Technical Report: What is a Sound Level Meter? (16)

This regulation was promulgated on June 10, 1968, and came into effect on December 1, 1968, to establish regulations on noise generated by business activities such as factories and to set permissible limits for automobile noise.

Article 1 states that the purpose of this law is "to protect the living environment and contribute to the protection of public health by implementing necessary regulations on noise generated over a considerable area in connection with business activities at factories and workplaces, as well as construction work, and by establishing permissible limits for automobile noise, etc." and regulates "specific factories, etc.", "specific construction work", and "permissible limits for automobile noise, etc."

The "Permissible Limits for Automobile Noise, etc." includes "Permissible Limits for the Magnitude of Automobile Noise" for noise emitted by automobiles and "Orders Setting Limits for Automobile Noise in Designated Areas" for environmental noise. Both were revised and came into effect on April 1, 2000. An excerpt from the Noise Regulation Law is provided below for your reference. For further details, please refer to this law and related laws and regulations, such as prefectural and municipal ordinances established based thereon.

Table 13-7 "Noise generated at specific factories, etc."

Area classification	Time divisions			Remarks
Daytime	morning and evening	night time
(7 or 8 AM - (6, 7, or 8 PM)	(5, 6-7, 8 AM) (6, 7, 8 PM - 9, 10, 11 PM)	(9, 10, 11 p.m. to 5, 6 a.m. the following day)
(Type 1 area) Areas where maintaining a quiet environment is particularly important in order to preserve a good residential environment.	45-50 dB or less	40 to 45 dB or less	40-45 dB	The standard value is the noise level at the factory site boundary. Time divisions are determined according to the lifestyle of the region.
(Class 2 area) Because it is used for residential purposes, it is an area where the maintenance of tranquility is required.	50-60	45-50	40-50
(Type 3 area) Areas that are used for residential purposes as well as for commercial and industrial purposes, and where it is necessary to prevent the generation of noise in order to preserve the living environment of the residents within that area.	60-65	55-65	50-55
(Type 4 area) Areas primarily used for industrial purposes, etc., where it is necessary to prevent the generation of excessive noise in order to avoid worsening the living environment of residents within the area.	65-70	60-70	55-65

Table 13-8 "Noise generated during specific construction work"

Types of work		Regulatory standards	conditions				Remarks
Types of work		Regulatory standards	Nighttime or late-night work	Daily working hours	Work period	Sundays and other holidays	Remarks
1. Pile driving machine, pile extraction machine, or work using a pile driving or pile extraction machine.	Excluding pile driving. Excluding press-in pile driving and pile extraction machines. Excluding work where the pile driving machine is used in conjunction with an earth auger.	85 dB or less	Area ① is prohibited from 7 AM to 7 AM the following day. Area ② is prohibited from 10 PM to 6 AM the following day.	Area ①: 10 hours Area ②: 14 hours	Six consecutive days in the same location	Prohibited	Area ① includes the areas of Category 1, 2, and 3, as well as the area within approximately 80 meters of the premises of schools, daycare centers, hospitals, clinics with facilities for accommodating patients, libraries, and special care homes for the elderly. Area ② is an area other than area ①. Regarding the conditions, there are exceptions in cases of emergencies, danger prevention, etc.
2. Work using a nail gun
3. Work using a rock drill	For work where the work location moves continuously, this applies only to work where the maximum distance between two work locations in a single day does not exceed 50 m.
4. Work involving the use of an air compressor	For applications using prime movers other than electric motors, the prime mover must have a rated output of 15 kW or more. This excludes operations where it is used as the power source for a rock drill.
5. Work performed using a concrete plant or asphalt plant.	The mixing capacity of the mixing machine is 0.45 ^m³. This applies only to the items listed above. This applies only to mixing machines with a mixing capacity of 200 kg or more. Excluding work performed at a concrete plant for the purpose of manufacturing mortar.
Noise measurements shall be carried out using a sound level meter that meets the requirements of Article 71 of the Measurement Law. In this case, the frequency weighting circuit shall use A-weighting, and the dynamic characteristics shall be fast dynamic characteristics (Fast). For the time being, the noise measurement method shall be in accordance with the noise level measurement method specified in Japanese Industrial Standard Z 8731 (1983 edition, former JIS), and the determination of noise level shall be as follows: If the sound level meter reading does not fluctuate or fluctuates only slightly, that reading will be used. If the reading of the sound level meter fluctuates periodically or intermittently, and the maximum value of the reading remains approximately constant, the average of the maximum values for each fluctuation should be used. If the sound level meter reading fluctuates irregularly and significantly, the upper end of the 90 percent range of the measured value should be used. If the sound level meter reading fluctuates periodically or intermittently, and the maximum value of the reading is not constant, the upper limit of the 90 percent range of the maximum value for each fluctuation shall be used.

The reference value changed from L ₅₀ to L _Aeq on April 1, 2000.

Table 13-9 Required limits for automobile noise
(Prime Minister's Office Ordinance establishing limits on automobile noise within designated areas)

Area classification

Time divisions

Daytime

night time

Areas a and b that face a road with one lane

65 dB

55 dB

a. Areas within the zone that face roads with two or more lanes.

70 dB

65 dB

b. Areas within the zone that face roads with two or more lanes and
c. Area within the zone that faces a road with lanes

75 dB

70 dB

Notwithstanding the above table, the limit for areas adjacent to roads that carry main traffic (meaning the area within 15 m from the boundary line of the road property in the case of roads with two lanes or less, and within 20 m from the boundary line of the road property in the case of roads with more than two lanes) shall be 75 dB during the day and 70 dB at night.

In areas where facilities requiring particular tranquility, such as schools and hospitals, are concentrated, the prefectural governor, mayor, and prefectural planning committee can consult and determine the regulations.
Areas a, b, and c refer to the areas designated by the prefectural governor as follows:

a area	Area used exclusively for residential purposes
b area	Areas primarily used for residential purposes
c area	Areas used for commercial, industrial, and other purposes, in addition to a considerable number of residences.

Daytime	6:00 AM to 10:00 PM
night time	10 PM to 6 AM the following day

Main transportation routes: Expressways, national highways, motorways, prefectural roads, and municipal roads with four or more lanes.

Noise measurements should be taken at the boundary line of the road if there are residences, hospitals, schools, or other buildings adjacent to the road. If the residences are located at a distance from the road, measurements should be taken at a point where the level of noise reaching the residences can be measured. The height at which measurements are taken should be the vertical position at the point where noise poses the greatest problem in terms of preserving the living environment. Intersections should be avoided.
Measurements will be evaluated using equivalent sound levels for three consecutive days out of seven that are deemed representative of the automobile noise situation. The noise level will be the energy average of the measured values over the three days, in principle, for each time period.
Noise levels shall be measured using a sound level meter that meets the requirements of Article 71 of the Measurement Law, and in a location that avoids the influence of reflections from buildings, according to the noise level measurement method specified in JIS Z 8731. If the influence cannot be avoided, the measured value shall be corrected taking that influence into account. If there is an influence from noise other than automobile noise, the measured value shall be corrected taking these influences into account.

Table 13-10 Permissible limits for the level of automobile noise (Ministry of the Environment Notification, 2000)

Vehicle types			Permissible limits on the level of automobile noise
Vehicle types			Steady-state driving noise	Proximity exhaust noise	Acceleration noise
Regular automobiles, compact automobiles, and light automobiles (excluding automobiles with a seating capacity of 10 people or less used exclusively for passenger transport and motorcycles)	Vehicles with a gross vehicle weight exceeding 3.5 tons and a maximum engine output exceeding 150 kW	Vehicles equipped with a power transmission system that can transmit power to all wheels, towing vehicles for semi-trailers, and crane operation vehicles.	83 dB	99 dB	82 dB
		Vehicles equipped with a power transmission system that can transmit power to all wheels, other than towing vehicles and crane operation vehicles that tow semi-trailers.	82 dB	99 dB	81 dB
	Vehicles with a gross vehicle weight exceeding 3.5 tons and a maximum engine output of 150 kW or less.	Equipped with a power transmission system that can transmit power to all wheels.	80 dB	98 dB	81 dB
		Other than those equipped with a power transmission system that can transmit power to all wheels.	79 dB	98 dB	80 dB
	Vehicles with a gross vehicle weight of 3.5 tons or less		74 dB	97 dB	76 dB
Regular automobiles, compact automobiles, and light automobiles (excluding motorcycles) used exclusively for passenger transport with a seating capacity of 10 people or less.	Vehicles with an engine at the rear		72 dB	100 dB	76 dB
	Vehicles other than those with an engine at the rear		72 dB	96 dB	76 dB
Small vehicles (limited to motorcycles).			72 dB	94 dB	73 dB
Light vehicles (limited to two-wheeled vehicles).			71 dB	94 dB	73 dB
Type 1 motorized bicycle (referring to a Type 1 motorized bicycle as defined in Article 1, Paragraph 2 of the regulations; the same applies hereinafter.)			65 dB	84 dB	71 dB
Second-class motorized bicycle (referring to a second-class motorized bicycle as defined in Article 1, Paragraph 2 of the regulations; the same applies hereinafter.)			68 dB	90 dB	71 dB

The Environmental Impact Assessment Act, based on the Basic Environment Act, was enacted in June 1999 with the ultimate objective of contributing to securing a healthy and cultured life for present and future citizens by recognizing that it is extremely important for the environment for businesses that carry out projects such as altering the shape of land or constructing new structures to conduct environmental impact assessments in advance before implementing those projects. This is based on the recognition that it is extremely important for the environment to be protected, and by clarifying the responsibilities of the national government and other entities, establishing procedures for conducting environmental impact assessments appropriately and smoothly, and by reflecting the results of environmental impact assessments in the content of projects and taking measures to give due consideration to environmental protection. Environmental assessment was institutionalized in the United States in 1969, and due to the current rise in environmental pollution problems, legislation is progressing in countries around the world.

What is an environmental impact assessment?

The environmental impact of the project will be investigated, predicted, and evaluated in advance for each component of the environment. (Scoping)
During the implementation of the project, measures and considerations will be taken to ensure that the environment related to the project is protected.
Comprehensive assessment of environmental impacts after implementation and when measures are taken,

The law designates projects of a certain size or larger ("Type 1 projects") that are large in scale, have a significant potential to have a major impact on the environment, and are implemented or licensed by the national government, and for which an environmental impact assessment is mandatory. It also designates projects of a similar scale to Type 1 projects ("Type 2 projects"), and establishes a system (screening) that involves discussing the necessity of conducting an environmental impact assessment based on the differences between each project and region.

Designated as Category 1 projects include the construction and reconstruction of expressways, national highways, and large-scale forest roads; the construction and reconstruction of power generation facilities, dams, weirs, railways, and airports; the establishment and modification of final disposal sites for general and industrial waste; land reclamation and drainage projects; land readjustment; industrial park development; new residential area development; new urban infrastructure development; and distribution business park development.

When conducting an environmental impact assessment, the process of determining effective survey items and methods for the assessment (scoping) is stipulated. The project plan will be advertised to widely solicit opinions from residents. Our company offers environmental noise prediction software, "SoundPLAN," to address noise concerns.

Table 13-10 Summary of noise evaluation quantities in environmental noise measurement in Japan

kinds	Evaluation quantity	law	JIS Z 8731 citation
Road traffic noise	Equivalent noise level L_Aeq	Basic environmental law	new
Railway (Shinkansen) noise	L_A Power average of the peak value of (Slow)		Old
Railway (conventional line) noise	L_AE twist L_Aeq To seek
Aircraft noise	WECPNL L_A (Slow)
Aircraft noise (enforced in April 2013)	L_den (Time-weighted equivalent noise level)		new
Factory, business, and construction noise	In the case of steady-state noise, the indicated value L_A (Slow)	Noise Regulation Law	Old
	For fluctuating noise: Upper limit of the 90% range (L₅) L_A (Fast)
	In the case of intermittent noise: If the maximum value is constant, then the average value If the maximum value fluctuates, use the 90% range. Upper limit (L₅) L_A (Slow)
Automobile traffic noise	Equivalent noise level L_Aeq		new
Car noise	L_A (Fast)		new
Workplace noise	L_Aeq (Slow) Equivalent sound level over 10 minutes	Industrial Safety and Health Regulations	Old