IIAR Moves Forward on CO2 Standard

The use of carbon dioxide as a refrigerant has continued to increase, and the IIAR is moving closer to finalizing a new CO2 standard, which will address several critical aspects of CO2 refrigeration, such as installation, startup, inspection, testing and maintenance.

“It will be a document that end users, contractors and business operators can reference and know it is covering what they need for CO2 ,” said John Collins, industrial sales manager for Zero Zone and chairman of the IIAR committee developing the standard. “It is more comprehensive than many of the other documents the industry has available. Some of the current codes that are covering CO2 have some limitations.”

Tony Lundell, director of standards and safety for IIAR, said the new CO2 standard is intended to be a comprehensive safety standard document that provides minimum safety requirements for the food processing distribution, cold storage, food retail and other sectors of the refrigeration industry.

The rise in the popularity of CO2 has led to the need for a standard. “As CO2 has taken off and become a common refrigerant, it became apparent that a standard was needed to define the parameters for safe design, operation and maintenance of systems utilizing CO2 refrigerant,” said Chuck Taylor, president of CRT Design and Engineering.

Bob Czarnecki, a member of IIAR’s board, led the task force that first explored the need for a standard. “It will provide a document that doesn’t have just design, but has operation, startup and maintenance,” he said. “That is something not currently available, and that will be of value to the end user.”

Collins said the expectation is that the standard will make it easier for those who have been considering CO2 for new applications to choose the refrigerant. “One of the items that is a limiting factor right now for end users and contractors is the uncertainty around how to apply CO2 , how to install the piping, and what is necessary to have a safe system,” Collins said. “This document addresses more completely many of those aspects.”

The structure and the format of the CO2 standard is based on the existing suite of IIAR standards. “We took the content and the structure of IIAR 1 through 6 and incorporated it into one CO2 document,” Collins said.

The standard outlines consistency in design as well as a basic minimum level of quality, Lundell said. It will also improve safety operations in end user facilities for technicians and operators.

The CO2 standard provides directions for designers and engineers, said Ekle Small, vice president of engineering at JAX-MEAS, a contractor. “It gives us a document we can reference when advising regulatory officials of what we use for a minimum code for safety and design,” he said. “You can always exceed the requirements of the document, but it gives the engineer a sound basis to start with, and it defines the minimum safety standard for the community as a whole.”

Small said there is a lot of hesitation related to what to do and what is required in terms of a contractor installation. “I think the standard will help,” he said, adding that the standard will give contractors a consistent and familiar template to follow.

Mike Trumbower, design engineer for Parker Hannifin, said that having a standard is also helpful for component manufacturers such as Parker Hannifin. “It will help steer and give direction to where we go with our design to ensure safety,” he said.

Taylor said the standard will make the application of CO2 systems more uniform, which will make them more reliable systems and easier for the end user to operate and maintain.


This standard is intended for the refrigeration industry as a whole. “It had been created with the intention to cover not just the heavy industrial side of our industry, but also the commercial side. That is a much broader group than what is typically looking at the IIAR ammonia standards,”

Collins said. Collins said IIAR realized it should broaden its vision in terms of the audience for its standards. “Recognizing the fact there is so much more CO2 in the retail or commercial side of the refrigeration world than ammonia, we have been very intentional about trying to engage that side of the refrigeration industry,” he explained.

As a result, IIAR engaged other organizations, including the North American Sustainable Refrigeration Council (NASRC), to gain a broader perspective for the standard. “Right now, we’re encouraging engagement from as many people that have an interest. Our philosophy has been to engage with as wide of a group as we can and make sure the document is solid and is comprehensive,” Collins said.

CO2 has some unique properties and characteristics that make defining a standard necessary so that the industry has criteria and standards developed by experts to facilitate a safe, reliable and fully operational systems, Taylor said. “The last thing our industry needs is a person that really doesn’t understand the unique properties of a CO2 design system resulting in a faulty project that could damage the reputation of the technology for everyone.”

CO2 ’s properties require different materials as well as specific practices for managing pressure, operating the systems and designing the equipment, Collins said. “Having one document specific to CO2 will make it easier for the industry to move to using the refrigerant going forward,” he said.

One of the biggest areas that is unique to CO2 is pipe materials. “The industry is evolving and developing rapidly to make CO2 more widespread. Some of the things being developed on the product level are piping material, valves and other system components,” Collins said. “Because CO2 is unique and operates at higher pressures, the technology is specific to CO2 .”

Trumbower said the high operating pressure of CO2 is the biggest challenge. “With keeping CO2 in mind, we’ve been developing products to address that.” “The standard is going to help us address other parts of the CO2 systems and the higher-pressure characteristics of CO2 .”

Dolbec said that as a rack manufacturer, the challenge is to get components approved for installation in North America. “The CO2 market is growing, so we get demand for systems that are larger and larger, so we need components that are designed and manufactured to install in these larger systems,” he said. “The UL components aren’t following at the pace [development] needs to be.”

Requirements for CO2 systems change significantly depending on how the system is arranged and the type of operating conditions, Collins said. “The fact that air-cooled systems operate in a transcritical mode is unique to CO2 . Addressing that reality in this standard has been one significant thing that is unique to CO2 and has required time to determine how to evaluate those elements of design and safety aspects of operating in a transcritical mode,” he explained.

Collins said one of the biggest issues the CO2 industry is dealing with is technology and system design processes that aren’t fully established for CO2 at this point. “To a degree, it’s like shooting at a moving target because the industry is evolving so quickly,” he said. “We’re trying to create a framework and definition that doesn’t tie the hands of the industry to develop and evolve as these new technologies come to light.”

Lundell said standards development is a difficult project that is never done. As new technology and experience evolves, revision for continuous improvement is a normal part of the process. Under the IIAR/ANSI procedures, we are required to update each standard every five years to ensure they address new technology and changes that have occurred in the industry.


The document has been out for public review and garnered more than 130 comments, which the IIAR standards committee is reviewing. “As we address these 130-plus comments, the committee will respond to the originating commenters and see if we can reach a consensus on each topic,” Lundell said.

The goal is to make the standard available for a second public review prior to the IIAR annual conference in March 2020, Collins said. “Coming out of that we’ll have a very good picture as to how things stand and how much work we have remaining. I think everybody would like to see the published document sooner rather than later.”

Lundell said the release depends on input from public review, how many comments are received and how quickly the committee and association resolve them. He added that the timeline is a consensus process that follows specific ANSI guidelines.

Taylor said responding to comments forces the committee to really evaluate what they’ve written to produce a better document. “There were several points raised that sparked significant discussions.”

The committee has tried not to over-specify safety issues which those in the ammonia industry are used to addressing. “We’ve come at this from a much more safety-focused industry but continuously have had to think through and consider whether it really needs to have a certain safety feature or if it can be specified more like other commercial refrigeration systems,” Taylor said.


Collins said because CO2 is a natural refrigerant, it made sense for IIAR to develop the standard. “We already have a CO2 handbook that has been published for a number of years. The standard is a logical progression for our organization to address current design and safety issues with this document.”

IIAR’s board of directors instructed the standards committee in 2015 to evaluate what a CO2 standard should cover and what it would look like. Over the course of the intervening five years, the committee has been working with the refrigeration industry to develop this document,” Collins said.

“Our intent is that all parties working with CO2 refrigeration will benefit. It is a document we can all look at and give us a commonplace to understand how we’re going to build, install, inspect, test and maintain these systems. It is comprehensive in that regard in terms of scope and audience,” Collins said. Taylor said ultimately the benefit is to the end user because the result is the contractors and engineers have a level playing field of how to safely design and install a system.

Lundell said “IIAR’s vision is to create a better world through the safe and sustainable use of natural refrigerants” and “IIAR’s mission is to provide advocacy, education and standards for the benefit of the global community in the safe and sustainable design, installation and operation of ammonia and other natural refrigerant systems. The new CO2 safety standard is a significant step forward to improve our industry and achieve this mission.”