Punjab PSEB Sr. Sec. NSQF Plumbing (Advanced Plumbing Technician) flashcards

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

30 mA RCD

A residual current device that trips at 30 milliamps earth leakage; used on portable electrical tools on construction sites to reduce electric shock risk.

Confined space oxygen range

Safe entry oxygen concentration is 19.5 to 23.5 percent by volume; outside this range, ventilate and do not enter without breathing apparatus and permit.

Flashback arrestor

A device fitted to an oxy-acetylene torch or regulator that stops a flame from travelling back into the hose or cylinder, preventing explosion.

BSPT thread taper

British Standard Pipe Taper thread has a 1:16 taper on diameter; it seals by thread interference and is used on galvanised steel plumbing pipes and fittings.

Gate valve versus globe valve

Gate valve gives low-resistance isolation and is fully open or closed; globe valve is for throttling because its seat gives gradual flow control but higher pressure loss.

Copper tube types K L M

Copper water tube types K, L and M have decreasing wall thickness; type K is heaviest for underground, type M lightest for above-ground low-pressure use.

Dielectric union

A fitting with insulating material between dissimilar metals, such as copper and galvanised steel, that breaks electrical continuity and reduces galvanic corrosion in plumbing.

Capillary soldering

A joining method where cleaned copper surfaces and flux draw molten lead-free solder into a close-fitting joint gap by capillary action, forming a leak-tight bond.

Brazing filler melting point

Brazing uses filler metals that melt above 450 degrees Celsius, higher than soldering, giving stronger joints for copper, steel and dissimilar pipe connections.

Solvent cement cure time

PVC solvent-cemented joints need cure time before pressure testing; it increases with pipe diameter and decreases with temperature, often 24 hours for large pipes.

PP-R socket fusion temperature

Polypropylene random copolymer pipes are joined by heating pipe and fitting on a hot plate at about 260 degrees Celsius, then pushing together and holding until cool.

Water flow velocity limit

Domestic water supply pipes are usually sized for 1.0 to 1.5 metres per second; velocities above about 3 metres per second cause noise, erosion and water hammer.

Air gap backflow prevention

The unobstructed vertical distance between a water supply outlet and the flood-level rim of a fixture; it is the most effective backflow prevention method.

Water fixture unit

A dimensionless measure of the probable demand of a plumbing fixture; fixture units are added and used with Hunter curves to size water supply pipes and meters.

Trap water seal depth

A plumbing trap must retain a water seal of 50 to 75 millimetres to block sewer gas; a seal below 50 millimetres is likely to evaporate or siphon away.

Vent stack purpose

A vertical pipe connected to the drainage stack that admits air, protects trap seals from siphonage, and allows sewer gases to escape above the roof.

Drainage pipe slope

Gravity drainage pipes are laid with a fall, commonly 1 in 50 to 1 in 100 for 100 mm soil pipe, so wastewater flows at self-cleansing velocity without blocking.

Dual flush WC volume

A dual-flush water closet has two flush buttons delivering a small flush of about 3 litres and a full flush of about 5 to 6 litres, saving water.

T and P relief valve

A temperature-and-pressure relief valve on a storage water heater opens if temperature or pressure exceeds set limits, preventing tank rupture; it must not be plugged or capped.

Sacrificial anode rod

A magnesium or aluminium rod inside a storage water heater tank that corrodes preferentially, protecting the steel tank lining from rust and extending heater life.

Invert level

The level of the inside bottom of a drain or pipe at a given point; drawings show invert levels to calculate excavation depth and pipe fall.

Bill of quantities

A priced document listing plumbing items with descriptions, units and quantities, such as pipe in running metres and fittings in numbers, used for tendering and payment.

Break-even point formula

Break-even quantity equals total fixed cost divided by selling price per unit minus variable cost per unit; it shows the sales volume at which neither profit nor loss occurs.

Hydrostatic pressure test

A leak test in which a completed water pipe system is filled, air vented, and pressurized usually to 1.5 times working pressure and held to check for pressure drop.

Water hammer cause

Water hammer is pressure surge caused by rapid valve closure or pump stop; loose pipes, high velocity and missing arrestors make the banging worse.

Dry trap drain smell

A floor drain or fixture trap that has lost its water seal through evaporation allows sewer gas into the room; refill the trap and check for venting faults.

STAR interview answer

A structured interview response that describes the Situation, Task, Action and Result, giving a concrete example of the candidate's plumbing work and outcome.

GST invoice essentials

A tax invoice must show supplier GSTIN, invoice number and date, recipient details, HSN or SAC code, taxable value, tax rate and CGST, SGST or IGST amounts.

Change order

A written amendment to an agreed plumbing work order that records added or omitted work, revised price and time impact before the extra work is done.

Rainwater harvest yield

Harvestable rainwater in litres equals catchment area in square metres multiplied by rainfall in millimetres multiplied by the runoff coefficient; 1 mm on 1 m² gives 1 litre.

First flush diverter

A device that discards the first rainwater from a roof, which carries dust and bird droppings, before cleaner water enters the storage tank.

Greywater reuse limit

Greywater from baths, basins and laundry can be treated and used for flushing or subsurface irrigation, but not for drinking, cooking or direct food contact.