Preservation

Table 1. Classification System for Identifying the Climate Control Potential for Buildings

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Category of Control Classification Designation Practical Limit of Climate Control Systems Employed Expected Benefit Typical Construction Features Typical Structure Types
Uncontrolled I. None No Systems None Open Structure Privy, stocks, bridge, sawmill, well
Uncontrolled II. Ventilation Exhaust fans, open windows, supply fans, attic venting; no heat Reduce summer temperature extremes; reduce moisture accumulation Sheathed post and beam Cabins, barns, sheds, silos, icehouse
Partial Control III. Heating, ventilation Low level heating, summer exhaust ventilation, humidistatic heating winter control employed Summer: same as II.
Winter: good temperature control and limited humidity control; no winter occupancy
Uninsulated masonry, framed and sided walls, single-glaxed windows. Boat, train lighthouse, rough frame house, forge
Partial Control IV. Basic HVAC Ducted low level heating; summer cooling, on/off control; DX cooling, some humidification; reheat capability Reduction of all T&H extremes year-round; winter maximum indoor temperature 60 degrees F. Heavy masonry or composite walls with plaster; tight construction; storm windows Finished house, church, meeting house, store, inn
Climate Controlled V. Climate control with seasonal drift Ducted heating; cooling, reheat and humidification with control dead band Precision T&H control, but gradual season drift allowed Insulated structures, double glazing, vapor retardant, double doors Museums, research libraries, galleries, exhibits, storage rooms
Climate Controlled VI. Special constant Environments Special heating, cooling, and humidity control systems with precision constraint stability control Constant year-round T&H without drift Metal wall construction, interior rooms with sealed walls and controlled occupancy Vaults, storage rooms, cases

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