N Furniture/ Equipment
N13 Sanitary appliances and fittings: 10, 11, 25, 30, 300, 302, 331, 335, 341, 346, 500

R Disposal systems
R10 Rainwater drainage systems: 241
R11 Above ground foul drainage systems: 21, 315, 345

S Piped supply systems
S90 Hot and cold water supply systems - domestic: 53, 540

T Mechanical heating, cooling and refrigeration
T90 Heating systems - domestic: 50, 410

Y General engineering services
Y10 Pipelines: 130