Heating, Ventilation, and Air Conditioning (HVAC) System Maintenance and Cleaning

On this page

• Background
• Hazards
• Hazard elimination and control
• Regulatory requirements for employers

Background

A Heating, Ventilation, and Air Conditioning (HVAC) system aims to maintain thermal comfort (heating or cooling) while ensuring indoor air quality (IAQ) through ventilation, filtration, and the introduction of outside air.

The maintenance and cleaning of the HVAC system are essential to prevent hazards that can affect the IAQ. The employer is responsible for establishing and implementing a preventive maintenance and cleaning program for the HVAC system under their full authority, following the guidelines of a qualified person.

Different factors related to the maintenance and cleaning of HVAC systems can affect IAQ and present health and safety hazards. Various hazards can be present simultaneously.

Hazards

Hazard elimination and control

HVAC systems should, whenever possible, meet the ASHRAE Standard 62 entitled "Ventilation for Acceptable Indoor Air Quality" as amended from time to time.

Hazards should, whenever possible, be eliminated or reduced at the source. The design of the HVAC system must consider the various factors and hazards.

A qualified person must set out the instructions for the operation, inspection, verification, cleaning, and maintenance of the HVAC system. Both outdoor and indoor factors must be considered to ensure IAQ.

Various elements must be considered, including:

• The HVAC system's capacity and the building's occupancy levels (people present at the same time);
• The contaminants in the external environment that can be captured by the HVAC system and introduced into the building;
• The building's intended use. In buildings with mixed-use space (office and industrial activities):
  • that the HVAC system must not spread contaminants into office areas.
  • Specific ventilation systems, including source capture of contaminants, may be implemented.
  • Contaminant exposure limits must comply with regulatory provisions (Part X of the Canada Occupational Health and Safety Regulations).
• Humidity levels can also affect IAQ:
  • A too low level of humidity can be associated with discomfort (dry skin, dermatitis, irritation of the mucous membranes of the nose and throat).
  • A too high level may foster mold growth.

A qualified person must establish a maintenance and cleaning plan. This plan helps maintain system efficiency. The CSA Guideline Z204-94 entitled "Guidelines for Managing Air Quality in Office Buildings" states:

• Regular cleaning helps minimize exposure to dust, bacteria, or mold in the air conditioning system.
• Cleaning methods must avoid releasing dust or mold into the HVAC system.
• A record of maintenance activities must be kept.

The maintenance and cleaning plan must include the frequency of filter changes or cleaning for the HVAC system. A qualified person must choose the appropriate HVAC filter based on the system's characteristics and the contaminants to be controlled, as these filters play an essential role in maintaining indoor air quality.

The instructions on maintenance and cleaning of the HVAC system must include procedures to ensure the health and safety of those conducting the maintenance and cleaning.

Regulatory requirements for employers

Canada Occupational Health and Safety Regulations, titled "HVAC Systems," addresses requirements related to HVAC systems, including:

• standards;
• records;
• operation;
• inspection;
• cleaning;
• testing;
• maintenance; and
• investigations.

Employers under the federal jurisdiction must meet all these provisions for any HVAC systems under the employer's control.

An employer who rents premises or does not have full authority over the HVAC system must investigate any reports of IAQ issues, in accordance with Section 2.27 of the COHSR.

For further information please contact the nearest ESDC Labour Program office  or visit our website.