KOTOBUKI

KOTOBUKI's pioneering spirit is based on our confidence in our fundamental technologies which have been developed during many years of manufacturing, research and planning. KOTOBUKI continues to innovate in the design and engineering of quality products, and to provide excellence and total quality control ensuring complete customer satisfaction. See examples of the TS Standard series here >>> or configure your own TS chair here >>>

• 
• KOTOBUKI also manufactures custom TS designs. more>>>

Specification varies across the product range, but most products feature the components in the table below.

• 
• Offering a wide range of seating products ensures that we can provide a seating solution for any venue regardless of its size or function.

Number and letter plates.

KOTOBUKI offers various sizes and methods of attaching plates. See the examples detailed above. Material is PVC / Aluminium. Typeface : round gothic 50 or square gothic 56 Color : red, black. Please contact our sales personnel in advance about the plate size and method of attachment for each product.

Generally, number is assigned in the order 1,2,3,... from left to right facing the stage. Row letters are attached in the order of A,B,C,D,... from the first row.

Removable chairs are set on castors and can be moved if required, to create space for wheelchairs, passageways or an orchestra pit etc. Depending on the aisle dimensions and chair structure, a single armrest or double armrest chair is selected. Two or three chairs are linked together in accordance with the seating layout. When the chairs are in position, the base can be fixed temporarily to the floor.

Number and letter plates.

To fold the back, raise it first and then fold it forward.

These chairs feature backs which can be folded when TV cameras or a sound controller are set up above, or when the chairs are stored under the stage.

Aisle with horaizontal/sloped floor

If the aisle has a horizontal/sloped floor, the lights are installed in equal intervals along the aisle. Illuminance is measured on the center line of the aisle closest to the guiding lights, and the horizontal illuminance is required to be 0.2 lux or more.

Minimum number of lights is (1/4 * length of the passageway - 1). (Standard established by the Tokyo Fire Department.)

Aisle with a tiered floor

If the aisle has a tiered floor, the center line of each aisle tread must be lit across the whole width of the aisle. In this case, the horizontal illuminance is required to be 0.2 lux or more. (Standard established by the Tokyo Fire Department)

• 
• Aisle lights are lit by an ordinary power supply. In case of the mains power failure, the emergency power will be activated, ensuring the aisles are lit consistently.

Separate emergency power supply

During both normal times and emergency, a small 5W bulb is turned on. Since this device does not have a built-in emergency power supply, a separate emergency power unit is required.<br /><br />
Type approval no.4CL-01<br /><br />
Cover/hard polyvinyl chloride/ivory

Separate emergency power supply

Chair with built-in emergency power supply (with integrated electric lighting and power supply) Type approval number: 4AX-1001 Cover/molded synthetic resin /gray / White LED lighting

A standard floor fixing method for Kotobuki products is shown here. Alternative methods may be used for special floors. Please contact our sales personnel for the most suitable method for your floor.

Concrete floor

Anchor bolt fixing (compression strength = 24N/mm2 )
Due to the strength of concrete floors, expansion type anchor bolts are used. In the case of light concrete floors (Light concrete floor, ALC board floor), the fixing method
will vary according to the material thickness and foundation structure.

Wooden floor

Setting by flanged hexagon head tapping screw. In the case of wooden floors, such as plywood, a joist is provided under the leg attachment position. The hexagon tapping screw has a higher pull out capacity than wood screws and coach bolts.

Removable chair fixing

KOTOBUKI offers a solution which neatly covers fixings when removable chairs are not in use.

We are happy to develop a custom-made fabric for the specific requirements which cannot be met by our extensive standard fabric range. Continuous development and research ensure that all our fabrics are of the highest quality and durability.

To allow spectators to enjoy the show comfortably, it is essential that good sight lines are secured. If there are seats with poor sight lines, the view may be improved by raising the tier height or by creating a staggered seat layout. When arranging seats and tiers, it is essential to secure sight lines at the earliest stage. Calculation is the simplest method to check the basic sight values. A two-dimensional check using a drawing is useful for quick understanding. Three-dimensional rendering by computer graphics may be used for a more detailed study of visual fields.

Based on the venuse's cross sectional drawing the 'c' values are calculated, as shown in the drawing above, to ensure that the best sight lines are achieved.

Required data for calculating sight lines
A. Height of focal point from stage floor
B. Height of stage from floor
'C' value
D. Height from floor to eye level
E. Height from floor to level of seating
F. Row rise
G. Depth of focal point from stage front
H. Distance from stage to back of first row
K. Chair layout space

The arrangement of linked chairs in theaters, halls and assembly halls is regulated by safety laws and fire regulations. The example below is from Tokyo's ordinances.

The seat centers shall be 420mm or more.
The row depth shall be 800mm or more and the horizontal projection distance between the rearmost part of the seat in front and the frontmost part of the seat behind shall be 350mm or more.
If there are more than eight seats, the row aisle shall be widened in the ratio of 10mm per seat with a horizontal projection distance of 350mm.
The maximum number of seats shall be twenty seats between vertical aisles. In the case of (n) seats: 350mm + 10 x (n-8) mm
In the case of the longitudinal aisle, the space shall be 800mm or more (600mm or more in the case of a one-sided aisle), and the width shall be calculated according to the estimated number of persons who may evacuate through that aisle. Minimum width = Number of persons x 6mm

In the case of the lateral aisle, the space shall be 1,000mm or more and the width shall be calculated according to the estimated number of persons who may evacuate through that aisle. Minimum width = Number of persons x 6mm

Fixed seat above Automatic seat below

A hall must have reverberation times that are suited to its purpose. Reverberation refers to the phenomenon whereby, after a sound source ceases, the reflection of sound exponentially and smoothly fades away. "Reverberation time" is a defined amount of time used to express the length of reverberation. Suitable reverberation time depends on the purpose and size of the hall. In the example of a typical hall, the horizontal axis shows the hall's capacity and the vertical axis shows optimum reverberation time at 500Hz. However, these values are only intended to be a guide. Each hall must be designed with consideration given to various conditions.

The fact that all curves rise to the right indicates that, even among halls having the same purpose, a longer reverberation time is desirable for a larger hall capacity. Even among concert halls, small- and medium-sized halls for chamber music have shorter reverberation times compared to large halls that are primarily designed for symphonies.

• 
• Reverberation times vary with frequency. In general, concert halls should have slightly longer reverberation times in the bass range than in the middle and upper ranges. In order to achieve this effect, it is important to consider the sound-absorbing qualities of decorating materials and building structures, as well as of the seats.

The seating area is reasonably large and is usually a major factor in designing the room acoustics. The level of sound absorption has the greatest effect on the sound reverberation time of the room. Therefore chairs should be selected which achieve the required acoustic performance.

Classical music halls

Less sound absorption for longer reverberation

Conference halls / Theatres

Medium sound absorption for clarity of speech

Cinemas

Maximum sound absorption for optimum sound effects