BSEH Secondary NSQF Construction cheat sheet

Hard hat, safety footwear, high-visibility vest and eye protection are the minimum PPE on any active construction site; hearing and respiratory protection are added for noise above 85 dB(A) or dust-generating tasks.

Fall protection is required at heights of 1.8 m or more in most Indian site rules; use guardrails, full-body harness with double lanyard anchored above shoulder level, and inspected scaffolds with toe boards.

Excavations deeper than 1.5 m need shoring, benching or sloping; spoil heaps and plant kept at least 1 m clear of the edge; ladders for access every 7.5 m of travel and inspection before entry.

Scaffold rules: base plates on firm ground, standards spaced per design, ledgers and transoms complete at each lift, ties to the structure, working platform fully boarded and never overloaded.

Electrical safety: 110 V or residual current device (RCD/ELCB) protection for portable tools, no trailing cables across walkways, lockout-tagout before maintenance, and earth-leakage testing at defined intervals.

Fire safety: extinguishers selected by class (A solid, B liquid, C gas, D metal), hot-work permit for welding/cutting, 6 kg ABC dry powder or CO2 near electrical panels, and clear escape routes.

Lifting operations require a colour-coded, load-tested chain/sling set, a competent banksman, exclusion zone under the load, and never standing or passing beneath a suspended load.

Report every near miss; the accident pyramid shows many near misses precede one serious injury, so near-miss reporting is the leading indicator used for correction.

Silica dust from cutting, grinding and drilling concrete causes silicosis; control by wet cutting, on-tool extraction, and respirators rated at least FFP2/N95 with fit check.

Noise action level is 85 dB(A) over an 8-hour shift; doubling of sound intensity adds about 3 dB, so halving exposure time is not equal to removing the hazard - use engineering controls first.

Cement is alkaline (pH around 12–13); wet cement causes irritant and allergic contact dermatitis, so use gloves, barrier cream and wash facilities, and report persistent rashes.

Heat stress controls: drinking water within reach, shaded rest cycles, work scheduling away from peak afternoon heat, and monitoring for cramps, dizziness and cessation of sweating.

Segregate waste at source into recyclable, inert (concrete, bricks), hazardous (paint, solvent, asbestos) and organic; never burn construction waste on site.

Air pollution control: cover stockpiles, water-spray haul roads, wheel-wash at exits, and enclose or screen cutting and mixing operations near site boundaries.

Spill response: stop the source, contain with absorbent or bunding, protect drains, and dispose of contaminated material as hazardous waste with a record.

First aid: know the location of the first-aid box, trained first-aider, emergency numbers, and the assembly point; electrical shock requires isolating supply before touching the casualty.

Ordinary Portland cement grades 33, 43 and 53 denote 28-day compressive strength in MPa; initial setting time is at least 30 minutes and final setting time not more than 600 minutes.

Concrete nominal mixes: 1:3:6 (M10), 1:2:4 (M15), 1:1.5:3 (M20) by volume; water-cement ratio controls strength and durability, with lower w/c giving higher strength up to full compaction.

Aggregate: coarse aggregate is retained on 4.75 mm sieve, fine aggregate passes it; good grading reduces voids and water demand, and flakiness/elongation indices should be low.

Bricks: first-class burnt clay bricks are table-moulded, well burnt, uniform in colour, give a clear ringing sound, and absorb not more than about 20% water by weight.

Steel: mild steel is ductile with lower yield strength; HYSD/TMT bars have higher yield strength (Fe415, Fe500, Fe550), ribs for bond, and must be free of rust scale and oil before placing.

Timber: moisture content must be reduced before use; shrinkage is greater along the tangential than radial direction, causing warping, and seasoning reduces cracking and improves strength.

Mortar and plaster: 1:3 to 1:4 cement-sand mortar for structural masonry, 1:6 for internal plaster; lime improves workability and water retention but reduces early strength.

Bitumen, PVC, GI and copper: PVC conduit is used for concealed wiring, GI for exposed water lines, copper for conductors; bitumen is waterproofing and road binder, softened by heat.

Hand tools must be inspected before use: no mushroomed chisel heads, no loose hammer heads, no split handles, and cutting edges sharpened to the correct bevel.

A try square checks 90° angles, a spirit level checks level and plumb, a plumb bob transfers verticality, and a marking gauge scribes a line parallel to a face.

Saws: rip saw cuts along the grain with chisel teeth, crosscut saw cuts across the grain with knife teeth; set and sharpening control kerf width and binding.

Power tool safety: guard in place on grinders and circular saws, correct blade for material and RPM, no loose clothing or gloves near rotating parts, and disconnect before changing blades.

Drills: hammer action for masonry, rotary only for metal and wood; select bit type and speed by material, use a centre punch for metal, and clamp the work before drilling.

Concrete vibrator: insert vertically at regular spacing, withdraw slowly, avoid over-vibration causing segregation, and never use the vibrator to spread concrete.

Compaction and lifting equipment: plate compactors for granular fill in layers, rammers for confined areas; check slings, shackles and hooks for load rating and damage.

Portable electrical tools on site should be double-insulated or supplied through an RCD; test the RCD trip function and keep cables off wet ground and away from traffic.

Standard scales: 1:100 for plans, 1:50 for enlarged plans, 1:20 or 1:10 for details; always state the scale on the drawing and measure with a scale rule, not by estimation.

Line conventions: continuous thick lines for visible outlines, dashed for hidden edges, chain-dotted for centre lines and grid lines, and thin lines for dimension and extension lines.

Dimensioning: place dimensions outside the outline where possible, in a continuous chain, in millimetres for building work, with the figure above a continuous dimension line.

Plan, elevation and section together describe a building; a plan is a horizontal cut about 1 m above floor level looking down, a section is a vertical cut showing heights and construction.

North arrow, title block, drawing number, revision, date and scale must appear on every sheet; the title block identifies the project and the drawn-by/checked-by status.

Symbols: door swing arcs, window lines in wall thickness, stair arrows showing up direction with number of risers, and standard sanitary and electrical symbols per the drawing legend.

Grid lines labelled A, B, C and 1, 2, 3 locate columns and walls; levels are shown with a datum and reduced levels (RL) in metres with three decimals.

Site plan shows boundaries, setbacks, building footprint, access, drainage, and north direction; it is drawn at 1:200 or 1:500 and checked against local setback rules.

Units: lengths in metres, areas in square metres, volumes in cubic metres, and reinforcement in kilograms or tonnes; keep one consistent unit system through the bill of quantities.

Earthwork excavation volume = length × breadth × depth; for trenches use centre-line length × width × depth and deduct for overlaps at junctions.

Masonry measured in cubic metres as length × height × thickness, deducting openings above the specified area threshold (commonly 0.1 m²) and deducting lintels and beams.

Plaster measured in square metres of finished surface; deduct openings over 0.5 m² and add for jambs, soffits and reveals; state thickness and mortar mix in the description.

Concrete measured in cubic metres by net volume placed, excluding reinforcement; formwork measured separately in square metres of contact area.

Steel reinforcement: weight = (d²/162) kg per metre for bar diameter d in mm; total weight = number of bars × length × unit weight, plus laps and hooks.

Rate analysis builds the unit rate from materials, labour, plant, overheads and contractor profit; the estimate is quantity × rate plus contingency and taxes.

Paints and finishes: primer, putty and coats measured in square metres per coat; wastage allowances of a few percent are added to material quantities for cutting and breakage.

Brick masonry: soak bricks in water before laying, use a full bed of mortar, keep joints 10 mm and uniform, and stagger vertical joints (bond) so no joint runs continuously through the wall.

Bonds: stretcher bond for half-brick walls, English bond alternating header and stretcher courses for strength, Flemish bond alternating header and stretcher in the same course.

Plumb and level every course; use a line and spirit level, limit daily lift to about 1.5 m, and cure masonry by keeping it damp for at least 7 days.

Concrete sequence: batching, mixing, transporting, placing, compacting and curing; place in layers, compact with a vibrator, and cure for at least 7 days (10–14 for harsh exposure).

Slump test measures workability; typical slumps are 25–75 mm for normal RCC, and a collapse or shear slump indicates an overly wet or poorly proportioned mix.

Cube testing: 150 mm cubes cured and tested at 7 and 28 days; 7-day strength is typically about two-thirds of 28-day strength for OPC concrete.

Formwork must be tight, braced and oiled, with props on firm base; stripping times depend on member type and strength gain, and props are not removed early under self-weight.

Cold and hot weather: protect fresh concrete from rapid drying and from freezing; in hot weather cool the ingredients, place early, and start curing immediately.

Joints: mortise and tenon for frames, dovetail for drawer corners resisting pull, halving joint for flush framing, and dowel or biscuit joints for edge-to-edge boards.

Wood defects: knots weaken tension zones, shakes and checks are cracks along grain, and warping results from uneven shrinkage; select clear timber for structural tension members.

Seasoning reduces moisture content to equilibrium with service conditions; kiln seasoning is faster and gives more uniform results than air seasoning.

Hand tools: plane for surfacing, chisel for mortises and paring, marking gauge for parallel lines, and brace/bit for boring; sharpen with a stone at the correct bevel angle.

Door frames and shutters: check diagonals for square, keep a 2–3 mm gap at edges, and provide clearance at the floor; hinges must be set in matching recesses.

Plywood and particle board: plywood is strong and stable in both directions due to cross-lamination; particle board is weaker at edges and needs edge support and sealing.

Preservative treatment protects timber from termites and rot; brush, dip or pressure treatment, and cut ends must be re-treated on site.

Machine safety: push sticks near the saw blade, guard in place, no reaching over the blade, and dust extraction to control fine wood dust exposure.

Water supply layout: a ferrule and water meter at the connection, an underground or overhead storage tank, and distribution by gravity or pump; keep potable lines separate from non-potable.

Pipe sizes and materials: GI for exposed lines, PVC/CPVC for cold and hot water respectively, and copper for hot water; slope horizontal drainage at about 1 in 60 to 1 in 100.

Drainage: soil pipe carries foul water from WCs, waste pipe carries sullage from sinks and basins, and the vent pipe equalises pressure to protect trap seals.

Every fixture needs a water seal trap of 50–100 mm; a P-trap or bottle trap prevents sewer gas entry, and the vent stack prevents siphonage of the seal.

Inspection chamber and manhole spacing depends on pipe diameter; provide a gully trap at the boundary, and connect rainwater separately from the foul drainage system.

Testing: water lines are pressure-tested before concealment, and drainage lines are tested with water or smoke to prove watertightness and trap seals.

Sanitary fixtures: WC, wash basin, sink, floor trap and urinal have standard waste outlet sizes; check the fixture outlet matches the pipe diameter and the trap is accessible.

Storage tank hygiene: cover the tank, screen the overflow, clean periodically, and never run a drain or waste pipe through or over the tank.

Supply system: single-phase 230 V or three-phase 415 V at 50 Hz in India; distribution board with a main switch, RCCB/ELCB, MCBs for circuits, and earthing.

Wire colours: phase red/yellow/blue (or brown in flexible cords), neutral black (or blue), earth green or green-yellow; never use the earth conductor as a neutral.

Earthing: provide a pipe or plate earth electrode with specified resistance, earth continuity to all metal enclosures, and test the earth resistance periodically.

Lighting circuits use 1.5 mm² copper conductor and power circuits 2.5 mm² or more depending on load; the circuit rating must protect the cable, not the appliance.

Switch and socket heights: switches about 1.2 m above floor, sockets about 0.3 m for general use and higher in wet areas; keep switches out of bathrooms and near doors.

Conduit work: concealed PVC or steel conduit with bends of large radius, not more than the permitted number of bends per run, draw wires after plastering, and no joints inside conduit.

Load calculation: total connected load in watts divided by supply voltage gives current; diversity factor reduces the maximum demand for the main switch and cable sizing.

Safety: no temporary twisted joints, use proper connectors and junction boxes, keep wiring away from water pipes, and isolate the circuit before any work on fittings.

Plaster: 12 mm single coat for internal and 20 mm two-coat for external; wet the surface, apply a scratch coat, cure, and finish with a smooth even surface free of cracks.

Mortar mix for plaster is typically 1:4 to 1:6 cement-sand; richer mixes increase shrinkage cracking, and lime or plasticiser improves workability.

Painting sequence: surface preparation, primer, putty and sanding, then undercoat and two finish coats; moisture content of the substrate must be low before painting.

Paint types: distemper for dry interior ceilings, emulsion for interior walls, exterior emulsion or cement paint for facades, and enamel for wood and metal.

Flooring: cement concrete, tile, marble, granite and timber; check level and slope to drains, provide expansion joints, and cure screed before laying finishes.

Tiling: check substrate flatness, soak or prime tiles as required, use notched trowel adhesive, keep joints even with spacers, and grout after the adhesive sets.

Skirting, dado and cornice are measured and finished as separate items; protect finished surfaces from following trades with covers and masking.

Defects: crazing, blistering, flaking and efflorescence indicate moisture, poor preparation or wrong product; correct the cause before recoating.

Communication on site: use clear, short instructions, confirm understanding by repeat-back, and record important instructions in writing or a site diary.

Teamwork and behaviour: punctuality, PPE compliance, respect for trades, and reporting hazards are the observable employability behaviours employers assess.

Résumé and interview: one page with skills, tools known, safety training and certificates; prepare specific examples of work done and safety actions taken.

Entrepreneurship basics: a business plan states the service, market, pricing, costs, break-even and cash flow; separate business and personal money from day one.

Costing for a small contractor: direct costs (material, labour, plant), overheads, contingency and profit margin; underestimating labour and wastage is the common cause of loss.

Legal and compliance: GST registration thresholds, labour and safety obligations, written contracts with scope and payment terms, and insurance for workers and plant.

Customer relations: quote clearly, agree variations in writing before doing them, keep records of measurements and payments, and hand over with a completion checklist.

Digital skills: use a smartphone for measurement records, photo evidence, quotations and payments; digital records reduce disputes and support repeat business.