Air conditioning noise test standard is clear

For many years, noise from household appliances has always occupied the top position in consumer complaints. Most of them fall into the category of product quality. However, some of them are due to the different testing methods used or the inconsistent adoption of units that cause great confusion to consumers. There are also some unscrupulous companies who have drilled standard holes and used unfair competition to mislead consumers. This is one of the reasons why noise complaints remain high. In order to solve the impact of noise pollution on wide consumers, it is necessary to put forward higher requirements for the noise limits of various home appliances.

The current national standard GB 19606-2004 "Noise limits for household and similar electrical appliances" is a mandatory national standard that specifies the noise limits for six types of household electrical appliances (refrigerators, air conditioners, washing machines, microwave ovens, range hoods, and electric fans). And its test methods. However, the test methods used and the evaluation amount of noise are not uniform, and the express values ​​of various products are not uniform, resulting in the phenomenon that the noise value of the nominal value of the products currently sold on the market varies greatly. In order to ensure the healthy development of the industry, standardize market behavior, protect the rights and interests of consumers, and revise the unified test methods and labeling values ​​through standards, it is imperative to increase the noise limit indicators for various home appliances.

It is reported that the main contents of this revision relate to refrigerators, air conditioners, washing machines, microwave ovens, range hoods, electric fans, waste food processors, shavers, oral hygiene appliances, indoor heaters, humidifiers, and air purifiers. Vacuum cleaners and suction cleaners, dishwashers, dryers, electric massage chairs, food processing appliances and hair care appliances. 18 types of household appliances, of which 12 products are new. After the implementation of the standard, the above-mentioned household appliances need to express the noise of the product and meet the requirements of the standard's mid-limit value.

This revision unifies the sound power test method for household appliances, adjusts the noise limit values ​​of various types of products, and achieves the unity of the apparent noise values ​​of 18 types of home appliances.

At present, there are two clear ways of noise for electrical products on the market: sound pressure level and sound power level. Comparing the two methods, the size of the sound pressure level is greatly influenced by the location of the measuring point and the change in the measurement environment. The sound pressure level is reduced by 6 dB for every doubling of the measurement distance. The sound power refers to the sound energy emitted by a sound source per unit time. The sound power level obtained under different measurement distance conditions is a fixed value. The identification sound power level can realize the reproducibility and stability of noise measurement values ​​among different laboratories, and is more scientific in acoustic evaluation. This standard revision adopts the sound power level to describe all kinds of home appliances.

As far as the evaluation of air conditioner noise performance is concerned, the current standard GB7725 uses its radiated sound pressure level [Lp, dB(A)] to evaluate. There are many deficiencies in this method, and the sound pressure level will vary greatly with the test environment. The noise received by the noise receiver is the sum of the direct sound and the reflected sound of the interface. If the sound absorption properties of the wall in the room are different, the noise sound pressure level at the same location may differ by 20 dB! Therefore, the test data is not objective and not unique; the comparability of data obtained by different laboratories in the same prototype is poor; for some Businesses have left the opportunity to drill standard holes. They only give numerical values ​​but do not indicate test conditions. Flicker consumers. Even if consumers complain, they can't safeguard their rights due to defects in the standard formulation; the sound pressure level data of air conditioners cannot be compared with the noise power levels of other home appliances. Because the physical unit of measure is different. The unit of sound pressure level is Pascal Pa, and the unit of sound pressure level is Watts W; this gives chaos to the quality control of air conditioner companies, evaluation of R&D effects, and modification guidance; when the air conditioner is exported, this value cannot be recognized abroad. Difficulties for domestic companies.

The revised air conditioner noise standard adopts a unified international standard evaluation amount of sound power Lw as the air conditioner noise evaluation amount. It can effectively solve the following problems that have plagued China's air-conditioning industry for many years: the new standard evaluation of air-conditioner noise, Lw, and the evaluation of noise in other household appliances such as refrigerators, washing machines, and microwave ovens have finally been unified. At the same time, the ISO standard and the IEC standard have also been unified; the air conditioner sound power Lw is an objective performance index of the product. In different environments (anechoic room or reverberation room), different laboratories, different methods will get the same value. Blocking the loopholes of bad attempts to drill standard loopholes; the new method also solves the problem of poor comparability of test data among home appliance companies. It is very conducive to its quality control and product development needs; when consumers complain, there is evidence to follow. The data is not dependent on the test environment and is the only objective data; the new standard specifies four methods, and three methods have been added to the previous standard. The test results obtained by these four test methods are the same. His advantages are: According to the different uses of the test data, the corresponding test methods can be selected to provide convenience for the testers [enterprises, quality supervision agencies, etc.] to optimize test resources, and save test resources. The new standard added diffusion field test method has the advantages of simple test methods, low cost of test facilities, and high test efficiency.

After the implementation of the new standard, the existing test equipment of certain enterprises will need to be upgraded. The internal technical documents [quality control index, quality system revision, enterprise standard, etc.] of the company need to be revised accordingly, but in the long term this time The amendment to the company is far more advantageous than the disadvantages.

Then, does the lower value indicate the lower the noise value? In this regard, the Deputy Director of the Home Appliances Institute, Mei Xiaochun, explained that from the calculation formula of sound power, it can be seen that the noise value represented by the sound power level increases the sound on the envelope surface than the noise value expressed by the sound pressure level. Integral, so not the lower the identification value, the lower the noise, to determine the sound pressure level or sound power level. Household appliances that identify sound pressure levels may have noise that exceeds the value of the home appliance that identifies the sound power. We can compare the noise values ​​of air conditioners and air purifiers on the market. We will find that air conditioners can be marked with 10 decibels, while air purifiers are mostly above 40 decibels, and many are marked with 60 decibels. Is the noise really several times higher than the air conditioner noise? The reason for this phenomenon is that the value of the identified physical quantity is not uniform and mislead consumers. Including air conditioners, this standard revised 18 types of products to identify the sound power value, to achieve a variety of home appliances using a unified physical value to measure, help consumers in the purchase of home appliances through the noise express value for all types of products Compare.

Changing the long-term test sound pressure and noise level expressed in sound pressure level has a process for some household appliances industry to accept. However, from a long-term point of view, the value of the sound power of household electrical appliance products is a trend, and the realization of uniform values ​​of noise and testing methods will help protect the interests of consumers.