Key Considerations for Service Openings in High-Rise Buildings

In a multi level building mechanical and electrical system lines move vertically up and down, up to full height of the building. These include chilled and hot water pipes from plant room to air handling unit rooms. Air ducts from AHU rooms to each floor move both vertically and horizontally.

Structural provisions are planned during design stage. These are coordinated with architectural and structural teams. Location of these openings is selected keeping in view access for maintenance. Easy access is required to these shafts during operation of the building. Working space in front of access panels is provided for ease of maintenance work.

These openings are coordinated with building layout. Wall along elevator well is used for this purpose. This is normally concrete wall which is vertically built. Slab openings are provided at each level along this wall, outside of well. When mechanical rooms are provided at each level, this shaft opens inside each room. All rooms are connected with this opening.

Where duct branches move horizontally from main ducts within these openings, drop beam is avoided. Drop beam further lowers duct levels. Space for fire dampers is provided for branch take offs. Units are located at a distance from these openings to provide sufficient space for unit discharge straight runs and return duct connections. Size of vertical shafts is selected keeping in mind future extensions and other services. Plumbing and fire fighting services also run along ducts and chilled water or condenser water pipes.

Normally shafts are split according to services required. Water and air services are kept separate from electrical cables and wires. Communication and data cables run in separate ducts from power cables. Splitting ducts as per services and close to area of usage reduces system losses. Instead of one large duct, two or three ducts are used at opposite ends of the building for large floor areas. Ducts and pipes for each wing or zone are separated from plant room. Building is vertically split in to sections. Services of each section run in its own riser close to area being served at each level. Less fan and pump power is used with this scheme. System performance improves.