F-Gas English Low GWP
All questions
HFC | Flammable | CO₂ | NH₃
Easy questions |
Medium questions |
Difficult questions
1
Difficult
What additional protective equipment will you use when brazing systems containing HC refrigerants?
| Ear defenders |
| A high-visibility vest |
| A flammable gas detector |
| Latex gloves |
2
Difficult
Why can’t a sealed high-pressure switch be replaced with a standard mechanical one in a system containing a flammable refrigerant?
| Dust and moisture may enter |
| The pressure switch setting will not be correct |
| There is a risk of refrigerant leakage |
| It is a potential source of ignition |
3
Difficult
What is the minimum (recommended) distance from a work area with HC refrigerants within which there must be no sources of ignition?
| 3 m |
| 0.5 m |
| 1 m |
| 2 m |
4
Difficult
What is the maximum safe R32 fill of a recovery cylinder approved for flammable gas that holds 20 kg of R410A (the liquid density of R32 is about 8-10% lower)?
| 33 kg |
| 9 kg |
| 18 kg |
| 20 kg |
5
Difficult
What is the maximum charge of an A3 refrigerant for a hermetic display cabinet with an integral condenser located in the ground-floor sales area of a supermarket?
| 2.5 kg |
| 1.0 kg |
| 10 kg |
| 0,494 kg |
6
Difficult
How can a vacuum pump be used safely to evacuate a system containing a flammable refrigerant?
| Such systems need not be evacuated before charging |
| Ignition-source-free pump, good ventilation, exhaust to a safe place |
| Place the pump directly on the floor, as low as possible |
| Position the pump at least 3 m above floor level |
7
Difficult
What safety measure must you carry in your vehicle when transporting flammable refrigerant cylinders?
| Tinted safety goggles |
| A fire extinguisher |
| A fire blanket |
| Thick gloves |
8
Difficult
How would you prepare a 10 kg R32 water chiller located outdoors for debrazing its joints?
| Vent the R32 outdoors and purge the system |
| Vent the R32 outdoors, then fill and vent the system with nitrogen three times |
| Recover the R32 to a vacuum and start desoldering immediately |
| Recover the R32 to a vacuum, then fill the system with nitrogen to a slight positive pressure (approx. 0.1 bar g) |
9
Medium
What is R1270?
| Propane |
| Propene (propylene) |
| n-Butane |
| Isobutane |
10
Difficult
Which of the following leak detection methods should NOT be used to locate an HC refrigerant leak?
| Soapy water solution |
| Electronic leak detector for flammable refrigerants |
| Leak detection foam |
| Electronic HFC leak detector |
11
Difficult
What is the most important difference between a flammable refrigerant recovery unit and a standard one?
| Different connection sizes |
| Different low-pressure switch setting |
| A flammable refrigerant recovery unit has no ignition sources |
| A different colour for the station |
12
Difficult
Which of the following is a source of ignition?
| An Ex-certified fan motor |
| A contactor (sparking contacts) |
| An 'n'-type (non-sparking) thermostat |
| A sealed NTC temperature sensor |
13
Difficult
What particularly hazardous substance is formed when R32 burns?
| Hydrogen chloride (HCl) |
| Phosgene |
| Sulphur dioxide (SO₂) |
| Hydrogen fluoride (HF) |
14
Difficult
What type of refrigerant is R1234ze(E)?
| CFC (chlorofluorocarbon) |
| HC (hydrocarbon) |
| HCFC (hydrochlorofluorocarbon) |
| HFO (hydrofluoroolefin) |
15
Difficult
What hazards does a safety group A3 refrigerant pose?
| Higher toxicity, moderate flammability |
| Higher toxicity, higher flammability |
| Lower toxicity, higher flammability |
| Lower toxicity, moderate flammability |
16
Difficult
According to EN 378, what is the maximum R290 charge in a cold room measuring 5 m × 3 m × 2.5 m (LFL of R290 = 0.038 kg/m³, access category a, location class I, no additional measures))?
| 0.285 kg |
| 1.0 kg |
| 4.93 kg |
| 1.5 kg |
17
Difficult
What is the approximate ratio of the volumetric cooling capacity of R32 to that of R410A (same compressor and conditions)?
| approx. 0.6 |
| approx. 1.3 |
| approx. 0.75 |
| approx. 1.05–1.1 |
18
Difficult
Why are Ex-certified evaporator fan motors used in some systems with flammable refrigerants?
| Because they are more energy-efficient |
| To avoid a source of ignition in the event of a flammable refrigerant leak |
| Because they are more reliable |
| Because they must be kept running continuously to disperse the leaking refrigerant |
19
Difficult
Why is the density difference between HC and HFC refrigerants important?
| Because HCs operate at much higher pressures |
| Because it determines the system's energy efficiency |
| An HC charge in kg is roughly half that of an HFC |
| Because HCs must be charged much more slowly than HFCs |
20
Difficult
What is the GWP of R290 according to Annex VI to Regulation (EU) 2024/573?
| 675 |
| 150 |
| 7 |
| 0.02 |
21
Difficult
Which of the following is NOT a source of ignition?
| An unsealed mechanical pressure switch |
| An electrical switch |
| A light switch |
| An Ex-certified fan motor |
22
Difficult
What is R290?
| Butane |
| Isobutane |
| Propene (Propylene) |
| Propane |
23
Difficult
What is the maximum A2L charge for a hermetic display cabinet with integral condenser in the ground-floor sales area of a supermarket?
| 1.5 kg |
| 150 g |
| 1.2 kg |
| 2.5 kg |
24
Difficult
Why can’t a standard relay be fitted when retrofitting a compressor’s electrical system for flammable refrigerants?
| Current consumption differs for compressors using flammable refrigerants compared to those using HFCs |
| It could be a source of ignition |
| The method of starting the compressor motor differs from that used with HFCs |
| A relay is never required for compressors using flammable refrigerants |
25
Difficult
What is the minimum (recommended) distance from a work area with HC refrigerants within which there must be no ignition sources?
| 1 m |
| 3 m |
| 10 m |
| 5 m |
26
Difficult
A recovery cylinder holds 10 kg of R404A (filling ratio 0.82 kg/l). What is the maximum R290 charge for this cylinder (propane filling ratio 0.43 kg/l per ADR P200)?
| approx. 5.2 kg |
| 20 kg |
| approx. 17 kg |
| approx. 8 kg |
27
Difficult
How can a vacuum pump be used safely to evacuate a system containing R290?
| Position the pump at least 3 m above floor level |
| Ignition-source-free pump, good ventilation, exhaust to a safe place |
| Place the pump directly on the floor, as low as possible |
| R290 systems need not be evacuated before charging |
28
Difficult
Under ADR, what equipment must you carry in your vehicle when transporting flammable refrigerant cylinders (under the 1.1.3.6 exemption)?
| Thick gloves |
| A fire blanket |
| A fire extinguisher (at least 2 kg dry powder) |
| Tinted safety goggles |
29
Difficult
How do you make sure it is safe to light the torch for desoldering joints in a system from which a flammable refrigerant has been removed?
| Purge the system with compressed air |
| Such joints must never be desoldered; they must be cut with a pipe cutter |
| Ensure good ventilation and check the work area with a flammable gas detector |
| Working outdoors is sufficient |
30
Difficult
How would you prepare a system containing 100 g of R1270 for debrazing, if local regulations allow controlled venting of small HC quantities?
| Vent the R1270 into the room and open a window |
| Recover the R1270 to a vacuum and start brazing immediately without a nitrogen purge |
| Vent the R1270 to a safe outdoor location, then purge with OFN three times (pressurise and vent), and braze with OFN flowing |
| Vent the R1270 outdoors and start brazing immediately |
31
Difficult
Which method should NOT be used to locate an R290 leak?
| Fluorescent dye and UV lamp (if approved by the manufacturer) |
| Leak detection foam |
| An electronic leak detector designed for HFCs |
| An electronic detector for flammable refrigerants |
32
Difficult
Why can’t recovery stations designed for HFCs be used with R600a?
| The recovery unit cannot withstand the working pressure of R600a |
| The low-pressure switch setting will not be suitable for R600a due to its lower operating pressure |
| The oil in the recovery unit is not soluble in R600a |
| They contain ignition sources |
33
Difficult
According to EN 378, what is the maximum R1234ze(E) charge in a cold room measuring 5 m × 3 m × 2.5 m (LFL = 0.303 kg/m³, access category a, location class I, no additional measures)?
| 2.27 kg |
| 618 kg |
| 6.18 kg |
| 227 kg |
34
Difficult
What type of refrigerant is R32?
| Hydrofluorocarbon |
| Carbon dioxide |
| Hydrocarbon |
| Hydrofluoroolefin |
35
Difficult
What hazards do A2L refrigerants pose?
| Higher toxicity, lower flammability |
| Higher toxicity, higher flammability |
| Lower toxicity, lower flammability (burning velocity ≤ 10 cm/s) |
| Lower toxicity, higher flammability |
36
Difficult
What hazard is associated with the combustion of HFO or HFC refrigerants?
| Ozone is formed |
| Phosgene is formed |
| Hydrogen fluoride (HF) is formed |
| Nitrous oxide is formed |
37
Difficult
Approximately what compressor displacement is required for R600a compared with R134a for the same cooling capacity?
| About seven times as large |
| The same |
| About twice as large |
| About half |
38
Difficult
What is the GWP value for R32 according to Regulation (EU) 2024/573?
| 3 |
| 0 |
| 7 |
| 675 |
39
Difficult
Why is charge accuracy more important in critically charged R290 systems than in HFC systems?
| Because R290 is only used in systems below 150 g |
| The charge mass is much smaller than in an HFC system, because the liquid density of R290 is much lower |
| Because such systems never have liquid receivers |
| Because of lower operating pressures |
40
Difficult
Why does the condenser fan run continuously in some systems using R1270?
| To prevent the build-up of contaminants in the condenser |
| To dilute the refrigerant in the event of a leak |
| To reduce energy consumption |
| To ensure that the discharge pressure never becomes excessive |
41
Medium
What is the main design difference in hydrocarbon refrigeration systems?
| Lower energy efficiency |
| No need for safety measures |
| Higher operating pressures |
| The need to eliminate ignition sources and limit the charge because of the refrigerant's flammability |
42
Medium
How do compressors used in hydrocarbon systems differ?
| They must be approved by the manufacturer for the specific flammable refrigerant (e.g. electrical components that are not ignition sources, suitable oil) |
| They must operate at higher pressures than HFC compressors |
| They need no lubrication |
| There is no difference |
43
Difficult
What must the label of a flammable refrigerant cylinder include?
| The refrigerant name, the UN number, the hazard label (e.g. 2.1 – flammable gas) and basic safety information |
| Only the net weight |
| Information about the cylinder owner |
| Only the refrigerant name |
44
Difficult
Why is the absence of a 'flammable refrigerant' label on equipment a serious hazard?
| It reduces system efficiency |
| It may lead to the use of tools that are ignition sources |
| It has no significant effect on safety |
| It may lead to the wrong oil being selected |
45
Difficult
Which set of information on the label of a flammable refrigerant cylinder is crucial from a safety perspective?
| Gross weight and batch number |
| Manufacturer’s name and country of origin |
| Cylinder colour and date of manufacture |
| Name of the substance, hazard label (ADR) / GHS pictogram (CLP), UN number |
46
Easy
What is the requirement regarding the labelling of an installation containing a flammable substance?
| Labelling is not required for hermetically sealed systems |
| Colour-coding of pipes is sufficient |
| The labelling must indicate the type of substance and the flammability hazard |
| Labelling is required only in technical rooms |
47
Easy
What are the potential consequences of using unsuitable connections in a system containing a flammable substance?
| Merely a reduction in efficiency |
| No impact on safety |
| Merely installation difficulties |
| Risk of leakage and the formation of an explosive mixture |
48
Difficult
What is the purpose of gas detectors in a room with a refrigeration system?
| Early leak detection and triggering of measures preventing health risks and explosive atmospheres (alarm, ventilation, shut-off) |
| Monitoring pipe pressure |
| Controlling compressor capacity |
| Measuring refrigerant temperature |
49
Difficult
How often should gas detection sensors in a machinery room be checked?
| Before every start-up of the unit |
| Only after a leak has occurred |
| According to the manufacturer's instructions and regulations – at least every 12 months |
| Once every 5 years |
50
Difficult
Where should a gas detector be located according to EN 378?
| Only at the room entrance |
| Near the control panel |
| Anywhere in the room |
| Where the refrigerant would accumulate: low (near the floor) for refrigerants heavier than air, high (near the ceiling) for lighter ones such as NH₃ |
51
Easy
How should an employee respond when a gas alarm is triggered?
| Reduce the pressure in the system |
| Switch off the system and wait for the alarm to stop |
| Leave the room immediately and notify their supervisor |
| Carry on working until they see a leak |
52
Difficult
What safety checks should be carried out when installing a new refrigeration system with a flammable refrigerant?
| Only that the air filter is new |
| The presence of health and safety signage, adequate ventilation and gas detectors |
| Only the compressor power |
| The colour of pipes and hoses |
53
Easy
Gas detectors should be installed in rooms where:
| Ventilation is natural |
| The amount of refrigerant exceeds a specified permissible threshold |
| The room is less than 5 m² |
| Any refrigerant is present, regardless of the quantity |
54
Difficult
What are the requirements for emergency exits from a refrigeration machinery room?
| In small machinery rooms emergency exits need not be signed |
| One exit with a sign stating the refrigerant type is sufficient |
| Outward-opening doors and signed escape routes (number of exits per the standard) |
| At least two exits are required and signage is optional |
55
Difficult
Which installation measure for a flammable-refrigerant system improves its energy efficiency?
| Omitting the filter-drier |
| Restricting room ventilation |
| A thorough tightness test and evacuation (dehydration) of the system |
| Charging above the nameplate quantity |
56
Easy
How do leaks affect systems using flammable refrigerants?
| Have no effect |
| They cause refrigerant loss, reduced efficiency and a fire hazard |
| They improve efficiency |
| They lower the temperature |
57
Difficult
Why is it important to limit the refrigerant charge in HC systems?
| It lowers the temperature |
| It limits the possibility of reaching a flammable concentration (≥ LFL) in a leak, increasing safety |
| It doesn't matter |
| It increases capacity |
58
Easy
Why is the cleanliness of heat exchangers in HC systems important?
| It doesn’t matter |
| Causes leaks |
| It improves heat transfer and reduces energy consumption |
| It increases the pressure |
59
Easy
What maintenance measures improve the efficiency of a system using a flammable refrigerant?
| Regular checks for leaks and operating parameters |
| Disabling safety devices |
| Lack of servicing |
| Increasing the refrigerant charge |
60
Easy
How does the correct selection of components affect a system using a flammable refrigerant?
| It lowers the temperature |
| It ensures safe and optimal operation and minimises energy losses |
| It increases the amount of refrigerant |
| It doesn’t matter |
61
Easy
Why is it important to use the correct service tools in HC systems?
| It ensures operational safety and reduces refrigerant losses |
| It doesn’t matter |
| Causes leaks |
| It increases energy consumption |
62
Easy
How does pipe insulation affect the efficiency of systems containing HC?
| It reduces energy losses and improves efficiency |
| It doesn’t matter |
| It increases the pressure |
| Causes leaks |
63
Difficult
What hazards are associated with a safety group A3 refrigerant?
| Lower toxicity, no flame propagation |
| Higher flammability, lower toxicity |
| Lower flammability, lower toxicity |
| Higher toxicity, no flame propagation |
64
Difficult
What is the GWP of R32 (per AR4, as used in Regulation (EU) 2024/573)?
| 3922 |
| 675 |
| 6 |
| 0 |
65
Difficult
What factors are taken into account when determining the maximum charge for comfort air-conditioning/heating applications?
| Lower flammability limit, height of the indoor unit, floor area |
| Lower flammability limit, room volume |
| Practical limit, height of the indoor unit, floor area |
| Practical limit, room volume |
66
Difficult
What compressor displacement is required for R1270 compared with an R404A compressor in the medium-temperature range (cold room)?
| About 1.5 times larger |
| Similar |
| About 6 times larger |
| About half |
67
Medium
What distinguishes class 2L refrigerants from class 2?
| Higher toxicity |
| Heat of combustion above 19 MJ/kg |
| No lower flammability limit |
| A maximum burning velocity of no more than 10 cm/s |
68
Medium
What is the lower flammability limit (LFL) of propane R290?
| Approx. 0.307 kg/m³ |
| Approx. 0.038 kg/m³ (approx. 2.1% by volume) |
| Approx. 0.38 kg/m³ |
| Approx. 1.8 kg/m³ |
69
Difficult
What is the maximum R290 charge per circuit of a commercial refrigerating appliance (e.g. a cabinet) according to EN IEC 60335-2-89:2022?
| 1.2 kg |
| 13 × LFL ≈ 494 g |
| 1.5 kg |
| 150 g |
70
Difficult
Calculate the maximum R32 charge (LFL = 0.307 kg/m³) for a wall-mounted air conditioner (h₀ = 1.8 m) in a 20 m² room using m_max = 2.5 × LFL^1.25 × h₀ × A^0.5.
| approx. 4.6 kg |
| approx. 13.8 kg |
| approx. 1.5 kg |
| approx. 0.46 kg |
71
Medium
Equipment marked 'Ex II 3G' may be used in zone:
| 2 (explosive gas atmosphere unlikely and short-lived) |
| 1 |
| 0 |
| 20 (dusts) |
72
Medium
How is explosion hazard zone 2 defined?
| An area where flammable refrigerants are never used |
| An explosive atmosphere is present continuously or for long periods |
| An explosive atmosphere is not likely in normal operation and, if it occurs, persists only for a short period |
| An explosive atmosphere is likely to occur in normal operation |
73
Medium
Under which UN number is propane (R290) carried under ADR?
| UN 1978 |
| UN 3252 |
| UN 1005 |
| UN 3337 |
74
Difficult
What is the maximum quantity of R290 (class 2, group F) that may be carried per transport unit under the ADR 1.1.3.6 exemption?
| 1000 kg |
| Unlimited |
| 20 kg |
| 333 kg |
75
Medium
At what concentration should a portable flammable gas detector used for R290 work raise an alarm at the latest?
| At 150% of LFL |
| No higher than 25% of LFL |
| At 5% propane by volume |
| At 100% of LFL |
76
Medium
How should a recovery cylinder be prepared before filling it with a hydrocarbon refrigerant?
| Evacuate it (no air) and label it for the specific flammable refrigerant |
| Partly fill it with nitrogen to 5 bar |
| Purge it with compressed air |
| No preparation is needed |
77
Medium
What is the correct approach in a risk analysis before work on an HC system?
| Having a fire extinguisher is sufficient |
| The risk analysis is done after the work is finished |
| First eliminate hazard sources (e.g. ignition sources); where this is not possible, identify them and apply mitigating measures (ventilation, detection, PPE) |
| First select PPE, then possibly remove ignition sources |
78
Difficult
What is the charge limit m₃ = 130 m³ × LFL for R290 (LFL = 0.038 kg/m³) according to IEC 60335-2-40?
| approx. 0.15 kg |
| approx. 4.94 kg |
| approx. 0.99 kg |
| approx. 13 kg |
79
Medium
Why must the charge of small, critically charged R290 systems be weighed to within a few grams during service?
| Because R290 is more expensive than HFCs |
| Small charge deviations significantly change superheat/subcooling and efficiency, and overcharge increases the risk in a leak |
| Because scales are not needed – charging is done by sight glass |
| Because extra R290 improves efficiency |