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Asset Classes

Focus Area

Accessibility and Wellness


Thermal Comfort

Question #

A2.1 — Humidification


Are humidification systems present and properly maintained?


Applicable to all buildings (systems or equipment in the owner or landlord’s control)


Select one of the following:

    • Yes – humidification systems are present and properly maintained
    • Not applicable – humidification systems were considered but deemed not necessary/there are no systems within the owner’s control
    • No


Low indoor relative humidity is a common problem in cold climate buildings during winter months and a common source of indoor air quality complaints. The addition of a carefully maintained whole building humidification system, that is focused on human comfort, can help maintain a more comfortable work environment.

Humidification systems should be cleaned and inspected annually. ASHRAE 180-2018 recommends annual inspection and cleaning of strainers, drain pans, distributors and semi-annual cleaning of steam traps, pumps and controls


a. Describe the type of humidification system present at the building 
b. Maintain the humidification system in accordance with manufacturer’s recommendations


c. Describe the steps taken to understand the building’s humidification needs (e.g. not needed in humid climate)
d. Explain why humifidication systems are not used at the building


  • Humidification System Maintenance Program and Maintenance records
  • Annual cleaning and inspection logs

Adapted BB3 Question

New in BOMA BEST 4.0

Suggested Lead



ASHRAE 180-2018 Standard Practice for Inspection and Maintenance of Commercial Building HVAC Systems, Table 5-11, 

For more guidance on creating this risk management plan, please review the Hazard Analysis and Critical Control Point (HACCP) risk management plan in ASHRAE Standard 188, Prevention of Legionellosis Associated with Building Water Systems.



Other Notes

Requirements apply to humidification delivered to occupied spaces.


    • If steam humidification is used, confirm whether clean steam rather than treated boiler water utilized. The steam must not be provided from a source using chemical water treatment, such as the central heating plant, because of potential air contamination from boiler additives used to control scale and corrosion. Independent steam generation, using potable water in equipment such as re-boilers, instantaneous electric, or gas fired steam generators is required. Water treatment in HVAC equipment must, at all times, meet local provincial and/or federal guidelines and regulations.
    • If spray humidification is used, confirm whether the system is rigorously maintained and free of rust, algae, or loose contaminants of any kind. Poor maintenance of spray humidification systems may increase the likelihood of microbial growth and legionella. A Risk Management Plan must include documented records of inspection with respect to: preventing standing water in drain pans; limiting water droplet carry-over; minimizing stagnant water in humidifier and water spray sumps.

Water treatment in HVAC equipment must, at all times, meet local provincial and/or federal guidelines and regulations.


2 Points