Indoor Air Quality Occupational Safety& Health Section Labour Department
Factors Affecting IAQ • Environmental Air Quality • Work activities • Building design • Ventilation system - mechanical vs. natural • Animals including insects • Temperature • Humidity • People
Factors Affecting IAQ • Housekeeping standards in the work area • Personal habits e.g. perfumes, insecticides • Storage • Housekeeping in area of the air conditioning system • Temperature control • Changes to the building design not compatible with the ventilation system
Factors Affecting IAQ • Carpeting and soft furnishings • Use of split system units • Pest control application/Painting etc without venting the area after • Duct conditions (mold growth/animal danger) • Odours • Office 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
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)
Forms of Heating, Ventilation and Air Conditioning (HVAC) Systems • Natural ventilation • Mechanical ventilation • Combination of Natural and Mechanical Ventilation
NaturalVentilation • An 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.
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
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.
HVAC Considerations • Choosing 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?
HVAC Considerations (2) • 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?
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?
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 categories • Building Related Illness • Sick 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.
More Common Substances • Nitrogen oxides - vehicular exhaust; tobacco smoke • Ozone - copy machines • Volatile Organic Compounds (VOC) - paints; cleaning compounds; moth-balls; • Ammonia • Cleaning agents
‘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)
Occupational Safety & Health SectionLabour Department Promoting the attainment and maintenance of desirable standards of occupational safety and health practice in Barbados. AElcock