PROCEEDINGS of the
23rd International Congress on Acoustics
9 to 13 September 2019 in Aachen, Germany

Construction noise management and control policy in Hong Kongand innovative quieter methods for renovation work
Joe MOK1; C.L. WONG2, C.W. LAW3; C.K. LEE4
1, 2, 3, 4

Environmental Protection Department, The Government of the Hong Kong Special Administrative Region,
The People’s Republic of China

ABSTRACT
Many concerns revolve around construction noise particularly in such a densely populated metropolis as
Hong Kong. The statutory permit system for construction work during restricted hours and labeling systemfor powered mechanical equipment (“PME”) have been well established in Hong Kong to manage andcontrol construction noise. However, renovation work within high-rise residential buildings remains one of
the most challenging noise sources as the renovation cycle is relatively short and it usually involves noisy
PME. Common noisy activities in Hong Kong, such as demolition of concrete partitions, reformation offlooring and various types of fitting-out work, produce intrusive noise disturbing quite a number ofneighboring flats through both air-borne and structure-borne transmissions. Structure-borne noise isdifficult to be mitigated without substantial treatment in the noise transmission path which is almost
impossible in a dense residential setting. Owing to rising public aspiration for a quieter living environment,
it is necessary to address the concerns associated with renovation work within multi-flatted residentialbuildings. This paper will give an account of the statutory and administrative noise control framework in
combating noisy construction and explore the effectiveness of innovative quieter construction methods tofurther mitigate renovation noise at source to achieve a quieter living environment.
Keywords: Noise Control, Renovation, Powered Mechanical Equipment

1. INTRODUCTION
With a total population of over 7.4 million, Hong Kong is one of the most densely populated cities
in the world, having a population density of 6,300 people per square kilometer. It has a total land areaof 1,111km2 with a highly developed transportation network and densely populated buildings. The
urban environment is dominated by closely packed high-rise residential or commercial buildings.
According to the Census and Statistics Department of the Hong Kong Specia l Administrative Region(“HKSAR”), as of September 2018, there are more than 1,500 construction sites in the territory (1).
Alongside economic development in recent years, a number of mega infrastructure projects, such as
Shatin to Central Railway Link, The Lok Ma Chau Loop Innovation and Technology Park, The Third
Runway, etc., are under construction. In addition, many refurbishment and redevelopment projects arein full swing to respond to the growing demand for housing and economic development in Hong Kong.
Apart from construction sites, it is estimated that more than 20,000 residential units are renovatedevery year in Hong Kong. Construction noise, including renovation noise, is often a concern for thecommunity. Around 16,000 pollution complaints were received by the Environmental Protection
Department (“EPD”) in 2017, and noise complaints accounted for more than 20% (approximately
4,700 cases) (see Figure 1).

12
3

joescmok@epd.gov.hk

clwong@epd.gov.hk

cwlaw@epd.gov.hk
4cklee@epd.gov.hk

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Number of pollution complaints in 2017
4785

4500

3855
2684
565

Figure 1 – Pollution complaints received by the EPD in 2017
Furthermore, the number of prosecutions associated with construction noise is the highest among
various categories of environmental pollution. Of the 102 prosecution cases related to noise in 2017,
95 were violations related to construction noise (see Figure 2).
Industrial andcommercial
noise, 7%Construction
noise, 93%

Figure 2 – Prosecution cases related to noise in 2017
The Noise Control Ordinance (“NCO”) of the HKSAR provides statutory control over the noise
generated by construction activities and the noise emission performance of certain noisy equipment
through the Construction Noise Permit (“CNP”) system and Noise Emission Label (“NEL”) system
respectively (2). In addition to the statutory noise control, the EPD has also implemented anadministrative instrument, namely Quality Powered Mechanical Equipment (“QPME”) Label system,
since 2005 to encourage the use of significantly quieter PME. Moreover, the EPD is committed to
exploring other low noise innovative construction equipment to replace traditional equipment in orderto mitigate noise annoyance caused by renovation work in residential buildings.
This paper outlines an overview of the noise control and management framework implemented in
Hong Kong; low noise innovative equipment and methods for different renovation and building
maintenance work; and the collaboration among stakeholders to prevent and mitigate renovation noise.

2. CONSTRUCTION NOISE MANAGEMENT AND CONTROL IN HONG KONG
2.1 Legislative Policy
The EPD manages noise from construction work through the CNP system, which is preventive innature. A CNP must be obtained from the EPD before the commencement of general construction work
during the restricted hours (i.e. between 7 pm and 7 am on weekdays and any time on public holidays
including Sundays), and for percussive piling between 7 am and 7 pm on any day other than a public
holiday. Such permit may only be issued if the cumulative noise level, not only from the concerned
work, but together with all neighboring site(s), is in compliance with the relevant requirements as set
out in the Technical Memoranda issued by the EPD under the NCO (3, 4). Thus the requirement
prevents “creeping up” of noise levels due to increasing number of work sites. More stringent controls
are imposed on certain noisy manual construction activities as well as certain PME within the
Designated Areas established under the NCO, which generally represent built-up areas with dense
population. If the construction works are carried out within the Designated Areas and involve the useof 5 types of specified PME or 3 kinds of prescribed construction works, the works will be subject tomore stringent control in terms of noise limits or noise mitigation requirements in order to o fferadditional protection for noise sensitive receivers in densely populated areas (5). Percussive piling is
entirely prohibited in the territory during the restricted hours. The use of noisy diesel, steam and4357

pneumatic piling hammers is generally banned. As for noise caused by renovation works in domestic
premises, it remains a challenging issue in Hong Kong since each residential flat can be the one whichemits noise and the one which is affected. While noise from domestic renovation can be intrusive to aneighboring flat, it is of transient nature and at present not subject to any legislative control during the
non-restricted hours. For most residential estates, house rules are developed to address the need andconstraints for individual buildings with respect to the management for domestic renovation noise interms of say, mutually agreed days and hours of operation.
Besides, the NEL system mitigates noise from construction equipment at source. It prevents Hong
Kong from being a dumping ground for 2 types of commonly used and noisy PME, i.e. hand-held
percussive breaker and air compressor (6). Breakers that weigh more than 10kg and air compressorsthat can supply compressed air at 500kPa or above must be fitted with NELs when being operated forcarrying out construction work (see Figure 3 and 4).

Figure 3 – Sample of NEL

Figure 4 – Hand-held percussive breaker with NEL
In order to obtain an NEL, or even to import / supply these two types of PME for use in the Hong Kong,the equipment must comply with the international noise standards specified in the relevant regulations.
2.2 Administrative Policy
The QPME Label system serves as a product labeling scheme to recognize significantly quieter
equipment (7). To be eligible for a QPME label, the equipment should be in compliance with noise
limits stipulated in Article 12 of the Directive 2000/14/EC relating to the noise emission in theenvironment by equipment for use outdoors of the European Union; or the equipment has been
designated and issued with Low Noise or Super Low Noise Emission Label under the relevant Low
Noise Construction Equipment Regulations by the Ministry of Land, Infrastructure, Transport andTourism of Japan (see Figure 5).

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Figure 5 – Sample of QPME label
At present, 15 types of commonly used PME are included in the QPME Label system, including
tracked bulldozer, wheeled bulldozer, tracked loader, wheeled loader, excavator; generator, mobile
crane, vibratory roller, road roller, asphalt paver, vibratory compactor, power rammer, hand held
percussive breaker, air compressor and concrete crusher. As of May 2019, more than 8,300 QPME
labels have been issued for those QPME.
There are several incentives for the construction industry to adopt QPME. Firstly, the chance ofobtaining a CNP for construction work with QPME will be relatively higher. Moreover, the QPME
items are recognized in the Public Works Projects initiated by the HKSAR Government as being
eligible for additional monetary benefits. In addition, construction companies which purchase QPME
are entitled to have profit tax concession.

3. INNOVATIVE QUIETER METHODS FOR RENOVATION WORK
Near 90% of Hong Kong residents live in multi-family dwellings of a single concrete building
structure. More and more new high-rise residential buildings have more than 50 floors with more than
8 units on the same floor, which means more buildings contain more than 400 families together in one
building structure, and almost all dwellings can be affected by renovation noise from even one
renovation work (see Figure 6).

Figure 6 – Closely-packed high-rise residential buildings in Hong Kong
Moreover, according to our statistics in 2012, the movement of families in Hong Kong was about 5
years (8). Hence, noise due to the frequency, density and influence of domestic renovation work in
Hong Kong is always an issue. The EPD strives to explore and promote the quietest practicable
construction methods for the industry. In general, annoying structure-borne noise from renovation
work comes from demolition activities with the use of percussive breakers. The sound power level of
traditional hand-held percussive breakers can be as high as 108dB(A). Given the control ofstructure-borne noise transmission along multiple transmission paths is nearly impracticable, using
low noise innovative equipment appears to be the only option.
3.1 Diamond Coring Tool
Diamond coring tool can be used for fastening fixtures, as well as installing brackets for water
pipes or electrical cables (see Figure 7).

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Figure 7 – Diamond coring tool
Along with the electrically-powered water management system, wet coring can be performed inconcrete and other metallic materials. The water management system can supply water a nd recycle
water for the operation of wet coring, thus minimizing structure-borne noise and vibration. Moreover,it can also collect debris and hence reduce dust (see Figure 8 and 9).

Figure 8 – Electrically-powered water management system

Figure 9 – The operation of diamond coring tool together with water management system
To evaluate the noise emission performance of diamond coring tool, the EPD has conducted a study
about structure-borne noise transmission to compare the coring tool with a traditional hand-held
drilling tool. The noise measurement was carried out in two separate rooms, namely the noise source
room and noise receiver room. A vertical concrete wall between the two rooms isolates the air -borne
noise transmission. Compared to traditional drilling tool, not only could the use of diamond coring tool
reduce the transmission of structure-borne noise by 4dB(A), it also gave a resultant noise level of even
14dB(A) lower in the noise receiver room (see Table 1). In addition, air pollution gener ated by dust
formation during machine operation can be minimized.
Table 1 – Noise comparison between diamond coring tool and traditional drilling tool
Tool

Noise level, dB(A)Noise difference, dB(A)Source room

Receiver room

Diamond coring tool

87

62

-25

Traditional drilling tool

98

76

-21

3.2 Battery-driven Fastening Tool
The battery-driven fastening tool is capable of fastening cables or conduits, and installing drywall
or wood tracks into concrete and steel plates (see Figure 10).

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Figure 10 – The battery-driven fastening tool is capable of fastening conduits into concrete
Its advantages include low recoil, dust-free and virtually no vibration. According to a soundpropagation report commissioned by the manufacturer, compared to traditional hammer drills, the useof battery-driven fastening tool can reduce the transmission of structure-borne noise by 8dB(A). Inside
the noise receiver room, the noise level of operating a battery-driven fastening tool is 9dB(A) lower(see Table 2). It greatly reduces the noise impact on neighboring flats without compromising on the
productivity. Compared to gas-actuated fastening tool, changing of gas cans and cleaning of dirty
cartridges are not required.
Table 2 – Noise comparison between battery-driven fastening tool and traditional hammer drill
Tool

Noise level, dB(A)Noise difference, dB(A)Source room

Receiver room

Battery-driven fastening tool

88

65

-23

Traditional hammer drill

89

74

-15

3.3 Wall Chaser
Wall chaser is used for preparing grooves on the interior walls for installation of in -wall electricalsockets, conduits, water pipes, etc. (see Figure 11).

Figure 11 – Wall chaser is used for preparing grooves on walls
Experimental results reveal that the application of a wall chaser achieves a significant
structure-borne noise reduction of 19dB(A) more as compared to using a traditional hand-held
percussive breaker. In the noise receiver room, the noise level of operating a wall chaser is 9dB(A)lower (see Table 3). In the use of removing wall plaster, a wall chaser can be alternately used with achisel, which can largely reduce the noise annoyance to neighboring flats.
Table 3 – Noise comparison between wall chaser and traditional hand-held percussive breaker
Tool

Noise level, dB(A)Noise difference, dB(A)Source room

Receiver room

Wall chaser

109

80

-29

Traditional hand-held percussive breaker

99

89

-10

3.4 Other Low Noise Innovative Equipment
In addition to the above portable tools for renovation work in residential units, there are some otherlow noise equipment in the market for building repair / maintenance work as well, such as highpressure water jetting machines, hand-held concrete crushers and wall cutters, as quieter alternatives
to the traditional percussive PME (see Figure 12, 13 and 14).

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Figure 12 – High pressure water jetting machines can be used for removing deteriorated concrete and tiles

Figure 13 – Hand-held concrete crushers can be used for concrete breaker

Figure 14 – Wall cutters can be used for dismantling plaster, brick and mortar walls

4. PROMOTING AWARENESS OF QUIET CONSTRUCTION
In the past, the construction industry may have a lack of awareness of innovative quieter
construction equipment and methods. Many contractors tend to stick to conventional practices as aculture and take advantage of the convenience from some traditional tools such as a breaker and adrilling device that can primarily perform most of the tasks for renovation works. But now, many
innovative quieter alternatives have been proved to be not only quiet but effective in carrying out thosetasks. The Government realizes the importance of raising the environmenta l awareness of all
stakeholders because they can play an active role in reducing noise nuisance from renovation work. To
achieve this aim, the EPD has produced a variety of education / publicity materials and establishedclose collaboration with the relevant sectors, such as the construction industry, the property
management sector and the vocational training institutes, to promote the adoption of moreenvironmentally friendly equipment or methods.
The EPD and the Hong Kong Construction Association have set up a Quiet Construction Working
Group to regularly explore and promote the use of quieter construction methods and low noise
equipment for projects ranging from large-scale infrastructure development projects to domestic
renovation work.
In addition, the EPD has set up a website to promote the use of the latest quieter alternatives and thenoise mitigation measures (9). Moreover, the EPD partners with the property management sector topromote green property management and establish house rules. For smaller scale renovation works indomestic flats, the EPD has developed relevant guidelines for addressing the common interests of all
stakeholders and for the property management sector to better manage domestic renovation noise (10).
At present, many residential estates have developed their own house rules , such as working time
restrictions and timetables for renovation work mutually accepted by all parties involved, to deal with
the noise issues arising from renovation activities. The EPD has also developed a set of educational
package to disseminate knowledge about basic acoustics, noise generation, minimization and4362

prevention of noise problems for the general public (11).
Besides, the EPD cooperates with the Construction Industry Council in enhancing theenvironmental awareness of the construction industry through better understanding of the legislative
control on construction noise, and sharing on quieter construction methods and practical experience.
The EPD also values every opportunity to facilitate frontline construction practitioners to familiarize
with low noise innovative equipment through seminars and demonstrations.

5. CONCLUSIONSWith the concerted efforts of the Government and various partnering sectors, including theconstruction, property management and education, some quiet construction equipment and goodmanagement practices have been promoted and even adopted to control the impact of renovation noise.
Looking ahead, the EPD will continue to adopt a "win-win-win" approach in minimizing construction
noise, by meeting the public’s rising aspiration for a quiet environment, addressing the need of
construction efficiency through innovative technologies, and enhancing public service by exploringand promoting low noise construction methods.

ACKNOWLEDGEMENTS
The authors wish to extend their appreciation to the EPD of the HKSAR Government for thepermission to publish this paper. The opinions in this paper are those of the authors and do notnecessarily reflect the views or policies of the HKSAR Government.

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