Brief definition
Cost group 400 under DIN 276 comprises technical installations (heating, ventilation, plumbing, electrical, conveying systems, etc.) — separate from building structures (KG 300).
Relevance for quantity take-off
Many KG 400 items are represented via bills of materials, pipe runs, and connections. Floor-plan geometry alone does not cover all KG 400 quantities; it is nevertheless the starting point for interfaces and coordination with KG 300.
AIGO relevance
AIGO focuses on verifiable take-off from 2D architectural PDFs (rooms, areas, component lengths). Exported data supports assignment in downstream estimating and procurement systems.