Ventilation and air filtration are important considerations for building design.

Here are the following

Air Exchange: The best home ventilation systems have achieved a perfect balance between energy
efficiency and adequate air exchange. It is important to have a way for stale air to escape from a home.
Stale air often smells musty or dirty. A home that is sealed too tightly can also trap harmful airborne
particles, such as radon or volatile organic compounds found in many paints and cleaning products.
Allowing too much air to escape can result in costly energy bills, which is why it’s important to calibrate
your ventilation system so as to allow just enough air exchange.

Preserve insulation: The insulation in a building that is improperly ventilated often collects moisture.
Wet insulation loses its ability to do its job properly. This can result in energy bill increases and will
eventually necessitate new insulation. Preserving the integrity of the existing insulation is another
reason to make sure the building is properly ventilated.

Avoid Excess Moisture: Excessive moisture can also do damage to the basic structure of the building.
Mold, mildew and rot occur not only below the roof, but also all throughout an improperly ventilated
home. These are often considerable expenses associated with replacing structurally unstable rotten
wood. Mold and mildew are also associated with negative health effect that homeowners should avoid.

Occupancy Rates and Activities: Proper warehouse ventilation is important to ensure the health,
comfort and safety of the human beings who will be working in the space. The higher the occupancy
rate, the longer the time people spend in the area, and the more strenuous the work demands, the
more critical ventilation will be.

Material Storage Requirements: Some materials—like dry goods, paper products or pharmaceuticals—
may require temperatures and humidity levels to stay within a defined range. Other materials, such as
construction materials, may be more forgiving. Warehouse ventilation is an important component of
maintaining appropriate indoor temperatures and humidity levels..

Filtration Needs: Ventilation principles to bring fresh air in and exhaust stagnant air to the outside.
However, it may be desirable to add filtration options to improve indoor air quality. Filtration can be
used with supply fans to remove outdoor contaminants such as dust, pollen or air pollution from intake
air. If the warehouse is heated or cooled, this will reduce the strain on HVAC system filters. Warehouses
rarely produce enough emissions to require filtration on exhaust fans. However, if excessive fumes and
particulate are building up in the breathing zone due to the use of material handling equipment, it may
be desirable to use portable air purifiers in areas where humans are working.
Dilution ventilation controls pollutants generated at a worksite by ventilating the entire workplace. The
use of general ventilation distributes pollutants, to some degree, throughout the entire worksite and
could therefore affect person who are from the source of contamination.

Dilution ventilation can be made more effective if the exhaust fan is located close to exposed workers
and the makeup air is located behind the worker so that the contaminated air is drawn away from the
worker’s breathing zone.

When used to control chemical pollutants, dilution must be limited to only situations where;

The purpose of a dilution ventilation system is to dilute the concentration of contaminants in the air
with uncontaminated air so as to reduce the concentration below a given level, usually the threshold
limit value (TLV) of the contaminant. This is accomplished by removing or supplying air so as to cause
the air in the workplace to move and, as a result, mix the contaminated air with incoming
uncontaminated air.

In order to accomplish the objective of a dilution ventilation system, it is necessary that air movement
be present. If the air is stagnant, the contaminant will move slowly within the workroom atmosphere.
Thus, the highest concentration will be present near the source and, as a result, in the worker's
breathing zone occur as a result of air currents.

If the air is caused to move, the concentration of hazardous material will be mixed with the surrounding
uncontaminated air in the workplace, resulting in a lower concentration of contaminant for a given area.
If the mixed air is then removed from the workplace and replaced by uncontaminated air, the level of
contaminant can be controlled in the entire work area. The objective of dilution ventilation is to mix the
contaminated air thoroughly with a large volume of uncontaminated air in the workplace and then to
remove the mixture at a rate such that a build-up of contamination will not occur.

A dilution ventilation system is a simple system. It requires a source of exhaust for contaminated air.
This may involve vents through which the contaminated air will escape and a mechanical air mover to
exhaust the contaminated air. A source of air supply is necessary to replace the air mixture that has
been removed with uncontaminated air. This can involve an

In let for uncontaminated air, such as doors, windows, or vents; or it may involve a mechanical fan to
supply the necessary air.

In most cases, since it is desirable that a complete mixing of the entire workroom air occur, a duct
system is required to supply or remove air throughout the work area. The necessary duct is used to
distribute the supply air and remove the contaminated air to assure that small pockets of low air flow do
not exist where contamination build up can occur minimum duct requirement, the cost of installing a
dilution ventilation system is often relatively low, even though the air mover required to operate the
system is itself large and expensive.

Filtering is used to remove any particulate contamination in the air being supplied. Tempering of the
supply air is required when the outside air temperature is so low or so high as to cause uncomfortable
conditions in the work area. Most often tempering involves heating cold air before it enters the work
environment.

Decay Techniques

The principal moisture situations and construction features most responsible for the occurrence of
decay in various building parts.

Promote durable building materials and methods of construction that prevent premature deterioration
of the built environment rather than accelerate deterioration.

Interventions should use building materials of equal or greater durability than existing building fabrics or
design for disassembly and replacement.

Air Distribution

Air distribution systems serve as the pathway for conditioned air to travel from HVAC equipment to the
spaces inside the building. They usually consist of a long network of metal ducts arranged in a pattern
that allows for efficient dispersal of air. When heated or cooled air is produced by the HVAC system, the
air is blown into the ductwork using powerful fans or air handlers. The air exits from vents and either
increases or decreases the temperature in the building. Return ducts bring air back to the HVAC unit to
be filtered, reconditioned and redistributed.

The design of air distribution system will be influenced by the physical configuration of the building and
the available space for installing ductwork.

The air distribution system includes air handlers, ductwork, and associated components for heating,
ventilating and air conditioning buildings. They provide fresh air to maintain adequate indoor-air quality
while providing conditioned air to offset heating or cooling loads. Their many components need to
operate in unison to properly maintain desired conditioned.

Dilution ventilation is often used as the primary exposure control where source control is inadequate,
not entirely reliable, impractical, or too expensive, and when standards require it. It is most cost
effective when air pollutants are relatively lower-toxicity vapors, gases, or fine particles; when emissions
occur uniformly in time, are widely dispersed, and do not occur close to occupants’ breathing zones; and
where moderate climatic conditions prevail and the dilution air is much less contaminated than the air
to be diluted.

In some cases, a major source control, such as local exhaust ventilation, also provides dilution
ventilation through the makeup or replacement air required for the local exhaust systems. HVAC
systems routinely provide outdoor air (OA) dilution ventilation while heating and cooling the
environment.
Dilution ventilation is the addition of fresh, clean air into potentially contaminated air to reduce the
concentration of airborne contaminants—for example, vapors, gases, viral aerosols, particles, or smoke
—to acceptable exposure levels chosen by the OEHS professional. These levels could be the OSHA Action
Level or a certain percentage of a relevant occupational exposure limit, but they could also refer to
levels “below the odor threshold,” “non-detectable levels,” and so forth.