June 2006
Building Subsystems
The prototype system design includes six specific building subsystems that are referred to as
integrated subsystems: structure, partitions, and walk-on platform (interstitial deck) are "shell"
subsystems; HVAC, plumbing and electrical are "service" subsystems. Other subsystems such
as foundations, exterior closure, roof, and conveying systems have been excluded and are re-
ferred to as non-integrated subsystems. Communications systems were originally considered
non-integrated systems. The increases in the numbers and complexity of telephone/data and
other "low-voltage" sub-systems warrant considering them as integrated service subsystems.
Shell Systems
Structural: The structural system may be steel frame or reinforced concrete frame. Selection
would be based on engineering and economic analysis.
Partition: Partition subsystem is the generic term used in the Red Book for non-load bearing,
vertical, interior construction used to subdivide or enclose portions of the building volume.
Components must provide a wide range of performance in terms of impact resistance, finishes,
fire and/or smoke resistance, acoustics, x-ray shielding, etc. In current practice, "partitions" with
fire or smoke resistance ratings are called "fire barrier walls" or "smoke barriers" as defined in
NFPA 101. Except as required for code compliance, construction will typically terminate under-
side of the platform. The Red Book envisioned that the final service runs in the functional zone
would be installed outside, or on the surface of, the partitions. In current practice, vertical ser-
vice drops to a room or area are to be concealed within the partitions. Horizontal distribution of
services is to remain in the defined service zones.
Platform: The walk-on platform/ceiling subsystem has also evolved from the system originally
described in the Red Book. The Red Book defined subzone S-6 as the ceiling: a combined
walk-on platform or interstitial deck with surface applied finishes and fixtures on the underside
(exposed to the functional zone). Current practice uses two subzones, S-6 and S-7. The S-6
subzone is the platform. The S-7 subzone includes the space below the platform and the sus-
pended finish ceiling. Light fixtures are typically recessed in the finish ceiling. Refer to Section
4 Application to New Projects and Appendix C for examples of walk-on platform and ceiling con-
struction.
Service Systems and Subzones
The service subsystems for each service module are located within the service zone, i.e., within
the service bay and/or the horizontal portion of the service zone (interstitial space) above the
functional zone. To many A/E's the platform/ceiling subsystem and the interstitial space it cre-
ates are the most prominent features of the VAHBS. The platform allows for better organization
of service distribution, improved access for maintenance or modification of services with re-
duced impacts to functional zones. The integration and coordination of building services are
much more important to the successful application of the VAHBS.
The service zone is highly organized into reserved subzones for the various mechanical, plumb-
ing, fire protection, electrical and tele/data services. The purposes of this "pre-coordination" are
to provide clear channels for access and passage for all trades, to minimize crossovers and
other conflicts, to assure reasonable space for future extensions and additions, and to permit
positive location of all components. All services, except gravity drains, downfeed into the func-
tional zone below.
SUPPLEMENT TO RESEARCH STUDY REPORT
VA HOSPITAL BUILDING SYSTEM
SECTION 2-5
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