PROCEEDINGS of the23rd International Congress on Acoustics
9 to 13 September 2019 in Aachen, Germany

Revision of Chinese national standard GB 50118 - Code for design ofsound insulation of civil buildings
Guojun YAN; Weibin WU; Jie LIN; Chun XU; Qiyuan Zhao
Department of Building Acoustics, China Academy of Building Research, China
ba@cabr.com.cn

ABSTRACTThe national standard GB 50118 Code for design of sound insulation of civil buildings, issued by Ministry of
Housing and Urban-Rural Development (MOHURD), is the basic code for indoor acoustical quality of civilbuildings in China. It stipulates the limits for indoor noise levels and sound insulation performance ofbuilding elements, and specifies the design criteria of noise control. The current version was published in
2010, in which requirements had been raised compared to previous version. However, with the rapid
development in China during the last decade, current regulations could not meet the growing needs for bettersound environment. Traffic noise, HVAC noise and structure-borne noise from service equipment havebecome increasingly annoying, and inadequate sound insulation aggravates the situation. Therefore,MOHURD commissioned China Academy of Building Research to undertake the revision of current
standard in 2018. Based on the correlation between field measurement results and occupants’ perception, andreferring to guidelines and regulations in developed regions, we’d like to put forward stricter requirements
for indoor noise and sound insulation performance of building elements. Besides, limits for structure-borne
noise caused by vibrations of building service equipment or any other noise sources will be introduced toassess the dominant low-frequency noise.
Keywords: Noise, Structure-borne, Insulation

1. INTRODUCTION
The national standard GB 50118-2010 Code for design of sound insulation of civil buildings, issued
by Ministry of Housing and Urban-Rural Development of the People’s Republic of China (MOHURD),
is the basic code for indoor acoustical quality of civil buildings in China, covering dwelling, school,
hospital, hotel, office and commercial building. It stipulates the limits for indoor noise levels andrequirements for sound insulation performance of building elements, and specifies the design criteria
of noise and vibration control.
The original adoption of GB 50118, drafted by China Academy of Building Research (CABR), wasfirst released in 1988. Twenty-two years later, the first replacement was published, which has beenvalid until now. Compared to the previous edition, the subjects of office and commercial building wereincorporated, and stricter requirements for indoor noise and sound insulation were imposed as well.
However, with the rapid development and urbanization in China during the last decade, the current
regulations could not meet the habitants’ growing needs for better and healthier sound environment.
Traffic noise, HVAC noise and structure-borne noise from service equipment have become more andmore pervasive and annoying, and inadequate sound insulation aggravates this situation, which leads
to increasing complaints or even lawsuits. Therefore, MOHURD commissioned CABR to undertakethe revision of GB 50118 in 2018.
Based on the correlation between field measurement results and occupants’ perception, andreferring to guidelines and regulations in developed regions, we would like to put forward stricter
requirements for indoor noise levels and sound insulation performance of building elements,
especially for dwelling. Besides, limits for structure-borne noise caused by vibrations of building
service equipment or any other noise sources will be introduced to assess the dominant low-frequency
noise.
In view of space constraints, emphasis is placed on the modified requirements related to dwelling,which is also the main work of this revision.

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2. REVISED REQUIREMENTS FOR DWELLING
2.1 Indoor Noise
The limit values of indoor noise for dwellings are shown in Table 1. The basic requirements in bold
are compulsory provisions and should be strictly implemented, while the higher requirements areconditional recommendation for upscale housing.
Table 1 – Indoor noise requirements for dwelling
LA,eq [dB]
Rooms

Higher requirements

Basic requirements
Day-time

Night-time

Day-time

Night-time≤45≤37→≤33≤40≤30

Bedroom
Living room

≤40

≤45

Note: Day-time is from 6:00 to 22:00. Night-time is from 22:00 to 6:00.
Here, the limit value for night-time noise inside bedroom, which is underlined within the table, isthe only modification to noise requirements, tightened up from 37dB to 33dB. This limitation ismainly based on the Guidelines for Community Noise published by WHO in 1999. In this document,noise level inside bedroom is supposed not to exceed 30dB at night. Though LA,eq is adopted by boththe Guidelines and GB 50118 as the noise indicator, the integration time T, the measured time interval,
is distinctly different from each other. T is over a long term of 8 hours during the night time according
to the Guidelines, whereas the measurement should be taken during the noisiest period and T depends
on the types of noise source prescribed in GB 50118, varying from 30 seconds for steady andcontinuous noise, to 20 minutes or even longer for unsteady and intermittent noise. Considering thenoise is measured during the “peak hours” as per GB 50118, for example the service time of shopping
mall or subway, it is supposed to get higher equivalent sound pressure level due to the exclusion ofquiet hours at midnight. That is why we set 33dB as the updated basic requirement for night-time noise
inside bedroom.
2.2 Structure-borne NoiseIn the current version of GB 50118, there is only one indicator, LA,eq , applied to assess the indoor
noise environment. However, the structure-borne noise caused by the vibrations of service equipment
generally includes a large proportion of low frequency components, and LA,eq could not adequately
characterize the presence of low-frequency noise due to the suppression while A-weighted. It is notrare that LA,eq meets the noise requirements but still inhabitants feel uncomfortable with the humming.
In order to make up for the lack of requirements for low-frequency noise, limit values for Lf,eq inoctave bands, centered at 31.5Hz, 63Hz, 125Hz and 250Hz, are introduced to assess thestructure-borne noise, which are presented in Table 2. The basic requirements in bold are compulsory
provisions and should be strictly implemented, while the higher requirements are conditional
recommendation for upscale housing.
Table 2 – Structure-borne noise requirements for dwelling
Rooms

Class
Basic requirements

Bedroom
Higher requirements

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Time

Lf,eq in octave bands [dB]31.5Hz

63Hz

125Hz

250Hz

Day-time

≤79

≤63

≤52

≤44

Night-time

≤74

≤57

≤45

≤37

Day-time

≤76

≤59

≤48

≤39

Night-time

≤69

≤51

≤39

≤30

LivingBasic requirements

All-day

≤79

≤63

≤52

≤44

roomHigher requirements

All-day

≤76

≤59

≤48

≤39

Note: Day-time is from 6:00 to 22:00. Night-time is from 22:00 to 6:00.
The above values are determined by the following equation:(1)
NR = LA,eq − 10Here, LA,eq denotes the existing limit values for indoor noise, and NR is the Noise Rating values.
For example, the maximum allowable LA,eq inside living room is 45dB, thus the associated limit
values for structure-borne noise are determined by NR-35 curve. These values are harmonized withthose in the Chinese national standard GB/T 50355-2018 Standard for limits and measurement
methods of vibration in the room of residential building, which is newly issued by MOHURD in2018.
2.3 Airborne Sound Insulation
Table 3 and Table 4 present the airborne sound insulation requirements for building elements andadjacent rooms, which are supposed to be derived from laboratory tests and field tests respectively.
The basic requirements in bold are compulsory provisions and should be strictly implemented, while
the higher requirements are conditional recommendation for upscale housing.
Table 3 – Airborne sound insulation requirements for building elementsBasic requirements

Higher requirements

[dB]

[dB]

Rw+C>45→>48>50→>53

Rw+Ctr>51—

Rw+Ctr≥45—

Rw+Ctr≥30→≥35—

Other exterior window

Rw+Ctr≥25→≥30—

Entry door

Rw+C≥25→≥30—

Interior bedroom wall

Rw+C

≥35→≥40—

Other interior wall

Rw+C≥30→≥35—

Building elements

Indicators

Partition wall / Floor slab
Floor slab between dwelling andnon-residential space(1)Exterior wall
Exterior window
towards traffic artery(2)Notes:(1) Non-residential space denotes noisy areas such as underground garage or machine rooms.
(2) For windows used for bedroom or living room.
Table 4 – Requirements for airborne sound insulation between rooms
Rooms
From outside to bedroom(1)(newly adopted)
From adjacent unit
to bedroom / living room(2)From non-residential space
through floor slab to dwelling(3)Adjacent bathrooms

Basic requirements

Higher requirements

[dB]

[dB]

D2m,nT,w+Ctr

≥35

≥40

DnT,w+C≥45→≥48≥50→≥53

DnT,w+Ctr≥51—

DnT,w+C—≥45

Indicators

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Notes:(1) For exterior walls installed with window.
(2) Horizontally or vertically.
(3) Non-residential space denotes noisy areas such as underground garage or machine rooms.
In the past residential partition walls were generally built of solid bricks in China, characterized bymassiveness and soundproofing. However, due to the requirements for energy efficiency, lightweightwalls have become more and more popular, leading to deterioration in sound insulation. Based on thetest results we gathered in the past few years, 200mm~250mm partition walls built of hollow blocks
and plastered on both sides, which are common in high-rise buildings, can reach the DnT,w+C value
above 45dB in compliance with present basic requirement. Inhabitants, nevertheless, feel dissatisfied
with such performance and complain that it is easy to hear the talking or other activities from next door.
Therefore, minimum allowable values for Rw+C of partition walls, as well as associated DnT,w+C
between units, are both raised by 3dB, in order to better insulate against neighborhood noise.
Besides, the limit values for exterior windows are also raised by 5dB, with the aim of protecting
against outdoor noise. Since there is no limitation for site test results of exterior walls or windows inpresent standard, and allowing for the difficulty in checking the wall and window separately, thecombined sound insulation requirements for exterior walls installed with window are introduced toprovide the criterion for quality acceptance.
2.4 Impact Sound Insulation
The impact sound insulation requirements for floor slab are presented in Table 5. The basic
requirements in bold are compulsory provisions and should be strictly implemented, while the higher
requirements are conditional recommendation for upscale housing.
Table 5 – Impact sound insulation requirements for floor slab
Building elements
Floor slab

Basic requirements

Higher requirements

[dB]

[dB]

Ln,w (laboratory test)<75→<70<65→<60L′nT,w (field test)≤75→≤70≤65→≤60

Indicators

Note: In case of difficulty, limit values could be relaxed to 85dB only if there is room forfurther improvement in impact sound insulation.
There are two main changes in the impact sound insulation requirements. Firstly, the note
describing the conditional relaxation of limit values is now withdrawn. Considering that the Ln,w ofbare concrete floor is around 80dB, this note actually means that developers are allowed to take no
acoustic treatment of the floor. Surely the room for maneuver was reserved on account of economic
and technical reasons during the last revision. However, as soundproofing solution is progressing andbecomes affordable nowadays, it is time to remove this non-binding provision. Meanwhile, all thelimit values are now 5dB stricter than before, enforcing developers to improve the impact soundinsulation of floor by necessary means.

3. CONCLUSIONS
Protecting against noise is a long campaign. Allowing for the national conditions, we haven’t maderadical revisions to the current GB 50118, and yet this is a step in the right direction. Criticalrequirements for noise and sound insulation have been tightened, for the purpose of enforcing
developers and manufacturers to pay more attention to the noise and vibration control, and creating ahealthier acoustic environment.
It should be noted that all the limit values presented in this paper are cited from the exposure draft.
The final version is supposed to be officially issued in autumn, and further amendment might beadopted depending on the review comments.

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REFERENCES
1. Chinese national standard. GB 50118-2010: Code for design of sound insulation of civil buildings.
Beijing, China; 2010.
2. Chinese national standard. GB/T 50355-2018: Standard for limits and measurement methods ofvibration in the room of residential building. Beijing, China; 2018.
3. World Health Organization. Guidelines for community noise. Genova; 1999.

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