Installation Practice
This domain tests how you actually install: setting out, jointing, supporting, protecting and testing.
Jointing
Copper capillary joints need clean, fluxed pipe and even heat until solder is drawn in; press fittings need the correct jaw and full insertion; compression needs the olive square and only nipped up; push-fit needs the insert and a depth mark.
Support and protection
Clip distances depend on material and temperature - plastics need more support and allowance for expansion. Sleeve pipes through walls, fire-stop where a compartment is penetrated, keep pipes out of the cold zone and insulate.
Notching and drilling
A hole in a joist should not exceed 0.25 of its depth and should sit between 0.25 and 0.4 of the span from the support, with holes at least three diameters apart. Notches belong on the top edge and are shallower.
Testing
Pressure-test before concealment. BS EN 806-4 sets the test at 1.5 times the maximum design pressure; check the manufacturer's limit for plastics, which can be lower. Record the result.
Worked example
A 200 mm by 4 m joist needs a route across a first floor. Maximum hole = 50 mm, and it must lie between 1.0 m and 1.6 m from the support. A 22 mm pipe plus insulation will not fit, so the reasoned answer is to run below the joists in a service void or along a wall, not to notch the joist.
Traps that cost marks
Over-tightening compression fittings; not reaming copper; testing after boxing in; forgetting expansion allowance on long plastic runs; drilling a joist at mid-span.