Odisha CHSE +2 Plumber General (VOC-ITV) flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Pipe wrench jaw size

The wrench jaw opening should exceed the pipe outside diameter by about 10-15 mm so the teeth grip the full wall without slipping or crushing the pipe.

Hacksaw blade TPI choice

Use 18 teeth per inch for steel and GI pipe above 25 mm, 24 TPI for copper and thin tube, and 32 TPI for PVC and thin brass; blades cut on the forward stroke.

PPR fusion temperature

The heating plate for polypropylene-random pipe is held at 260 degrees Celsius plus or minus 5 degrees, and joints cool at least four minutes before pressure testing.

Confined space entry test

Before entry, oxygen must be 19.5 to 23.5 percent, flammable gas below 10 percent of the lower explosive limit, and hydrogen sulphide below 10 parts per million.

Trap seal depth

A wash basin or floor trap must hold a water seal of 40 to 50 mm; a shallower seal lets sewer gas pass and a deeper seal slows flow.

Geyser relief valve setting

A domestic storage water heater carries a pressure-relief valve set at 6 to 8 bar, and its discharge pipe must run to a safe drain and never be capped.

Dual flush cistern volume

Common Indian market dual-flush water closets use 6 litres for a full flush and 3 litres for a reduced flush; legacy 10 litre cisterns are being phased out.

Static head to pressure

Pressure in bar equals height in metres multiplied by 0.0981, so a 10 metre column of water gives about 0.98 bar at the base.

Overhead tank sizing

Domestic demand is about 100 to 135 litres per person per day, so tank capacity equals persons times 135 litres plus a 20 percent reserve.

Supply pipe velocity limit

Flow velocity in water supply pipes is kept between 1.5 and 2.0 metres per second; above 2.5 metres per second noise and erosion-corrosion appear.

Gate valve versus globe valve

A gate valve is for isolation and must be fully open or fully shut, while a globe valve is used for throttling and regulating flow.

Drain gradient rule

A 100 mm drain is laid at 1 in 60 to 1 in 100 and a 150 mm drain at 1 in 100 to 1 in 150; flatter than 1 in 200 lets solids settle.

Self-cleansing velocity

A drain must reach 0.6 to 0.75 metres per second at design flow to carry solids; below 0.6 metres per second deposition begins.

Inspection chamber spacing

Inspection chambers are placed at intervals not exceeding 12 metres on a straight run and at every change of direction greater than 45 degrees.

Vent pipe minimum size

A vent pipe must be at least half the diameter of the drain it serves and never smaller than 32 mm, so a 100 mm drain needs a 50 mm vent.

BSP pipe size mapping

A 15 mm pipe takes half-inch BSP thread, 20 mm takes three-quarter inch, and 25 mm takes one inch, with thread length about 18 to 20 mm.

Soldered copper joint clearance

Capillary clearance in a soldered copper joint is 0.05 to 0.15 mm; flux is applied sparingly and cleaned off after soldering to stop corrosion.

Compression fitting tightening

Tighten a compression fitting hand-tight plus one to one and a quarter turns with a spanner; further tightening crushes the olive and causes leaks.

Pipe support spacing

Support horizontal copper or GI runs every 1.8 to 2.4 metres, PVC runs every 1.0 to 1.5 metres, and vertical runs at every floor level.

Pressure test acceptance

Test at 1.5 times working pressure for at least one hour; a domestic installation passes if the gauge drop does not exceed 0.05 bar.

Drip loss estimate

One drip per second is about 0.05 litres per minute, which adds up to roughly 26 cubic metres of water wasted in a year.

Cistern running continuously

A cistern that never stops running usually has a perished flush valve washer or a float valve set too high, so the water spills into the overflow.

Indoor sewer smell cause

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

Water hammer remedy

Banging pipes are cured by fitting a water hammer arrestor near the quick-closing valve, replacing a worn washer, or reducing fixture pressure below 3 bar.

Drawing scale reading

At a scale of 1 to 50, one millimetre on the drawing equals 50 millimetres on site, so a 20 mm drawn length is 1.0 metre actual.

Pipe length wastage

Estimated pipe length equals the sum of horizontal runs plus vertical risers, with 5 to 10 percent added for cutting waste and offcuts.

Estimate rate build-up

A rate is built from material cost plus labour cost plus overheads of 10 to 15 percent plus contractor profit of about 10 percent, then tax.

Solvent cement eye first aid

If solvent cement enters the eye, irrigate with clean water for at least 15 minutes without rubbing, then seek medical help immediately.

Site electrical safety

Use 110 volt or residual-current-device protected power tools on site, and never operate an unearthed tool while standing on a wet floor.

Small job pricing margin

Job price equals direct cost plus overhead plus profit, and a small plumbing service typically carries a 20 to 30 percent gross margin.

Quotation contents

A quotation must state the scope of work, exclusions, material brand and grade, warranty period, payment terms, and the date it expires.

Practical exam marking

Practical trade assessment commonly weights hands-on work at 60 to 70 percent, viva and record book at 15 to 20 percent, and project report at 15 to 20 percent.