17 cfm/person because a large body of
evidence shows an increase in the prevalence of building-related upper respiratory symptoms when ventilation rates
decrease. We look at commissioning
documents, test and balance reports and
real-time airflow station data to determine whether the design intent was met.
These spaces were provided additional
ventilation prior to occupancy. Total aldehydes and TVOCs have never exceeded
criteria. During the next year, data will
increase four-fold as we baseline over a
million square feet of new space.
Volatile Organic Compounds
We characterize total volatile organic
compounds (TVOCs), formaldehyde and
total aldehydes (including formaldehyde)
to baseline exposure and verify the effectiveness of our material selection program. Four-hour samples are collected
on multisorbent tubes and 2,4-dini-
torophenylhydorazine (DNPH) cartridges.
Results are presented in Table 2.
Criteria for TVOC and formaldehyde
are from the 2009 LEED Rating System
for New Construction and Major Renovations. Unlike LEED, we continue to evaluate total aldehydes because it is a better
exposure metric for the irritant effects of
these compounds than formaldehyde
alone. The panel includes 2-butenal, acetaldehyde, benzaldehyde, 2,5-dimethyl-
benzaldehyde, 2-methylbenzaldehyde,
3-and/or 4-methylbenzaldehyde, butanal,
3-methylbutanal, hexanal, pentanal and
propanal. This list was developed by the
GreenGuard Environmental Institute for
testing building materials, casegoods and
system furniture.
To date, 18 percent of the formaldehyde
samples collected exceeded the criterion.
Acoustical Assessment
We use the RC Mark II Noise Rating to
characterize the acoustical environment.
The method was originally developed to
rate the acceptability of HVAC noise but
is applicable to all sources of broadband
noise. The rating takes the form of RC xx
(yy). The first term is the value of the RC
reference curve. The second term identifies the character of the noise: (N) for
neutral, (LF) for low frequency rumble,
(MF) for mid-frequency roar and (HF) for
high-frequency hiss. The Quality Assessment Index (QAI) measures spectral imbalance and estimates occupant
satisfaction using Acceptable, Marginal
and Objectionable as keywords.
Calculations are beyond the scope of
this article, but several spreadsheets are
available on the Internet. We simply load
octave band data into the application,
and it calculates the rating and the QAI
and graphs the RC curve.
Our standard for open architecture is
RC 35-40 (N). Most locations meet the
criteria, but we find outliers in space underneath or adjacent to mechanical
rooms and in mixed-use space where
auxiliary cooling is provided for computers and servers.
Table 3. Post-Occupancy Evaluation Criteria
Post-Occupancy Evaluation
HVAC Diagnostics
After the building is occupied for six to
twelve months, we return for a post-occupancy evaluation. Direct-reading instruments are placed in representative
space for five to seven days to trend carbon dioxide, carbon monoxide, temperature, relative humidity and dew point.
Twenty-four-hour samples are collected
to characterize PM10 and PM2.5. Data is
compared with the criteria in Table 3.
Most of our new buildings meet the
criteria. If problems are identified, we review trend data from the energy management control system and consult with
engineering and maintenance staff to
determine causal factors and develop
cost-effective solutions.
Operations and Maintenance
(O&M) Program
We review the O&M program and perform a second mechanical hygiene assessment to verify its effectiveness. We’ve
adopted ASHRAE Standard 180 in service
contracts and work with facilities to do a
gap analysis if problems are identified.
Most of our service providers have
loaded the required tasks and frequencies
into their asset management system to
generate routine maintenance tickets.
Metric
Criteria
Carbon dioxide
400 ppm delta between indoor and out-
door levels
Carbon monoxide
9 ppm
Occupant Surveys
The Center for the Built Environment
(CBE) at the University of California,
Berkeley has developed a web-based
“Occupant Indoor Air Quality Survey”
that includes questions on office layout,
furnishings, thermal comfort, air quality,
lighting and acoustic quality. Survey results can be reviewed immediately using
online reporting tools and benchmarked
against data from several hundred buildings. We plan to launch the survey at
three new buildings totaling over a million square feet in 2012–2013.
Temperature
Relative humidity
72 ± 2 degrees Fahrenheit
60 percent
PaulK.Buckmaster,MS,CIH,CIEC,isanindustrial
hygieneconsultantforadefenseagencylocatedat
FortMeade,Md.Hecanbereachedatpkbuckmaster
@ msn.comor(410)961-2299.
PM10
50 µg/m3
PM 2.5
15 µg/m3
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