Indoor Air Quality
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Transcript of Indoor Air Quality
Indoor Air Quality
Occupational Safety& Health Section
Labour Department
Factors Affecting IAQ
Environmental Air QualityWork activitiesBuilding designVentilation system - mechanical vs. naturalAnimals including insectsTemperatureHumidityPeople
Factors Affecting IAQ
Housekeeping standards in the work areaPersonal habits e.g. perfumes, insecticidesStorage Housekeeping in area of the air
conditioning systemTemperature controlChanges to the building design not
compatible with the ventilation system
Factors Affecting IAQ
Carpeting and soft furnishingsUse of split system unitsPest control application/Painting etc without venting the area afterDuct conditions (mold growth/animal danger)OdoursOffice plants
Ventilation [S 52]
Effective and suitable provision shall be made for Circulation of fresh air Removal of all substance, fumes, dust
and other impurities that are likely to be injurious to health
Temperature [ S 51 ]Required to:
Use methods to ensure reasonable temperature
Chief Labour Officer may order the following: Raising the height of the roof of a building or
room Insulating of the roof (use of insulating
materials; construction of a double roof) Increase in the number of air changes per hour
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Acceptable Indoor Air Quality
Acceptable indoor air quality is air in which there are no known contaminants at harmful levels; and
With which the majority of persons (at least 80%) do not express dissatisfaction based on several criteria such as relative humidity, odours and air movement.
(ASHRAE Standard 62-2001 – Ventilation for Acceptable Indoor Air Quality)
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Forms of Heating, Ventilation and Air Conditioning (HVAC) Systems
Natural ventilation
Mechanical ventilation
Combination of Natural and Mechanical Ventilation
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Natural VentilationAn example of natural ventilation is the use
of open windows to utilise the ‘fresh’ air and the natural breeze.
Advantage: There are numerous air exchanges.
Disadvantage: Limited control of the temperature.
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Mechanical Ventilation
An example of mechanical ventilation is the use of fans.
Advantage: Utilises natural fresh air with some control over air movement.
Disadvantage: Minimal control of the temperature.
90 degrees F
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Mechanical Ventilation (2)
Another example of mechanical ventilation is the use air conditioning systems.
Advantage: Greater control of the room temperature to provide a
cooler atmosphere.
Disadvantage: Some degree of circulation of the same air.
Window AC Unit
Ductless Single Zone Mini-Split Wall-Mounted Cool Only Air Conditioner
Central System
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HVAC ConsiderationsChoosing the correct system for the area and
activities undertaken The type of system (central system, split system,
window unit) Filter type) Materials used (galvanised vs. fiberboard ducting)
Are there provisions for the intake of make up air or the exhaust of contaminated or stale air?
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Where are the intake and exhaust located?How often is the system serviced and what
is involved in the service?How often is the area serviced by the
system cleaned?What are the housekeeping practices,
particularly in the plant rooms?
HVAC Considerations (2)
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The compartmentalisation of the building -
How is the building divided ? Is one room at a different potential to
another? Are there closed doorways or ceiling
partitions which restrict the flow of air? Are there intake and exhaust vents in each
room?
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The presence of indoor sources of contaminants and their magnitude -
What goes on in the rooms being serviced by the system?
Are there pollution sources near intake areas?
Are there items which would cause the accumulation of dust?
Are there conditions which would create biological contaminants?
Health Effects of IAQ
Two main categoriesBuilding Related IllnessSick Building Syndrome
Building Related Illness
Illnesses where the specific diagnosis can be made, including the identification of the causative agent
e.g. Breakdown of building materials (Sinusitis)
Sick Building Syndrome
Sick building syndrome is defined as a persistent set of symptoms occurring in greater than 20 percent of a building’s occupants, with no readily recognisable cause.
Sick Building Syndrome
Signs and symptoms include
headache
nausea
dizziness
coughing
muscle pain
fatigue
dermatitis
eye, nose, throat, and respiratory irritation
difficulty concentrating
sensitivity to odors
Some Common Substances
Carbon dioxide - from human respiration and processes involving combustion.
Carbon monoxide - sources include tobacco smoke and vehicular exhaust.
Formaldehyde - from the off-gassing from plywood; particle board; carpeting and fabric; glues and adhesives.
Nitrogen oxides - vehicular exhaust; tobacco smoke
Ozone - copy machinesVolatile Organic Compounds (VOC) -
paints; cleaning compounds; moth-balls; Ammonia Cleaning agents
More Common Substances
‘Mould Invasion!! – Fungi in my air
The cold hard fact is - MOULD IS EVERYWHERE ALL THE TIME! Indoors, outdoors and in the home.
Mould should not be ‘growing’ indoors.If indoor levels are higher than outdoor
levels it is possible that indoor conditions might be promoting growth.
Mould requires moisture and nutrients to grow.
Relative humidity and moisture sources (e.g. leaks) must therefore be strictly controlled to prevent mould growth.
Mould produces toxins which can cause allergic reactions in some ‘susceptible’ persons e.g. persons with compromised immune systems; respiratory conditions (asthma; sinusitis) .
Many persons do not experience any adverse effects from the presence of mould.
Mould can be cleaned by using mild detergent and water or commercially available fungicide products.
Care should be taken to wear respiratory protection in addition to gloves and eye protection. The Material Safety Data Sheet must also be followed.
Cleaning can only be done if the material is non-porous. It is also essential that the item be allowed to dry thoroughly.
Evaluating IAQ
The basic parameters considered when evaluating IAQ are
• Relative humidity
• Temperature
• Carbon dioxide
Depending on the circumstances other parameters could be considered.
Recommended levels: Relative humidity: 30 – 60% (should be
maintained below 70%)
Temperature: 23 – 26 oC (air conditioned)
Carbon dioxide: 1000 ppm (less than 700 ppm above outdoor levels; complaints
may occur above 800 ppm)
Outdoor air requirement vary with facility but for offices 20 cfm/person is recommended (ACGIH)
Other Related Issues
Psycho-social relationships (labour relations)
Psychological component (stress, psychosomatic)
AElcock
Occupational Safety & Health SectionLabour Department
Promoting the attainment and maintenance of desirable standards of occupational safety and
health practice in Barbados.