06-06
any assistance from the external shading devices, such
as, venetian blinds and/or curtains.
3.
Insulating glass with lower "U" value might be necessary
to prevent condensation while maintaining the required
30% Relative Humidity (RH) in perimeter spaces with
-4oC (25oF) outdoor design temperature and below.
The "U" values are expressed as W/m2/oC (BTUH/Hr/FT2/oF).
4.
5.
The "U" values for floors, are for floors of heated spaces
over unheated areas, such as, sub-basements (pipe
basements), garages, crawl spaces, etc. The
requirements of insulation for the slabs-on-grade for
the heated spaces are shown under perimeter
insulation.
2. Overall "U" Value: The above recommended values should be used to
establish the overall "U" factor (Uo) for the building gross wall
area.
Designer A/E shall compute these values and demonstrate
that they do not exceed the limiting values listed below in Table
6.2.
Table 6.2
Degree-Days
Uo (Overall)
3000 & Below
0.73 (0.36)
3001 to 5000
0.63 (0.31)
5001 & Above
0.59 (0.28)
Uo
=
Uw x Aw + Ug + Ag + Ud x Ad
Ao
Uo
=
Overall Transmission Factor
Ao
=
Overall Gross Wall Area
Uw
=
Wall "U" Factor
Aw
=
Wall Area
Ug
=
Glass "U" Factor
Ag
=
Glass Area
Ud
=
Door "U" Factor
Ad
=
Door Area
Notes:
1.
The roof or floor "U" factors and areas do not enter into
computation.
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