BPC/VBA Building Design (Draftsperson) Exam cheat sheet

Occupant load = floor area ÷ occupant load factor; egress capacity = occupant load × unit width factor (e.g., 5 mm per person for level components, 7.6 mm for stairs in many codes; verify jurisdiction).

Exit access travel distance limits: typically 60 m in sprinklered non-residential buildings, 45 m unsprinklered; measured along the path of travel to the nearest exit.

Two exits required when occupant load exceeds 50 (or per local code); remote distance between exits ≥ half the diagonal of the floor area.

Fire-resistance ratings: structural elements per building height/area table; fire walls 2–4 h; shaft enclosures 1–2 h; corridor walls 1 h with 20-min doors.

Accessibility: minimum clear width 815 mm for doors, 915 mm for corridors; ramp slope max 1:12 with landings every 9 m of run; handrails 865–965 mm above finished floor.

Sanitary facilities: number of water closets based on occupant load and gender ratio per plumbing code; calculate from Table 403.1 (IPC) or local equivalent.

Natural light and ventilation: window glazing area ≥ 10% of floor area for light, operable area ≥ 5% for ventilation (typical residential code; confirm local amendments).

Allowable building area = base area from table × occupancy factor × sprinkler increase (up to 200% for fully sprinklered) × frontage increase; check height limits separately.

Drawing sheet sizes: A0 841×1189 mm, A1 594×841 mm, A2 420×594 mm, A3 297×420 mm, A4 210×297 mm; title block on right edge with project, sheet number, scale, date, revision.

Line weights: cut elements 0.7–1.0 mm, visible edges 0.35–0.5 mm, hidden/dashed 0.25 mm, grid lines 0.18 mm; maintain hierarchy across plans, sections, elevations.

Scale notation: 1:100 means 1 mm on paper = 100 mm real; enlarge details at 1:5 or 1:10; never scale from drawings-use written dimensions.

Sheet numbering: discipline prefix (A architectural, S structural, M mechanical, E electrical, P plumbing) + two-digit sequence; revisions clouded with delta symbol and revision number.

North arrow, graphic scale bar, and key plan required on every floor plan; match lines and drawing references (e.g., 'See A-301') for coordination.

Dimensioning: string dimensions to grid lines, overall dimensions, and clear opening sizes; avoid duplicate dimensions; use consistent unit (mm) and decimal precision.

Schedules (door, window, finish) must cross-reference room numbers and sheet details; tag format D-01, W-01; include fire rating, hardware set, and glazing type.

CAD layering per ISO 13567 or AIA CAD Layer Guidelines: discipline, major group, minor group, status (e.g., A-WALL-FULL).

Concrete cover: 20 mm for slabs, 40 mm for beams/columns exposed to weather, 50 mm for cast against earth; minimum grade C20/25 for structural elements.

Brick masonry: standard brick 215×102.5×65 mm; 10 mm mortar joint; 1 m² wall requires ~60 bricks; cavity wall with 50 mm insulation and weep holes at 800 mm centres.

Timber stud wall: studs at 400 or 600 mm centres; nogging rows at 1350 mm max; sheathing 9–12 mm OSB or plywood; vapour barrier on warm side.

Roof pitch: minimum 1:80 for sheet metal, 1:60 for concrete tiles, 1:12 for asphalt shingles; underlayment lapped 100 mm horizontally, 150 mm vertically.

Waterproofing: membrane turned up 150 mm at walls, 300 mm at shower; fall 1:80 to drains; test by flood test 24 h before tiling.

Steel connections: bolted bearing-type with min 2 bolts per connection; weld symbols per ISO 2553; galvanic isolation between steel and aluminium.

Thermal insulation: U-value = 1/R; typical wall U ≤ 0.35 W/m²K, roof ≤ 0.25 W/m²K in temperate zones; avoid thermal bridging at slab edges.

Door detailing: frame anchored at 600 mm centres; clearance 3 mm at sides/top, 8–10 mm at floor; fire doors self-closing with intumescent seals.

Beam depth rule of thumb: span/20 for simply supported steel, span/12 for concrete; check deflection limit L/360 for floors, L/240 for roofs.

Service zone allocation: ceiling void ≥ 400 mm for ducts, 150 mm for sprinkler, 100 mm for electrical; coordinate penetrations with structural engineer-no cutting rebar without approval.

Clash detection: combine architectural, structural, and MEP models; resolve hard clashes (physical overlap) before tender; soft clashes (clearance) within 25 mm tolerance.

Shaft sizes: riser shafts minimum 300×300 mm for plumbing, 600×600 mm for HVAC; access panels 600×600 mm at valves and dampers.

Sprinkler spacing: max 4.6 m between heads, 2.3 m from walls for light hazard; 150 mm clearance below ceiling; pipe slope 1:500 to drain.

Structural grid coordination: column offsets from grid ≤ 25 mm; slab openings > 300 mm require trimmer bars; coordinate with mechanical risers early.

Electrical: consumer unit at 1.4–1.8 m above floor; socket outlets at 300 mm, switches at 1.2 m; cable routes not within 50 mm of plumbing.

Fire stopping: seal all penetrations through fire-rated elements with tested systems; maintain integrity rating equal to the wall/floor.

Site coverage = building footprint ÷ site area × 100%; typically max 40–60% in residential zones; plot ratio = gross floor area ÷ site area.

Setbacks: front 3–6 m, side 1.5–3 m, rear 3 m (typical residential; verify local planning scheme); measured from property boundary to building line.

Orientation: long axis east–west to maximise north/south daylight in temperate zones; north-facing glazing for consistent light, south for solar gain with shading.

Stormwater: impervious area must be attenuated; detention volume = (post-development runoff − pre-development) × design storm; soakaway sized per soil infiltration rate.

Accessibility: accessible parking bay 3.7 m wide (or 2.4 m + 1.2 m shared aisle); gradient ≤ 1:50; route to entrance ≤ 1:20 slope.

Environmental: erosion control silt fence, sediment basin; tree protection zone = 12× trunk diameter; construction waste diversion target ≥ 50%.

Solar access: minimum 2–3 hours sunlight to living areas on winter solstice; overshadowing check for neighbouring properties.

Noise: facade attenuation required where external noise > 55 dB(A) day; use double glazing Rw ≥ 35 dB.

Measurement rules: use NRM2 or SMM7; bill items described by net dimensions, no deduction for openings < 0.5 m² in walls; measured in m, m², m³, nr, kg.

Quantity takeoff: length × width × height; add 5–10% waste for cutting; concrete volume = plan area × thickness; formwork = contact area.

Cost estimate: unit rate × quantity; elemental cost plan by building elements (substructure, superstructure, finishes); contingency 5–10% design, 3–5% construction.

Valuation: interim certificates monthly; retention 5% held (half released at practical completion, half after defects liability period).

Variation order: documented instruction, priced by BOQ rates or fair valuation; time impact assessed separately.

Programme: critical path method (CPM); float = late start − early start; milestone reviews at design freeze, tender, practical completion.

Document control: revision numbering P01, P02 for preliminary, C01 for construction; transmittals logged with date, recipient, purpose.

As-built drawings: record actual dimensions, services routes, and changes; submit within 28 days of completion.

Duty of care: exercise reasonable skill and care of a competent professional; document advice and decisions in writing; avoid conflicts of interest.

Confidentiality: project information not disclosed without client consent; exceptions for legal requirement or public safety.

Fee basis: percentage of construction cost, lump sum, time charge, or fixed fee; scope defined in appointment agreement with deliverables and exclusions.

Communication: issue minutes within 5 working days; use formal RFI (request for information) numbering; respond to contractor queries within agreed turnaround.

Ethical conduct: honesty about competence, no misrepresentation of qualifications, no bribery, fair treatment of contractors, sustainability responsibility.

Copyright: drawings remain author's intellectual property; client licensed for project use; reuse for other projects requires permission.

Record keeping: retain project records for statutory period (typically 6–12 years); maintain site inspection reports with dates and photos.

Professional indemnity insurance: maintain cover for negligence claims; disclose claims history; cooperate with insurer.