CTVET Ghana Certificate II - Plumbing cheat sheet

Hierarchy of control, in order: eliminate the hazard, substitute, engineer controls, administrative controls, then PPE as the last line of defence.

PPE for plumbing: hard hat, safety boots, goggles or face shield, gloves, hearing protection when using cutters or core drills, dust mask for silica and cement dust.

Before any excavation or penetration, confirm buried services: call the utility locator, check drawings, and hand-dig trial holes near marked routes.

Confined spaces (manholes, tanks, pits) require a permit, atmospheric testing for oxygen and toxic gas, forced ventilation, a standby person, and retrieval harness.

Manual handling rule: keep the load close to the body, bend the knees, avoid twisting; two-person lift or mechanical aid above roughly 25 kg.

Ladder rule: 4:1 ratio (1 m out for every 4 m up), three points of contact, top extending about 1 m above the landing point.

Electrical safety: 110 V centre-tapped site tools or RCD protection; never work on wet floors with unearthed portable tools.

Environmental controls: segregate waste (metal, plastic/PVC, packaging), contain solvent cement and primer fumes, prevent cement slurry and wash water entering drains or watercourses.

Emergency response: know the location of first-aid kit, fire extinguisher, eyewash station, and assembly point; report every incident and near miss.

Common scales: 1:20, 1:50, 1:100 for plans; 1:10 or 1:5 for details; always state the scale and units on the drawing.

Standard line types: continuous thick for visible outlines, dashed for hidden detail, chain dotted for centre lines, continuous thin for dimension and projection lines.

First-angle projection: the view is placed on the far side of the object (plan below elevation); third-angle places the view on the near side (plan above elevation).

Isometric axes are at 30 degrees to the horizontal; true lengths are drawn along the axes, circles appear as ellipses.

Dimensioning rules: dimension lines parallel to the measured edge, arrowheads at both ends, figures above the line, no repeated or closed dimensions.

Pipe length from a drawing = centre-to-centre run, minus fitting allowances (two 45-degree or 90-degree take-outs) plus thread or socket engagement.

Gradient formula: fall = length x gradient (e.g. 6 m at 1:60 = 100 mm fall).

Area and volume: pipe cross-section area = pi x r squared; cylinder volume = pi x r squared x length; convert mm to m before volume in cubic metres.

Scale conversion: real length = drawing length x scale denominator; drawing length = real length / scale denominator.

Pipe size designation: nominal bore (DN) is approximate internal diameter; outside diameter governs fitting choice for plastics (e.g. 20 mm PPR, 110 mm PVC soil).

Common materials: uPVC for soil and waste, cPVC or PPR for hot water, copper for potable hot and cold, galvanised steel for exposed cold lines, HDPE for buried mains.

Cutting: wheel cutter or hacksaw for plastics (square the cut, deburr), pipe cutter with reamer for copper, hacksaw or power saw for steel with threads cut afterwards.

Bending springs are sized to the pipe bore; a 20 mm spring goes in a 20 mm pipe to prevent kinking during cold bending.

Pressure test: water test at 1.5 times working pressure (commonly 10 bar for domestic cold) held for at least 1 hour with no drop.

Valves: gate valve for isolation (fully open or closed), globe valve for throttling, check valve for one-way flow, air admittance valve for venting.

Support spacing: plastics need closer clips than copper or steel; vertical plastic pipe roughly every 1.2 m, horizontal roughly every 0.5-1 m depending on diameter.

Thread standards: BSP parallel for most plumbing joints; use PTFE tape or jointing compound on male threads only, 3-5 turns in the direction of tightening.

Minimum cold bend radius for copper is about 3-4 times the outside diameter; below that use a bender or anneal the pipe first.

To anneal copper, heat to dull red and cool quickly (quench) for soft temper; slow cooling leaves it soft but work-hardened bends crack.

Spring bending: insert spring, bend slowly with even pressure over the knee or a former, then twist the spring slightly to remove it.

Solvent welding (uPVC): cut square, chamfer, clean with primer, apply cement to both surfaces, push fully home with a quarter turn, hold 30 seconds, do not disturb for at least 15 minutes.

Compression joint: pipe fully inserted past the olive, nut hand tight plus about half to one turn; over-tightening splits the olive and leaks.

Capillary soldering: clean to bright metal, flux sparingly, heat the fitting not the solder, feed solder when the flux bubbles; wipe the joint while hot.

Threaded joint: cut thread with die, check with a ring gauge, apply PTFE tape clockwise, tighten by hand then with a wrench no more than 2-3 turns past hand tight.

Fabrication check: measure twice, dry-fit the assembly before permanent jointing, allow for expansion loops on long hot runs.

Direct system: mains feeds all cold outlets directly; relies on adequate mains pressure and is unsuitable where supply is intermittent.

Indirect system: mains fills a storage tank (cistern), which feeds a cold distribution tank and, via a feed-and-expansion or cold feed, the hot water cylinder.

Tank sizing rule of thumb: about 100-150 litres per person per day for domestic storage; check the local water utility requirement.

Tank installation: at least 1 m above the highest outlet for gravity pressure (roughly 0.1 bar per metre head), insulated, covered, with a screened vent and overflow.

Backflow prevention: air gap or a non-return/check valve on the mains inlet; never connect a mains hose directly into a tank below the water line.

Pressure: static head in metres x 0.0981 = bar; a 10 m head gives about 1 bar at the outlet before friction losses.

Pipe sizing: velocity in domestic cold services should stay around 1-1.5 m/s to limit noise and erosion; larger diameter lowers velocity and friction loss.

Isolation: fit a stop valve on the rising main, a drain cock at the lowest point, and label the main isolator clearly.

Two-pipe system separates soil (WC) and waste (sinks, basins) pipework; one-pipe system combines them into a single stack with a common vent.

Trap seal depth should be 50-75 mm; a seal below 50 mm risks evaporation and gassing off, above 100 mm risks self-siphonage.

Branch gradient: 1:40 to 1:60 for 32-50 mm waste; 1:60 to 1:80 for 75-110 mm soil, ensuring self-cleansing velocity of about 0.7 m/s.

Vent pipe: the stack must extend above the roof (typically 0.9 m minimum) to relieve pressure; an air admittance valve may replace a branch vent where permitted.

S-trap and P-trap: the P-trap with a horizontal outlet is preferred; an S-trap can self-siphon and is normally avoided.

Rodding eye or access cap at the base of the stack and at every change of direction greater than 45 degrees for maintenance access.

Gully and inspection chamber: use a trapped gully for surface water, an untrapped gully for rainwater; inspection chamber at every junction and at intervals of about 45 m.

Connection to the public sewer requires approval; maintain the drain invert level and never discharge soil water into a surface water drain.

WC pan set-out: soil pipe centre typically 200-300 mm from the finished wall; check the pan's own dimension before setting the connector.

Cistern fill valve set to the marked water line (usually 12 mm below the overflow); flush volume for a dual-flush is about 6/4 or 4.5/3 litres.

Basin and sink waste: fit the trap below the outlet, seal with a rubber washer above and a friction washer below the basin, then tighten the back nut.

Water heater installation: fit a temperature-and-pressure relief valve, expansion vessel on a sealed system, and a drain cock at the lowest point.

Washing machine and dishwasher: use a standpipe or appliance trap with a 600 mm minimum upstand and a hose hooked above the trap weir to prevent backflow.

Fixture fixing heights (typical domestic): basin rim 800-850 mm, WC seat 400-420 mm, shower mixer 1000-1100 mm, kitchen sink 900 mm.

Waterproofing: seal the bath or shower tray perimeter with silicone before tiling; use a waterproof backing behind wet-area walls.

Commissioning: flush all lines, check for leaks at every joint, test the trap seal, and record the pressure test result.

Leak at a compression joint: first tighten the nut a quarter turn; if it persists, cut out and remake with a new olive, never add more tape to an olive.

No water at a tap: check the isolation valve, aerator strainer, and stopcock in that order before dismantling the tap body.

Running WC: a worn flapper or fill valve is the usual cause; dye-test the cistern to confirm a leaking flush valve.

Noisy pipes (water hammer): fit a shock arrester or check valve, secure loose clips, and reduce velocity by upsizing the pipe.

Blocked waste: use a plunger or drain snake before chemicals; a trap with a rodding eye is cleared from the access point, not from the fixture.

Low hot water pressure: check for scale in the shower head and aerator, a partially closed valve, or a failed pressure-reducing valve.

Frozen or airlocked pipe: isolate, drain, and refill slowly from the lowest point; airlocks clear by opening the highest tap while the lowest is fed.

Fault log: record symptom, probable cause, action taken, parts replaced, and test result for every repair.

Job cost = materials + labour + overhead + contingency; price = cost / (1 - desired profit margin), not cost x (1 + markup) when margin is stated.

Labour rate = annual labour cost / billable hours per year; include holidays, NI/social contributions, tools, and vehicle in the labour cost.

Contingency for plumbing work is typically 10-15 percent on labour and materials for renovation, less for planned maintenance.

Quote vs estimate: a quotation is a fixed offer; an estimate is an approximate figure and must be labelled as such to avoid disputes.

Cash flow: invoice on completion or at agreed stages; retain a deposit of 20-30 percent on materials for larger jobs.

Record keeping: keep receipts, a job sheet, and a simple cash book; register the business and meet tax and local authority requirements.

Customer care: confirm the appointment, protect floors and furniture, explain the fault in plain language, and leave the work area clean.

Variation order: any change to the agreed scope must be agreed in writing with price and time impact before work proceeds.

Licensing and registration: work only within the scope of your certificate and local registration; do not sign off work you did not perform or supervise.

Codes and standards: follow the Ghana Building Code and manufacturer instructions; where they conflict, the more stringent requirement applies.

Confidentiality: do not disclose customer details, access codes, or site information to third parties without consent.

Conflict of interest: disclose any relationship with a supplier or subcontractor before recommending their product or service.

Communication: confirm instructions in writing (job sheet or message), use clear language with the client, and record agreed changes.

Site conduct: arrive at the agreed time, wear identification, respect the client's property, and never work under the influence of alcohol or drugs.

Reporting: report unsafe conditions, defective materials, and any accident to the supervisor immediately; keep a written record.

Bribery and gifts: refuse payments or gifts intended to influence inspection, procurement, or certification decisions.

Risk assessment: identify the hazard, decide who may be harmed and how, evaluate the risk, record the control measures, and review when the work changes.

COSHH-style rule for chemicals: obtain the safety data sheet, use the smallest quantity, ventilate, and store solvents away from heat and ignition sources.

Hand tool safety: use the correct size spanner, never extend a spanner with a pipe, and inspect hammers and chisels for mushroomed heads.

Power tool safety: isolate before changing blades or discs, keep guards in place, and never use a damaged abrasive wheel.

Working at height: use a podium or tower rather than a ladder for tasks over about 30 minutes; never stand on the top two rungs.

Hygiene: wash hands after handling soil pipework and before eating; use gloves and eye protection when mixing cement or solvent.

Waste segregation: keep copper and brass scrap separate for recycling, and never burn PVC offcuts or cable insulation.

First aid: for chemical splash to the eye, irrigate with clean water for at least 15 minutes and seek medical help.

Orthographic layout: front elevation, plan, and end elevation aligned on the same projection lines; hidden detail shown with dashed lines.

Section views: hatch cut material with evenly spaced thin lines at 45 degrees; do not hatch shafts, bolts, or pipes shown unsectioned.

Pipe isometric sketch: draw the three axes at 120 degrees apart, then offset pipe runs parallel to the axes; label sizes and flow direction.

Fall calculation check: 1:60 over 12 m = 200 mm fall; 1:80 over 12 m = 150 mm fall.

Circumference = pi x diameter; use it to calculate the length of a wrap-around template or insulation.

Thermal expansion: expansion = coefficient x length x temperature rise; for uPVC the coefficient is about 0.07 mm per metre per degree C.

Volume of a rectangular tank = length x width x depth; a 1 m x 0.5 m x 0.5 m tank holds 250 litres.

Material take-off: measure pipe runs between fitting centres, add 10-15 percent waste, and list fittings by size and type.

Pipe identification: colour code and marking on the pipe wall give material and pressure rating; never mix solvent cement types across materials.

uPVC solvent cement joints need a chamfer of about 15 degrees and a clean dry surface; wet joints will fail.

Copper tube sizes are stated by outside diameter (15, 22, 28 mm); imperial sizes are still found in older installations.

Galvanised steel must not be joined to copper without a dielectric union to prevent galvanic corrosion.

Hacksaw blade selection: 18-24 teeth per inch for steel and plastic, finer blades for thin-wall tube.

Pipe wrench (Stillson) for gripping threaded pipe; strap wrench for polished or plastic surfaces to avoid crushing.

Pressure gauge and test pump: fit the gauge at the lowest point, isolate the section, and record the pressure at start and end of the test.

Storage: keep plastic pipe out of direct sunlight, support it along its length, and cap open ends to keep out debris.

Hot bending of plastics uses a former and controlled heat (hot water or heat gun) until the pipe is pliable; cool in air, not water, to hold shape.

Bend allowance: for a 90-degree bend, the developed length is approximately 1.57 x centre-line radius.

Press-fit joints require the correct jaw and full insertion mark; a partially inserted fitting will leak under pressure.

Flange joint: use a gasket matched to the service, align the bolt holes, and tighten bolts in a star pattern to even torque.

Brazing copper: use a flux suitable for the filler, purge with nitrogen on refrigeration lines, and cool slowly to avoid cracking.

Fusion welding of HDPE uses a heated plate and controlled pressure and time; the bead must be even all round.

Support after fabrication: fit clips or brackets close to every bend and branch so the joint is not load-bearing.

Leak test after fabrication: isolate, fill slowly, vent air, and hold at test pressure for the specified period before boxing in.

Mains pressure typically 1-4 bar in urban supply; above about 5 bar fit a pressure-reducing valve to protect fittings.

Storage cistern capacity check: 24-hour storage for the household plus fire or emergency reserve where required by the local authority.

Cistern overflow must discharge visibly to a warning pipe; the overflow diameter is normally one size larger than the inlet.

Water quality: use a WRAS-type approved or locally approved tank and fittings for potable water; cover and screen the tank to keep out insects and light.

Booster pump: fit after the tank, not directly on the mains unless the utility permits; include a low-level cut-out to prevent dry running.

Pipe insulation: lag cold pipes in unheated spaces to prevent condensation and freezing; lag hot pipes to reduce heat loss.

Water meter and stopcock: locate the meter and the customer stopcock, and label the internal isolator for the client.

Cross-connection control: maintain a physical air gap between the tap and any contaminated source when filling tanks or containers.

Drain testing: air test at about 38 mm water gauge for 3 minutes, or water test with a 1.5 m head above the highest point of the section.

Inspection chamber benching: channels should be smooth and half-round, with benching sloped to the channel to avoid solids settling.

Rodent protection: fit a rat guard or non-return flap on the drain outlet where required, and keep covers secure.

Soil stack offset: use two 45-degree bends rather than one 90-degree bend to reduce blockage risk.

Branch connection: use a swept junction in the direction of flow; a square junction against the flow causes solids to catch.

Gully grating must be removable for cleaning; keep the trap accessible and the seal intact after maintenance.

Rainwater system: separate from the foul drain; size gutters and downpipes from the roof area and local rainfall intensity.

Drain gradient check: a 1:60 fall on a 30 m run is 500 mm; confirm the invert level at each chamber before laying.

WC connector: use a flexible pan connector with a sealed joint; the pan must sit level and be screwed to the floor or wall bracket.

Cistern inlet: fit a double-check valve or air gap on the fill valve to prevent backflow into the supply.

Shower installation: fit a shower tray on a firm bed, seal with silicone, and check the waste trap is accessible for cleaning.

Bath installation: support the bath on a frame or feet, level it, and leave an access panel for the trap and waste.

Tap installation: fit the O-ring or washer on the correct side of the basin, use a basin wrench for the back nut, and check for drips after opening the supply.

Water heater safety: the pressure relief valve discharge must terminate safely, not be plugged or capped; test the relief valve annually.

Appliance connection: use a new hose with a sealing washer, fit a check valve where required, and check for leaks at the hose union.

Accessibility: where required, fit grab rails and lever taps at the heights specified by the local building code.

Diagnose by symptom: low flow, noise, leak, or blockage; test each section by isolation to localise the fault before opening anything.

Dripping tap: replace the washer or ceramic cartridge; check the seat for scoring and reseat or replace if damaged.

Leaking tank: check the tank joint washers, the ball valve seating, and the overflow; a crack needs a patch or replacement, not sealant alone.

Water hammer cure order: secure pipe clips, fit a shock arrester, check the pressure-reducing valve setting, then upsize the pipe.

Pump faults: check power supply, float switch, impeller for debris, and non-return valve before replacing the pump.

Preventive maintenance schedule: inspect tanks and valves annually, descale shower heads every 3-6 months, and test relief valves annually.

Spare parts: record the make and model of every appliance and fitting so the correct spare is ordered first time.

Handover after repair: explain the cause, the work done, and any user checks; provide a written record and warranty terms.

Break-even point = fixed costs / (selling price per job - variable cost per job); use it to set the minimum monthly job volume.

Markup vs margin: a 25 percent markup on cost equals a 20 percent margin on price; state which one is used in the quote.

Material wastage allowance in a quote is typically 5-10 percent; add it as a separate line so the client sees it.

Payment terms: state the due date, accepted payment methods, and late-payment terms in the quotation and invoice.

Customer complaint handling: listen, acknowledge, agree the remedy and timescale, record it, and follow up after the fix.

Marketing: a simple record of past customers, referrals, and local advertising channels is more effective than untargeted advertising.

Legal: keep a written contract for jobs above the agreed threshold, and check insurance and registration requirements before starting.

Business records: separate business and personal money, keep invoices numbered sequentially, and reconcile monthly.

Competence limits: decline or refer work outside your training rather than guess; a wrong gas or electrical connection can be fatal.

Honesty in reporting: record test results as measured, never write a pass for a test not carried out.

Respect at work: no harassment or discrimination; report concerns through the supervisor or the company procedure.

Client property: obtain permission before using facilities, and compensate or report any damage caused.

Data protection: store client records securely and dispose of them as required by local data rules.

Team communication: use a clear handover note at shift change covering work completed, work outstanding, and any isolation in place.

Environmental duty: dispose of chemicals and waste through approved routes, not into drains or open ground.

Continuing development: keep certificates current and update skills when materials or regulations change.

Toolbox talk topics: manual handling, excavation, confined space, electrical tools, and housekeeping; record attendance.

Permit to work: required for hot work, confined spaces, and work on live services; the permit states the precautions and the isolation.

Isolation procedure: identify the supply, switch off, lock off, tag, and prove dead before working on electrical or water systems.

Fire safety: keep extinguishers serviced, know the class of fire (A solid, B liquid, C gas, E electrical), and never use water on electrical or oil fires.

Housekeeping: clear offcuts and packaging as work proceeds; a tidy site reduces slips, trips, and cuts.

Noise: hearing protection is required where noise exceeds about 85 dB(A); core drilling and power saws exceed this.

Vibration: limit use of hammer drills and breakers; report tingling or numbness in fingers as early signs of HAVS.

Welfare: provide drinking water, washing facilities, and a place to rest and eat away from the work area.

Pipe run take-off: measure centre-to-centre, subtract the take-out of each fitting, then add thread or socket engagement.

Take-out for a 90-degree elbow is roughly the centre-to-face dimension; for a 45-degree elbow it is smaller and must be looked up from the manufacturer's table.

Gradient in percent = (fall / length) x 100; a 1:60 fall is about 1.67 percent.

Tank capacity in litres = volume in cubic metres x 1000; check against the daily demand per person.

Pipe surface area for insulation = pi x outside diameter x length; add for fittings at roughly 10-15 percent.

Scale drawing check: a 1:50 plan of a 4 m wall is 80 mm on paper.

Sketch conventions: label flow direction with an arrow, mark sizes (e.g. DN 110), and note the gradient on drainage runs.

Bill of quantities: list items by description, unit (m, nr, m2), quantity, and rate, then total.

Pressure ratings: uPVC drainage is not for pressure service; use pressure-rated uPVC or PPR for pumped or mains lines.

Temperature limits: uPVC is for cold and warm waste only; use cPVC, PPR, or copper for hot water above about 60 degrees C.

Jointing selection: solvent weld for uPVC, compression or press for copper, threaded for steel, fusion for HDPE.

Tool care: clean and oil pipe cutters, replace blunt blades, and store measuring tools away from moisture.

Measuring tools: tape for long runs, steel rule for short, spirit level for gradient, and a plumb bob or laser for vertical alignment.

Hole saws and core drills: use the correct size for the pipe, start slowly, and keep the bit cool with water.

Safety equipment check before use: inspect gloves, goggles, and harness for damage; replace damaged PPE, never repair it.

Material compatibility: use dielectric unions between dissimilar metals and check that sealants and tapes suit the pipe material.

Bend radius check: a bend tighter than the minimum radius will flatten or kink; use a former or bender for tight bends.

Spring removal: after bending, twist the spring in the direction of the bend to release it, then pull out.

Solvent weld cure times: about 15 minutes before handling, longer for larger diameters and cold weather; follow the cement manufacturer's table.

Solder joint leak: drain, clean, reheat, and re-solder; never add solder over a dirty or wet joint.

Threaded joint leak: dismantle, clean, renew the tape or compound, and retighten; do not over-tighten to stop a leak.

Fabrication drawing: mark the joint positions on the pipe before cutting, and number the parts to match the assembly drawing.

Expansion: long hot runs need an expansion loop or offset; allow roughly 1 mm per metre per degree C for plastics.

Final test: pressure test the fabricated section before boxing in, and record the result on the job sheet.

Head calculation: pressure at the outlet = (height of water above outlet in metres x 0.0981) minus friction loss in bar.

Friction loss rises with flow and falls with diameter; check the manufacturer's pipe chart rather than guessing.

Tank refill rate: size the inlet valve and float so the tank refills within the daily draw-off period.

Air gap: the inlet must discharge at least twice the inlet diameter above the overflow water level to prevent backflow.

Isolation and draining: fit a stop valve on the rising main and a drain cock at the lowest point so the system can be drained for repair.

Legionella control: keep stored cold water below 20 degrees C and hot water above 60 degrees C; avoid dead legs.

Pipe layout: keep runs short and direct, group services in ducts, and avoid burying joints in walls where possible.

Commissioning: flush, test, label the valves, and show the client where the main stopcock is.

Trap seal loss causes: evaporation in unused fittings, self-siphonage from a long branch, induced siphonage from a nearby discharge, and compression from a blocked vent.

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

Branch length limit: an unvented branch from a 100 mm stack is limited (commonly about 1.5-2 m) to avoid self-siphonage.

Drainage fall check: a 1:60 fall on a 20 m run is 333 mm; set the invert level at each end before laying.

Inspection chamber spacing: at every change of direction, at every junction, and at intervals of about 45 m on straight runs.

Testing: plug the lower end, fill to 1.5 m head above the highest point, and hold for at least 30 minutes before inspecting.

Materials: use uPVC soil and waste above ground, and suitable buried drainage pipe below ground with flexible joints at the building line.

Blockage prevention: avoid sharp bends, keep the gradient within range, and rod from the access point in the direction of flow.

Setting out: mark the centre lines on the wall and floor before drilling; check the fixture dimensions against the manufacturer's sheet.

Fixing: use the correct anchor for the wall type (masonry plug, chemical anchor, or timber noggin); plasterboard alone will not hold a basin.

Sealing: use sanitary silicone, not grout, at the junction of the fixture and the wall or floor.

Waste connection: fit the trap with a 50-75 mm seal, and ensure the waste pipe falls continuously to the stack.

Supply connection: fit isolation valves on each supply so the fixture can be serviced without draining the system.

Testing after installation: open the supply, flush, check for leaks at every joint, and check the trap seal holds.

Handover: show the client the isolation valves, explain the flush settings, and leave the manufacturer's instructions.

Access: leave access to the trap, valves, and cistern mechanism for future maintenance.

Systematic diagnosis: confirm the complaint, test the simplest cause first, isolate the section, then dismantle only what is needed.

Leak source test: dry the pipe, wrap with tissue, and observe which point wets first to locate a hidden leak.

Pressure loss test: isolate the section, fit a gauge, and watch for a drop to confirm a leak or a faulty valve.

Blocked drain: rod from the access point, flush with water, and check the flow before replacing the cover.

Pump not running: check the power, fuse, float switch, and overload; if the motor hums but does not turn, the impeller may be jammed.

Cistern overflow: check the float valve setting and the seating washer; replace worn parts rather than bending the arm.

Record keeping: keep a repair log with date, fault, action, parts, and the next service date.

Customer handover: explain what failed and why, and advise on prevention (e.g. not pouring fat down the sink).

Quote structure: scope, materials list, labour, contingency, exclusions, price, payment terms, and validity period.

Labour estimate: use a time allowance per fitting (e.g. hours per WC or basin) and multiply by the hourly rate.

Overhead recovery: add a percentage to each job for rent, vehicle, insurance, and admin; do not absorb it silently.

Cash flow forecast: list expected receipts and payments week by week to spot shortfalls before they happen.

Customer retention: follow up after the job, keep a maintenance reminder, and ask for a referral.

Complaint remedy: fix the fault first, then discuss compensation; record the outcome in writing.

Ethical pricing: do not inflate a quote because the client seems unaware of the market rate; explain the basis of the price.

Record of work: keep a signed job sheet and photos of the work before and after for warranty and dispute purposes.

Written communication: use clear, short sentences, state the date and job reference, and keep a copy of every message.

Verbal handover: confirm the listener has understood by asking them to repeat the key points.

Client boundaries: do not discuss other clients' jobs or prices, and do not use the client's facilities without permission.

Safety reporting: report near misses as well as accidents; a near miss is a free warning of a future accident.

Whistleblowing: report unsafe or illegal practice through the proper channel, and keep a written record.

Professional development: keep a log of training and certificates, and renew them before expiry.

Respect for diversity: use inclusive language and adapt communication to the client's needs, including language or disability.

Conflict resolution: separate the person from the problem, focus on the facts, and agree a written outcome.

Risk matrix: likelihood x severity gives the risk rating; use it to prioritise controls and decide if work can proceed.

Excavation safety: support the sides where required, keep spoil back from the edge, and provide a safe access route in and out.

Confined space entry: never enter to rescue without breathing apparatus; use the retrieval line and call for trained help.

Electrical isolation: lock off and tag, then test with a proving unit before and after to confirm the tester works.

Chemical storage: keep solvents in a locked, ventilated store with a spill kit and the safety data sheets available.

Environmental spill: contain with absorbent, prevent entry to drains, and dispose of the absorbent as hazardous waste.

Personal hygiene: change out of contaminated clothing before eating, and wash before handling food or drink.

Emergency plan: know the exit routes, the assembly point, and who is trained in first aid on site.

Conversion factors: 1 inch = 25.4 mm, 1 foot = 0.3048 m, 1 litre = 1000 cm3, 1 bar = 100 kPa = 10.2 m water head.

Flow rate: litres per minute = volume in litres / time in minutes; use it to check the pump or supply capacity.

Velocity check: velocity (m/s) = flow (m3/s) / pipe cross-section area (m2); keep domestic cold below about 1.5 m/s.

Pressure at a tap: static head in metres x 0.0981 = bar, then subtract friction loss from the pipe chart.

Roof drainage: downpipe capacity is sized from the roof area and local rainfall intensity; check the manufacturer's chart.

Tank sizing: daily demand per person x number of occupants x storage days = tank volume in litres.

Drawing check: confirm the scale, the north point, the levels, and the pipe sizes before using a drawing for take-off.

Sketch for a client: show the layout, the size of pipe, the location of the isolation valve, and the gradient on drains.

Pipe selection rule: match material to service (cold, hot, buried, pressure), then to jointing method, then to support spacing.

Pressure test values: domestic cold at 1.5 times working pressure, minimum 10 bar where the pipe is rated for it; hot at the system test pressure.

Valve selection: isolation (gate or ball), regulation (globe or pressure-reducing), prevention of backflow (check or RPZ).

Support and expansion: allow for thermal movement on hot runs and fit guides and anchors at the correct spacing.

Corrosion: dissimilar metals need a dielectric union; buried steel needs protection; copper in aggressive soil needs sleeving.

Tool check before use: inspect for damage, confirm the rating matches the task, and use the correct size for the fastener.

Material take-off: list by size and type, add waste, and check the delivery lead time before starting.

Commissioning record: pipe sizes, test pressure, test duration, and the signature of the person who tested.

Bend calculation: developed length of a 90-degree bend is about 1.57 x radius; mark the start and end of the bend on the pipe.

Spring bending limit: do not exceed about 90 degrees with a spring; for tighter or multiple bends use a bender or fittings.

Solvent weld sequence: cut, chamfer, clean, prime, cement, assemble with a quarter turn, hold, and allow to cure before pressure testing.

Compression joint sequence: cut square, deburr, insert fully, hand tighten, then half to one turn with a wrench.

Solder joint sequence: clean, flux, assemble, heat the fitting, feed solder, cool, and wipe.

Threaded joint sequence: cut thread, check with a gauge, apply tape, assemble, tighten 2-3 turns past hand tight.

Pressure test after fabrication: isolate, fill slowly, vent, hold at test pressure, and inspect every joint.

Record and label: mark the pipe with its service and size, and record the test on the job sheet.

System choice: direct where mains pressure and reliability are adequate; indirect where storage is needed for security of supply.

Tank position: high enough to give the required head at the highest outlet, and supported on a rigid, level base.

Tank protection: close-fitting lid, screened vent, screened overflow, and insulation against heat and frost.

Backflow prevention: air gap on the inlet, check valve on the mains, and no direct connection between the mains and a contaminated source.

Pipe sizing: check velocity and friction loss on the chart, and keep the pressure at the furthest outlet above the minimum required.

Isolation and labelling: stop valve on the rising main, drain cock at the lowest point, and a label at the main isolator.

Water quality: use approved materials for potable water and flush the system before handover.

Commissioning: pressure test, flush, check the flow at each outlet, and record the results.

System choice: one-pipe for compact layouts with a common vent; two-pipe where separate soil and waste routes are required.

Trap selection: P-trap with a 50-75 mm seal; avoid S-traps and use an air admittance valve where a vent cannot be run.

Gradient rule: 1:40 to 1:60 for small waste, 1:60 to 1:80 for soil, and never flatter than the self-cleansing gradient.

Vent rule: the stack extends above the roof, branch vents are sized to the drain, and the vent must not be blocked.

Access rule: rodding eye at the base of the stack, access cap at every change of direction, and inspection chamber at every junction.

Testing rule: air test at about 38 mm water gauge for 3 minutes, or water test with a 1.5 m head.

Connection rule: separate foul and surface water, and obtain approval before connecting to the public sewer.

Maintenance rule: keep covers accessible, keep the gully grating removable, and check the trap seal after every repair.

Setting-out rule: mark centre lines and fixing points from the finished wall and floor, and check against the manufacturer's dimensions.

Fixing rule: use the correct anchor for the wall type, and never rely on plasterboard alone for a basin or cistern.

Sealing rule: use sanitary silicone at the fixture-to-wall and fixture-to-floor junction, and leave a gap for movement.

Waste rule: fit a trap with a 50-75 mm seal, and fall the waste continuously to the stack.

Supply rule: fit isolation valves on each supply, and connect hot on the left and cold on the right.

Testing rule: open the supply, flush, check every joint, and confirm the trap seal holds.

Safety rule: the relief valve discharge must terminate safely and must never be capped.

Handover rule: show the client the isolation valves, explain the settings, and leave the instructions.

Diagnosis rule: confirm the complaint, test the simplest cause first, isolate the section, and dismantle only what is needed.

Leak rule: dry and wrap the pipe with tissue to locate the leak, then repair or remake the joint.

Blockage rule: rod from the access point in the direction of flow, flush, and check the flow before replacing the cover.

Cistern rule: check the float valve setting and seating washer, and replace worn parts rather than bending the arm.

Pump rule: check power, fuse, float switch, and overload before replacing the pump; a humming motor may have a jammed impeller.

Prevention rule: advise the client on use (no fat down the sink, no wipes in the WC) and set a service interval.

Record rule: keep a repair log with date, fault, action, parts, and the next service date.

Handover rule: explain the cause, the work done, and any user checks, and provide a written record.

Costing rule: job cost = materials + labour + overhead + contingency; price = cost / (1 - margin) when margin is stated.

Quote rule: state scope, materials, labour, contingency, exclusions, price, payment terms, and validity.

Cash flow rule: forecast receipts and payments week by week, and keep a reserve for slow payers.

Record rule: number invoices sequentially, keep receipts, and reconcile monthly.

Customer care rule: confirm the appointment, protect the property, explain the fault in plain language, and leave the area clean.

Variation rule: agree any change in writing with price and time impact before the work proceeds.

Ethics rule: do not inflate a price because the client seems unaware of the market rate; explain the basis of the price.

Retention rule: follow up after the job, keep a maintenance reminder, and ask for a referral.

Competence rule: work only within your training and registration, and refer work outside your competence.

Honesty rule: record test results as measured, and never sign off work you did not perform or supervise.

Confidentiality rule: do not disclose client details, access codes, or site information without consent.

Conflict rule: disclose any relationship with a supplier or subcontractor before recommending their product.

Communication rule: confirm instructions in writing, keep a copy, and use clear language with the client.

Safety rule: report accidents and near misses immediately, and keep a written record.

Respect rule: use inclusive language, respect the client's property, and never work under the influence of alcohol or drugs.

Development rule: keep certificates current and update skills when materials or regulations change.

Hierarchy of control: eliminate, substitute, engineer, administrate, then PPE last.

Risk assessment: identify the hazard, who may be harmed, the risk rating, the controls, and the review date.

PPE: hard hat, safety boots, eye protection, gloves, hearing protection, dust mask, and high-visibility clothing where required.

Excavation and confined space: locate services, support the sides, test the atmosphere, ventilate, and use a standby person and retrieval line.

Electrical safety: isolate, lock off, tag, prove dead, and use RCD-protected or 110 V tools.

Manual handling: keep the load close, bend the knees, avoid twisting, and use a two-person lift or aid above about 25 kg.

Chemicals: obtain the safety data sheet, ventilate, store away from ignition, and use a spill kit.

Environment: segregate waste, contain slurry and solvents, and never discharge them to drains or watercourses.

Emergency: know the first-aid kit, extinguisher, eyewash, and assembly point, and report every incident.

Scale: real length = drawing length x scale denominator; state the scale and units on every drawing.

Projection: first-angle places the view on the far side; third-angle places it on the near side.

Isometric: axes at 30 degrees to the horizontal; draw true lengths along the axes.

Dimensioning: dimension lines parallel to the edge, arrowheads at both ends, figures above the line, no closed dimensions.

Gradient: fall = length x gradient; percent = (fall / length) x 100.

Area and volume: pipe area = pi x r squared; cylinder volume = pi x r squared x length; tank volume = L x W x D.

Take-off: measure centre-to-centre, subtract fitting take-outs, add thread or socket engagement, and add 10-15 percent waste.

Conversions: 1 inch = 25.4 mm, 1 bar = 100 kPa = 10.2 m water head, 1 litre = 1000 cm3.

Sketch conventions: flow arrows, pipe sizes, gradients, and the location of isolation valves.

Material selection: uPVC for soil and waste, cPVC or PPR for hot water, copper for potable hot and cold, HDPE for buried mains.

Jointing selection: solvent weld for uPVC, compression or press for copper, threaded for steel, fusion for HDPE.

Cutting: square the cut and deburr; use a wheel cutter or hacksaw for plastics, a pipe cutter with reamer for copper.

Bending: use a spring sized to the bore, or a bender for tight radii; anneal copper before tight bends.

Pressure test: 1.5 times working pressure, minimum 10 bar where rated, held for at least 1 hour.

Valves: gate or ball for isolation, globe for throttling, check for one-way flow, air admittance for venting.

Support: plastics need closer clips than copper or steel; fit clips close to every bend and branch.

Threads: BSP parallel, PTFE tape on male threads only, 3-5 turns in the direction of tightening.

Storage: keep plastic pipe out of sunlight, support it along its length, and cap open ends.

Bend radius: minimum about 3-4 times the outside diameter for copper; below that use a bender or anneal.

Spring bending: insert the spring, bend slowly, twist to release, then pull out.

Solvent weld: cut, chamfer, clean, prime, cement, assemble with a quarter turn, hold, and cure before testing.

Compression: cut square, deburr, insert fully, hand tighten, then half to one turn with a wrench.

Solder: clean, flux, heat the fitting, feed solder, cool, and wipe.

Thread: cut, check with a gauge, apply tape, assemble, and tighten 2-3 turns past hand tight.

Fabrication: dry-fit before permanent jointing, mark the joint positions, and number the parts.

Expansion: allow for thermal movement on long hot runs with a loop or offset.

Test: isolate, fill slowly, vent, hold at test pressure, and record the result.

System choice: direct where mains pressure and reliability are adequate; indirect where storage is needed.

Tank sizing: about 100-150 litres per person per day for domestic storage.

Tank position: high enough to give the required head, on a rigid level base, with a lid, screened vent, and screened overflow.

Pressure: static head in metres x 0.0981 = bar, minus friction loss.

Backflow: air gap on the inlet, check valve on the mains, and no direct connection to a contaminated source.

Pipe sizing: keep velocity around 1-1.5 m/s to limit noise and erosion.

Isolation: stop valve on the rising main, drain cock at the lowest point, and a label at the main isolator.

Water quality: use approved materials, flush before handover, and keep stored cold water below 20 degrees C.

Commissioning: pressure test, flush, check the flow at each outlet, and record the results.

System choice: one-pipe for compact layouts; two-pipe where separate soil and waste routes are required.

Trap seal: 50-75 mm; avoid S-traps and use an air admittance valve where a vent cannot be run.

Gradient: 1:40 to 1:60 for small waste, 1:60 to 1:80 for soil, and never flatter than the self-cleansing gradient.

Vent: the stack extends above the roof, branch vents are sized to the drain, and the vent must not be blocked.

Access: rodding eye at the base of the stack, access cap at every change of direction, and inspection chamber at every junction.

Testing: air test at about 38 mm water gauge for 3 minutes, or water test with a 1.5 m head.

Connection: separate foul and surface water, and obtain approval before connecting to the public sewer.

Maintenance: keep covers accessible, keep the gully grating removable, and check the trap seal after every repair.

Materials: uPVC above ground, suitable buried drainage pipe below ground, with flexible joints at the building line.

Setting out: mark centre lines and fixing points from the finished wall and floor, and check the manufacturer's dimensions.

Fixing: use the correct anchor for the wall type, and never rely on plasterboard alone for a basin or cistern.

Sealing: use sanitary silicone at the fixture junction, and leave a gap for movement.

Waste: fit a trap with a 50-75 mm seal, and fall the waste continuously to the stack.

Supply: fit isolation valves on each supply, and connect hot on the left and cold on the right.

Testing: open the supply, flush, check every joint, and confirm the trap seal holds.

Safety: the relief valve discharge must terminate safely and must never be capped.

Handover: show the client the isolation valves, explain the settings, and leave the instructions.

Access: leave access to the trap, valves, and cistern mechanism for future maintenance.

Diagnosis: confirm the complaint, test the simplest cause first, isolate the section, and dismantle only what is needed.

Leak: dry and wrap the pipe with tissue to locate the leak, then repair or remake the joint.

Blockage: rod from the access point in the direction of flow, flush, and check the flow before replacing the cover.

Cistern: check the float valve setting and seating washer, and replace worn parts rather than bending the arm.

Pump: check power, fuse, float switch, and overload before replacing the pump; a humming motor may have a jammed impeller.

Prevention: advise the client on use and set a service interval.

Record: keep a repair log with date, fault, action, parts, and the next service date.

Handover: explain the cause, the work done, and any user checks, and provide a written record.

Costing: job cost = materials + labour + overhead + contingency; price = cost / (1 - margin) when margin is stated.

Quote: state scope, materials, labour, contingency, exclusions, price, payment terms, and validity.

Cash flow: forecast receipts and payments week by week, and keep a reserve for slow payers.

Records: number invoices sequentially, keep receipts, and reconcile monthly.

Customer care: confirm the appointment, protect the property, explain the fault in plain language, and leave the area clean.

Variation: agree any change in writing with price and time impact before the work proceeds.

Ethics: do not inflate a price because the client seems unaware of the market rate; explain the basis of the price.

Retention: follow up after the job, keep a maintenance reminder, and ask for a referral.

Competence: work only within your training and registration, and refer work outside your competence.

Honesty: record test results as measured, and never sign off work you did not perform or supervise.

Confidentiality: do not disclose client details, access codes, or site information without consent.

Conflict: disclose any relationship with a supplier or subcontractor before recommending their product.

Communication: confirm instructions in writing, keep a copy, and use clear language with the client.

Safety: report accidents and near misses immediately, and keep a written record.

Respect: use inclusive language, respect the client's property, and never work under the influence of alcohol or drugs.

Development: keep certificates current and update skills when materials or regulations change.