• DOOR JAMBS SEALS
ACTIVE LEAF
(SADDLE
ASTRAGALS
AUTOMATIC
DROP SEALS
• DOOR BOTTOMS
SEALSY
To seal doors all round requires a soft type of weather stripping, and a bottom door-closer must be fitted to make the door as air-tight as reason- able.
III. Installation. A flat door, care- fully and solidly installed is important in order to achieve a good result. If the door with seals is installed too tightly or out of line, it can place great pres- sure on the latchset and hinges as well as making closing difficult.
Noise control is best achieved by
-MIN. SPACE 4*
• DOUBLE DOOR WITH CASKETS G
• SOUND LOCK =
containing the noise at its source wherever practical. Equipment rooms should be provided with properly fit ted doors with seals. In some cases a two-door unit or sound lock should be employed.
Windows
e) As with doors on interior walls, windows are the weak link in external walls, but with one difference win- dows can provide an acoustical ad- vantage by allowing a controlled *masking sound' to enter and help cover up noise from adjacent spaces. The advent of air-conditioning as a common feature in new buildings al- lows the windows to be sealed to reduce noise problems.
Two items should be taken into account: Location and selection.
windows (not two glasses in one frame); a minimum of 4in. air space, preferably 8in., between glazing; two glass panes of different thicknesses, say in. and 5/16in.; opening units over or in tracks and pressure-sealed when closed; felt or vinyl weather- stripping to both sashes; and absorbent reveals (fibreglass, carpeting, etc.)
NEOPRENE
OR VINYL
CHANNEL
CONCRETE
- WOOD -
I. Location. On the noisy sides of the building keep the number and size NEOPRENE of windows to a reasonable minimum.
FRAMING Attempt to keep opening sashes as far apart as possible, to reduce cross-talk and avoid cross-reflection. Over court- yards, windows transmit noise in both directions; use sealed windows to courtyards.
apphapple
Arrange windows to open in same direction to avoid cross-reflection.
As a general rule, the larger the pane of glass the greater the vibration and thus a lesser ability to stop noise. This can be partly offset by making the glass thicker.
II. Selection. As with doors the single, most important factor in im- proving window performance is air- tightness. This requirement can be met readily in most fixed window units, but is often not met properly at the 'fixing in' points to the window open- ing and is rarely met in most opening windows of cheaper manufacture.
In single glazed opening windows, employing even 3/8in. glass, the noise reducing ability is at best inferior and should be considered inadequate for rooms requiring above-average noise protection, or marginal for average conditions (windows when closed).
Double-glazed windows have much greater noise reducing ability. Maxi- mum ability is obtained by employing the following features: Two separate
SEAL
NEOPRENE -
Setting glazing in resilent mountings increases its noise control ability.
around the frames between the glass panes.
Window units with all these fea- tures may be considered adequate for most rooms requiring above-average noise protection and very good for average conditions (windows when closed).
Single-glazed fixed windows with 3/8in. glass and thicker can be con- sidered to have a similar ability to the double-glazed opening windows.
~50UND ABSORBER
·SILICA GEL
TI
Fixed windows double glazing mounted resiliently, with sound absorbent material in reveals - inner glass removable for cleaning.
Double-glazed fixed windows with 2in. or 3/8in. thick panes, an 8in. air space and absorbent reveals are equal to or better than the normal wall con- structions housing them.
In this comparison of windows the outside noise level would be average city noise.
Far East BUILDER, June 1970
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