DASM Noise Measurement and Sound Insulation – Absorption Consulting: Sotetsu Grand Frésa Saigon Hotel Meets Japanese Standards and International 4-Star Class

In March 2022, the Institute of Development & Application for Sound Materials (DASM) was selected to survey and measure noise and to advise on sound insulation and sound absorption solutions for the Sotetsu Grand Frésa Saigon Hotel project.

Since opening, this international 4-star accommodation, with 125 high-end guest rooms and a full range of amenities and support services in line with current standards in Japan, has been rated “Excellent” and “Exceptional” by guests on many travel platforms worldwide and in Vietnam.

“Fresh, Sense, Amenity” & the standard of optimal acoustic performance

On the occasion of the 50th anniversary of diplomatic relations between Vietnam and Japan, on the morning of July 6, 2023, at 8 Ly Tu Trong Street, Ben Nghe Ward, District 1, Ho Chi Minh City, the Sotetsu Grand Frésa Saigon Hotel held a grand opening ceremony. Construction began in July 2020; the project has a total area of nearly 800 m², with 19 floors above ground and 2 basement levels, and is the result of cooperation between Japan’s Sotetsu Group and Thanh Van Hotel Development Investment JSC – two companies with extensive experience in the hotel sector. The event was also attended by Japanese Consul General Ono Masuo, representatives of the Japanese Chamber of Commerce and Industry in Ho Chi Minh City (JCCH), representatives of SMBC bank, and other guests and VIPs. Consul General Ono Masuo said: “I hope that Sotetsu Grand Frésa Saigon Hotel will be chosen by many visitors to Ho Chi Minh City as a place to stay, to work, or to enjoy a peaceful retreat, thereby promoting economic relations and exchange between Japan and Vietnam.”

In the accommodation segment, Sotetsu Hotels currently manages and operates more than 70 hotels across the land of cherry blossoms and several Asian countries. Sotetsu Grand Frésa Saigon is a special highlight – the No. 1 landmark steeped in the essence of Japanese culture and architecture in Southeast Asia (Vietnam is the first country in the region chosen by Sotetsu Group for investment in the hotel sector).

Sotetsu has more than 100 years of history and development, with operations spanning transportation, logistics, real estate… and hotels. Meanwhile, the main contractor of the Sotetsu Grand Frésa Saigon project is VINATA International Co., Ltd. – 100% owned by Japan’s TAISEI (the oldest of the five super general contractors in the Land of the Rising Sun). VINATA trusted and selected the Institute of Development & Application for Sound Materials (DASM) as the direct provider of noise survey and measurement and of sound insulation and sound absorption consulting for this key project.

Accordingly, for more than one month, DASM experts used world-class advanced equipment on site, analyzed and reported results, advised on construction, and recommended solutions and sound insulation and sound absorption materials that ensure quality and optimal acoustic performance… After completion and opening, Sotetsu Grand Frésa Saigon achieved an international 4-star rating with “a full range of amenities and support services in line with current standards in Japan”. Occupying a prime location in the heart of District 1, it is equipped with meeting rooms, a swimming pool, a modern gym and a contactless self check-in system. The restaurant serves Japanese cuisine, with a breakfast buffet, lunch and, especially, Japanese-style dinner prepared by a chef from a famous Japanese restaurant in Ginza. As part of Sotetsu Hotels’ Grand Frésa chain, where FRÉSA stands for “Fresh, Sense, Amenity”, Sotetsu Grand Frésa Saigon is positioned as a place to stay that brings guests comfort through attentive staff hospitality, convenience, cleanliness, quality and a convenient location.

In particular, soundproof guest rooms are promoted as a brand strategy and the unique selling point/unique selling proposition (USP). “All 125 rooms, including 95 double rooms and 30 twin rooms, are soundproofed, so there is no need to worry about noise” – this introduction to the facility attracts the attention of most travelers. The “Amenities” category scored 9.6/10 and the “Cleanliness” category scored 9.7/10, together with “Excellent” and “Exceptional” ratings on many travel platforms worldwide and in Vietnam, which is clear proof of the professionalism and reputation of Sotetsu Hotels, VINATA and DASM.

DASM – optimal acoustic services & solutions for hotels and resorts

For the Sotetsu Grand Frésa Saigon project, DASM experts prepared a 58-page report, covering the main contents below:

1. Noise measurement standards

Parameter tested	Standard
Airborne sound transmission between rooms in a building	ISO 16283 ISO 140 ASTM E-336 ISO 354 ISO 717
Calculation of noise criterion (NC)	ISO 3382

Parameter tested	Standard
Heavy impact floor	JIS A 1418

According to ISO 16283 and ISO 140, for each measurement the report includes the average sound levels L1 and L2 across the frequency bands. These parameters are used to evaluate the sound insulation of a partition, wall or any other location. The NC rating is determined from the background noise level at each evaluated location. The TL value must take into account the absorption area, since the room has been fitted with some furnishings that increase its sound insulation.

2. Measured rooms

Three rooms were acoustically measured to determine NC and TL: Rooms 404, 406 and 407 (see the floor plan).

Site survey

Parameter	Room 407	Room 406	Room 404
Calculated volume [m3]	49.81	41.56	41.76
Large glass area [m2]	9.126	11.61	9.018
Plasterboard wall area [m2]	10.9	N/A	8.91
Main door area [m2]	3.86	3.86	3.86
Large glass door size [m2]	1,55 x 2,42	1,55 x 2,42	1,55 x 2,42
Bathroom door size [m2]	1,94 x 2,4	0,8 x 2,4	0,8 x 2,4
Main door size [m2]	0,9 x 2,2	0,9 x 2,2	0,9 x 2,2

 3. NC rating

Ambient noise arising from empty spaces or around the building – such as air-conditioning systems, traffic noise, etc. – not only causes discomfort, stress and fatigue but also reduces productivity and concentration, and to some extent affects safety. In serious cases, it can even impair communication.

NC (Noise Criterion), or the NC curve, describes measured noise levels across the frequency spectrum from 63.5 Hz to 8 kHz. NC curves are useful for determining the noise level produced by mechanical systems such as motors in noise-sensitive environments such as hotels and hospitals.

The criterion defines the upper limits that each octave-band spectrum must not exceed.

Category	Application	Recommended NC level
Residential	Private house or apartment	25-35
	Suburban house	25-30
	Bedroom	20-30
	Living room	25-35
Hotel	Individual rooms or suites	25-35
	Meeting or banquet room	25-35
	Service and support areas	45-50
	Halls, corridors	40-45
Public areas	Courtroom	30-40
	Library	35-40
	Church, mosque, temple	30-35
Factory	Production area	40-65
	Administrator / Accountant	40-46
Office	Meeting / conference room	25-35
	Private office	30-35
	Open-plan office area	40-45
	Business machines / Computers	40-45
	Break area / Lounge	40-45
Hospitals and Clinics	Radiology department	35-40
	Operating theater	25-30
	Patient ward area	35-40
	Laboratories	35-40
	Consultation room / Clinic	35-40
	Corridor / Public area	40-45
Commercial areas	Theater	30-35
	Restaurants	45-50
	Recording studio / Audio broadcast / TV broadcast	15-20
	Performance / Concert / Recital hall	15-20
	Sports stadium	45-55
	Spa / Facial treatment / Massage center	25-35
	Retail store	40-45
	Gym / Exercise room	40-45
Schools	Lecture hall	35-40
	Classroom	35-40

4. TL rating

TLD: Transmission Loss Difference: the difference in the level of energy lost through a sound-insulating wall.

Each sound-insulating wall with different materials and construction has a different level of energy loss. Depending on the intended use, different partition designs can be developed. Transmission loss tends to increase at high frequencies, and at low frequencies the sound insulation can be improved with suitable additional measures.

When incident sound strikes a barrier (wall or partition), three mechanisms occur simultaneously: reflection, absorption and transmission through the wall. Part of the incident sound is reflected back toward the source, part is absorbed by the barrier, and the remainder is transmitted to the space on the opposite side of the barrier. Transmission loss is the term used to describe how a barrier performs as sound insulation between two spaces, with transmission loss increasing as the performance of the sound barrier increases. It is given by:

Where W_I is the sound power (Watts) incident on the wall and W_T is the sound power transmitted to the space on the opposite side of the barrier.

5. Measurement method and procedure

a. Method

In general, a sound level meter is used to measure the sound level in the indoor space, next to the sound source. This source generates a spherical sound field higher than the background level in order to determine the sound insulation of the wall (TLd value). The sound level meter is used to determine the NC and TLd values at the same time.

b. Measurement procedure

Determining the NC value

Equipment: 1 sound level meter 

Results: The different noise levels measured as indoor noise.

Procedure:

• Use a sound level meter (SLM) to measure the different noise levels at 6 different points in each room.
• The average sound level in the room is then determined. This average value is used to determine the NC rating.

 

Determining the TL value

Equipment: 1 sound level meter and 1 loudspeaker 

Results: The TL result curve across the frequency range

Procedure:

• Step 1: Measure the background noise of the receiving room and the source room, and set the source level at least about 20 dB above the background noise of the room.

• Step 2: Determine the dimensions of the receiving room, the source room, and the wall whose TLd value is to be determined (Sw).
• Step 3: Measure the sound level in the source room at no fewer than 6 different points (paying attention to the measurement distance and the distance to the walls) with the OMNI 4” source switched on. (L1)
• Step 4: Measure the sound level in the receiving room at no fewer than 6 different points (paying attention to the measurement distance and the distance to the walls) with the OMNI 4” source switched on. (L2)
• Step 5: Measure the reverberation time in the receiving room at no fewer than 6 different points (paying attention to the measurement distance and the distance to the walls). (T)
• Step 6: Measure the background noise of the receiving room. (Lb)

 

6. Measurement positions

In each room, 6 measurement positions are selected at the most acoustically unfavorable points, where the sound level fluctuates unstably. A non-uniform environment will affect the determination of the average sound level in each room. This is why acoustic measurements are taken at these positions.

 Each measurement position must be at least 1 m² from the wall and 1 m above the floor to ensure accurate sound level measurement.

Position 1

This is the position closest to the glass door frame. Because the construction changes to a single layer of glass, the sound insulation is also unstable and may be weaker.

Positions 2 & 3

These two positions are affected by the internal structural shape of the room, where there is a right-angle corner.

Position 4

This is the position beside the entrance door, affected by many factors such as door gaps, the joint with the wall, and the door threshold. These are all acoustically unfavorable locations where sound tends to leak through.

Position 5

At the junction between two different shapes of the room, there is a change in sound level.

Position 6

This is the center of the hotel room, where the sound level is the most stable.

 Measurement position outside, on the scaffold

This is a special position used when measuring the sound insulation of the wall separating the room interior from the exterior. The sound source is placed on the scaffold and a sufficiently strong source is activated, much higher than the background level. Only when there is a difference in sound level can the sound insulation of the wall or partition be determined.

7. Results

The NC and TL results are issued separately. Each result is a certificate of measurement results accompanying this calculation report.

The results were analyzed after the field measurements. The NC value meets the requirement at NC 24. The plasterboard wall and glass door meet the 50 dB requirement at high frequencies, but do not reach the desired performance at low frequencies.

In particular, the main door position does not meet the requirement because its construction and sound insulation method are not up to standard.

As one of the first and leading scientific organizations in sound consulting in Vietnam, DASM is proud and committed to transparency and effectiveness in providing customers with optimal acoustic solutions for hotels and resorts:

√ Services for determining sound insulation in buildings and building structures – hotels and resorts
√ Noise measurement and analysis services for hotels and resorts
√ Services for measuring and improving overall acoustics for hotels and resorts
√ Services for improving the sound insulation performance of hotels and resorts.

Please contact the Hotline 0968018216 of the Institute of Development & Application for Sound Materials (DASM) for detailed advice!

Some photos of DASM experts surveying, measuring and advising on sound insulation and sound absorption for the Sotetsu Grand Frésa Saigon Hotel project:

Some photos of the international 4-star Sotetsu Grand Frésa Saigon Hotel after it began operating:

An Nhien / DASM