The American Society of Heating, Refrigerating and Air-Conditioning Engineers’ (ASHRAE’s) Standard 62, “Ventilation for Acceptable Indoor Air Quality,” has been around since the early 1970s. The standard sets ventilation requirements for commercial and institutional buildings.

This standard has undergone quite a few updates and revisions. In fact, the 1999 version of the standard has been under continuous maintenance for the last three years. The ASHRAE committee in charge of revising the standard has been looking for ways to make the guidelines clearer and more precise, while at the same time trying to adopt criteria that would make indoor environments healthier and more comfortable.

According to Andrew Persily, Ph.D., chairman of the Standard 62 committee, several addenda have been approved for publication in the standard. If all goes as planned, ASHRAE may be able to unveil its revised version of Standard 62 at its Winter Meeting in Atlantic City, NJ, Jan. 14-16, 2002.

While the additions are not earth-shattering, there are more than a few changes contractors will need to be aware of when servicing and installing ventilation systems for commercial buildings.


Persily says that only seven addenda are being implemented in the revision. He believes that the addenda that are most important to contractors are 62l, 62m, and 62s.

“This adds a new section on construction and system start-up,” said Persily about 62l. “It includes steps to take to ensure that the ventilation system does what it is intended to do.” So when a contractor has installed a ventilation system, the system must be tested to make sure that it operates and meets the design goals that are intended.

The next addendum, 62m, will add a section on operation and maintenance. This standard will require ventilation systems to be inspected on a more periodic basis. There is no set guideline in the standard on how often a contractor needs to perform routine system checkups (this will depend on the application and installation); but the standard will make it mandatory to perform them more than once or twice a year.

Contractors also will be required to perform more routine maintenance on the systems, such as filter changes and other inspections that can affect the performance of the unit.

Another significant addendum is 62s. This addition clarifies requirements for equipment-related particle filtration. Accord-ing to Persily, the addendum makes it mandatory for contractors to install a filter with a Minimum Efficiency Reporting Value (MERV) of 6 in all commercial ventilation systems upstream of cooling coils and other wetted surfaces. This is only the minimum filter that is required; a more powerful filter can be used.


Other addenda for the standard have not yet been approved.

Addendum 62y would define different classifications of indoor air. These air types will range from one to five, with a classification of one being the worst indoor air. The addendum also would limit the recirculation of lower-quality air into spaces where there is better-quality air.

Addendum 62t would replace Section 5.11. This section deals with microbial contamination on equipment. With the new addendum, this microbial contamination will relate to drain pans, humidifiers, and cooling coils. It also will require cleaning and maintenance of such equipment, as well as accessibility for inspection.

Addendum 62j, which revises Section 5.1, will require that sufficient natural ventilation be demonstrable. It will also specify natural ventilation opening sizes based on floor area, and will add requirements for control and accessibility.


Standard 62 has had its share of controversy and debate. The standard has set requirements on the proper amount of ventilation needed within commercial spaces, as well as other issues that have caused contractors and industry to take sides.

This time around, the changes that have been approved for the republishing of Standard 62 have not sparked much controversy.

According to Eli Howard, Sheet Metal and Air Conditioning Contractors’ National Association (SMACNA) representative on the standard committee, most of the changes that have been implemented will be more beneficial to hvac contractors.

“As a whole, it’s not going to be detrimental,” said Howard. “[The standard] will open new opportunities for facility owners, operators, and contractors to ensure proper efficient operation of hvac systems.” For example, contractors should find addenda 62l and 62m to be beneficial. Both will make it necessary for contractors to perform more maintenance, thus increasing work orders.

Mike Mamayek, contractor member on the standard committee and hvac and process department manager for Illingworth Corp., agrees. Mamayek says that under the new operations and maintenance section of the standard, building owners will be responsible to maintain their ventilation systems. This includes changing filters and keeping the system clean.

The changes to the standard will also benefit contractors in terms of accuracy, according to Mamayek. Under the start-up section, after the system is designed and installed, it is required to verify that it is working up to the intended level. For example, contractors must make sure that the correct amount of cfm is being delivered.

Mamayek says that the additions to the standard are beneficial as a whole. The operations and maintenance portions will require provisions, such as changing of air filters, which will promote better IAQ.

He also says that additions to the standard are only asking for more checks and balances. Mamayek says that the new addenda come down to common sense. “These are things most people should be doing now anyway.”

For more information on Standard 62, visit (website).

Publication date: 12/24/2001