JB/T 4330-1999Determination of noise emitted by refrigeration and air conditioning equipment (English PDF)

1 Scope

This standard specifies the determination methods for sound power level of noise on the reflection plane under the free-field conditions. Annex C (Normative Annex) presents the measuring methods for sound pressure level of noise. And Annex D (Normative Annex) presents the measuring methods for sound pressure level of noise emitted by air conditioners.

This standard is applicable to the refrigerating and air conditioning Equipment/parts (hereinafter referred to as "units") assembled by facilities.

2 Normative References

The following standards contain provisions which, through reference in this text, constitute provisions of this standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below.

GB/T 3785-1983 Electric, sonic properties and measuring methods for sound level meters

JJG 176-1984 Verification regulation of sound calibrators

JJG 188-1984 Verification regulation of sound level meter

3 Measuring Environment

6 Unit Installation and Operation

7 Datum Body and Measuring Surface

8 Measurement of Sound Pressure Level

8.3.2 10 measuring points are totally arranged on the hemisphere measuring surface (see Figure B1 and Table B1).

8.3.3 The measuring points on the rectangular hexahedron measuring surface include 9 basic measuring points and 8 additional measuring points (see Figure B2 and Table B2).

8.3.4 Measuring points shall be added under the following conditions:

a) Any side of the datum body is larger than 2d (d is the measuring distance);

b) The measured difference between the maximum sound pressure level value and the minimum sound pressure level value on the basic measuring points is larger than the number of the measuring points;

c) If the measured unit is very large or smaller measuring distance is adopted, then the additional measuring points shall be kept on increasing to make the spacing of the measuring points on the measuring surface not exceeding 2d and distribute uniformly.

10 Measuring Records

The measuring records shall include the following contents. The recommended record list form is given in Annex E (Informative Annex).

Annex A (Normative)

Verification Methods for Measuring Environment Al Summary This annex specifies the absolute comparison method and reverberation time method shall be adopted to determine the environmental corrected value K.

A1.1 The environmental correction may not be carried out in the following conditions (namely, K=0):

a) The outdoor sites where there is no reflector within l0m away from any of the measuring points;

b) The semi-anechoic rooms certified according to the relevant standards.

NOTE: Acoustic reflectors mainly refer to buildings and some larger Equipment. As for impediments which are close to the sound sources and whose width (for instance, the diameter of piles and pillars) is larger than 1/10 of their distance apart from the sound sources, then it is deemed as acoustic reflectors. A1.2 Environmental Corrected Value K

a) This standard requires that the environmental corrected value K shall not be larger than 2dB;

b) If the measured K value is larger than 2dB, then sound absorption measurement may be adopted, or the measuring distance shall be appropriately decreased to reduce the environmental corrected value. However, the measuring distance shall not be less than 0.5m;

c) If the K value is larger than 2dB and less than 7dB, then the […]

Annex C (Normative)

Measurement for Sound Pressure Level of Noise Emitted by Refrigerating and Air Conditioning Equipment C1 Application Scope This annex specifies measuring methods for sound pressure level of noise emitted by refrigerating and air conditioning Equipment.

C2 Measuring environment The measuring environment is a semi-free sound field of a reflection plane. The difference between the measured unit noise and the background noise shall be over 6dB. If this requirement cannot be met, then sound isolation measurement may be adopted to reduce the background noise. If the difference is less than 10dB, then the measuring environment shall be corrected according to 8.1.2.

C3 Measuring Equipment The measuring Equipment shall meet the requirements of 5.1. In addition, they also shall be calibrated according to 5.2.

C4 Unit Installation and Operation The unit installation shall meet the requirements of 6.1. In addition, the units shall be operated according to 6.2.

C5 Measuring Point Positions The measuring points shall be placed according to 1-4 positions specified in 8.3.3. If the unit height is not more than lm, then its measuring points shall be placed at the altitude of 1m. If the unit height is larger than lm, then its measuring points shall be placed at the altitude of 1.5m. As for large-scale units, additional measuring points may be increased according to those specified in 8.3.4 and their measuring points shall be placed at the altitude of 1.5m. If the measuring points are placed at the air outlet or cooling fan position of the unit and the wind speed is larger than 4-level as well, then they may be measured at a place 45° off the air outlet.

Annex D (Normative)

Measurement for Sound Pressure Level of Noise Emitted by Air Conditioners D1 Application Scope This annex specifies the measuring methods for the sound pressure level of noise emitted by air conditioners.

D2 Measuring Environment The measuring environment shall be the semi-free sound field on the reflection plane. The difference between the measured unit noise and the background noise shall be over 6dB; if it is less than 10dB, then the measuring environment shall be corrected according to those specified in 8.1.2.

D3 Measuring Equipment The measuring Equipment shall meet the requirements of 5.1. In addition, they also shall be calibrated according to 5.2.

D4 Operation Conditions The Equipment shall be installed on the rack according to the relevant technical requirements.

They can maintain stable operation under rated voltage and rated frequency. In addition, their operation conditions shall be close to those specified in the technical requirements. However, in the situation that the refrigerant circulating noise may be negligible, the unit noise in the determination room may also be adopted in the ventilation state for the split type units. As for those units with speeders, the noise of all the velocity stages shall be measured, respectively.

D5 Measuring Point Positions D5.1 Indoor Measurement The measuring points shall be in the positions shown in Figure D1~Figure D7. And the units shall be measured under the maximum noise condition.

a) Cabinet-type air conditioner (whose refrigerating output is less than or equal to […]