LCA Graphics and Construction Studies cheat sheet

Orthographic projection uses separate plan, elevation and end-elevation views arranged in first-angle or third-angle layout; first-angle places the plan below the elevation, third-angle places it above.

Scale is drawing length divided by real length; a scale of 1:50 means 1 mm on paper represents 50 mm on site, so a 20 mm drawn line equals 1 m.

Line hierarchy: continuous thick lines for visible outlines, continuous thin lines for dimension and projection lines, dashed lines for hidden edges, chain lines for centrelines and section cut positions.

Dimension lines carry the measurement, with arrowheads or oblique strokes at each end; extension lines start about 1.5 mm clear of the object outline and extend about 3 mm beyond the dimension line.

A section view shows internal construction by cutting along a chain-line plane; hatching at 45 degrees identifies cut solid material, and adjacent components are hatched in opposite directions.

A site plan is drawn at 1:200 to 1:1250 and locates the building on the plot, showing boundaries, access, drainage runs, levels and north point.

A detail drawing at 1:5 or 1:10 must show material specification, jointing, fixings and tolerances, since at that scale every drawn line represents a real construction decision.

A north point, title block, scale bar, drawing number and revision cloud are the standard controls that make a drawing traceable and unambiguous on site.

U-value measures thermal transmittance in W/m2K; lower is better, and total resistance is the sum of surface resistances plus each layer thickness divided by its thermal conductivity.

Thermal conductivity (lambda) is measured in W/mK; a lower lambda means better insulation, so 100 mm of a 0.022 W/mK board resists heat flow far more than 100 mm of 0.040 W/mK board.

Density, strength and thermal performance trade off: lightweight aerated concrete blocks give good insulation but lower compressive strength than dense concrete blocks.

Timber is anisotropic; strength and shrinkage differ along and across the grain, so joists are graded by strength class and moisture content must be controlled to limit movement.

Steel has high tensile and compressive strength and a similar thermal expansion to concrete, but it conducts heat and corrodes unless protected by galvanising, paint or intumescent coating.

Concrete gains strength with curing time; characteristic cube strength at 28 days is the normal specification basis, and the water-cement ratio governs both strength and durability.

Clay bricks and tiles are fired ceramics; frost resistance, water absorption and soluble salt content determine suitability for exposed external use.

Vapour control layers restrict moisture diffusion, while breather membranes allow vapour out but resist liquid water; their position in the build-up depends on the direction of heat and vapour flow.

Strip foundations suit firm subsoil and load-bearing walls; pad foundations suit isolated columns; raft foundations spread load over weak or variable ground; piles transfer load to deeper competent strata.

Foundation depth must reach below the frost line and below the zone affected by seasonal moisture movement in shrinkable clay.

Cavity walls typically use two leaves of masonry with a 50-100 mm cavity, wall ties at set spacing, and a damp-proof course at least 150 mm above external ground level.

A damp-proof membrane under a ground-bearing slab laps and seals to the damp-proof course in the walls to form a continuous barrier.

Timber frame walls rely on a structural sheathing panel for racking resistance; a breather membrane and drained cavity protect the frame from wind-driven rain.

Roof pitch is limited by covering: plain tiles need about 35 degrees minimum, interlocking tiles lower, and sheet metal or single-ply membranes can go much flatter with sealed laps.

Lintels span openings and must have a minimum end bearing, commonly 100-150 mm depending on material, to transfer load into the masonry each side.

Concrete floor slabs need a compacted hardcore sub-base, a blinded surface, a damp-proof membrane and edge insulation to control cold bridging at the perimeter.

Heat loss by fabric is calculated from area multiplied by U-value multiplied by temperature difference; ventilation loss adds a term based on air change rate and volume.

Air permeability is measured in m3/(h.m2) at 50 Pa; lower values reduce infiltration heat loss but require designed background ventilation to maintain air quality.

Natural ventilation relies on stack effect (warm air rising) and wind pressure; both are driven by opening size, height difference and exposure.

A boiler's efficiency is highest at low return-water temperature, which is why condensing boilers need weather compensation or low-temperature emitters to perform near rated efficiency.

Electricity supply is single-phase 230 V domestic or three-phase 400 V for larger loads; protective devices must be selected with discrimination so the downstream device trips first.

Water supply pressure and flow rate fall with pipe length and fittings; a 22 mm distribution pipe carries far more flow than 15 mm at the same pressure.

Daylight factor is internal illuminance divided by simultaneous external horizontal illuminance under an overcast sky, expressed as a percentage.

Sound insulation between dwellings is governed by airborne and impact performance; a resilient layer under a screed reduces impact transmission, and mass plus isolation reduces airborne transmission.

Working at height is the leading cause of fatal injury in construction; the hierarchy is avoid work at height, prevent falls using a collective system, then mitigate residual risk with personal fall protection.

A risk assessment records hazard, who is harmed, existing controls, likelihood and severity, and residual risk; a method statement describes the safe sequence of work.

Excavations deeper than 1.2 m normally require support or battering, and any excavation must be inspected by a competent person at the start of each shift.

Before any excavation, underground services must be located using plans plus a cable avoidance tool and safe digging practice; assume services are present until proven otherwise.

Scaffold towers and mobile towers must be erected by competent people, founded on firm level ground, braced, and fitted with guardrails, toe boards and safe access.

Hazardous substances require a safety data sheet and COSHH-style assessment covering exposure route, control measures, personal protective equipment and waste disposal.

Site fire precautions include escape routes kept clear, fire points with the correct extinguisher class, hot-work permits, and statutory signage for prohibitions, warnings and mandatory actions.

Welfare provision on site includes drinking water, washing facilities, sanitary conveniences, rest area and changing facilities, and must be available from the first day of work.

Design brief to concept to developed design to technical design is an iterative loop; each stage tests the proposal against constraints and returns to earlier decisions when a constraint fails.

Constraints fall into statutory (planning, building regulations), physical (site, ground, climate), economic (budget, programme) and user needs; a design that ignores one will fail at that stage.

Passive design hierarchy: reduce demand through form, orientation and fabric first, then use efficient systems, then add renewable supply to meet the residual load.

Orientation rule for temperate northern latitudes: glazing predominantly within about 30 degrees of south maximises winter solar gain while summer overheating is controlled by shading.

Buildability and standardisation reduce risk: repeating a structural grid and component size lowers cost and error rate more than bespoke detailing.

A design decision matrix scores options against weighted criteria such as cost, carbon, buildability and maintenance, making the trade-off explicit and auditable.

Accessibility design requires level or ramped approach, adequate door widths and turning space; step-free routes and accessible sanitary provision are design requirements, not finishes.

Whole-life carbon sums embodied carbon of materials plus operational carbon over the building life; reducing embodied carbon early (structure, substructure) is far cheaper than later.

A practical project must state the design brief, constraints, research sources, options considered, chosen solution with justification, and evidence of testing or evaluation.

Evidence should be primary (site measurements, photographs, test results) where possible; secondary sources must be cited so the assessor can verify the claim.

Scale model and drawing work should be checked against a stated scale and dimensioned, so the assessor can confirm the model matches the design intent.

Health and safety must appear in practical work as a documented risk assessment before the activity, with controls matched to the actual task and materials used.

Evaluation is judged on quality of reasoning, not on whether the outcome was perfect; identify what failed, why, and what you would change next time.

Material and component selection must be justified against performance, cost, availability and sustainability, not simply described.

Records such as a project diary, test log and revision history demonstrate process and are usually assessed alongside the final artefact.

Referencing must be consistent and complete; uncited borrowed text or images are treated as plagiarism and can invalidate the submission regardless of technical quality.