Page 311 - The Engineering Guide to LEED-New Construction Sustainable Construction for Engineers

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building at entryways that are directly connected to the outdoors and that serve as
regular entry points for building users. Acceptable entryway systems include
permanently installed grates, grilles, or slotted systems that allow for cleaning
underneath. Roll-out mats are only acceptable when maintained on a weekly basis by
a contracted service organization.
• Where hazardous gases or chemicals may be present or used (including garages,
housekeeping/laundry areas and copying/printing rooms—LEED 2009 also
specifically lists science laboratories, prep rooms, art rooms and shops of any kind),
exhaust each space sufficiently to create negative pressure with respect to adjacent
spaces with the doors to the room closed. For each of these spaces, provide self-
closing doors and deck to deck partitions or a hard lid ceiling. The exhaust rate
shall be at least 0.50 cfm/sq. ft., with no air recirculation. The pressure differential
with the surrounding spaces shall be at least 5 Pa (0.02 inches of water gauge) on
average and 1 Pa (0.004 inches of water) at a minimum when the doors to the rooms
are closed.
• In mechanically ventilated buildings, provide regularly occupied areas of the building
with air filtration media prior to occupancy that provides a Minimum Efficiency
Reporting Value (MERV) of 13 or better. Filtration should be applied to process both
return and outside air that is to be delivered as supply air.
• LEED 2009 also requires that closed containment be provided for storage of hazardous
liquid wastes for appropriate off-site disposal in a regulatory compliant storage area
(preferably outside) in places where water and chemical concentrate mixing occurs
(e.g. housekeeping, janitorial and science laboratory areas).

Potential Technologies and Strategies
Design facility cleaning and maintenance areas with isolated exhaust systems for
contaminants. Maintain physical isolation from the rest of the regularly occupied areas
of the building. Install permanent architectural entryway systems such as grills or grates
to prevent occupant-borne contaminants from entering the building. Install high-level
filtration systems in air handling units processing both return air and outside supply air.
Ensure that air handling units can accommodate required filter sizes and pressure
drops.

Considerations and Exemplary Performance (LEED 2009)
Most of the prescriptive items in IEQc5 are well detailed in the requirements section
already noted and there are many additional suggestions for controlling indoor
pollutant sources in the LEED 2009 Reference Guide, such as not locating HVAC
intake grills near outdoor sources of pollution. There is also an additional
requirement listed in the LEED 2009 Reference Guide for facilities which have
temporary backup power battery banks in that these battery banks must be
segregated from other areas. Note also that even though there are requirements to
treat copier/printing rooms as hazardous chemical areas, this excludes what are
referred to as “convenience” printers and copiers, those small units typically used
at one’s workstation. The requirements for IEQc5 are summarized in Fig. 6.5.1. It
should be added that in the design phase, care should be taken to specify HVAC
equipment that filter media with an MERV rating of 13 or better can fit, and that
these filters are installed and used on the equipment at all times, even prior to
occupancy (see IEQc3.1 and 3.2).
There is no EP point associated with this credit for either the 2.2 or the 2009 version
of LEED.