explosion

Flammable refrigerants demand caution

Regulatory gap allows sale to public
Tuesday, October 15, 2013
By Barbara Carss

Do-it-yourself refrigerant conversion kits threaten to blow inadequate Canadian safety regulations wide open. Literally. Heating, ventilation, air conditioning and refrigeration (HVACR) industry insiders warn that cylinders of isobutane or propane now on sale in prominent national retail outlets could fuel a calamity.

“We are seeing certain companies promoting hydrocarbon refrigerants without explaining they are quite dangerous,” says Jim Thomas, president of Refrigerant Services Inc., which collects, recycles and decommissions refrigerant. “It seems to be falling through the cracks in terms of regulations. Manufacturers and distributors can sell flammable refrigerants even though they aren’t approved for use in any air conditioning system.”

Worldwide, flammable refrigerants still have a fairly narrow scope of application but they are gaining attention with the phase-out of CFCs (chlorofluorocarbons) and HCFCs (hydrochlorofluorocarbons) and moves to phase down the use of HFCs (hydrofluorocarbons). Potential replacements include hydrocarbons, propane and isobutane, and a new category of emerging HFO (hydrofluoro-olefin) refrigerants, designated as mildly flammable or A2L under the American Society of Heating, Refrigerating and Air-Conditioning Engineers’ (ASHRAE) flammability and toxicity classifications.

“The major driver is efforts to find low global warming potential refrigerants,” says Warren Heeley, president of the Heating, Refrigeration and Air Conditioning Institute (HRAI) of Canada. “There is quite a lot of research going on now on what the next generation of refrigerants is going to look like.”

Standards bodies like ASHRAE, the International Organization for Standardization (ISO) and UL (Underwriters Laboratories) are also grappling with how to safely introduce more volatile and hazardous chemicals. Although legislators in jurisdictions like the European Union have set rapidly approaching deadlines for phase-out or elimination of some uses of HFCs – in household refrigerators and freezers, automobile air conditioning and as expansion agents for foam insulation – current regulations only allow low volumes of flammable refrigerant to be used in any system.

“The size of the charge is really the size of the risk,” explains Refrigerant Services’ Thomas. “A very small system might have a charge of 50 to 100 grams of refrigerant. That would be something like domestic refrigerators or the pop coolers you see in stores and restaurants.”

In contrast, a commercial rooftop chiller would have a charge of 50 to 100 pounds. Air conditioning systems for single-family homes also have charges well above the allowable limit, while even the small charge in a refrigerator is perilous in the hands of amateurs or in a system not specifically designed for it.

Over-the-counter hazards
It’s conceivable that flammable refrigerants have been used in all these scenarios since it is now being sold to the public in Canada, most frequently with a product name incorporating some variation of “22-a” to denote that it’s a substitute for HCFC-22. For example, Canadian Tire sells a 237 gram (eight ounce) cylinder of 22a hydrocarbon refrigerant for $21.99, advertising that it is “designed as an environmentally safe, efficient refrigerant replacement for ozone depleting R22.” A 22a replacement and retrofit kit is also available for $79.99.

Several serious safety and environmental risks come into play: fires and/or explosions could occur due to leaks or improper handling in systems not designed for flammables; service technicians subsequently working on the equipment could be endangered if they are unaware it contains flammable refrigerants; and untrained homeowners or building maintenance staff could release global warming potential and/or ozone-depleting substances into the atmosphere while performing the conversions.

Both HRAI and the U.S. Environmental Protection Agency (EPA) have recently issued warnings about the product. HRAI is also working with the Ontario Fire Marshal to make fire services aware of the issue and to develop a public awareness strategy.

“The fire code states that, ‘An air conditioning system must be operated and maintained so as not to create a hazardous condition.’ That’s the first and only thing we’ve found that could be applied to this do-it-yourself situation,” says the HRAI’s Heeley. “If you look at isobutane or propane as a fuel, it is regulated to the hilt but the regulations are virtually silent on flammable refrigerants.”

In the U.S., the EPA’s SNAP (significant new alternatives policy) program evaluates and regulates any substitute for ozone-depleting chemicals slated for phase-out under the U.S. Clean Air Act.

“At this time, the EPA has not approved the use of propane or other hydrocarbon refrigerants in any type of air conditioner,” it stated in an advisory released in July. “The EPA has approved the use of propane as a substitute refrigerant for R-22 in industrial process refrigeration systems and in new stand-alone retail food refrigerators and freezers that are specifically designed to use flammable hydrocarbon refrigerants.”

Ominous unknowns
Environment Canada’s contemplated code of practice for refrigerant conversions – posted in draft on the ministry’s website – acknowledges flammable refrigerants and points prospective converters to the Canadian Electrical Code, the CSA B-52 Mechanical Refrigeration Code, applicable building and fire codes, and municipal regulations for further directions.

“Highly flammable refrigerants may require that AC&R (air conditioning and refrigeration) systems and associated facilities, including storage facilities, meet explosion-proof requirements,” it adds.

Refrigerant Services’ Thomas foresees few conversions involving flammable refrigerants because the cost would likely be higher than simply installing a new system. However, he doesn’t expect to see many new systems in the short-term either.

“I think part of the problem is that nobody really knows right now what we have to do to make these systems safe when we’re using a flammable refrigerant,” he reflects. “Even with the HFOs that are being used in the automotive market, the equipment to recycle these products hasn’t yet been developed because they aren’t sure what they have to do to make them safe.”

Beyond very small charges, he projects earlier adoption in larger industrial facilities or arena complexes that have secondary loop systems. That would provide more safety assurance since the cooling/refrigeration plant is housed in a location separate from the building it serves so that the building’s occupants shouldn’t encounter any potentially escaping refrigerant. This has already long been the practice for indoor rink facilities that make ice with ammonia, which, notably, has a B2L ASHRAE classification to indicate that it is mildly flammable and highly toxic.

To be deemed mildly flammable, a substance must burn at a velocity no greater than 10 centimetres or 3.9 inches per second. By comparison, Usain Bolt’s world record 100-metre time equates to 1,043 centimetres per second, while hydrocarbons burn many times faster.

“Hydrocarbon refrigerant is under high pressure. It can escape into the atmosphere, it boils at low temperatures, it vaporizes and it explodes,” says Thomas. “I think I would feel a little more comfortable with an HFO than a hydrocarbon but if you had a leak of an HFO in an occupied building, it could get to the level in the atmosphere where there could be an explosion.”

Oversight required
A UL whitepaper from 2010, Revisiting Flammable Refrigerants, similarly itemizes a long list of potential risks and triggers to disaster but concludes it is important to develop the safety standards, controls and redundancies that will be a necessary conjunct of an evolving market. HRAI’s Heeley agrees, emphasizing that all sectors – refrigerant producers, equipment manufacturers, service providers, safety oversight agencies and regulators – have a role to play.

“Our stance on flammable refrigerant is that products using these refrigerants have to follow the standard regulatory process and be certified. If they want the product to be regulated properly, there is whole infrastructure that has to be built around it,” he says. “There has to be a regulatory understanding of where and how these products are going to be used.”

Barbara Carss is editor-in-chief of Canadian Property Management and Building Strategies & Sustainability magazines.

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