In the construction industry, Tier 1 is a Contractor referred in ISO 19650 as the Lead appointed party, who provide goods or services directly to the ultimate client.
The Tier 1 are equivalent of the PAS 1192‑2:2013 lead suppliers

In the construction industry, Tier 1 is a Contractor referred in ISO 19650 as the Lead appointed party, who provide goods or services directly to the ultimate client.
The Tier 1 are equivalent of the PAS 1192‑2:2013 lead suppliers
Life Safety Generator selection guide If the secondary power supply
Wiring in Protected Escape Route Compliance with fire safety regulations
Create unlimited lighting variations with advanced parametric control Introduction The