Refrigerants, rules and safety

The refrigerant is what makes the vapour-compression cycle work, and it is also the part of a refrigeration system that carries most of the regulation and much of the risk. Some refrigerants are powerful greenhouse gases if they leak; some are flammable; one widely used industrial refrigerant is toxic; another runs at very high pressures. Handling the most common family, the fluorocarbons, is a licensed activity in Australia. A business that owns refrigeration plant does not need to handle refrigerant itself, and should not, but it needs to understand enough to choose plant sensibly, to engage the right people, to keep its obligations and to keep its people safe.

This chapter covers the refrigerants a factory is likely to meet and their hazards, the licensing and legal frame for handling them, leak management and records, the safety hazards of cold rooms and refrigeration plant beyond the refrigerant itself, and how refrigerant choice enters a design such as CS-1’s. The failure case is a plant that was topped up repeatedly by an unlicensed contractor without anyone finding the leak.

This chapter is general information. The specific requirements that apply to a business, a refrigerant and a system come from the legislation, the licensing body, the applicable standards and the work health and safety regulator, and should be confirmed with them and with licensed refrigeration professionals.

Refrigerant families

Figure 1Refrigerant families a factory may meet

	Main hazards and concerns	Typical uses
Hydrofluorocarbons, HFCs	high global warming potential if leaked; licensed handling; supply being phased down	many existing commercial and industrial systems
Newer low-warming fluorinated refrigerants	some are mildly flammable; licensed handling	replacements for HFCs in new equipment
Hydrocarbons, such as propane and isobutane	flammable; charge limits depend on the space	small self-contained units, some chillers and heat pumps
Ammonia	toxic and, at some concentrations, flammable; pungent, so leaks are noticed	large industrial refrigeration, cold stores, food processing
Carbon dioxide	very high operating pressures; an asphyxiant in enclosed spaces	supermarkets, heat pumps for hot water, low-temperature systems

Each family has trade-offs. Fluorocarbons are non-toxic and mostly non-flammable, which made them dominant, but their climate impact has led to controls on their supply. Hydrocarbons and carbon dioxide have very low climate impact, but bring flammability or high pressure. Ammonia is efficient and has no direct climate impact, but its toxicity limits it to well-engineered industrial plant with trained operators. Standards classify refrigerants by toxicity and flammability, and set limits on how much of each can be used in a given space.

Licensing and the legal frame

In Australia, the handling of fluorocarbon refrigerants is controlled under the Ozone Protection and Synthetic Greenhouse Gas Management Act 1989 and its regulations. People who handle fluorocarbon refrigerants must hold a refrigerant handling licence, issued by the Australian Refrigeration Council on behalf of the Australian Government, and handling them without the right licence is an offence. Businesses that acquire, store or dispose of these refrigerants may need their own authorisation. Refrigerants outside that scheme, such as hydrocarbons, ammonia and carbon dioxide, are not covered by the refrigerant handling licence, but their handling is subject to other requirements, including work health and safety, dangerous goods and the applicable standards.

For a factory that owns refrigeration plant, the practical consequence is simple: every job that opens the refrigerant circuit, recovers, adds or handles refrigerant must be done by a licensed technician working for an appropriately authorised business. The owner should check the technician’s licence, keep records of the work, and make sure the contractor’s business holds any authorisation it needs to buy and handle the refrigerant it brings to site.

Figure 2An owner's refrigerant obligations and good practice for CS-1

• Do: Refrigerant circuit work done only by licensed technicians from authorised businesseslicence checked and recorded
• Do: Every refrigerant addition and recovery recorded with the amounta growing total points to a leak
• Do: Leaks found and repaired before the system is rechargednever top up without finding the cause
• Do: Refrigerant type and charge labelled on the plantso nobody adds the wrong one
• Do: Recovered refrigerant returned for recycling or destructionnever vented
• Ask: Refrigerant choice for new plant reviewed for safety, efficiency and future supplywith the designer
• Avoid: Allowing anyone without a licence to handle fluorocarbon refrigerantan offence

Leaks: three costs

A refrigerant leak costs three ways. Environmental: fluorocarbons released to the air add to climate change, many times more strongly per kilogram than carbon dioxide. Efficiency: a system short of refrigerant runs with a wider lift and longer running hours, as Chapters 3 and 6 showed. Money: refrigerant must be replaced, and some refrigerants are becoming more expensive as their supply is phased down. Regular leak checks, comparing service readings with previous ones, and recording every addition, are the defences. On CS-1, the total refrigerant added in each year is reported in the yearly review alongside the electricity benchmark from Chapter 6, so that a leak shows up in two places at once and cannot be quietly topped up for years, as the failure case below describes.

Safety beyond the refrigerant

Cold rooms and refrigeration plant carry hazards that have nothing to do with refrigerant chemistry:

• Entrapment. A person shut inside a cold room can suffer cold injury. Cold room doors have internal release mechanisms that open from inside, and many rooms have an alarm button inside; both are tested regularly.
• Cold exposure. Staff working in cold rooms for extended periods need suitable clothing and breaks, managed under work health and safety duties.
• Slips. Frost, condensation and spilled product make floors slippery.
• Refrigerant in enclosed spaces. A large leak of any refrigerant into a closed room can displace oxygen; flammable refrigerants can ignite; ammonia is toxic. Systems above certain sizes, and in certain spaces, need refrigerant detectors and ventilation set by the applicable standard.
• Pressure and electricity. Refrigeration plant is pressure equipment driven by electrical machinery. Isolation before maintenance, as for any plant under the model Code of Practice on managing plant risks, applies.

When a leak is suspected

A suspected leak, whether from a gas detector’s alarm, a hissing fitting, an oily stain on pipework or a plant that is struggling, needs a planned response.

Figure 3Responding to a suspected refrigerant leak at CS-1

1. 1Keep people safeif a detector alarms or a strong release is evident, leave the area and ventilate it before re-entry
2. 2Isolate electrically if safestop the plant from outside the room if the leak is near electrical equipment
3. 3Call the licensed techniciandescribe the symptoms, the refrigerant and the plant
4. 4Protect the productmove product if the room cannot hold temperature, and record its temperatures
5. 5Find and repairthe technician locates the leak, repairs it and pressure-tests before recharging
6. 6Recordrefrigerant recovered and added, the cause and the repair, in the plant's log

Service agreements and records

Most owners rely on a refrigeration contractor for servicing, and the agreement with that contractor is where obligations become routine. CS-1’s service agreement sets out the visit frequency, the readings recorded at each visit, the leak check method, the response time for breakdowns, and the requirement that every refrigerant addition and recovery be recorded with its amount, its type and the reason. The contractor’s licence and authorisation details are on file, checked when the agreement is renewed. The service records, kept with the plant’s design data and the room’s temperature logs, give the owner a complete history and give the next contractor everything needed to understand the plant.

Ammonia and carbon dioxide

The two main natural refrigerants used in larger industrial plants each demand particular care. Ammonia is toxic, and in some concentrations flammable, but it has a strong, pungent smell at concentrations far below dangerous levels, so even small leaks are usually noticed quickly. Ammonia plants are engineered with detectors, ventilation, emergency shut-downs and emergency plans, and their operators are trained for them. Carbon dioxide is non-flammable and of low toxicity in small amounts, but it is odourless, heavier than air and displaces oxygen in enclosed or low-lying spaces, and carbon dioxide systems run at pressures several times those of other refrigerants. Detectors in occupied spaces, pressure relief arrangements and technicians trained in high-pressure systems are essential. Both refrigerants are excellent engineering choices in the right hands and the right plant; neither belongs in a system designed or serviced by people unfamiliar with it.

End of life

When a refrigeration system or heat pump is decommissioned, its refrigerant must be recovered by a licensed technician before the equipment is dismantled or scrapped, and returned for recycling or destruction. Equipment sent for scrap with its refrigerant still inside, or with its pipes cut and the refrigerant vented, releases the whole charge at once. CS-1’s replacement plan includes recovery of the old plant’s refrigerant as a line item, with the record of the recovered amount kept with the plant’s history.

Heat pumps carry the same obligations

A heat pump is a refrigeration system, and everything in this chapter applies to it. The heat pump water heater considered in Chapter 4 would contain a refrigerant charge, need licensed servicing if its refrigerant is a fluorocarbon, and need its refrigerant recovered at the end of its life. Its refrigerant also shapes its performance at high water temperatures, as Chapter 4 noted. A heat pump’s purchase decision should therefore include its refrigerant type, its charge and the availability of technicians licensed and trained to service it locally, alongside its COP and price.

Planning for supply changes

Australia, like many countries, is phasing down the supply of high-warming fluorocarbon refrigerants. Existing plant can generally continue to be serviced, but the refrigerants it uses may become scarcer and dearer over its remaining life, and some may eventually be replaced in servicing by alternatives that need system changes. An owner planning the next ten or fifteen years should know which refrigerant each system uses, how old each system is, and roughly when each will need replacing, so that replacements can choose refrigerants with secure future supply, rather than being forced into a rushed choice when an old system fails.

Training on site

The factory’s own staff do not handle refrigerant, but they work beside refrigeration plant every day and need to know enough to work safely. CS-1’s induction covers the cold room’s internal door release and alarm, how to recognise a struggling plant, what to do if a refrigerant detector alarms or a strong smell or hissing is noticed, the prohibition on anyone other than licensed technicians touching the refrigerant circuit, and the importance of keeping the door closed and the condenser clear. A few minutes of induction, repeated when the plant changes, prevents many of the failures described in this book.

Choosing a refrigerant for CS-1

When CS-1’s plant is next replaced, refrigerant choice will be part of the design, not an afterthought. The designer will weigh the refrigerant’s efficiency at CS-1’s temperatures, its safety class and the charge limits for the room and plant area, the availability and price of the refrigerant over the plant’s life, given the phase-down of high-warming refrigerants, the skills and licensing of local service technicians, and the purchase and running costs of each option over its life, as Chapter 6 recommended. A small, self-contained unit with a low-warming refrigerant and a small charge is often the simplest answer for a room of CS-1’s size; larger sites may justify ammonia or carbon dioxide systems engineered for them.

A failure case: topped up, never fixed

This is an illustration. Before its present maintenance arrangements, CS-1’s plant was serviced by a general maintenance contractor. Each summer, the room struggled to hold temperature, and each summer the contractor “topped up the gas”, after which the room recovered for a few months. Nobody recorded how much was added, and nobody looked for a leak.

When the business engaged a licensed refrigeration contractor, the technician’s first service found the plant short of charge, with the pattern of high superheat and low pressures from Chapter 3, and found a leaking fitting on the condenser. The technician also found that the previous contractor’s top-ups could not be verified as the correct refrigerant, so the whole charge was recovered, the leak repaired, the system evacuated and recharged by weight with the specified refrigerant, and the work recorded.

The detection came from engaging a properly licensed technician who measured, diagnosed and recorded. The correction was the repair, the full recharge and a new rule: only licensed refrigeration technicians work on the refrigerant circuit, every addition is recorded with its amount, and any addition prompts a leak search before the system is left. Topping up without fixing a leak had cost refrigerant, electricity and product risk for years, and the earlier handling may itself have breached the licensing requirements.

How this applies to a small Australian business

Know which refrigerant each of your systems uses, label it, and understand its main hazards. Use only licensed refrigeration technicians, from authorised businesses, for any work on the refrigerant circuit, and check their licences. Record every refrigerant addition and treat additions as evidence of a leak to be found and fixed. Manage cold room safety, including entrapment, cold exposure and refrigerant detection where required. And when buying new plant, choose the refrigerant with your designer, weighing safety, efficiency, future supply and life-cycle cost.

Exercise: the cost of a leak

A plant with a 5 kg refrigerant charge loses about 20% of it each year through a slow leak, and runs about 10% less efficiently on average because of the low charge. Its electricity at full charge costs about A$3,730 a year. If the refrigerant costs about A$120 per kilogram to replace, installed, and a leak repair costs about A$600, what does the leak cost each year, and how long does the repair take to pay back? These prices are an illustration.

Worked answer. The plant loses 0.2 × 5 = 1 kg a year, costing about A$120 to replace. Its electricity rises by about 10%, about A$373 a year. The total is about A$490 a year, before counting the environmental cost of the released refrigerant or the risk to product when the room struggles on hot days. The A$600 repair pays back in a little over one year on running costs alone, and stops the release. Leaks are always worth finding and fixing.