Title means "Quietness", "Comfortable Sound" and "Excellent Acoustics"

Nagata Acoustics News 00-02 (No.146)
Issued : February 25, 2000

Toyama City's New International Conference Center "Otemachi Forum"

by Satoru Ikeda

Plan of Otemachi Forum
The Exterior of Otemachi Forum
Toyama City, on the northern (Japan Sea) coast of Japan, offers many venues for both the performing arts and other audience gatherings. Nagata Acoustics served as the acoustical consultant for Toyama Shimin Plaza and for Toyama City Theater for Performing Arts: "Aubade Hall". These halls have a chamber-music size concert hall and a theater with a large stage for full-scale operatic productions. Together, the two locations serve the cultural and artistic needs of the people of Toyama City well, and have earned a place in the hearts of the city's residents.

The focus of this article is yet another facility, the Toyama International Conference Center, which opened its doors in August 1999. Also known by the name Otemachi Forum, the new Convention Center complex is located in the central, Otemachi section of Toyama City and features an international-class hotel as well as facilities for hosting international conferences and other gatherings. Geographically, Toyama City is in an excellent location to serve as a meeting place for the growing multinational interaction among countries on the Japan Sea rim. Otemachi Forum helps make Toyama City ready for the burgeoning convention and conference market in this region.

<< The Otemachi Forum Neighborhood >>

The Otemachi section of Toyama City extends from the end of Joshi Park (the site of an ancient castle), about 1km south of the Japan Railroad Toyama Station. The area is home to provincial government offices, city hall, the Kenmin Kaikan public conference center, the main library and other official government buildings, as well as to the downtown shopping area and Otemachi Mall.

Toyama Shimin Plaza and Otemachi Mall are two of the newer additions to the Otemachi section of the city, having been completed just 10 years ago. Shimin Plaza surrounds an atrium and has facilities that include the 308-seat Ensemble Hall, an art gallery, and a multipurpose studio, as well as a community learning center, a foreign language school, restaurants, shops and a fitness center. Shimin Plaza is very popular with Toyama City residents and it exemplifies the right mix of cultural, informational, learning and recreational offerings for a public center in an urban setting. Otemachi Mall is an open promenade that runs along Otemachi Avenue across from Shimin Plaza. The Plaza and the Mall were designed together to complement each other and their diversity and vitality support the quality of daily life in the community.

Compared with Shimin Plaza and Otemachi Mall, with its focus on enriching the daily lives of the city's residents, the new International Convference Center looks to the city's more cosmopolitan future. Otemachi Forum, which is geographically close to Shimin Plaza and Otemachi Mall, will be the venue where local businesses and commercial interests hold their gatherings. Otemachi Forum will also provide support for local organizations that wish to arrange and host international exchanges, meetings and conventions. The increased concentration of facilities in the Otemachi section of the city will increase the activity in the area and it is everyone's hope that there will be a symbiotic effect, as the Convention Center generates new traffic for Shimin Plaza and Otemachi Mall, and vice versa.

<< Otemachi Forum's Facilities and Organization >>

Otemachi Forum was built as the first phase of the Toyama City Otemachi Urban Renewal Project. The site of the convention center straddles Otemachi Mall from east to west. Otemachi Forum's hotel stands on the east side of the mall, and on the west side is the international conference building. Together, the center's two towers provide full-service conference, banquet and lodging facilities.

Otemachi Forum's international conference building is managed by Toyama Otemachi Convention Company, an incorporated entity funded by a consortium that includes the prefectural and city governments, as well as other governmental bodies. The first floor features an atrium designed for use as a convention hall. It is appropriate for poster sessions, trade exhibitions and similar events. The first floor also has an art salon and a "conversation gallery" where visitors and event attendees can meet and mingle. The building's second floor has a 500‡u multipurpose conference hall that can be divided into a configuration of four separate halls, and a number of smaller conference rooms. On the third and fourth floors of the building is the main conference hall, which boasts an expansive foyer.

<< The West Building's Exterior and Unique Interior Wood Lattice Screens >>

The exterior of the international conference center building is a glass curtain wall, complemented on the inside by wood lattice screens. The combined effect of these exterior and interior treatments creates a serene appearance. The use of wood latticework inside the glass curtain wall apparently serves multiple purposes, including filtering the amount of sunlight into the building, allowing outside passersby glimpses of activity in the building and enabling people inside the structure to view the "world" outside. The wood latticework also provides a sense of warmth, which is an appropriate and appealing design approach for this northern Japan location. The Otemachi Forum architect was the firm Maki and Associates, the same firm that designed Shimin Plaza and Otemachi Mall. The complex's east building is a 19-storey hotel, occupied by Toyama ANA Hotel. Both buildings have underground garages that are connected to each other, providing indoor access between the two buildings.

<< Otemachi Forum's Comfortable Main Conference Hall >>

The Main Conference Hall
Otemachi Forum's main conference hall has a single-floor audience area, with a seating capacity of 825 persons arranged in symmetrical, fan-shaped configuration around the hall's open-style stage. This seating configuration produces an excellent sense of connection between the stage and the audience, a feature that will appeal to presenters who must keep their audiences' attention focused on the podium during long conference hours. Each comfortably large audience seat is equipped with a writing surface and a small light so that attendees can take notes when the room is darkened for slide and video presentations using the hall's large-screen AV equipment. In addition to the well-appointed seating and large projection screen, the hall has an interpreters' booth and wiring capable of handling simultaneous interpretation for up to six foreign languages, as well as a forced-air ventilation system installed beneath the audience seating for quiet circulation of heated and cooled air. Otemachi Forum's sponsors requested that top-of-the-line equipment and apparatus be installed in the main conference hall, and the results show in this admirably outfitted hall.

<< The Main Conference Hall's Acoustics >>

I. Planning for the variety of ways the hall may be used

In designing the main conference hall's acoustics, we needed to consider how the hall would be used. Certainly, its main intended purpose, as determined by both the building's sponsors and the hall's architect, is international conferences involving speeches, lectures and panel discussions, supplemented by AV materials. Aubade Hall (with 1650 - 2200 seats and a proscenium stage) and Shimin Plaza's Ensemble Hall (with 308 seats and an open-style stage), are located close to Otemachi Forum and offer venue alternatives with different acoustical characteristics, configurations, sizes, availabilities, costs and regulations for use. Yet despite the nearby availability of two halls designed for musical performances, we initially included the possibility of classical music performances among its intended uses, based on the scale of the hall and our past experience with similar projects.

II. Requirements for grafting concert hall acoustics onto a conference hall

The flat-floor, open-style stage configuration of Otemachi Forum's main conference hall is an excellent configuration for a conference hall. In this environment, if our goal were solely to obtain the best acoustics for conference purposes, our acoustical consulting work would primarily aim to attenuate the room's reverberation. In the early stages of our work on this project, however, in addition to designing conference hall settings that would create optimal conference-use acoustics, our design plans included the ability to create the rich reverberation requirements of a concert hall. To achieve concert hall acoustics, a conference hall would need a certain ampleness of space and acoustical support apparatus that would allow the generation of sufficient early reflections (which affect the quality of a hall's sound) and lengthen the reverberation time. In addition, a concert hall perspective would need to be applied to the acoustical evaluation and implementation of sound isolation and equipment noise attenuation requirements, as well as to the selection of the hall's interior finishes and furnishings.

III. Otemachi Forum's main conference hall: a " pure" conference hall

At the design drafting stage of Otemachi Forum project, the project sponsors made the decision that the main conference hall should be built with the focus on international conferences and not include concert hall acoustic capabilities. From the acoustical perspective, this decision eliminated the difficult challenge of designing one hall with two, virtually non-overlapping personalities.

Accordingly, in our acoustical design for Otemachi Forum's main conference hall, the hall's reverberation time is short enough to ensure the clarity of human speech. In addition, because the hall will be used for multi-lingual international conferences, and because the hall's sponsors wanted the hall fully equipped with visual and audio presentation and recording capabilities, our AV system design includes in-hall recording and reproduction equipment for sound and video as well as voice amplification and simultaneous translation systems.

Early on in this project, we began our sound isolation and noise attenuation planning using concert hall standards, which are generally more rigorous than the standards for conference halls. Even when the concert hall capability portion of the project was dropped, we maintained the standards that we originally set for the level of quiet in the hall. As a result, we succeeded in designing Otemachi Forum's main conference hall to feature both excellent conference hall acoustics and a concert hall level of quietness that will make this hall an exceptional conference experience for those on stage and in the audience alike.

<< Otemachi Forum's First "Season" and Future Expectations >>

The new international conference center opened for business in August 1999, the height of the season for academic symposia and conferences. The Otemachi Forum's main conference hall calendar was filled with day after day of academic gatherings, forums, symposia, ceremonies and rallies, lectures and exhibitions. Concerts and traditional Japanese story-telling events appeared, too, but they were few and easily overshadowed by the plethora of events that perfectly matched the hall's conference hall acoustics. But, but, here is a hall with an open-style stage that looks like a concert hall stage and a beautiful space with fine intimacy between the stage and audience seating. Naturally, many people still hope that concerts will be planned and held here. Granted that the acoustics are designed for conference hall use, there are still a vast variety of productions that can be successfully staged in this acoustical environment. Toyama City has many special events planned for this year, in a program called "United Toyama 2000," and some of these events will be lucky enough to have Otemachi Forum as their venue. Conference attendees with the destination of Toyama can now expect international excellence and comfort. Hopefully, many people not connected to the conference circuits and academia will have the opportunity to experience and enjoy this venue, too.

For more information on Toyama International Conference Center call 76-493-4455 or look on the web at http://www.ticc.co.jp.
The center's address is 1-2, Otemachi, Toyama City, Toyama Prefecture.

ISO 2603 and ISO/FDIS 4043: Standards for Interpretation Booths

by Akira Ono (ISO 2603) and Katsuji Naniwa (ISO/FDIS 4043)

I. ISO 2603 Third Edition for Conference Hall Interpretation Booths

International conference centers seem to be the newest construction boom in Japan. Wherever I go, I hear about the completion of yet another international conference center. In November 1999, our News & Opinions featured an article about the new Tsukuba International Conference Center and this month we have an article about the new international conference center in Toyama City. Looking just a few months forward, Osaka International Conference Center is scheduled to open sometime this spring. A decade ago, the Japanese government planned to stimulate the domestic economy by supporting the construction of specialty use (as opposed to multipurpose) building projects. That funding was on hold for the last 10 years, but has recently become available and is probably one of the stimuli creating the increased construction of international conference centers.

Simultaneous interpretation booths are an essential part of any international conference center, and the importance of these booths is evidenced by the fact that their specifications have been addressed in ISO 2603. In 1999, the ISO organization released the third edition of ISO 2603.

The third edition of the ISO 2603 standard for interpretation booths begins with a preamble that explains the value in adopting ISO standards, how to apply ISO standards, the sources of the ISO body's authority, and a glossary of terms used in the standards. The main portion of the ISO 2603 standard considers in great detail the following aspects of interpretation booths:

1. Structural and performance-related design requirements
2. Supplementary facilities and apparatus for the interpreters to use
3. Performance characteristics and size of Interpretation equipment
4. Location requirements.

In this article, I will focus on ISO 2603's construction and related requirements.

<< Location of Interpretation Booths >>

The first condition to be fulfilled is that each interpretation booth be placed at a sufficient height so that the person(s) inside it can survey the event's proceedings, the speaker(s), projection screens that may be in use and the hall's sound booth.

When many countries participate in a conference, the sound booth operator sends the speaker's voice to the English-language interpreter while simultaneously sending the English-language interpreter's voice to all of the interpreters of other languages and their voices to the respective members of the audience who require each language. Therefore, the interpreters and the sound booth operator must work in close cooperation with each other without interfering with the event's proceedings. In case an interpreter or the sound booth operator needs to tell the other one something, or alert one of them to an accident or problem concerning the interpreting, the interpreters and the sound booth operator must be able to make eye contact and signal the situation between interpretation booth(s) and the sound booth using gestures. It would be difficult and impractical if such communications had to be done verbally. The sound booth and interpreters' booth(s) must also be located so that they are physically easily accessible to each other.

<< Construction Requirements of Interpretation Booths >>

Fig.1 Booth for
Simultaneous Interpretation
The ISO standard's required dimensions for interpretation booths, as well as for the booths' desks and windows are shown in Figure 1. The minimum dimensions for a two-person booth are 2.5m wide x 2.4m deep x 2.3m high (8.2 ft x 7.9 ft x 7.5 ft). For halls that anticipate having long conferences, the interpretation booth(s) are sometimes built to accommodate three interpreters, in which case, the minimum width is at least 3.2m (10.5 ft).

Interpretation booths must have windows on both their front and side walls, and placement of window sashes at a booth's corners should be avoided in order to maximize the booth's sight lines. The window glass must either be non-reflective or slightly angled to prevent reflections from the lighting fixtures used by the interpreters.

The doors to interpretation booths must take into consideration the need to create a soundproof environment in the booth. In addition, to help ensure that no one enters the booth while it is in use, the door must have a small, 20 cm x 22 cm (7.9" x 8.7") window so that a person can check whether the booth is in use without opening the door.

Interpretation booths' interior materials must primarily be sound absorbing materials. The color scheme must be appropriate to the work environment in the booths and should have a matte finish.

The interpreters' desks should extend the entire length of the window, and must be appropriately covered so that the interpreters' microphones do not pick up noise from the movement of objects on the surface of the desk. The required dimensions of the desk, including its height from the floor and its depth, as well as the dimensions of the space beneath the desk, are all shown in Figure 1. Shelves for reference materials should be placed on the wall behind the interpreters, not underneath the desk. The use of racks on rolling casters may also be recommended to hold reference materials.

Regarding chairs, the standard advises the preference that they be five-legged, with noiseless casters. Their height should be freely adjustable, they should have backrests and armrests, and they should be made of a material that does not retain heat.

<< Construction-related Provisioning Inside Interpretation Booths >>

Because interpreters may spend the entire day inside a booth, attention must be given to providing adequate ventilation. The air change rate must be seven air changes per hour, the replacement air must be 100% outside air, and the CO2 density must be 0.1% or lower. The booths' temperature must be between 18 - 24‹C (65 - 76‹F) and humidity must be maintained at 45 - 65% RH. The supply and exhaust grilles of the HVAC system must be placed so that the interpreters do not feel a draft, and the air velocity must not exceed 0.2m/sec. The HVAC system for the interpretation booth should be separate from that of the hall and any other-purpose booths or rooms.

The lighting inside the interpretation booths is divided into two separate types: general ambient lighting and lighting for the desk. The desk lighting should be non-florescent, compact table lamps that can be moved freely. The switch for the booths' ambient lighting must be within reach of the interpreters when they are seated at the desk, and the lighting should be 100 lx - 350 lx in strength. Alternatively, two sets of ambient lighting can be used, one being 100 lx - 200 lx in strength, and the second being 300 lx - 350 lx in strength. The ambient lighting may not emit any noise from its transformers. In order to prevent lighting from the interpretation booths from shining into the conference hall, attention should be given to the light footprints generated by the combination of the light bulbs and the reflective surfaces of the lighting fixtures.

<< Acoustical Requirements in Interpretation Booths >>

The ISO standard's sound isolation requirements for interpretation booths are as follows:

1. From the booths to the conference hall, R'w = 48 dB
2. Between the booths, R'w = 43 dB
3. From the booth to the corridor, R'w = 41 dB.

The R'w method of evaluation was set in ISO 717-1. In this method, the data measurements are evaluated by comparing them to the evaluation performance curve. For the purposes of this article, R'w may be considered to indicate that the sound isolation performance standards are based on evaluations using measurements of mid-register sound.

Because the isolation of sound from an interpretation booth into the hall depends mostly on the sound isolation capabilities of the windows, this part of the ISO 2603 standard can be said to be a difficult requirement to meet. To achieve the standard's requirement for sound isolation performance between interpretation booths, sealants must be applied around the openings of the cable conduits that run from one booth to the next. The booth's reverberation time should aim for 0.3 sec. - 0.5 sec. (at an octave band of 125 Hz - 4 KHz, in an empty booth).

<< Apparatus for Interpreters' Use >>

In addition to providing requirements for interpretation booths, ISO 2603 addresses the desirability of having a separate interpreters lounge be located near the booth(s). Here, the interpreters can study reference materials and relax. Safety, emergency and other notices and rules should be posted in the lounge. The following apparatus are also essential in the lounge: relaxing chairs, tables, a coat rack, lockers, a telephone, FAX machine and copier, and a bulletin board.

As for the sound system equipment inside interpretation booths, the ISO defers to the specifications set in IEC 60914. The newest edition of the IEC 60914 standard contains all of the equipment requirements for interpretation booths as well as their performance characteristics.

II. ISO/FDIS 4043 Final Draft for Knockdown Interpretation Booths

In addition to interpretation booths that are permanently built into a hall, there are also knockdown interpretation booths. ISO/FDIS 4043 will provide the standards for these interpretation booths. The document is now in its final draft stage.

The specifications for knockdown interpretation booths are based on the requirements in ISO 2603 with some additions and modifications to satisfy the dismantling, assembly and transport aspects of these interpretation booths.

<< Placement of Knockdown Interpretation Booths and Booth Dimensions >>

Knockdown booths have the same sight-line requirements as specified in ISO 2603. In addition, to ensure that interpreters have an elevated view of an event's proceedings, the standards specify that the floor of the knockdown booths must be raised at least 30 cm (11.8") higher than the floor of the conference hall. The knockdown booths must be placed with at least 2m of space between the booths and the stage or other location in the hall from which persons appearing in events speak, in order to ensure that the sound of voices emanating from the interpretation booth does not disturb the presenters.

The standard dimensions for knockdown booths are widths of 1.6m (5.3 ft) for a booth for 1 - 2 persons, 2.4m (7.9 ft) for a 3-person booth, and 3.2m (10.5 ft) for a 4-person booth. The depth is 1.6m (5.3 ft) and the height is 2.0m (6.6 ft) regardless of the number of interpreters per booth. However, provision is made for situations that do not allow for deployment of full-sized interpretation booths. For these situations, a standard has been created for a reduced-size interpretation booth. For this kind of knockdown interpretation booth, the minimum dimensions are 1.5m (4.9 ft) x 1.5m (4.9 ft) x 1.9m (6.2 ft).

For the doors of knockdown interpretation booths, it is important that they open and close quietly. The doors should open outward from the interpretation booths and they do not need to be fitted with locks. Secondary (sliding) doors and curtains are not necessary for sound isolation. Cable conduits should be accessible from either the side or front panels of the interpretation booths. There should be a sufficient number of cables for the all of the equipment that may be hooked up inside the booths, using a layout that requires the minimum cable length.

<< HVAC Systems in Knockdown Interpretation Booths >>

The HVAC requirements for knockdown interpretation booths are the same as for permanent booths. However, because the knockdown interpretation booths do not have independent HVAC systems, separate ventilation apparatus are required instead. The ventilation fan should be installed in the ceiling of the booth, and the minimum air change rate is the same as for permanent interpretation booths (seven air changes per hour). The ventilation supply grille must be located at a low height on the rear panel of the booth to prevent the flow of air from creating a draft on the interpreters' feet. The HVAC system noise level must not be greater than 40 dB(A).

<< Acoustical Requirements in Knockdown Interpretation Booths >>

The noise isolation requirements of knockdown isolation booths stipulate that sound from the booth to the hall must not be above 15 dB(500Hz), and sound from one interpretation booth to another must not be above 21 dB(500Hz). The reverberation time limitations within knockdown interpretation booths are the same as for permanent interpretation booths (e.g., 0.3 sec. - 0.5 sec., at an octave band of 125 Hz - 4 KHz, in an empty booth). In order to achieve this short reverberation time, the standard stipulates that knockdown interpretation booth floors should be carpeted.

For all the other knockdown interpretation booth requirements, please refer to the ISO 2603 requirements described earlier in this article.

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Nagata Acoustics News 00-02iNo.146j
Issued : February 25, 2000

Nagata Acoustics Inc.
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