The standard currently states that reverberation time normalized impact sound pressure level (RTNISPL) and its corresponding single number rating, normalized impact sound rating (NISR) are not appropriate for receiving rooms of 150 m3 or greater. However there are some codes which currently specify the NISR rating. A number of members of the sub-committee felt that the standard should explain why the NISR is not appropriate in large rooms and indicate that the proper isolation metric in these cases is the non-normalized ISR.
Keywordsabsorption normalized impact sound pressure level; apparent impact insulation class; impact sound insulation; impact sound pressure level; impact sound rating; normalized impact sound rating; reverberation time normalized impact sound pressure level; tapping machine;
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