Section 2: Individual LEED Credit Reviews
LEED Credit EQ-7.1:
notes that humidification of general office spaces
can be considered if severe winter conditions
Thermal Comfort
would likely cause the relative humidity to fall
below 30 percent Projects that provide this active
Compliance w/
humidification, or that are located in mild climates
ASHRAE 55-1992
where winter humidification is not required, will
meet the full credit requirements.
For the purposes of this study, it is assumed that
Intent
natural ventilation strategies meeting the LEED
credit criteria are unlikely for most GSA building
Provide a thermally comfortable environment
types.
that supports the productive and well-being of
building occupants.
Basis for Cost Assumption
Requirement
In the Courthouse model, building-wide
Comply with ASHRAE Standard 55-1992,
humidification is included in the reference cost
Addenda 1995, for thermal comfort standards
budget. No premium is assumed to meet the credit
including humidity control within established
requirements.
ranges per climate zone. For naturally ventilated
The Office Building model does not include
buildings, utilize the adaptive comfort
humidification in the baseline reference costs.
temperature boundaries, using the 90%
Premiums have therefore been defined to provide
acceptability limits as defined in the California
a pneumatic atomizing humidification system. The
High Performance Schools (CHPS) Best
system costs include humidifiers, air compressors,
Practices Manual, Appendix C A Filed Based
and water deionizers, as well as RH sensors and
Thermal Comfort Standard for Naturally
system tie-backs to the Building Management
Ventilated Buildings, Figure 2.
System.
(1 point)
Because of moisture condensation concerns, this
credit is only considered viable in the full faade
renovation scenarios. As part of the faade re-
Cost Impact = 1 or 5
cladding, rigid insulation is provided within the
new pre-cast concrete panels. This "exterior"
insulation reduces the possibility of moisture
1
2
3
4
5
condensation within the exterior wall assembly. In
GSA
No
Low
Moderate
High
the minimal faade renovation scenarios, only
Standard
premium,
premium
premium
premium
interior batt insulation is provided at the exterior
(no cost)
psble svgs
(<50K)
(50-150K)
(>150K)
walls. Humidification is not considered prudent in
these cases because condensation can potentially
Practical Applications
form within the exterior wall cavities and lead to
mold growth and premature deterioration of the
For most GSA projects, the viability of this credit
wall assembly.
will depend upon the temperature and relative
humidity ranges that are maintained in the building
year-round. GSA's P100 includes criteria for
indoor design temperatures and relative humidity
(RH). The listed temperatures (winter and summer)
and maximum RH (summer) are consistent with
the established comfort ranges of ASHRAE
Standard 55-1992. P100 also requires minimum
wintertime relative humidity in Courtrooms and
Communications/Telephone Frame rooms, and
GSA LEED COST STUDY
150
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