Diagram illustrating the Hierarchy of Controls: Elimination, Substitution, Engineering Controls, Administrative Controls, and Personal Protective Equipment (PPE).

The Hierarchy of Controls: A Systematic Approach to Pathogen Management

When it comes to protecting people from pathogens and other workplace hazards, not all control measures are created equal. The Hierarchy of Controls is a systematic approach that prioritizes the most effective strategies for preventing exposure to hazards, including infectious agents. 

What is the Hierarchy of Controls? 

The Hierarchy of Controls is a framework used by safety professionals to implement effective control solutions. Developed by the National Institute for Occupational Safety and Health (NIOSH), this approach organizes hazard control strategies from most to least effective: 

  1. Elimination – Physically remove the hazard 
  2. Substitution – Replace the hazard 
  3. Engineering Controls – Isolate people from the hazard 
  4. Administrative Controls – Change the way people work 
  5. Personal Protective Equipment (PPE) – Protect the worker with PPE 

Most Effective: Elimination and Substitution 

At the top of the hierarchy are the most effective control measures: 

  • Elimination involves completely removing the hazard from the workplace. For pathogens, this might mean identifying and removing infected individuals from the environment or eliminating conditions that allow pathogens to survive. 
  • Substitution replaces a hazard with a less dangerous alternative. While challenging to apply directly to pathogens, it might involve replacing high-risk procedures with safer alternatives that achieve the same outcome. 

Engineering Controls 

Engineering controls are physical changes to the workplace that isolate people from hazards. These are particularly valuable for pathogen control and include: 

  • Advanced Disinfection Technologies 
  • Negative pressure rooms for airborne pathogens 
  • High-efficiency air filtration systems 
  • Physical barriers like sneeze guards 
  • Proper ventilation to reduce airborne transmission 

Administrative Controls 

Administrative controls change the way people work to reduce exposure: 

  • Developing policies for sick leave and remote work 
  • Implementing hygiene protocols 
  • Creating cleaning and disinfection schedules 
  • Training employees on infection prevention 
  • Adjusting work schedules to reduce crowding 

Least Effective: Personal Protective Equipment 

At the bottom of the hierarchy is PPE, which includes: 

  • Respirators and face masks 
  • Gloves 
  • Face shields 
  • Gowns and protective clothing 

While essential, PPE is considered the last line of defense because it relies on proper use by individuals and doesn’t eliminate the hazard at its source. 

Why The Hierarchy of Controls Works 

The Hierarchy of Controls provides a structured method for addressing pathogen risks. By focusing on elimination and engineering controls first, organizations can implement more reliable protections before resorting to measures that depend on individual compliance. 

For effective pathogen management, the best approach usually combines multiple controls across different levels of the hierarchy, creating layers of protection against infectious disease transmission. 

To learn more, check out the information at the source – The CDC.

Crowded indoor space with ASHRAE logo, representing efforts toward better indoor air quality.

Breathe Easy: ASHRAE’s Guidelines for Better Indoor Air

Ever wonder what makes the air inside buildings healthy to breathe? ASHRAE publishes standards and guidelines for indoor air quality. Here’s what you need to know in plain language. 

What Are These Guidelines? 

Think of ASHRAE Standard 62.1-2022 as a rulebook for good indoor air in commercial facilities. It sets minimum requirements for ventilation (bringing fresh air in) and other measures to keep indoor air healthy for people. The goal is simple: make sure the air we breathe indoors won’t make us sick. 

Who Do These Guidelines Affect? 

These guidelines apply to most buildings where people spend time, except for residential homes. They’re used when: 

  • Building new structures 
  • Adding to existing buildings 
  • Making certain changes to buildings 
  • Improving air quality in older buildings 

Better Indoor Air: The Main Points Made Simple

Fresh Air Systems 

The guidelines explain how to design, install, and maintain systems that bring fresh air inside and clean the air that’s already there. 

Indoor Air Pollutants 

The rules address things that can make indoor air unhealthy, including: 

  • Outdoor pollution coming inside 
  • Dust and chemicals from construction 
  • Moisture and mold 
  • Cigarette smoke 

Outdoor Air Quality 

Before designing a ventilation system, builders need to check if the outdoor air in the area is clean enough. If it’s not, they must add filters or air cleaners to remove particles and harmful gases. 

Equipment Requirements 

The guidelines have specific rules for air system parts like: 

  • Where outdoor air enters the building (keeping these intakes away from exhaust fans, garbage areas, and other sources of pollution) 
  • Surfaces that the air flows over (making sure they resist mold) 
  • Drain pans (ensuring they don’t become breeding grounds for bacteria) 
  • Humidifiers (devices that add moisture to the air) 

There’s also emphasis on preventing Legionnaires’ disease, a serious type of pneumonia that can spread through water systems. 

Air Classification 

Not all indoor air is equal. The guidelines sort air into four classes based on how contaminated it might be and set rules for when this air can be reused or moved to other areas. 

Determining How Much Fresh Air Is Needed 

Designers can use several methods to figure this out: 

  • A straightforward approach based on room type and size 
  • A more complex method analyzing specific pollutants 
  • Guidelines for systems using natural airflow (like windows) 

Keeping It Clean 

The rules emphasize keeping air ducts clean during construction and making sure fresh air dampers (valves that control airflow) work properly before people move in. 

Ongoing Maintenance 

Regular upkeep of ventilation systems is required to ensure they continue working effectively. 

Checking Results 

For projects using the more complex design method, testing is required after completion to verify the air is actually clean. 

ASHRAE: Your Resource for Better Indoor Air 

These guidelines are constantly being updated as new research emerges. While following them isn’t legally required (unless local building codes say so), they’re widely recognized as the gold standard for healthy indoor air. By understanding these basics, you can better appreciate the behind-the-scenes work that goes into making the air in your workplace, school, or public buildings safe to breathe. To fully understand the standard, you can access a readable version of the entire document by visiting ASHRAE’s Technical Resources.