Timothy Smerz, president of Air Comfort Corp., suggests warehouse
owners and managers step back to make sure they—and their
HVAC contractors—understand their HVAC requirements before
upgrading or installing a whole new system. Smerz offers this
advice:
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Understand the unique environmental needs of the products
to be stored. This is essential in order to make sure the
HVAC designer/contractor understands these needs. Do the products
stored in the warehouse have specific temperature or humidity
requirements? Do they produce or give off additional heat
to be considered when sizing the system? Food storage, molding
processes, printing and paper companies are just a few examples
of applications that will probably have special temperature
and humidity needs.
-
Recognize that proper air distribution is key. If items are
stacked to the ceiling—even periodically—they
can impede the air flow that adversely affects the air distribution
pattern. Cooling units and ductwork should be installed in
such a way so that the air can reach the aisles. Also, proper
air filtration will help control dust and dirt build-up.
-
Analyze how the warehouse is operated. Make sure the HVAC
activities are designed to fit in with the day-to-day operations
of the warehouse. How is the product moved throughout the
warehouse? What is the average length of time the product
is stored? Does it move to several locations throughout the
warehouse? How often are shipments sent and received? This
will have a significant effect on the heat loss and gain.
Exceptionally high frequency of loading doors being opened
may require special ventilation methods such as air curtains.
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Select HVAC equipment that best suits the needs of the warehouse.
If floor space is at a premium, as it often is in a warehouse,
consider rooftop units. Many warehouses utilize Unit Heaters—small,
self-contained heating units that hang from the ceiling and
do not require duct work. Other commonly selected units for
warehouse applications are Air Turnover and Make-Up Air Systems
which pressurize a warehouse with a high volume of heated
air, but which require a minimum of ductwork.
-
Understand the building pressure conditions. Is the warehouse
negatively or positively pressurized? A building will have
a negative pressure relative to the atmosphere when there
is more air being exhausted than there is being introduced
through make-up air systems and fresh air intakes. A building
will be positively pressurized if there is more outside air
being introduced than what is being exhausted.
It is important to understand which situation is more desirable
based on the circumstances of the warehouse. For instance, a
warehouse may stock items which produce odors or fumes. Under
this scenario, a negative pressure would more likely be preferred—so
that all contaminated air is being exhausted and the outside
air being introduced is only slightly less. This will cause
some additional air to be made up through infiltration. If however,
this particular warehouse were to be positively pressurized,
some of the air contaminated with odors or fumes would escape
through exfilatration from the higher pressure warehouse to
an adjacent area with lower relative pressure, which could include
office space or common areas. |
