Table 1-10 Recommended Perimeter Insulation
Degree-Days
Insulation Thickness
3000 & Below
25 mm (1 inch)
3001 & Above
50 mm (2 inch)
The insulation shall have "R" value (same units "U") of 5.0
1.9.2.2 Existing Construction: The designer shall examine the existing
building envelope and recommend the ways and means to improve its
thermal efficiency. It is recognized that retrofitting the existing
walls with new insulation is expensive; however, it should be evaluated
if economically and technically feasible. The existing single pane
windows shall, however, be replaced by insulating double pane windows
("U" Factor 0.5 & Shading Coefficient 0.5) as a part of the major
renovation effort involving heating, mechanical cooling, and winter
humidification.
1.9.3 DESIGN FEATURES
In addition to energy studies and decisions made in conjunction with
economic analysis, the following features shall be incorporated without
the need for a life cycle cost analysis.
degrees C (48 degrees F) outdoor temperature without refrigeration,
unless such refrigeration is used effectively as a heat pump with
overall energy savings.
1.9.3.2 Heat Recovery Devices: For all locations where the outdoor
winter design temperatures are below 1 degrees C (30 degrees F) and
the winter degree days are in excess of 3000, heat recovery devices,
comprising of either air to air plate heat exchangers or glycol run
around loop heat recovery coils, shall be installed in all 100 percent
outdoor air systems with capacities in excess of 85 Cu M/Min (3000
CFM). The exhaust air systems, from which the heat is to be extracted,
shall also have capacity in excess of 85 Cu M/Min (3000 CFM) per
exhaust fan, and shall be of continuously operating type. Controls for
heat recovery system shall be designed to avoid defeating any "free
cooling" (economizer cycle) operation. Controls shall also be designed
to avoid overheating the outdoor air during mild or warm weather and
prevent icing of the exhaust air coil below 0 Degrees C (32 Degrees F)
ambient air temperatures. Do not provide heat recovery systems in the
following special exhausts:
(a) All Fume Hood Exhaust
(b) Kitchen Exhaust (Range Hood and Wet Exhaust)
(c) Autopsy Exhaust
(d) Isolation Room Exhaust
(e) Wet Exhaust From Cage and Cart Washers
(f) ETO - Ethylene Oxide Sterilizers Exhaust
1.9.3.3 Except in spaces where constant air change rate and/or critical
pressure differential relationship are essential, variable air volume
HVAC DESIGN MANUAL
1-28
GENERAL REQUIREMENTS
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