Best Practices Are Essential - New A2L refrigerants require extra safety measures
The refrigerant landscape is changing. Over the next few years, we will see an acceleration in the availability of new refrigerants and equipment to comply with developing regulations. These new refrigerants are expected to be mildly flammable and best practices are essential for a safe transition.
The original regulatory control measures introduced in Canada were the Ozone Depleting Substances and Halocarbon Alternatives Regulations (ODSHAR). The ODSHAR is a domestic regulation that is Canada’s national commitment to, and official ratification of, the Kigali Amendment to the Montreal Protocol agreed to on October 15th, 2016. The publication in the Canada Gazette Part II on June 29, 2016 solidifies that commitment coming into effect on December 29, 2016.
The phase down of HFCs began in 2019, as refrigerant manufacturers were required to cut production by 10%. This includes R-410A, which is found in the majority of residential and commercial air conditioning equipment in Canada.
Product specific control measures are also regulated by Environment Canada and Climate Change as shown in the below chart:
While R-410A is a non-flammable (A1) refrigerant, it’s replacements include R-32 and R-454B, both of which are mildly flammable (A2L) refrigerants. In order to install or service equipment containing these new refrigerants, additional safety measures will need to be followed by HVAC contractors and technicians.
Some tips for a safe transition of A2L Refrigerants, complements of Jason Obrzut, director of industry standards and relations at ESCO Institute, as reported in The News last month.
When it comes to installing an A2L system, there aren’t too many differences when compared to an A1 system, provided the technician is already employing best practices, said Obrzut. In fact, when comparing installation and service practices between the two, there are three requirements for an A2L installation that are not required for A1 systems.
“These requirements are to purge the circuit with an inert gas, evacuate, and leak test the unit,” “However, based on industry best practices, these requirements were things that should have been done with an A1 installation as well. Technicians and contractors employing industry-accepted best practices will notice little or no change at all in their service practices or their installation practices.”
One of the biggest differences between installing an A2L and an A1 system involves evaluating the installation site and determining where the unit can be placed.
“For new construction, the biggest challenge will be with swap outs, where we're taking the unit out of a closet and putting in a new one that is charged with an A2L.”
Equipment manufacturers installation manuals will include details on where a unit may be placed, as mandated by the UL 60335-2-40 standard, which is the product safety standard for comfort cooling applications. Specific to the model this will include charging information, use application, use restrictions, etc. Note: it is important to always defer to the local authority having jurisdiction over the building code.
A2L units will also come with some type of refrigerant mitigation strategy, which is necessary in the case of a leak. Should a leak occur and a sensor embedded in the equipment detects that the refrigerant concentration has passed the predefined threshold, mitigation actions will be initiated, such as turning on fans and blowers to dilute the refrigerant concentration and maintain a concentration below the lower flammability limit (LFL).
Units will have active sensors and locking mechanisms, and all of this onboard the unit for the most part. It's not going to be up to the technician to install or calibrate the sensors.
Labels and Tools
A2L systems will also be labeled differently, so it will be apparent to technicians that they are working on a system that contains a mildly flammable refrigerant. The ISO triangle warning sign with the flame symbol will be affixed to the unit, as will another label containing information filled out by the installing technician.
“The installing technician must use a permanent marker to fill out the label with information such as the final charge, final test pressure, final evacuation level, etc.” said Obrzut.
As for tools, those that don't touch the refrigerant circuit – such as scales – can usually be used for both A1 and A2L systems. Other tools, such as recovery machines, leak detectors, and vacuum pumps must be rated for use with flammable refrigerants.
Charging and Recovery
When charging an A2L system, the process is essentially the same, so zeotropic and near-zeotropic refrigerant blends must still be charged as a liquid. Charging with an A2L refrigerant must be done carefully to ensure that the maximum allowable charge is not exceeded. And, the maximum allowable charge will be different for every system installation.
“It's going to be specific to the size capacity of the unit, as well as the air space that the system is servicing, so what works for one area may not work for another,” said Obrzut. “It's not going to be a universal number. It's going to be determined by the charging chart that manufacturers are going to provide based on the cubic volume of air and the location and capacity of the unit. Technicians won’t need to calculate it.”
When evacuating an A2L system, technicians should make sure the recovery machine is rated for use with A2Ls; otherwise, the process is virtually the same as for A1 systems. Best practices for recovery of both types of refrigerants will be included in HRAI’s Training material.
The color of all refrigerant cylinders is changing to gray-green, but A2L cylinders will also have a red stripe on them and the treading may be different.
“Another difference is that A2L tanks will have a pressure relief valve that can open, vent a little bit, lower the pressure, and then close back up,” he said. “This is unlike R-410A cylinders, which lose their whole charge if the rupture disc bursts.”
The HFC phasedown has started and technicians should recognize that training will be necessary to install and service A2L systems. There are R-32 systems already on the market in several U.S states and it is only a matter of time when codes will be adopted in Canada.
HRAI and ESCO Institute are jointly committed, through a collaborative effort, to ensure that the industry is properly trained on the handling, safety procedures, as well as the applicable standards and codes related to handling these new refrigerants. We are developing a Low GWP Refrigerant A2L Safe Handling Training Program, including an online course.
For more information contact Caroline Czajko @ HRAI, email@example.com
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