Page 26 - 14th @ Irving Basis of Design (internal)

3.2.9 THERMAL PROPERTIES OF THE BUILDING ENVELOPE
Item Thermal Value

Glass U=0.38, SHGC=0.4

Walls Above Grade R=13

Floor above outdoor air or R=19
unconditioned space

Roof R=19

3.3 GENERAL

a. All heating, ventilating and air conditioning work will include all materials, equipment, labor and miscellaneous
appurtenances to provide a complete installation of all system functions indicated herein.

b. The requirements from LEED 2.2 guidelines will be incorporated in HVAC design to achieve the Gold certification level.

3.4 SYSTEM DESCRIPTION

3.4.1 BUILDING AIR CONDITIONING SYSTEM

1. Air-cooled variable refrigerant flow (VRF) system with heat recovery is selected as the primary source of comfort cooling and
heating for this project. Ventilation air will also be provided via outdoor air processing VRF fan coil units coupled with
dedicated outdoor VRF units.

TYPICAL OFFICE FLOOR AIR CONDITIONING SYSTEM
1. Each office floor will be served by multiple outdoor VRF units and multiple indoor fan coil units.
2. The outdoor VRF units will be located in an outdoor plenum on the floor they serve. Each plenum will be protected from the
elements by stormproof louvers. The outdoor VRF units will be free standing within the plenum for a non-ducted air intake.
Each unit will be provided with a ducted connection from the fan discharge to the louvers.
3. The combined capacity of the VRF system providing comfort cooling and heating to a typical office floor is estimated at 28
tons.
4. Multiple indoor fan-coil units will be provided to serve interior open office areas, perimeter areas, private offices and
conference rooms. Multiple branch circuit controllers will be provided to facilitate energy recovery between the units serving
each floor. The system diversity factor will not exceed 120%.
5. In addition to the 3-pipe refrigerant distribution system, each indoor fan coil unit will be provided with a condensate pump.
The condensate will be piped back to the nearest mechanical room.

6. Outdoor air will be delivered via one local outdoor air processing (ventilation) unit to provide outdoor air for occupants and
for make-up air exhausted from the toilets. An additional outdoor VRF Unit will be provided on each floor to serve the outdoor
air processing units.

14th @ IRVING WSP
Project No. B1809809.000
RAL COMPANIES & AFFILIATES Page 26