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The following comparison of the test procedure for refrigerators under AS/NZS 4474.1 with US Department of Energy (AHAM) and International Standards Organisation test procedures is taken from the Foreword of AS/NZS 4474.1. The following text has been provided courtesy of Standards Australia.
In considering the performance of refrigerating appliances available in Australia and New Zealand, it is often necessary to consider the methods of testing used in Europe (i.e. International Standards Organisation) and in North America.
The scope of this Standard is covered by four International Standards Organisation (ISO) publications as follows:
ISO 5155 (freezers)
ISO 7371 (refrigerators without freezers)
ISO 8187 (refrigerator/freezers)
ISO 8561 (forced air/frost free units)
In North America, most energy consumption testing is carried out under US Department of Energy Code of Federal Regulations (CFR Part 430, Subpart B, Appendices A1 and B1) which is based on AHAM HRF-1-1988.
Where possible, this Standard harmonizes with the International Standards Organisation Standards, however there are two fundamental differences as follows:
(a) The various International Standards Organisation Standards provide for a choice of climate classes, each of which is considered to be too narrow for Australia and New Zealand, where, because of factors such as wide diurnal temperature ranges, the methods of house construction, and a diversity of climates, the ability to operate over a wide temperature range, i.e. 10°C to 43°C, is considered essential.
(b) The International Standards Organisation `star' (snowflake) marking scheme, the purpose of which is to indicate the freezing capability of the freezer compartment(s), is not used in Australia or New Zealand. It should be noted the International Standards Organisation `star' scheme is unrelated to the energy labelling scheme in Australia which uses `star' as a measure of the relative energy efficiency of the appliance.
There are also many significant differences between test conditions in this Standard and those of International Standards Organisation or North America, to the extent that direct comparison of results obtained under any two of the test regimes are generally not valid. Some of the main differences are set out in the following table and accompanying notes, however it should be noted that this is not a comprehensive comparison.
| Variable | AS/NZS 4474.1 | ANSI/AHAM1 | International Standards Organisation2 |
| Energy consumption ambient temperature | 32 ±0.5°C | 32.3 ±0.6°C | 25 ±0.5°C3 |
| Energy consumption fresh food temperature | 3°C | 3.3/7.22°C4 | 5°C |
| Energy consumption freezer temperature5 | -15°C | -15/-17.8°C6 | -18°C |
| Freezer for energy consumption | unloaded | unloaded7 | loaded |
| Operation test ambient temperatures8 | 10/32/43°C | 21.1/32.2/43.3°C9 | 16/32°C10 |
| Operation test fresh food temperatures11 | 0.5°C to 6°C | 1.1°C to 5°C | 0°C to 5°C12 |
| Operation test freezer temperatures13 | ≤-15°C | ≤-15/-17.8°C6 | ≤-18°C14 |
| Pull down test | yes | yes | no |
| Freezing capacity test | no | no | yes |
| Ice-making capacity | yes | yes | yes |
| Temperature rise time | no | no | yes |
| Other performance tests | no | yes15 | yes16 |
| Gross volume17 | compartment (including sub-compartment) | not specified | total only (not specified at sub-compartment level) |
| Storage volume18 | all levels | all levels | all levels |
| Volume used for Minimum Energy Performance Standards and energy labelling | gross | storage | storage |
| Freezer adjustment factor (adjusted volume) | 1.6 | 1.63 | 2.15 |
| Separate freezer energy adjustment | no | 0.7/0.8519 | no |
| Energy sources and refrigeration systems covered | mains powered electric vapour compression20 | all electric A.C. single phase systems21 | any22 |
| Humidity | not specified | not specified23 | 45% to 75% |
| Anti-sweat heaters during energy consumption tests | on | average on and off | only when needed |
FOOTNOTES:
1 The current AHAM refrigerator Standard is AHAM HRF-1-1988. However, most energy consumption data in the U.S.A. is determined under the U.S. Department of Energy Code of Federal Regulations (C.F.R. Part 430 Subpart V Appendices A1 and B1) which draws in parts on the AHAM Standard but also modified parts. Department of Energy regulations have precedence regarding all mandatory U.S. Government requirements for energy labelling and Minimum Energy Performance Standards. Note that Department of Energy regulations cite AHAM HRF-1-1979 and not the current version.
2 There are 4 main International Standards Organisation Standards for refrigerator performance and energy consumption. These are ISO 5155 (freezers), ISO 7371 (refrigerators without freezers), ISO 8187 (refrigerator/freezers) and ISO 8561 (forced air/frost free units). In 1996 ISO accepted a new work item proposal to combine these 4 Standards into a single document.
3 Ambient test temperature for energy consumption under International Standards Organisation is 25°C for all climate classes except Tropical, which is 32°C.
4 AHAM and Department of Energy regulations only specify a fresh food compartment temperature of 3.3°C for `all refrigerators' (i.e. fresh food compartments with either no freezer or a small ice-making subcompartment of less than 14.2 L). For tests on refrigerator/freezers, the fresh food temperature has only to be below 7.22°C.
5 Freezer compartments in this Table refer to compartments intended for the long term storage of frozen food. There are numerous other frozen and unfrozen compartment types not covered by this Table. AS/NZS 4474.1 freezer compartment temperature is determined from the average of the warmest 4 of the 5 air temperature sensors. International Standards Organisation report compartment temperatures as the warmest test package position at the warmest part of the cycle for all tests (AS/NZS 4474.1 also uses this method for loaded operation tests). ANSI/DOE compartment temperatures are the average of all temperature points taken at ≤ 4 min intervals over the test period (excluding defrost cycles).
6 A freezer temperature of -15°C applies to refrigerator-freezers while -17.8°C applies to separate freezers.
7 Note that HRF-1-1979 specifies that for energy consumption tests all freezer compartments shall be loaded. However, the Department of Energy CFR 430 test procedures specify that freezer packs are not to be used in the determination of energy consumption for automatic defrost (frost free) refrigerator-freezers (the most common appliance type in the U.S.A.) and `all refrigerators' with ice makers. In these cases, freezer compartment temperatures are measured with thermocouples inside metallic cylinders of 29 ±6 mm (the metal is not specified, but if it were copper, this would equate to a thermal mass of between 8 g and 28 g water equivalent). All other appliance types under AHAM (including all separate freezers) are tested with the freezer compartment loaded. The freezer test packs used under AHAM are 130 × 100 × 40 mm and contain sawdust or spinach. Under the AHAM Standard the freezer compartment is only loaded to 75% of its capacity. AHAM test packs are different from the test packs specified in International Standards Organisation which are 200 × 100 × 50 mm and contain oxyethylmethylcellulose. AS/NZS 4474.1 specifies test packs which are identical to International Standards Organisation -1°C packs. Under ISO and AS/NZS the freezer compartments are fully loaded (except for specified air gaps). AS/NZS specifies 15 mm air gaps between test packs and the freezer walls, while International Standards Organisation specifies that they should be in contact.
8 Temperature operation tests are conducted with freezer test packs for all three standards.
9 The `simulated load test' under AHAM has only recommended levels of performance and is not a mandatory requirement for refrigerators in the U.S.A. under Department of Energy regulations for labelling or Minimum Energy Performance Standards.
10 This is the temperature range for ISO Temperate, which is the most common climate rating in Europe. Other International Standards Organisation climate ratings include Extended Temperate (10°C/32°C), Sub-tropical (18°C/38°C) and Tropical (18°C/43°C).
11 Fresh food temperatures in all Standards are averages. AS/NZS 4474.1 specifies that thermocouples be placed inside copper or brass cylinders with a thermal mass of between 10 and 20 g water equivalent, while International Standards Organisation usually specifies cylinders which have 2.3 g water equivalent. AHAM allows thermocouples to be weighted or unweighted, but where weighted, the thermal mass must not be greater than 20 g of water equivalent.
12 International Standards Organisation average fresh food compartment temperatures are to remain at less than 5°C, but this may rise to 7°C during defrosting in a frost free appliance. In addition to this requirement, the temperature at each of the measuring points in the fresh food compartment (generally three points) must remain within the range 0°C to 10°C throughout the test (so a theoretical minimum average compartment temperature is 0°C, but in practice the actual minimum achievable would be higher). Note that fresh food compartment temperatures in International Standards Organisation are measured with single suspended M packages in ISO 8561 while they are measured with copper or brass masses in ISO 7371 and ISO 8187.
13 Allowable freezer pack temperature ranges for an operation test are generally less than or equal to the target temperature for energy consumption.
14 Test pack temperatures are allowed to rise to -15°C during defrosting cycles.
15 Other AHAM tests for performance are related to durability and include handling and storage test (for packaging), external surface condensation test, internal moisture accumulation test, environmental cracking resistance test and bottom breaker strip impact test. AHAM does not recommend minimum levels of performance for these tests.
16 Other International Standards Organisation performance tests include door air tightness, door opening force, durability of hinges and doors and mechanical strength of shelves. International Standards Organisation does specify minimum requirements for each of these performance tests.
17 Gross volumes for AS/NZS differ from International Standards Organisation (ISO) in a number of minor areas. However, the most significant difference is that the volume of air ducts (in a frost free system) within the liner shape is counted as part of the gross volume in AS/NZS but this is not allowed under ISO.
18 The only volume specified in AHAM (`refrigerated volume') is essentially a storage volume equivalent under ISO and AS/NZS. However there are minor differences in the determination of storage volume under all of these Standards.
19 The U.S. Department of Energy Code of Federal Regulations specifies that the measured energy consumption is adjusted by a factor of 0.7 for chest freezers and 0.85 for vertical freezers `to adjust for average household usage'.
20 This is the scope of AS/NZS 4474.2 which covers government requirements for energy labelling and Minimum Energy Performance Standards. The scope of AS/NZS 4474.1 includes all electric powered units but excludes low voltage D.C., portable and multi-fuel systems.
21 This is the scope of the U.S. Department of Energy Code of Federal Regulations for the purposes of energy labelling and Minimum Energy Performance Standards. The AHAM Standard includes all electric units (but specifically excludes gas powered types).
22 International Standards Organisation 8561 (forced air/frost free units) covers electric refrigerators only. The other three International Standards Organisation standards include products using any fuel type.
23 Humidity is specified for some of the other performance tests such as external condensation and internal moisture accumulation (at 75 ±2%), but not for operation or energy consumption tests.
A copy of the standard can be obtained from SAI Global under licence from Standards Australia.
This page last modified 09 May 2007
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