UPMSP High School Plumbing - Code 976 cheat sheet

Wear safety helmet, impact goggles, cut-resistant gloves, and steel-toe shoes; eye protection is mandatory during hacksawing, grinding, chiselling, and threading.

Fire classes: A solid fuels, B flammable liquids, C flammable gases, D metals, K cooking oils. Never use a water jet on class B, class C, class D, or live electrical fires.

Portable electrical tools must be supplied through a 30 mA RCD/ELCB; isolate and lock out the circuit before repairing a pump, geyser, or power tool.

Excavations deeper than 1.5 m need shoring, sloping, or a trench box; keep spoil at least 0.6 m from the trench edge and provide a ladder for access.

Solvent cement and primer are flammable and give off harmful vapour: use in a ventilated area, away from flame, with nitrile gloves and goggles.

Store oxygen and acetylene cylinders upright and at least 3 m from an open flame; never use oil or grease on oxygen regulators or fittings.

Manual lifting rule: keep the load close to the body, back straight, knees bent, and do not twist; use a team lift or trolley above about 25 kg.

First aid: irrigate chemical eye splashes with clean water for at least 15 minutes, cool burns under running water for 10 to 20 minutes, and report every injury and near miss.

Pipe wrench (Stillson): the jaw teeth must face the direction of handle rotation; pull the handle toward you and use the correct size, for example a 350 mm wrench for a 25 mm pipe.

Use a chain wrench or strap wrench on large, polished, or plastic pipes to avoid the deep tooth marks left by a pipe wrench.

Use a basin wrench for taps behind a sink, an adjustable wrench for nuts, and two wrenches back-to-back on a union so the pipe is not strained.

Hacksaw blade selection: 18 teeth per inch for thick-walled pipe and soft metal, 24 teeth per inch for thin tube; fit the blade with teeth pointing forward.

Pipe cutter: square the wheel to the pipe, tighten about a quarter turn per revolution, then ream the inside and outside burr with a reamer or half-round file.

Threading: clamp the pipe in a pipe vice, use a taper die and cutting oil, reverse half a turn to break the chips, and check the thread with the matching fitting.

Bending: insert a bending spring into PVC pipe before bending, anneal copper before bending, and fill GI pipe with dry sand for a hot bend to prevent flattening.

Files cut on the forward stroke; use a double-cut file for rough work, a single-cut file for finishing, and clean the teeth with a file card. A file must have a handle.

Pipe circumference equals pi times outside diameter, using pi = 3.1416; wrap a strip of paper or a flexible tape around the pipe to mark a square cut line.

For a 45-degree offset, travel = offset × 1.414 and offset = travel × 0.707; mark both cut points along the pipe centre line and add fitting take-outs.

Cut length = centre-to-centre distance between fittings minus the sum of the fitting take-outs; the take-out is the face-to-centre dimension supplied by the fitting manufacturer.

A fall of 1 in 60 equals about 16.7 mm per metre; convert any gradient to mm per metre by dividing 1000 by the slope number.

Use a spirit level for short runs, a water level for long distances around obstacles, and a plumb bob to check vertical pipe and riser alignment.

A common vernier caliper reads to 0.02 mm and an outside micrometer to 0.01 mm; close the jaws and confirm the zero marks coincide before measuring.

Mark with a scriber or fine marker against a try square, centre punch drilling points, and use a chalk line for long straight lines on pipe or sheet.

Allow about 12 to 14 mm of threaded length on a 15 mm GI pipe and leave two or three threads exposed after jointing so the fitting can still be tightened.

GI pipe: medium class for water supply, BSPT threads, jointed with hemp or PTFE tape plus zinc-rich paint; cut with a hacksaw or wheel cutter and ream the burr.

CI pipe: soil and waste service; joint by lead caulking, rubber ring gasket, or mechanical coupling. It is heavy and brittle, so support it well and do not drop it.

PVC-U: cold water and drainage; joint with solvent cement after a square cut, deburr, chamfer, primer, and cement application; insert with a quarter turn and hold about 30 seconds.

CPVC: hot water service up to about 93 degrees Celsius; use CPVC-specific solvent cement and allow the full cure time before pressure testing.

Copper: join by capillary soldering with lead-free solder and flux, by compression fittings, or by press fittings; anneal the tube before bending and clean oxide from the joint area.

HDPE: buried water mains; join by butt fusion, electrofusion, or compression fittings; it is flexible and coiled, so cut ends square and allow for thermal expansion.

Bending radius: keep a minimum bend radius of about 3 to 6 times the pipe diameter; use a bending spring for PVC, annealing for copper, and sand filling for a hot GI bend.

Support horizontal pipes at manufacturer-specified intervals, closer for hot pipes, and fit expansion loops or offsets on long straight runs to absorb movement.

Domestic water demand is commonly designed at about 135 litres per capita per day; add allowances for commercial use, institutions, fire fighting, and leakage.

Overhead tank capacity = number of users × litres per capita per day × days of storage, plus a reserve for breakdown or fire; size the tank from daily demand, not from pipe size.

Pressure from head: 1 m of water head equals about 9.81 kPa or 0.098 bar; 10 m of head is approximately 1 bar, which is used to check tap and fixture pressure.

Pump power in kW = 9.81 × flow in litres per second × head in metres ÷ (1000 × pump efficiency); add motor and transmission losses when selecting the motor.

A centrifugal pump must be primed before starting; a foot valve keeps the suction line full, a non-return valve prevents backflow, and running dry damages the seal and impeller.

Direct supply depends on mains pressure; indirect supply fills a storage tank and feeds fixtures by gravity, giving steadier pressure and a reserve during supply cuts.

Storage tank requirements: close-fitting insect-proof lid, screened overflow, drain valve, level indicator, and cleaning at least every six months.

Water hammer is caused by sudden valve closure; fit a water hammer arrestor, use slow-closing valves, and anchor the pipe to reduce surge pressure.

Soil pipe carries sewage from water closets, waste pipe carries discharge from sinks and basins, vent pipe admits air to protect trap seals, and rainwater pipe carries roof water.

A trap must keep a water seal of at least 50 mm to stop sewer gas entering the building; the seal is lost by evaporation, siphonage, back pressure, capillarity, or momentum.

Two-pipe system: soil and waste run in separate pipes with separate vents. One-pipe system: a single main pipe with a vent. Single-stack system: one stack with a ventilating valve or relief vent.

Drain gradient: about 1 in 60 to 1 in 40 for a 100 mm drain and about 1 in 40 for a 50 mm drain; aim for a self-cleansing velocity of about 0.6 m/s and avoid more than about 3 m/s.

Provide a manhole or inspection chamber at every junction, bend, change of gradient, and change of diameter, and at the intervals required by the local bye-laws.

Gully trap receives kitchen, bath, or floor waste before it enters the drain; a floor trap sits in the bathroom floor, a P-trap fits below the fixture, and a bottle trap is used where the trap is visible.

A grease trap is fitted on the kitchen waste line to intercept fats and oils before they reach the drain; it must be cleaned regularly or it will block.

A septic tank provides about 24 hours retention and sludge digestion; its effluent goes to a soak pit or drain field, and it does not replace a public sewer connection.

A plan is viewed from above, an elevation from the front, a section shows the cut interior, and an isometric view uses three axes at 30 degrees to show the layout in three dimensions.

Symbols: gate valve is a bow-tie of two triangles, check valve is a triangle or arrow showing one-way flow, and stop cock, bib cock, water meter, floor trap, gully trap, WC, wash basin, tank, and pump each have standard simple symbols.

Line types: thick continuous lines for visible work, dashed lines for hidden work, chain lines for centre lines, and break lines for omitted length.

Common drawing scales are 1:50 and 1:100; a scale of 1:50 means one unit on the drawing represents 50 units on site.

Label pipe sizes as DN or NB, show flow direction with arrows, and mark invert levels and gradients on drainage drawings.

A title block gives the project name, drawing title and number, scale, date, revision, and the name of the drafter or approver.

Sketch fittings as simple outlines: 90-degree and 45-degree elbow, tee, reducer, bend, socket, union, cap, plug, nipple, and cross, with the pipe size written beside each.

Abbreviations used on layouts include CW for cold water, HW for hot water, SW for soil and waste, VP for vent pipe, OHT for overhead tank, IC for inspection chamber, and MH for manhole.

Hydrostatic test of a water supply pipe: fill with water, raise to 1.5 times the working pressure or the specified test pressure, hold for at least one hour, and check for visible leaks and gauge drop.

Drainage water test: seal the lower end, fill the section to about 1.5 m head, and inspect after about 30 minutes; air test: apply about 100 mm water gauge and confirm the pressure holds for at least five minutes.

Smoke test: force smoke into the sealed drain and look for smoke escaping at joints, traps, and connections; it quickly finds open or broken connections.

Leak detection methods: observe the meter with all taps closed, listen with a listening stick or acoustic logger at night, use soap solution on gas joints, and use dye or a moisture meter on buried lines.

Before repairing a valve or tap, close the upstream isolating valve, drain the line, and open the fixture to confirm there is no pressure; then replace the washer, O-ring, or cartridge.

Descale aerators, shower heads, and heating coils with a mild acid such as citric acid or vinegar; flush the line after any repair and chlorinate drinking water lines to about 0.5 ppm residual chlorine.

Pump maintenance: check priming, clean the suction strainer, inspect the gland and bearings, check voltage and current, and confirm the non-return valve is not stuck.

Measurement units: pipe in running metre, fittings in numbers, excavation and concrete in cubic metre, plaster and painting in square metre, tanks in litres, and labour in days.

Openings up to 0.1 square metre are commonly not deducted from plaster or masonry measurement; deduct larger openings and add their frames and fixing separately.

Allow wastage of about 5 per cent on pipes, 2 to 5 per cent on fittings, and about 10 per cent on small consumables such as tape, hemp, and solder.

Rate analysis = material cost + labour cost + equipment + overheads + profit; add the applicable GST and wastage to get the final unit rate.

A bill of quantities lists description, unit, quantity, rate, and amount; the abstract totals the items and adds contingency and taxes.

Measure pipe along its centre line and count fittings separately as numbers; do not count the same fitting both in the pipe length and as a separate item.

Add contingency of about 5 to 10 per cent for unforeseen work, price rise, and minor changes, and keep it as a separate item in the estimate.

Cost of a storage tank can be estimated from its capacity in litres or from its surface area in square metres, using the current market rate for the selected material.

Identify hazards, assess the risk, and use a permit-to-work system for confined-space entry, hot work, and work at height; record the control measures before starting.

5S workplace practice: sort, set in order, shine, standardise, and sustain; it reduces accidents, lost tools, and rework on site.

Communication rule: listen fully, repeat the instruction back, record the agreed scope in writing, and inform the customer before any extra charge is incurred.

A quotation should state scope, quantities, unit rates, taxes, validity period, payment terms, warranty, and exclusions; keep a signed copy for both parties.

A GST tax invoice must show the supplier GSTIN, a unique invoice number and date, customer details, description with HSN or SAC code, taxable value, GST rate, and total amount.

Small businesses can register on the Udyam portal for MSME benefits and may qualify for schemes such as PM Vishwakarma, subsidised loans, and skill training.

Break-even quantity = fixed cost ÷ (selling price per unit − variable cost per unit); selling below this quantity produces a loss.

Profit margin percentage = (selling price − cost) ÷ selling price × 100; keep it separate from markup, which is calculated on cost.