Plumbing Tools, Equipment, Materials and Trade Calculations
Tools and equipment
Know hand tools (pipe cutters, deburring tools, wrenches, benders, flaring blocks), power tools (press tools, core drills, reciprocating saws), and test equipment (pressure gauges, manometers, flow cups, leak detection). Understand which tool suits which material: copper cutters and reamers versus plastic wheel cutters or shears; press fittings require the correct jaw and full insertion mark. Maintenance matters - calibrated gauges and sharp cutters prevent defects.
Materials
Compare copper, PEX, cross-linked polyethylene, PVC, and PP-R for pressure, temperature, and chemical suitability. Know that copper and steel can galvanise corrosion when joined, that dissimilar metals need dielectric separation, and that solvent-cemented joints need correct primer and cure time. Fixtures, traps, valves, and supports each have ratings; support spacing depends on pipe material and diameter.
Trade calculations
You must be able to compute pipe volume, flow rate, pressure, gradient, and material quantities. Key formulas: volume of a cylinder = πr²h; flow = area × velocity; pressure from head = height × density × gravity (roughly 9.8 kPa per metre of water). Fall on a drain = gradient × length. Allow for fittings and waste when ordering.
Worked example
How much water is in 20 m of DN50 pipe (internal diameter 50 mm)? Radius 0.025 m, area = π × 0.025² ≈ 0.001963 m², volume = 0.001963 × 20 ≈ 0.0393 m³ ≈ 39 litres. Trap: converting mm to m before squaring is the most common error, and using nominal diameter when the internal bore differs gives an overestimate.