Many workers spend long periods of time indoors, in air-conditioned buildings. If the air-conditioning system is not maintained, a number of problems, some potentially lethal, can occur. OHS reps have a role to play in ensuring that risks associated with air-conditioning are identified and reduced as much as possible.
Temperature: The acceptable zone of thermal comfort for most kinds of work lies between 16° - 26°C. (18° - 24°C for offices, shops, showrooms, canteens, dining rooms - depending on the outside temperature; as low as 13°C for heavy work in factories)
•Air Movement: 2 - 4 metres per second.
•Minimum Fresh Air Rate: Offices require 10 litres of fresh air per person per second (computer rooms 25 litres, cafeterias 15 litres).
•Oxygen Content: 18-21%.
•Carbon Dioxide: Limited of 1,000 parts per million.
•Microrganism Level: Less than 1,000 colony-forming units per cubic metre.
•Inspection of Air Intakes and Exhaust Outlets: At least annually.
•Cleaning and Replacement of Air Filters: In accordance with manufacturer’s specifications.
•Inspection of Humidifiers and Evaporative Coolers: At least monthly.
•Inspection of Ductwork: Annually.
A building’s air-conditioning system can be described as the lungs of the building. The air-conditioning system draws in outside air, filters it, heats, cools or humidifies it, circulates it around the building, then expels a portion of it to the outside environment.
An air-conditioning system is made up of intake ducts, air filters, cooling tower/s, a boiler and exhaust ducts.
The quality of the air many workers breathe at work is totally dependent on the operation of the building’s air-conditioning system. Substandard air-conditioning will lead to poor indoor air quality irritable and potentially very sick workers.
The cost of poor air-conditioning at work is enormous. Studies show that increased sick leave and lower productivity related to poor air-conditioning, costs many millions of dollars each year. The human costs of poor air-conditioning include viral illness, respiratory problems, and deadly Legionnaires Disease (or Legionella).
What are the health effects of poor Air Conditioning systems?
Often the cause of respiratory and nasal symptoms is not properly diagnosed; therefore the work related nature is not recognised. There are three major categories of health problems:
1. Lungs and respiratory tract problems e.g. runny nose, blocked nose, coughing, sore throat, sneezing.
2. Virus and bacteria reactions
E.g. fever, chills, headaches, muscular ache, nausea and vomiting. Diseases include influenza, bronchitis and Legionnaire’s Disease (see Hazard page on Legionnaire’s Disease).
3. Allergic reactions e.g. itchy nose, watering eyes, shortness of breath, wheezing and coughs. Illnesses include sinusitis, asthma and humidifier fever.
Who is at risk?
Large numbers of workers are at risk: •workers in air-conditioned buildings, including office staff, cleaning staff and security staff
•staff in air-conditioned venues such as hotels, museums, aquariums, gaming venues
•building maintenance workers (such as mechanics, electricians, etc)
•air-conditioning company workers