For residential, commercial, and public building owners and managers, following proper air filtration standards and best practices not only benefits occupant health and comfort but can also improve energy efficiency and regulatory compliance. Two organizations that produce standards and develop best practices for improving indoor air quality (IAQ) are ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) and CSA (Canadian Standards Association). This article will examine the standards and their benefits along with their limitations.
The Health Benefits of Improved IAQ
IAQ directly impacts building occupant health and comfort. Adopting ASHRAE and CSA standards improves IAQ by reducing allergens, pollutants, and airbourne viruses and leads to better overall well-being.
For commercial and public buildings, better IAQ can increase productivity and reduce sick days. Hospitals and healthcare facilities benefit because proper air filtration and ventilation mitigate the risk of airbourne virus spread and outbreaks.
What is ASHRAE?
ASHRAE is a global, professional association of engineers that establishes guidelines and standards focusing on the design, maintenance, and operation of heating, refrigeration, and air conditioning (HVAC) units, as well as on all related components such as ducts, boilers, pressure vessels, and coils.
What Are ASHRAE Standards?
ASHRAE Standards are essentially guidelines developed by engineers to achieve the best building comfort, energy efficiency, and IAQ through temperature control, adequate ventilation, proper airflow and circulation, and by establishing MERV (minimum efficiency reporting value) ratings.
It is important to note that the standards are not inherently part of a regulatory framework. However, they often become part of building codes in Canada and other countries, which influence legal and financial outcomes for non-compliance.
Ramifications for building code violations in Canada and in other countries include: fines for failing to meet codes, stop work orders, and demolition orders for continued non-compliance. Legal action from government entities or private parties is also a possibility. It may be difficult to obtain building insurance for a building if it doesn’t follow codes.
Although ASHRAE Standards have been widely adopted, their integration into building codes varies. ASHRAE itself is not part of Canada’s building code committees and associations. Legal action cannot be taken against someone for not following ASHRAE building standards unless they have been adopted as part of a building code.
Updates to ASHRAE Standards
ASHRAE updates its Standards as air filter, research, and filtration equipment technology advances.
Standard 52.2 Appendix J
Recent updates to ASHRAE filtration standards merged previous addendums, including Appendix J. The appendix focuses on proper air filter testing, though it remains a recommendation rather than a standard. However, this may change in the future in order to improve MERV rating accuracy.
ASHRAE Standard 62.1
Standard 62.1 is referenced by many U.S. and Canadian state and provincial codes and is acknowledged by the Centers for Disease Control (CDC).
ASHRAE 62.1 must be followed in order for a property to be considered for a LEED building certificate.
62.1 includes ventilation rate, indoor air quality improvement methods, and natural ventilation best practices. It also includes operations and maintenance methods that reduce pollutants such as PM2.5, carbon dioxide, carbon monoxide, and volatile organic compounds (VOCs).
The Standard has been updated with better IAQ procedures, revised maximum dew-point temperatures, and new exhaust air separation distances. It features increased efficiency requirements for particle size capture.
Standard 62.2
ASHRAE 62.2 covers residential buildings such as houses, low-rise multi-family dwellings, and mid-rise and high-rise residential buildings. It requires lower ventilation rates and less sophisticated air filtration systems than 62.1 because the buildings covered generally have lower occupancy densities and different activities. It generally recommends (0.03 x floor area in sq ft) + (7.5 x number of bedrooms +1) for airflow in CFM. It also recommends a supply of outside air to pressurize homes and force out stale air. 62.2 encourages the use of low-VOC building materials to reduce pollutant levels.
ASHRAE 62.2 recommends a minimum MERV 6 air filter for residential buildings but encourages the use of MERV 13 filters or higher when possible for more sensitive areas.
Standard 90.1-2022—Energy Standard for Sites and Buildings
ASHRAE Standard 90.1 sets minimum energy efficiency guidelines for buildings (excluding low-rise residential). It includes such things as the building envelope, HVAC systems, power distribution, building renewable energy, and energy use to reduce building energy consumption.
ASHRAE has begun to align its standards with ISO standards, particularly in terms of efficiency and energy usage. This shift is part of a growing industry-wide emphasis on sustainability and energy savings in HVAC design and operation.
ASHRAE has recently released guidelines for building design and air filtration to address concerns about future pandemics. One key recommendation is the use of portable air cleaners in conjunction with air filters in the HVAC system to reduce the transmission of viruses within rooms in buildings.
ASHRAE Standard 241-2023, titled “Control of Infectious Aerosols,” establishes minimum requirements to reduce the risk of airborne disease transmission in buildings. It recommends higher ventilation rates and using mechanical and natural ventilation to dilute infectious aerosols. It also recommends increasing ventilation, air cleaning, and filtration capacity when necessary during virus outbreaks, as well as real-time IAQ monitoring.
ASHRAE 241 recommendations for building types:
● Hospitals & clinics: MERV 14-16, HEPA in sensitive areas
● Schools & offices: MERV 13 or higher
● Recreation centres: MERV 13 or higher
● Airports & public transit hubs: MERV 13 or higher
● Residential buildings (high-rise): MERV 13 or higher
*It is important to note that 241 did not go through the ANSI approval process due to the fact that it was developed at an accelerated pace.
What does ASHRAE advise regarding efficiency, filters, and energy consumption?
As ASHRAE places greater emphasis on energy efficiency—like ISO—this trend should reduce building energy consumption. Most people think of lighting as a major source of energy consumption, and as a result, the amount of energy consumed by air filtration is often overlooked. Air filters designed for energy efficiency, coupled with variable frequency drive (VFD) controlled fans, can save a significant amount of energy.
A MERV 14/14A Durafil filter has the same initial pressure drop as a pleated filter with a MERV rating of 8 (30/30), which means it’s possible to have great efficiency and a low-pressure drop. Currently, in North America, there are no clear regulations requiring the use of filters with the lowest average pressure drop. The focus is primarily on particulate capture efficiency. This is why European standards, like those from ISO, are more advanced than ASHRAE standards.
ASHRAE is gradually beginning to align with ISO standards, which now include classifications for efficiency and energy usage. Instead of merely following ISO, ASHRAE is conducting its own investigations into how to develop energy-efficient air filters.
CSA Standards for air filtration
Unlike ASHRAE, CSA focuses heavily on electrical standards and, in relation to air filtration, only on healthcare-related standards. CSA standard Z317 provides guidance on infection control during construction, renovation, and maintenance of healthcare facilities.
What is CSA Z317.2?
CSA Z317.2 is called “Special requirements for heating, ventilation, and air-conditioning (HVAC) systems in health care facilities.” The requirements are stricter than industry standards applied to non-health-care facilities.
It includes specifications for the design, construction, operation, and maintenance of HVAC systems in healthcare facilities. By including ventilation rates, air filtration, airflow, pressure differentials, and temperature and humidity management in healthcare facilities, it seeks to improve IAQ, infection control, and patient safety.
Here are some CSA guidelines:
Ventilation & Airflow – CSA recommends minimum air changes per hour (ACH) and adequate air pressure to reduce airbourne contamination, decrease infection risk, and improve IAQ and health outcomes for patients.
Some examples of recommended AHU based on room type:
● Operating Rooms: 20–25 ACH
● Patient Rooms & General Care Areas: 4–6 ACH
● Isolation Rooms: 12 ACH
● ICU/NICU: 6–15 ACH
● Sterile Storage: 4–10 ACH
CSA states that HEPA filters must be used in critical areas, and minimum MERV levels should be followed for filter selection depending on room type or area of healthcare facilities.
Temperature & Humidity Control – CSA establishes adequate temperature and humidity ranges to ensure patient comfort, reduce infection, and prevent microbial growth.
Some examples of recommended temperatures and relative humidity (RH) levels:
● Operating rooms: 18–24°C, 40–60% RH
● Patient rooms & general areas: 21–24°C, 30–60% RH
● Isolation rooms: 20–24°C, 30–60% RH
● ICU/NICU: 22–26°C, 30–60% RH
● Sterile storage: 18–22°C, 35–60% RH
Maintenance & Monitoring – Regular inspections and monitoring of air quality, airflow, and circulation, and regular filter replacements to maintain IAQ.
Infection Control Measures – Linking HVAC with infection prevention measures, including airborne disease outbreaks.
What is CSA Z8000?
CSA Z8000 is CSA’s Canadian Health Care Facilities Standards. The Standards provide a framework for the “planning, design, and construction of healthcare facilities” in Canada. It includes hospitals, long-term care homes, and other healthcare facilities. It focuses on “safety, quality, and efficiency.”
It recommends integrated design to optimize energy use and life-cycle cost analysis for energy savings. It also recommends energy recovery ventilation (ERV) to reduce heating and cooling loads and air-tightness strategies to increase energy efficiency and improve IAQ.
Recently, CSA standards have expanded to include long-term care homes. CSA Z8004:22 Long-Term Care Home Operations and Infection Prevention and Control focuses on the “design, operation, and infection prevention and control practices in long-term care homes.” –Standards Council of Canada
CSA recent changes
Changes to CSA standards include cautions on the use of antimicrobial filters, selecting a suitable portable air cleaner, and the selection of appropriate media for molecular filtration.
The latest update from CSA specifies that healthcare facilities should not use antimicrobial filters. There is no substantial evidence to prove that antimicrobial filters are effective. For the antimicrobial properties to work, viruses or other microorganisms must come into direct contact with the chemicals in the filter. However, if dirt is present on the filter, particles may not adhere to the fibres that contain the antimicrobial chemicals. As a result, the filter will not effectively eliminate viruses. Furthermore, there are concerns that off-gassing from the filters could cause more harm than good for healthcare staff and patients.
CSA states that it is essential for an air cleaner to have a gasketed, properly sealed HEPA filter with no bypass. It also states that a portable air cleaner must not emit ozone and should not be used for odour, volatile organic compounds (VOC), or gas removal. Its airflow must be stated. Once this criterion is met, different units can be compared.
While some air cleaners utilize MERV 15 and MERV 16 filters, which can effectively clean the air, they may inadvertently recirculate some contaminants. This concern is particularly relevant in a hospital environment. Ideally, air cleaners should capture all contaminants on the first pass; therefore, for these uses, a HEPA filter is the best solution. Certain airflow and ACH thresholds must be followed.
The selection of suitable molecular filters for different areas within a hospital is critical. There has been some confusion regarding the appropriate types of carbon or potassium permanganate media to use in different applications, with some air filter companies suggesting unsuitable options.
The latest CSA document specifies the correct blend or type of media to use in key areas, allowing you to determine the size and capacity of the air handler required. For example, if a heliport is present, it is important to select a certain blend of media to eliminate harmful gases effectively.
Optimizing air filtration: The importance of average pressure drop and air filter lifespan
Something often overlooked in air filtration is that you should always base your air filter selection on the average pressure drop of a filter rather than the initial pressure drop. Additionally, the lifespan of a filter is another aspect that is not frequently discussed. Existing standards often fall short because they do not inform users that a high-quality filter is capable of lasting a year rather than needing replacement every three months.
When a filter is specified to last three months, it’s likely that the pressure drop will reach its maximum before that time frame is up. Having a filter at maximum pressure drop is detrimental to good IAQ.
What practical advice is there for building owners regarding best practices for air filtration?
Air filter testing, maintenance schedules, and certification
Unfortunately, many common practices are insufficient. For example, if someone finds a puddle of water at the bottom of an air handling unit, they may simply change the air filters and walk away thinking everything is fine. However, it’s important to investigate problems and determine their source. Ignoring issues like mould or standing water can lead to bigger problems in the future, some of which can be very costly.
When it comes to retrofitting existing systems, there are several challenges, including increasing costs and material availability. It’s essential to consider potential future problems when implementing new standards.
For instance, if you have an air handling unit designed with enough space for pleated 12-inch filters but then face issues like smoke from a wildfire, you’ll need to consider where to install a carbon filter. If you didn’t plan for it, you might find yourself with insufficient space to add the carbon filter. If the system is designed with additional space contingencies, adding a carbon filter would be much easier and more cost-effective. Therefore, it’s important to think ahead and accommodate future challenges when designing air filtration systems.
For those looking to save energy, consider using a high-efficiency filter, such as a Camfil Durafil. It’s a great option that can make a significant difference in energy consumption.
What are the benefits of working with professional contractors/HVAC contractors?
Contractors primarily earn money through service calls, and the more service calls they complete, the more revenue they generate. It’s essential to find a contractor whose priorities align with helping customers achieve longer equipment life and lower energy costs. Some contractors specialize in energy savings and can help you get great results.
The future of CSA and ASHRAE air filtration standards
The CSA and ASHRAE are expected to update their air filtration standards in the near future. ASHRAE is developing and improving guidelines for building energy usage and sustainability, and CSA may follow, particularly for healthcare facilities.
The new guidelines will likely include HEPA standards, UV standards, and LEED recommendations for air cleaners. Electronic or electrostatic filters may not be recommended in the future as the focus shifts to eliminating viruses from rooms and various areas within buildings rather than recirculating them.
Currently, CSA has a brief section addressing air quality monitoring. It is possible that ASHRAE and CSA will expand their recommendations regarding air quality monitoring and the implications of changes in air quality.
Practical Advice for Building Owners
To achieve the best HVAC performance and air quality, regularly inspect systems for mould, excess water or humidity, and clogged filters. Design for the future by allowing space for additional filtration options such as activated-carbon filters to address issues like wildfire smoke or for energy savings. Choose filters with the lowest average pressure drop instead of focusing on the initial stated pressure drop rating for better energy efficiency. Work with air quality experts who rely on long-term cost analysis and extended filter life, and ensure that your staff is educated on ASHRAE and CSA standards for proper air filtration selection and HVAC maintenance.
Would you like to improve the air quality in your building today? Start by contacting Camfil for a complimentary site survey for your commercial building, public building, or other facility. Use this contact form
About Camfil Canada Clean Air Solutions
For more than 60 years, Camfil has been helping people breathe cleaner air. As a leading manufacturer of premium clean air solutions, we provide commercial and industrial systems for air filtration and air pollution control that improve worker and equipment productivity, minimize energy use, and benefit human health and the environment. Read more about Camfil Canada
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Sources:
With information from air filter expert Berni Baier
ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) CSA (Canadian Standards Association)
Media Contact:
Phillip Ilijevski
Camfil Canada Inc.
T: 437-929-1161