Appendix E — STC, Aural Field and Proportion of Space Table 8.E.1: Typical STC Ratings for Building Elements

(Source: Stein, t al. 2006. Mechanical and Electrical Equipment for Buildings. John Willey & Sons, New Jersey) Improvements in STC Ratings of Studa Partitions b STC Ratings of Masonry Walls

                     Description                         STC                    Description                      STC
Basic partition: single wood studs,                      35     100 mm light weight hollow block                   36
    400 mm on centres, 13 mm gypsum board on                    100 mm dense hollow block                          38
    both sides, air cavity
                                                                150 mm lightweight hollow block                    41
Add to basic partition
                                                                150 mm dense hollow block                          43
    Double gypsum board, one side                        +2
                                                                200 mm lightweight hollow block                    46
    Double gypsum board, both sides                      +4
                                                                200 mm dense hollow block                          48
    Single thickness absorbent material in air cavity    +3
                                                                300 mm lightweight hollow block                    51
    Double-thickness insulation                          +6
                                                                300 mm dense hollow block                          53
    Resilient channel supports for gypsum board          +5
                                                                100 mm brick                                       41
    Staggered studs                                      +9
                                                                150 mm brick                                       45
    Double studs                                         +13
                                                                200 mm brick                                       49
a For application to metal stud partition, use adders
      as in note b, but begin with STC=40 for a                 300 mm brick                                       54
      90mm basic partition.                                     150 solid concrete                                 47
b When using two improvements, add an additional
      +2; for three improvements, add +3.                       200 solid concrete                                 50
c The STC figures are conservative. Other sources               250 solid concrete                                 53
      list the same constructions with 1 to 5 points            300 solid concrete                                 56
      higher STC.

a The STC figures are conservative. Other sources list

                Typical STC Value for Doors                          the same constructions with 1 to 5 points higher
                                                                     STC.
Door Construction                                        STC    b All ratings of lightweight block assume sealing with
                                                                     paint. Note that this reduces absorption.
Louvered door                                             15
Any door, 50 mm undercut                                  17
                                                                Modifications
38 mm hollow core door, no gasket                         22
                                                                     Add sand to core of hollow blocks            +3
38 mm hollow core door, gaskets and drop closure          25
                                                                     Add plaster to one side                      +2
44 mm solid wood door, no gasket                          30
                                                                     Add plaster to both side                     +4
44 mm solid wood door, gaskets and drop closure           35         Add furring strip, lath and plaster:
Two hollow core doors, gasket all around, with            45                                    One side          +6
  sound lock
                                                                                                Two sides        +10
Two solid core doors, gasket all around, with sound       55
     lock                                                            Add plaster via resilient mounting:
Special commercial construction, with lead lining and 45-65                                     One side         +10
  full sealing
                                                                                                Two sides        +15

Typical STC Ratings of Interior Partitions Typical STC Value for Windows

Type of Partition                         STC               Window Construction             STC

Demountable partition                                      20-30    Operable wood sash, 3 mm glass unsealed    23

Drywall partition up to acoustical ceiling                  30      Operable wood sash, 6 mm glass unsealed    25

Drywall partition extending 300 mm above                    35      Operable wood sash, 6 mm glass, with       30
 acoustical ceiling tile system into ceiling plenum                      gasket

Drywall partition with cavity insulation, full height to    40-45   Operable wood sash, laminated glass,       28
 the underside of slab above                                             unsealed

Two-layer drywall partition with insulation, erected        50      Operable wood sash, double-glazed, 3mm     29
 full height to underside of slab above                               panes, 10 mm air space, with gasket
                                                                    Fixed sash, double 3 mm panes,             44
                                                                       75 mm air space, with gasket
                                                                    Fixed sash, double 3 mm panes,             48
                                                                       100 mm air space, with gasket

                                                                                     Appendix E (Contd.)
     Table 8.E.2: Recommended STC for Partitions for Specific Occupancies
  (Source: Stein, B. et al., 2006. Mechanical and Electrical Equipment for Buildings.
                             John Wiley & Sons, New Jersey)
    Type of Occupancy                         Wall, Partition, or Panel Between              Sound Isolation
                                                                                              Requirement:
                                                                                           Background Level in
                                                                                              Room Being
                                                                                               Considered
                                 Room Being          and             Adjacent Area          Quiet     Normal
                                 Considered
Normal school buildings          Classrooms                  Adjacent classrooms           STC 42     STC 40
without extraordinary or                                     Corridor or public areas      STC 40     STC 38
unusual activities or
requirements                                                 Kitchen and dining areas      STC 50     STC 47
                                                             Shops                         STC 50     STC 47
                                                             Recreation areas              STC 45     STC 42
                                                             Music rooms                   STC 55     STC 50
                                                             Mechanical equipment rooms    STC 50     STC 45
                                                             Toilet areas                  STC 45     STC 42
                                 Music practice              Adjacent practice rooms       STC 55     STC 50
                                 rooms                       Corridor and public areas     STC 45     STC 42

Executive areas, doctors         Office                      Adjacent offices              STC 50     STC 45
suites; confidential                                         General office areas          STC 48     STC 45
privacy requirements
                                                             Corridor or lobby             STC 45     STC 42
                                                             Washrooms and toilet areas    STC 50     STC 47
Normal office; normal            Office                      Adjacent offices              STC 40     STC 38
privacy requirements; any
occupancy using rooms                                        Corridor, lobby, exterior     STC 40     STC 38
for group meetings                                           Washrooms, kitchen, dining    STC 42     STC 40
                                 Conference                  Other conference rooms        STC 45     STC 42
                                 rooms
                                                             Adjacent offices              STC 45     STC 42
                                                             Corridor or lobby             STC 42     STC 40
                                                             Exterior of building          STC 40     STC 38
                                                             Kitchen and dining areas      STC 45     STC 42
Large offices, drafting         Large general                Corridors, lobby, exterior    STC 38     STC 35
areas, banking floors, etc.     office areas
                                                             Data-processing area          STC 40     STC 38
                                                             Kitchen and dining areas      STC 40     STC 38
Motels and urban hotels,        Bedrooms                     Adjacent bedrooms a           STC 52     STC 50
Hospitals and dormitories
                                                             Bathroom a                    STC 50     STC 45
                                                             Living rooms a                STC 45     STC 42
                                                             Dining areas                  STC 45     STC 42
                                                             Corridor, lobby, or public    STC 45     STC 42
                                                             spaces

a Separate occupancy

Figure 8.E.1 Speech and Music in Aural Field Figure 8.E.2 Recommended proportion of a space