HRAI ODP Refrigerant Handling flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

ODP definition

Ozone Depletion Potential is a relative index, scaled so CFC-11 equals 1.0, expressing the relative amount of stratospheric ozone destruction per unit mass of a substance.

CFC-11 ODP value

CFC-11 (trichlorofluoromethane) is the reference compound with an ODP defined as exactly 1.0 against which all other substances are compared.

HCFC-22 ODP value

HCFC-22 has an ODP of about 0.055, roughly one-twentieth that of CFC-11, because its hydrogen atom makes it break down in the lower atmosphere.

HFC ODP value

HFC refrigerants such as R-134a and R-410A contain no chlorine or bromine, so their ODP is zero and they are not classified as ozone-depleting substances.

Bromine versus chlorine potency

Bromine atoms destroy ozone far more efficiently than chlorine atoms, roughly 45 to 60 times more per atom, so halons have high ODP despite small atmospheric concentrations.

What makes a substance ODS

A substance is an ozone-depleting substance if it carries chlorine or bromine and survives long enough in the atmosphere to reach the stratosphere and release those halogens.

Montreal Protocol Annex A

Annex A lists the original controlled substances: CFC-11, CFC-12, CFC-113, CFC-114, CFC-115 and the halons 1211, 1301 and 2402.

Kigali Amendment scope

The Kigali Amendment controls hydrofluorocarbons by phasedown of production and consumption based on GWP, but HFCs are not ozone-depleting substances under the Protocol.

ODP versus GWP

ODP measures ozone destruction relative to CFC-11 while GWP measures infrared radiative forcing relative to CO2 over 100 years; the two metrics are independent.

Recovery definition

Recovery is the removal of refrigerant from a system into an external container for storage, reuse, recycling, reclamation or destruction, without processing it.

Recycling definition

Recycling is the field reduction of contaminants such as oil, moisture and acids in recovered refrigerant, typically by filtering and separation, without full chemical analysis.

Reclamation definition

Reclamation is the reprocessing of recovered refrigerant to new-product specification, usually AHRI 700, verified by chemical analysis, and is required before resale or use in another owner's equipment.

AHRI 700 standard

AHRI Standard 700 specifies acceptable purity levels and test methods for new and reclaimed refrigerants, including composition, moisture, acidity and non-condensable gas limits.

Venting prohibition

Intentional discharge of ozone-depleting refrigerant to the atmosphere is prohibited; recovery equipment must evacuate the circuit to the required vacuum before opening or disposal.

De minimis charge exemption

Some regulations exempt very small ODS charges, commonly 5 pounds or less, from certain recovery and leak-repair requirements, but never permit deliberate venting.

Recovery cylinder fill limit

Recovery cylinders must not be filled above about 80 percent of water capacity by liquid, leaving vapor space for thermal expansion and preventing hydrostatic rupture.

Cylinder rating requirement

A recovery cylinder must be rated and stamped for the pressure of the refrigerant it holds, and must be labeled with the refrigerant identity and the applicable hazard class.

Zeotropic blend charging

Zeotropic blends such as R-407C change composition as they evaporate, so they must be charged as a liquid and cannot be fractionally topped off without composition drift.

Retrofit label update

When an ODS refrigerant is replaced with a non-ODS substitute, the equipment label must be updated to record the new refrigerant type and the full charge amount.

Asphyxiation hazard

Most ODS refrigerants are nonflammable but denser than air; they displace oxygen in low areas, so confined spaces require ventilation and atmospheric oxygen monitoring before entry.

Appliance disposal rule

Before an appliance is shredded or landfilled, its refrigerant must be recovered; ODS that cannot be reclaimed must be destroyed by an approved process rather than vented.

Leak repair requirement

When a leak is detected in equipment above the regulated charge threshold, the leak must be repaired within the specified period and the repair documented in service records.

HCFC phase-out status

HCFCs such as R-22 are scheduled for complete phase-out of production and consumption under the Montreal Protocol, with allowances for servicing existing equipment in some regions.

Carbon tetrachloride ODP

Carbon tetrachloride has an ODP of about 1.1, slightly above CFC-11, and is controlled under Annex B of the Montreal Protocol as an ozone-depleting substance.

Methyl bromide ODP

Methyl bromide has an ODP of about 0.6 and is listed in Annex E of the Montreal Protocol, with quarantine and pre-shipment uses treated separately from general controls.

Recovered refrigerant reuse

Recovered ODS refrigerant may be reused only in equipment owned by the same owner or if it has been reclaimed and certified to AHRI 700 purity for resale.

Non-condensable gas effect

Air or nitrogen trapped in a circuit raises discharge pressure and temperature, reduces capacity and efficiency, and must be purged or avoided during recovery and charging.

Moisture in ODS systems

Moisture in a CFC or HCFC circuit forms acids and sludge, degrades lubricant and can freeze at the metering device, so filter-driers and evacuation are required.

Evacuation before charging

A system must be evacuated to the specified micron level and hold that vacuum before charging, removing moisture and non-condensables that would otherwise damage the system.

Recovery equipment certification

Recovery machines must be certified to the applicable standard for the refrigerant type, and separate machines or verified changeover are needed for different refrigerant families.

Refrigerant mixing prohibition

Different refrigerants must never be mixed in one cylinder, because the resulting mixture has unknown properties, cannot be reclaimed and becomes a costly hazardous waste stream.

ODS recordkeeping

Regulations require records of refrigerant purchases, charges, recoveries, leak repairs and disposal, retained for the specified period and available for inspection.