Critical Care: HVAC Hygiene in Healthcare Environments

Indoor Air Quality (IAQ) and Infection Control (IC) is critically important in healthcare environments. Mould spores along with bacteria and other contaminants contribute to life-threatening hospital acquired infections (HAI), referred to as nosocomial infections. The Centers for Disease Control (CDC) has estimated that 1.7 million nosocomial infections occur each year, with nearly 100,000 associated deaths [1].  Scheduled hospital duct cleaning is a vital part of every healthcare institution's IC and IAQ plan.

There's a range of reasons for the cleaning of ducts and interstitial spaces, the most common include:

  1. Preventive Maintenance, ensuring optimal environmental conditions and HVAC performance
  2. Before and after mechanical upgrades, such as replacing air handlers or HVAC remodelling
  3. As part of a remedial cleanup from mould infestation, water damage or fire
  4. After an environmental concern such as an infection/disease outbreak. 

Considering the larger volume of air and the required exchange of outside air within healthcare environments, build up of contaminants in the duct system is a persistent issue. Because a hospital’s air conveyance system can push up to 30 cubic feet per minute ( of air through its ducts, collection of debris like human skin cells, hair, linen, and dust inside ducts provides an available food source for bacteria to proliferate. That’s why specialist care is required for hospital duct cleaning. The physical process to hygienically clean ductwork does not change in healthcare environments but what does change is the process for maintaining a safe environment for the patients and staff of the medical facility during the process.

The most important concern for a Facility Manager at a hospital is to ensure that contaminants are not spread throughout the building envelope. Collaboration between both the Facility Manager and HVAC Hygiene Specialist is vital to the success of a hospital duct cleaning project. Communication in conjunction with coordination, between the facilities staff, nurses, environmental health and safety, as well as other hospital stakeholders is of key importance. For example, the HVAC Hygiene Specialist and the facility staff will review the hospital’s Infection Control Risk Assessment (ICRA) together and determine which of those protocols apply to the HVAC hygiene project. If required, additional steps will be taken to comply with the hospital’s specific ICRA policies.

Environmental infection is a risk.  Bio-hazard containment enclosures with Negative HEPA Air Extraction reduce the risk of spreading harmful dust, fungi and bacteria, when working in a hospital or any healthcare ceiling space.

One of the key factors in the success of a hospital HVAC hygiene project is to ensure patient and staff safety during the duct cleaning process, this is achieved by establishing sufficient containment barriers while maintaining negative pressurisation with HEPA filtration vacuums during activity.  Mobile equipment such as bio-hazard containment enclosures are used anytime a ceiling tile is accessed or work is conducted outside of the air conveyance system. In other scenarios, larger containment areas will be constructed. Containment is not just a concept that applies to the occupied space of the hospital environment, it is also occurring behind the ceiling within the hospital ductwork. The ductwork is placed under a negative 5 Pascal field to ensure the contaminants being agitated are pulled into the direction of the HEPA filtered air collection device. Sections of the hospital ductwork are sealed off. Then filter media is placed in all supply and return registers. Finally these registers are covered with duct masking to prevent cross contamination.

Volatile Organic Compounds (VOCs) are harmful gases emitted by certain products or processes. VOCs include a variety of chemicals that cause adverse health effects and negatively impact the environment. Off-gassing is what occurs when products release particulate matter and gases that were formerly trapped in a liquid or solid form and the resulting gases are known as VOCs. 

No disinfectants are to be used in the hospital duct cleaning process without the HVAC Hygiene Specialist and Facility Manager approving the exact type of product requested for use, this is done by reviewing the product MSDS sheet and evaluating its potential for certain aspects, such as VOC off gassing, before deeming it suitably compliant.

The overall purpose of cleaning the ducts and entire HVAC system is to optimise indoor air quality. Hospitals are in a state of constant 24/7 operations compared to other commercial facilities that are only occupied during daytime hours and also have higher risk factors from cross contamination and infection outbreak. That’s why complying with strict protocols, being vigilant with containment, and testing the environmental conditions throughout the process are necessary extra steps in order to safeguard the well being of patients and workers during the entire process.


For more information on HVAC Hygiene, IAQ Testing and Duct Cleaning for Hospitals please speak with our experts (07) 2102 6788 or email