Odisha CHSE +2 Plumber General (VOC-ITV) cheat sheet

Pipe wrench sizing rule: choose a wrench whose jaw opening exceeds the pipe's outside diameter by about 10-15 mm; a 350 mm wrench suits pipes up to 32 mm OD, a 450 mm wrench up to 50 mm OD.

Hacksaw blade selection: 18 TPI for steel and GI pipe above 25 mm, 24 TPI for copper and thin-wall tube, 32 TPI for PVC and thin brass; blades cut on the forward stroke.

Pipe cutter wheel pressure: tighten the knob a quarter turn per revolution of the cutter; over-tightening burrs the pipe wall and raises the burr that must be reamed out.

Torque reference for threaded joints: 25-40 N·m for 15-25 mm GI fittings, 60-90 N·m for 32-50 mm; excess torque splits cast fittings and strips threads.

PPR fusion temperatures: heating plate at 260 ± 5 °C, heating time about 5 s for 20 mm, 7 s for 25 mm, 12 s for 32 mm; cooling time at least 4 min before pressure testing.

Solvent cement for PVC: apply a thin even coat to both socket and spigot, assemble with a quarter-turn twist, hold 30 s, cure 24 h before pressure test at full working pressure.

Confined-space entry order: test atmosphere (O2 19.5-23.5 %, LEL below 10 %, H2S below 10 ppm), ventilate, isolate, then enter with a standby attendant and retrieval line.

Leak-detection soap solution ratio: about 1 part liquid detergent to 10 parts water; bubbles indicate gas or air leaks at 0.5 bar test pressure or above.

Copper tube annealing: heat to dull red (about 600 °C) and cool in air to soften for bending; do not quench in water if the tube is to be re-hardened for pressure service.

Water closet flush volumes: 6/3 L dual-flush and 4.5 L single-flush are common Indian market ratings; 10 L cisterns are legacy and being phased out.

Wash basin trap seal must be 40-50 mm; a shallower seal allows sewer gas to pass, a deeper seal slows flow and collects debris.

Floor trap (nahani trap) grating size commonly 100 x 100 mm with 50 mm outlet; the trap seal is 50 mm and it must be accessible for rodding.

Water heater (geyser) pressure-relief valve setting: 6-8 bar for domestic storage units, with the expansion pipe discharging to a safe drain, never capped.

Bib tap and pillar tap flow: 15 mm nominal inlet gives about 0.15-0.2 L/s at 1 bar; 20 mm inlet about 0.3 L/s.

WC connection dimensions: 100 mm soil pipe outlet, 32-40 mm flush pipe from cistern, floor flange set level with finished floor tile.

Angle valve (stop cock) is fitted on the supply to each fixture so the fixture can be isolated without shutting the riser.

Indian standard reference for sanitary fittings is IS 2556 series (vitreous china sanitary appliances); check the IS mark and batch on delivered ware.

Static head formula: pressure (bar) = height (m) x 0.0981; a 10 m column gives about 0.98 bar at the base.

Minimum residual pressure at the ferrule of the topmost fixture is 1.5-2 m (about 0.15-0.2 bar) for a direct system.

Overhead tank capacity rule: 100-135 litres per person per day for domestic use; size tank = persons x 135 L plus 20 % reserve.

Down-take pipe sizing guide for a small house: 25 mm main, 20 mm branch to a group of fixtures, 15 mm to individual taps.

Flow velocity limit in supply pipes is 1.5-2.0 m/s to control noise and erosion; above 2.5 m/s water hammer and erosion-corrosion appear.

Air gap between the supply pipe outlet and the tank overflow level must be at least the pipe diameter, and never less than 25 mm.

Gate valve is used for isolation (fully open or shut), globe valve for throttling; never use a gate valve to regulate flow.

Water hammer arrestor is placed close to the quick-closing valve; the arrestor's air charge should equal the static line pressure.

Gradient rule: 100 mm drain at 1 in 60 to 1 in 100, 150 mm drain at 1 in 100 to 1 in 150; flatter than 1 in 200 causes solids deposition.

Self-cleansing velocity in a drain is 0.6-0.75 m/s at design flow; below 0.6 m/s solids settle.

Stack sizing: 100 mm stack serves about 20 WC equivalents; a 75 mm stack about 8; a 50 mm waste pipe about 3 fixtures.

Vent pipe sizing: the vent must be at least half the diameter of the drain it serves and never smaller than 32 mm.

Inspection chamber spacing: not more than 12 m on a straight run, and at every change of direction greater than 45 degrees.

Gully trap seal 50 mm, intercepting trap with a fresh-air inlet at the property boundary; the drain invert at the boundary must be at least 450 mm deep.

Two-pipe system separates soil (WC) from waste (bath, sink); one-pipe system uses a single stack with a relief vent.

Manhole cover class selection: light duty (LD) for footpaths, medium duty (MD) for driveways, heavy duty (HD) for roads.

Threaded joint sequence: cut square, ream the burr, cut BSP threads with a die, apply PTFE tape clockwise (2-3 turns) or jointing compound, tighten to 1-2 turns past hand-tight.

BSP thread standard: 15 mm pipe = 1/2 in BSP, 20 mm = 3/4 in, 25 mm = 1 in; thread length about 18-20 mm for 15-25 mm sizes.

Soldered copper joint clearance is 0.05-0.15 mm; flux must be applied sparingly and the joint cleaned after soldering to remove flux residue.

Compression fitting tightening: hand-tight plus 1 to 1.25 turns with a spanner; over-tightening crushes the olive and causes leaks.

Pipe support spacing: 15-25 mm copper or GI horizontal runs at 1.8-2.4 m; PVC at 1.0-1.5 m; vertical runs at every floor level.

Expansion allowance for PPR: about 0.15 mm per metre per °C; a 10 m run at 50 °C rise needs about 75 mm of expansion, absorbed by a loop or offset.

Pressure test: 1.5 times working pressure for at least 1 hour, or 1.0 bar for 30 min for a domestic installation; no drop beyond 0.05 bar is acceptable.

Fabrication drawing take-off: centre-to-centre length minus fitting allowances gives the cut length; subtract the socket depth at each end for push-fit joints.

Leak diagnosis order: isolate the fixture, check the visible joint, then check the concealed run with a dampness meter or thermal camera before opening the wall.

Drip rate estimate: 1 drop per second is about 0.05 L/min, which is about 26 m³ per year of water loss; fix drips early.

Cistern running continuously usually means a perished flush valve washer or a mis-set float valve; check the overflow level against the float setting.

Frozen or blocked trap remedy: rod with a 6 mm spring auger, then flush with 5 L of water; do not use caustic soda on a plastic trap above 60 °C.

Pipe freeze protection: lag exposed runs, keep a trickle running on the coldest nights, and open cabinet doors to warm internal runs.

Noise in pipes (water hammer) is fixed by fitting an arrestor, replacing a worn washer, or reducing the pressure to below 3 bar at the fixture.

Sewer smell indoors indicates a dry trap, a broken vent, or a cracked drain; refill traps and smoke-test the drainage system to locate the fault.

Repair log: record date, location, fault, part replaced, and test result; this shortens the next diagnosis and supports warranty claims.

Scale reading: 1:50 means 1 mm on the drawing equals 50 mm on site; a 20 mm drawn length is 1.0 m actual.

Pipe length take-off = sum of horizontal runs + vertical risers + 5-10 % wastage for cutting and offcuts.

Fixture count method (Hunter's curve) converts fixture units to probable flow; a WC is 4-6 fixture units, a wash basin 1-2.

Rate build-up: material cost + labour cost + overheads (10-15 %) + contractor profit (10 %) + GST as applicable.

Labour norms: a plumber plus helper installs about 8-12 fixture points per day in a domestic building.

Bill of quantities must list item description, unit (m, no., set), quantity, rate, and amount; measured lengths are taken to the nearest 0.01 m.

Contingency in an estimate is normally 5-10 % of the estimated cost, shown as a separate line.

Isometric plumbing drawing uses standard symbols: circle with cross for a floor drain, triangle for a hose bib, filled circle for a gate valve.

Communication sequence on a job: confirm the work order, state the time and material needed, report completion with a test result.

Personal protective equipment set for plumbing: safety helmet, goggles, gloves, ear plugs when cutting, safety footwear, and a respirator when solvent cement is used.

First aid for solvent cement in the eye: irrigate with clean water for at least 15 minutes and seek medical help; do not rub the eye.

Workplace 5S: sort, set in order, shine, standardise, sustain; tools go back to the marked place at the end of each shift.

Electrical safety: use 110 V or RCD-protected tools on site, and never work on a wet floor with an unearthed tool.

Team communication: use a hand signal or radio for valve operation; confirm the valve tag number before turning.

Time management on a service call: 10 min diagnosis, 30 min repair, 10 min test and clean-up is a workable standard for a simple leak.

Record keeping: a job card with customer signature protects both the worker and the customer in a dispute.

Pricing a job: price = direct cost + overhead + profit margin; a 20-30 % gross margin is typical for a small plumbing service.

GST registration is required above the turnover threshold set by the GST law; a plumber issuing a proper invoice builds trust and repeat business.

Quotation must state scope, exclusions, materials brand, warranty period, payment terms, and validity date.

Warranty practice: 12 months on workmanship, manufacturer warranty on materials; state both separately in writing.

Cash-flow rule: collect a 30-50 % advance on materials for a new customer, and bill progress payments at agreed milestones.

Ethics: never quote for a part that is not needed, disclose the material grade used, and return unused material or credit it to the customer.

Customer complaint handling: listen, acknowledge, inspect, fix within an agreed time, and record the outcome.

Business records: keep purchase bills, wage slips, and job invoices for the period required by tax law; they are also the basis for a loan application.

Assessment marking is typically split: practical work 60-70 %, viva/record 15-20 %, project report 15-20 %; confirm the split with the school's scheme.

A project report needs: title, objective, tools and materials list, procedure, observations, result, and a labelled sketch or photograph of the finished work.

A practical job is judged on: dimensional accuracy (within 2 mm), joint tightness under test pressure, neatness, tool care, and safe working.

Pressure test record for a project: fill, vent air, pressurise to 1.5 times working pressure, hold 1 hour, record start and end gauge readings.

Viva questions usually cover tool names, pipe sizes, joint methods, and the reason for a chosen gradient or trap seal.

Time discipline: a practical exam task is usually allotted 2-3 hours; plan cutting, joining, and testing within that window.

Housekeeping is marked: clear swarf, cap open pipe ends, and leave the work area dry and clean.

Safety observation during practical exam: PPE worn, correct lifting, no open flame near solvent cement, and electrical tools checked before use.