Design Guidelines For HVAC System Noise In Unoccupied Spaces

Space                                        RC(N) Level a,b
Private residences, apartments, condominiums     25-35                                   

Churches, mosques, synagogues                    25-35 c
with critical music programs

Hotels/Motels            
Individual rooms or suites                      25-35
Meeting/banquet rooms                           25-35
Corridors, lobbies, service areas               35-45


Schools
Classrooms up to 750 sq ft                      40 max
Classrooms over 750 sq ft                       35 max
Lecture rooms (>50 occ) with unamplified speech 35 max

Office buildings                         
Executive/private offices                       25-35
Conference rooms                                25-35   
Teleconference rooms                            25 max
Open plan offices                               30-40
Circulation and public lobbies                  40-45

Courtrooms
Unamplified speech                              25-35
Amplified speech                                30-40

Hospitals, clinics                       
Private rooms, operating rooms                  25-35
Wards, corridors, public areas                  30-40

Libraries                                        30-40

Performing arts spaces           
Drama theaters                                  25 max   
Concert and recital halls                       c
Music teaching studios                          25 max    
Music practice rooms                            35 max         

Indoor stadium and gymnasiums
School/college gyms                             40-50d
 natatoriums
Large seating capacity spaces                   45-55d
  (with amplified speech)

Laboratories with fume hoods
Testing/research, minimal speech                45-55
Research, extensive speech/phone                40-50
Group teaching                                  35-45

a.The values and ranges are based on judgment and experience, not on quantitative evaluations of human reactions. They represent general limits of acceptability for typical building occupancies. Higher or lower values may be appropriate and should be based on a careful analysis of economics, space usage and user needs. They are not intended to serve by themselves as a basis for a contractual agreement.

b.When the quality of sound in the space is important, specify criteria in terms of RC(N). If the quality of the sound in the space is of secondary concern, the criteria may be specified in terms of NC levels.

c.An experienced acoustical consultant should be retained for guidance on acoustically critical spaces (below RC 30) and for all performing arts spaces.

d.Spectrum levels and sound quality are of lesser importance in these spaces than overall sound levels.

The preceding information is reprinted from Table 2 in Chapter 43, "Sound and Vibration Control," of the 1995 ASHRAE Applications Handbook.

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