SONA-Technical Information(sound insulation-about"D-value")

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Sound Insuration > about D-value

The grading of performance of sound insulation is taken place by using D-Value. D-Value is the class of sound insulation and is stipulated by JIS A 1419: 1992*. The larger numeric value it indicates, the higher performance of sound insulation it shows.

* "Dr" in present JIS A 1419-1: 2000, revised on January, 2001, is comparable to D-value.

D-value is indicated by each 5 step. The larger numeric value it indicates, the higher performance of sound insulation it shows. For example, D-55 indicates that it is higher than D-50 in terms of performance of sound insulation.
D-value between 2 rooms is gained by investigating how much the level of noise in one room decreases in another room with respect to frequency (pitch of sound). The room in which noise occurs is called Sound Source Room, and the other room is called Sound Receiving Room. Find the difference of sound pressure level at each octave band from 125Hz to 4kHz (sound pressure level in Sound Source Room - the one in Sound Receiving Room), and the largest numeric value which does not underrun the standard curved line. And the 2 dB of margin is allowed at each frequency.
JIS regulates the sound pressure levels in the sound source room and sound receiving room are given by the average value of sound pressure levels at five points in each room. But in the case of the measurement of sound insulation performance of doors, windows, not the measurement of room-to-room, the value may be obtained by averaging sound pressure levels at three points at either side of the door or window.

Example) In the chart below, sound insulation performance outruns the standard curved line of D-45 in ranges other than 1kHz, but underruns that in the 1 kHz range. The result is D-40.

D-values recommended by the Architectural Institute for various rooms are listed below.
For studios, D-50 to D-70 is recommended in terms of sound insulation between Control room (MA room) and Studio (booth).

Architecture	Room	Section	Applicable Grade
			Special	1st	2nd	3rd
			extra	standard	acceptable	minimum
Collective Housing	Living room	Wall or Floor between houses	D-55	D-50	D-45	D-40
Hotel	Guest room	Wall or Floor between houses	D-50	D-45	D-40	D-35
Office	Rooms that require privacy for business reasons	Partition wall Wall between tenanted Rooms	D-50	D-45	D-40	D-35
School	Ordinary classroom	Partition wall	D-45	D-40	D-35	D-30
Hospital	Hospital room (private room)	Partition wall	D-50	D-45	D-40	D-35
Detached House	Bedrooms, private rooms (Privacy should be kept)	Partition wall	D-45	D-40	D-35	D-30

Special	extra grade	Architectural Institute Designated Grade	very excellent in terms of sound insulation performance	Applied when high insulation performance is required
1st	standard	Recommended by Architectural Institute	Acceptable in terms of sound insulation performance	Few complaints from dwellers. No problems.
2nd	acceptable	Allowed by Architectural Institute	Satisfactory in terms of sound insulation performance	Complaints may come from dwellers. Some troubles in terms of sound insulation performance. Dwellers are almost satisfied with sound insulation.
3rd	minimum	Out of Architectural Institute Recommended Level	Minimum sound insulation performance required	It is highly possible that there come complaints from dwellers.

[How measurement is made ]

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