CJJ/T 247-2016 in English

1 General provisions

1.0.1 This specification is formulated with a view to effectively controlling the influence of noise and vibration of heating stations on people and environment, and standardizing the design, construction, acceptance and operation maintenance of noise reduction and vibration suppression system.

1.0.2 This specification is applicable to the design, construction, acceptance and operation maintenance of noise and vibration control project of heating stations.

1.0.3 The noise and vibration control of heating stations shall be designed, constructed and accepted simultaneously with the heating project.

1.0.4 In addition to this specification, the design, construction, acceptance and operation maintenance of noise and vibration control of heating stations shall also comply with the requirements of the current relevant standards of the nation.
 
2 Terms and symbols

2.1 Terms

2.1.1 heating station
facilities and places that produce heating media, convert the types of heating media, change the parameters of heating media, or distribute, control and measure the heat supplied to heat consumers, including boiler rooms, boosting pump stations, and heat exchange stations

2.1.2 boundary
boundary of the place or building where the owner has the right to use (or ownership) as determined by legal documents such as land use permit, property ownership certificate, and lease contract

2.1.3 equivalent sound pressure level
average energy of A-weighted sound pressure level in the specified measurement time T

2.1.4 octave band
frequency band in which the ratio of the upper frequency to the lower frequency is equal to 2

2.1.5 octave band of sound pressure level
frequency band sound pressure level measured by octave band filter

2.1.6 octave band center frequency
geometric average of the upper and lower frequencies of each octave

2.1.7 vibration level Z
vibration acceleration level obtained by correcting with the whole-body vibration Z-weighting factor

2.1.8 day-time/night-time
day-time refers to the period from 6:00 to 22:00; and night-time refers to the period from 22:00 to 6:00 the next day

2.1.9 air-borne noise
noise transmitted by air in buildings

2.1.10 structure borne noise
secondary radiated noise induced by mechanical vibrations of buildings or equipment that spread through solids (structures)
 
2.1.11 average sound absorption factor
arithmetic average of sound absorption factors of the same material at different frequencies

2.1.12 dashpot
device used to reduce and eliminate vibration transmitted from equipment to foundation

2.1.13 mass of vibration
total mass involved in synchronous vibration in the vibration isolation system, including the vibration isolation object and the vibration isolation mass

2.1.14 damping hanger
suspended support member that can damp the vibration of equipment and pipelines

2.1.15 muffler
component for reducing airflow noise, which may serve as a part of the pipeline, and can reduce the noise after acoustic treatment inside, but allow airflow to pass through

2.1.16 sound reduction index
difference between the incident sound power level on one side of a wall or partition and the transmitted sound power level on the other side

2.1.17 natural frequency
frequency of the system when it vibrates freely

2.1.18 damping ratio
ratio of damping coefficient to critical damping coefficient

2.1.19 equivalent absorption area
area with the same absorption power as an object or a surface and with a sound absorption factor equal to 1. The equivalent absorption area of a surface is equal to its area multiplied by its sound absorption factor. The equivalent absorption area of an object placed somewhere in a room is equal to the increase in the total equivalent absorption area in the room after the object is placed

2.1.20 sound absorption factor
ratio of the sound energy absorbed by the material to the total sound energy incident on the material

2.1.21 A-weighted sound pressure level
sound pressure level measured with A-weighted network
 
2.2 Symbols

A——the total indoor equivalent absorption area at a specific frequency;

A1——the total indoor equivalent absorption area before sound absorption treatment;

A2——the total indoor equivalent absorption area after sound absorption treatment;

f——the working frequency of the vibration isolation object;

f0——the natural frequency of the vibration isolation system;

g——the gravitational acceleration;

IL——the insertion loss of the sound-proof cover;

△i——the corresponding A-weighted network attenuation value;

k——the total stiffness of the vibration isolation system;

ki——the stiffness of the selected single dashpot;

LA——the A-weighted sound pressure level at corresponding frequency;

Lp1, Lp2——the sound pressure level inside and outside the cover;

——the average indoor noise reduction;

Lpi——the i-th octave sound pressure level;

m——the total mass of the vibration isolation system;

N——the total number of dashpots;

NR——the noise reduction attenuation;

Pd——the interference force acting on the dashpot;

Pi——the allowable bearing capacity of a single dashpot;

R1——the sound reduction index of the sound-proof cover;

s0——the opening area of local sound-proof cover;

s1——the internal surface area of the cover;

s2——the internal surface area of the room;

Si——the area of all the indoor surfaces;

T——the indoor reverberation time;

T1——the indoor reverberation time before sound absorption treatment;

T2——the indoor reverberation time after sound absorption treatment;

V——the internal volume of the room;

W——the sound power of noise source;

Wr——the sound power radiated through the sound-proof cover;

α1——the average sound absorption factor of the internal surface area of the cover;

α2——the average sound absorption factor of the internal surface area of the room;

αi——the sound absorption factor of all the surfaces at a specific frequency;

——the average indoor sound absorption factor at a specific frequency;

——the average indoor sound absorption factor before sound absorption treatment;

——the average indoor sound absorption factor after sound absorption treatment

Contents
1 General provisions
2 Terms and symbols
2.1 Terms
2.2 Symbols
3 Basic requirements
4 Materials and equipment
5 Design
5.1 Vibration isolation
5.2 Noise reduction and sound reduction
6 Construction
6.1 General requirements
6.2 Equipment of vibration isolation
6.3 Damping hanger
6.4 Flexible joint and flange
6.5 Sound absorber
6.6 Sound-proof door and window
6.7 Muffler
6.8 Sound-proof cover
7 Project acceptance
7.1 General requirements
7.2 Inspection lot acceptance
7.3 Project pre-acceptance
7.4 Environmental acceptance
7.5 Completion acceptance
8 Operation maintenance
Annex A Record on acceptance of construction quality
Explanation of wording in this specification
List of quoted standards
Explanation of provisions