AHU) is a large central unit with filters, coils, fan and often fresh-air intake, serving zones through ducts. A fan coil unit (FCU) is a small local unit with a fan and coil serving one room.

ARC-072 · What are COP and EER?

COP is cooling or heating output divided by input power, both in kW, so it has no unit. EER is cooling output in BTU/h divided by input power in W. EER = 3.412 × COP. Higher values mean more efficient equipment.

ARC-073 · What is a chiller?

A machine that cools water using a vapour-compression or absorption cycle. The chilled water, typically around 6–7 °C, is pumped to AHUs and FCUs. Chillers are air-cooled or water-cooled; water-cooled units reject heat through cooling towers.

ARC-074 · What is a cooling tower?

A device that rejects heat from condenser water to the atmosphere mainly by evaporation. Water is sprayed over fill media while air flows through, cooling the water towards the ambient wet-bulb temperature.

ARC-075 · What is air changes per hour (ACH)?

The volume of air supplied to or removed from a space per hour divided by the room volume. ACH = Q (m³/h) ÷ V (m³). It is used to specify ventilation rates for toilets, kitchens, car parks and similar spaces.

Fire Safety

ARC-076 · What is the fire triangle?

Fire needs heat, fuel and oxygen. Removing any one puts it out: cooling removes heat, starving removes fuel and smothering removes oxygen. The fire tetrahedron adds the chemical chain reaction, which some extinguishing agents interrupt.

ARC-077 · How are fires classified by fuel?

Class A covers ordinary solids such as wood, paper and textiles. Class B covers flammable liquids, Class C flammable gases and Class D combustible metals. Electrical fires and cooking-oil fires are treated separately. The choice of extinguisher depends on the class.

ARC-078 · What is fire resistance rating?

The time, in minutes or hours, for which a building element keeps its load-bearing capacity, integrity and insulation in a standard fire test. Walls, floors, doors and structural members are specified as, for example, 1 h or 2 h rated.

ARC-079 · What is fire compartmentation?

Dividing a building into compartments bounded by fire-resisting walls and floors, with fire-rated doors and sealed penetrations. It confines fire and smoke to the area of origin and limits loss.

ARC-080 · What is a means of escape?

A continuous, protected route from any point in a building to a safe place outside: the exit access, the exit itself, such as a protected stair, and the exit discharge to open air. It must be sized for the occupant load.

ARC-081 · What is travel distance in fire safety?

The actual walking distance from the most remote point in a floor to the nearest exit. Codes limit it by occupancy and by whether the building has sprinklers, so that occupants reach safety before conditions become untenable.

ARC-082 · How does an automatic sprinkler system work?

Water-filled pipes have sprinkler heads closed by a heat-sensitive glass bulb or fusible link. When local temperature reaches the rated value, about 68 °C for a common red bulb, only that head opens and sprays water on the fire.

ARC-083 · What are wet risers and downcomers?

A wet riser is a vertical pipe permanently filled with water under pressure, with landing valves at each floor for firefighters' hoses. A downcomer is fed by gravity from a terrace tank and serves the floors below it.

ARC-084 · What is the difference between smoke and heat detectors?

Smoke detectors, optical or ionisation, sense combustion particles early and suit most rooms. Heat detectors respond to a fixed temperature or rate of rise and suit kitchens, car parks and dusty areas where smoke detectors give false alarms.

ARC-085 · How does NBC 2016 define a high-rise building?

A building 15 m or more in height. High-rise buildings must meet stricter fire requirements such as fire lifts, wet risers, sprinklers, pressurised staircases and refuge areas.

ARC-086 · What is a refuge area?

A fire-protected open or ventilated space at intervals in a high-rise building where occupants can wait safely during evacuation. It reduces congestion in stairs and helps people who cannot descend quickly.

ARC-087 · What is a fire-check door?

A door assembly, including frame, hardware and seals, tested to resist fire for a set time, such as 60 or 120 minutes. It must be self-closing and is used on staircases, shafts and compartment walls.

ARC-088 · What is a pressurised staircase?

An escape stair supplied with outside air by fans so it stays at higher pressure than the floors. Smoke cannot enter when doors open, keeping the stair usable for evacuation and firefighting.

Building Acoustics

ARC-089 · What is the range of human hearing?

About 20 Hz to 20 kHz in frequency for a young healthy adult. The ear is most sensitive between about 1 kHz and 5 kHz, and speech energy lies mostly between about 250 Hz and 4 kHz.

ARC-090 · What is a decibel?

A logarithmic unit of level. Sound intensity level L = 10 log₁₀(I/I₀) dB, where I₀ = 10⁻¹² W/m². Sound pressure level L = 20 log₁₀(p/p₀) dB, where p₀ = 20 µPa.

ARC-091 · What is the speed of sound in air?

About 343 m/s at 20 °C. It increases with temperature by roughly 0.6 m/s per °C. Sound travels much faster in water and solids.

ARC-092 · What is the sound absorption coefficient?

The fraction of incident sound energy that a surface absorbs and does not reflect, α, from 0 to 1. An open window has α = 1. Dense plaster is close to 0. It varies with frequency.

ARC-093 · What is an echo?

A distinct repetition of sound heard when a reflection arrives about 50 ms or more after the direct sound. This corresponds to a path difference of about 17 m. Large rooms with hard concave or rear walls are prone to echoes.

ARC-094 · What is the difference between airborne and impact sound?

Airborne sound, such as speech or music, travels through air and sets walls and floors vibrating. Impact sound, such as footsteps, is generated directly in the structure and travels through it. Floors need treatment for both.

ARC-095 · What is sound transmission loss?

The reduction in sound level as sound passes through a partition, in dB. Single-number ratings such as STC or Rw summarise it across frequencies. A higher rating means better sound insulation.

ARC-096 · What is the mass law in sound insulation?

For a single-leaf partition, transmission loss rises by about 6 dB for each doubling of surface mass or of frequency. Heavy walls insulate better, but doubling mass gives only a modest gain.

ARC-097 · What is a sabin?

The unit of sound absorption. One sabin (metric) is the absorption of 1 m² of a perfectly absorbing surface. Total absorption A = Σ Sα, in m² sabins.

ARC-098 · What are noise criteria (NC) curves?

Families of curves that rate background noise in a room across octave bands, mostly for HVAC noise. A room is rated by the highest curve its spectrum touches. Concert halls need low NC values; open offices can accept higher ones.

ARC-099 · What is a flutter echo?

A rapid series of echoes from sound bouncing between two parallel, hard, reflective surfaces. It is heard as a ringing or buzzing and is cured by absorbing, splaying or diffusing one of the surfaces.

ARC-100 · What is A-weighting, dB(A)?

A frequency weighting that reduces low and very high frequencies to approximate the ear's sensitivity at moderate levels. Most noise limits and environmental noise standards are given in dB(A).

ARC-101 · What are the main types of sound absorbers?

Porous absorbers, such as mineral wool and foams, work best at mid and high frequencies. Panel or membrane absorbers work at low frequencies. Helmholtz resonators, such as slotted or perforated panels over a cavity, absorb a tuned band.

Lighting & Daylighting

ARC-102 · What is the difference between lumen, lux and candela?

The lumen measures luminous flux, the total visible light output. Lux is illuminance, 1 lm/m², or light falling on a surface. The candela is luminous intensity, flux per unit solid angle in a given direction.

ARC-103 · What is luminance?

The brightness of a surface as seen by the eye, measured in cd/m². It depends on the illuminance on the surface and its reflectance. Large luminance contrasts in the field of view cause glare.

ARC-104 · What is luminous efficacy?

The light output of a source divided by its electrical power input, in lm/W. Incandescent lamps give about 10–15 lm/W; good LED lamps commonly exceed 100 lm/W.

ARC-105 · What is correlated colour temperature (CCT)?

The apparent warmth or coolness of a white light source, in kelvin. About 2700–3000 K is warm white for homes and hospitality. About 4000 K is neutral for offices. About 5000–6500 K is cool or daylight white.

ARC-106 · What is the colour rendering index (CRI)?

A measure, from 0 to 100, of how faithfully a light source renders colours compared with a reference source of the same CCT. CRI ≥ 80 is usual for offices; galleries, retail and healthcare often need 90 or more.

ARC-107 · What is the difference between discomfort glare and disability glare?

Discomfort glare causes annoyance or visual fatigue without necessarily reducing vision. Disability glare scatters light in the eye and reduces the ability to see detail, for example from a bright window behind a speaker.

ARC-108 · What is typical recommended illuminance for an office?

About 300–500 lux on the working plane, with 500 lux common for reading and computer work. Corridors need much less, about 100 lux, and fine detailed work needs more.

ARC-109 · What is daylighting?

Using natural light from windows, skylights, clerestories and light shelves to light interiors. It reduces electric lighting energy and improves wellbeing, but must be balanced against glare and solar heat gain.

ARC-110 · What is a clerestory window?

A row of windows high in a wall above eye level, often above a lower roof. It brings daylight deep into a space, allows stack ventilation and gives privacy.

ARC-111 · What is a light shelf?

A horizontal reflective shelf on a window, above eye level. It shades the lower glazing from direct sun and reflects daylight onto the ceiling, sending it deeper into the room and evening out light distribution.

ARC-112 · What is the difference between a skylight and a light well?

A skylight is a glazed opening in a roof that admits daylight directly below. A light well, or atrium, is a vertical open shaft or court that brings daylight and air to inner rooms on several floors.

ARC-113 · What is the working plane in lighting design?

The horizontal plane where visual tasks are done, usually about 0.75–0.85 m above floor for desks. Design illuminance and daylight factors are calculated on this plane.

ARC-114 · What are common lighting controls in buildings?

Occupancy or vacancy sensors that switch lights by presence, daylight sensors that dim lights near windows, time schedules, and scene-setting dimmers. ECBC and LEED encourage such controls to save energy.

Climate-Responsive & Green Buildings

ARC-115 · What is a green building?

A building designed, built and operated to reduce its impact on the environment and occupants. It uses less energy and water, uses sustainable materials, generates less waste and provides good indoor environmental quality across its life cycle.

ARC-116 · What is GRIHA?

Green Rating for Integrated Habitat Assessment, India's national green building rating system, developed by TERI and supported by the Ministry of New and Renewable Energy. It rates buildings from one to five stars on site, energy, water, materials, waste and health.

ARC-117 · What is IGBC?

The Indian Green Building Council, part of the Confederation of Indian Industry (CII). It runs rating systems for new buildings, homes, factories, campuses and cities, with Certified, Silver, Gold and Platinum levels.

ARC-118 · What is LEED?

Leadership in Energy and Environmental Design, the rating system of the US Green Building Council. Projects earn credits in categories such as energy, water, materials, site and indoor quality. LEED levels are Certified, Silver, Gold and Platinum.

ARC-119 · What is ECBC?

The Energy Conservation Building Code by India's Bureau of Energy Efficiency. It sets minimum energy performance for envelope, HVAC, lighting, electrical systems and service hot water in commercial buildings. The 2017 version adds ECBC+ and Super ECBC tiers.

ARC-120 · What is embodied energy?

The total energy used to extract, process, manufacture, transport and install a material or building, in MJ/kg or MJ/m². Cement, steel, aluminium and glass have high embodied energy; timber, earth and bamboo have low embodied energy.

ARC-121 · What are India's climatic zones for building design?

NBC 2016 and ECBC use five zones: hot-dry, warm-humid, composite, temperate and cold. Each zone has its own guidance on envelope, shading, ventilation and glazing.

ARC-122 · What is thermal mass?

The ability of heavy materials such as concrete, brick and stone to absorb, store and slowly release heat. It damps indoor temperature swings and delays peak heat. It works best in climates with large day–night temperature differences.

ARC-123 · What is passive cooling?

Keeping buildings cool without mechanical energy, using shading, orientation, insulation, thermal mass, natural and night ventilation, evaporative cooling, earth coupling and reflective surfaces.

ARC-124 · What is a cool roof?

A roof with a highly reflective and highly emissive surface, such as white coatings or tiles, that reflects sunlight and re-radiates heat. It lowers roof temperature, heat gain into top floors and the urban heat island effect.

ARC-125 · What is a green roof?

A roof partly or fully covered with vegetation over a growing medium, drainage layer and root barrier. It reduces heat gain and stormwater runoff, improves biodiversity and extends membrane life, but adds structural load.

ARC-126 · What is a net-zero energy building?

A building whose annual energy use is matched by renewable energy generated on site or nearby, so net annual consumption is zero. It needs very low demand first, then renewables such as rooftop solar PV.

Building Codes, Bye-laws & Planning

ARC-127 · What is the National Building Code of India?

A comprehensive model code by the Bureau of Indian Standards (SP 7), with the latest edition NBC 2016. Its parts cover administration, development control, fire and life safety, structural design, materials, construction, building services, plumbing and sustainability. States and cities adopt it through bye-laws.

ARC-128 · What is FAR or FSI?

Floor Area Ratio, also called Floor Space Index, is total built-up floor area on all floors divided by plot area. FAR 2.0 on a 500 m² plot allows 1000 m² of floor area. It controls building density.

ARC-129 · What is a setback?

The minimum open distance required between a building and the plot boundaries at the front, rear and sides. It ensures light, ventilation, fire access and privacy, and usually increases with building height.

ARC-130 · What is ground coverage?

The percentage of plot area covered by the building footprint at ground level. Bye-laws cap it to keep open space for light, air, drainage and landscape.

ARC-131 · What are building bye-laws?

Local regulations framed by a city or development authority that control building development: land use, FAR, ground coverage, height, setbacks, parking, open space, structural and fire safety and services. Plans must comply to get a building permit.

ARC-132 · What is a master plan or development plan?

A long-term statutory plan for a city or region, typically for 20 years, that sets land use, density, road networks, infrastructure and zoning. Building permits must conform to it.

ARC-133 · What is land-use zoning?

Dividing a city into zones, such as residential, commercial, industrial, institutional, recreational and mixed use, each with permitted, conditional and prohibited activities and its own development controls.

ARC-134 · What is Transferable Development Rights (TDR)?

A planning tool that grants a landowner development rights, as extra floor area, in exchange for surrendering land for public use or for heritage conservation. The rights can be used on other plots or sold.

ARC-135 · What is the difference between a completion certificate and an occupancy certificate?

A completion certificate confirms that construction is finished according to the approved plan. An occupancy certificate confirms the building is fit to occupy, meeting safety, services and other requirements. Occupying without it is illegal.

ARC-136 · What is RERA?

The Real Estate (Regulation and Development) Act, 2016. It requires registration of real estate projects, sale on carpet area, escrow of a share of buyers' money, timely completion and disclosure, and sets up state regulatory authorities.

ARC-137 · What is an equivalent car space (ECS)?

A unit for calculating parking provision. It includes the car space plus a share of circulation area, which varies for open, covered, basement and multi-level parking. Bye-laws set ECS per unit of floor area or per dwelling.

ARC-138 · What are the Model Building Bye-Laws 2016?

Guidelines issued by India's Ministry of Urban Development, prepared by TCPO, for states and cities to update their building regulations. They cover development control, green building, disaster safety, accessibility and online approvals.

BIM, Digital Tools & Project Management

ARC-139 · What is the difference between CAD and BIM?

CAD produces drawings as lines and shapes, with each view drawn separately. BIM builds a single intelligent 3D model of objects with properties. Plans, sections, schedules and quantities come from the model and update together.

ARC-140 · What is Level of Development (LOD) in BIM?

A scale, usually LOD 100 to 500, describing how detailed and reliable a model element is. LOD 100 is conceptual massing, LOD 300 is accurate geometry for design, LOD 400 is fabrication detail, and LOD 500 is a field-verified as-built.

ARC-141 · What is IFC?

Industry Foundation Classes, an open, vendor-neutral data schema by buildingSMART and published as ISO 16739. It lets BIM models move between different software platforms.

ARC-142 · Name common BIM software tools.

Autodesk Revit and Graphisoft Archicad for design authoring, Tekla Structures for steel and concrete detailing, Navisworks and Solibri for coordination and clash checking, and Synchro or similar tools for 4D scheduling.

ARC-143 · What is clash detection?

Automatic checking of a federated BIM model to find where elements from different disciplines collide, such as a duct passing through a beam, or lack clearance. Resolving clashes before construction avoids rework.

ARC-144 · What is a Common Data Environment (CDE)?

A single shared digital platform where project information is stored, managed and exchanged under controlled workflows, with statuses such as work-in-progress, shared, published and archived. ISO 19650 defines it.

ARC-145 · What is parametric design?

Design where geometry is driven by parameters and rules, so changing a value updates the whole form. Tools include Grasshopper and Dynamo. It is used for complex façades, optimisation and generative design.

ARC-146 · What is a Bill of Quantities (BOQ)?

A document listing every item of work with description, unit and quantity, prepared from drawings and specifications. Contractors price it for tendering, and it is used to value work and payments.

ARC-147 · What is a Gantt chart?

A bar chart showing project activities against a timeline, with start and end dates and durations, often with dependencies. It is used to plan and track construction schedules.

ARC-148 · What is the Critical Path Method (CPM)?

A scheduling technique that finds the longest chain of dependent activities through a project network. Activities on it have zero float, so any delay to them delays project completion.

ARC-149 · What is a Work Breakdown Structure (WBS)?

A hierarchical breakdown of a project into deliverables and smaller work packages. It is the basis for scheduling, cost estimating, assigning responsibility and tracking progress.

ARC-150 · What are as-built drawings?

Drawings or models revised at the end of construction to show what was actually built, including changes made on site. They are essential for operation, maintenance and future alterations.

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