Occupant Comfort
Comfort Zones
Because of high energy costs, the DPW&T Building Services Division has established temperature Comfort Zones for heating and cooling. In the winter, the set point for heating is 69 degrees (the standard acceptable temperature range is between 68 to 74 degrees). In the summer, the set point is 76 degrees (the standard acceptable temperature range is between 75 to 78 degrees). However, for facilities that provide services to seniors, the year-round set point is 76 degrees.
Heating and Cooling Seasons
The typical cooling season begins on April 15 and ends October 15 each year. The heating system is deferred as long as is practical after October 15 and is terminated as soon as possible prior to April 15. In addition to thermal comfort, the relative humidity, for most applications, should be between 40% and 70%, with a 65% threshold to help prevent the growth of mold. The relative humidity Comfort Zone should not be lower than about 30% (to prevent occupant discomforts such as dry eyes and throats, shrinking of wood flooring, and static electricity problems on carpet, and possible sick building syndrome symptoms) or higher than about 60% in the center of the room. The 60% level is intended to keep the relative humidity from exceeding 70% at surfaces, such as walls and floors.
Relative Humidity.
The relative humidity at surfaces is typically higher than it is at the center of a room. When the relative humidity at surfaces is above 70%, mold growth can occur. To control microorganisms, it is best to keep relative humidity below 60% to control mold and 50% to control dust mites. The accuracy of the standard humidity range is 3/5th% to 3% (say 2%) over the established comfort zone. For libraries and archival materials, a stable temperature of no higher than 70 degrees and a relative humidity of between 30% and 60% is recommended.
Lighting Standards
Because of increasing energy costs, Building Services has adopted the following lighting (illumination) standards after review of the recommendations provided by the Illuminating Engineering Society of North America. In 2005, a heavy duty light meter was purchased to assist building services personnel in periodically checking minimum lighting levels known as foot-candles (fc).
| Type of Activity | IL luminance (fc) | Typical Applications |
|---|---|---|
| Public areas with dark surroundings | 2 – 3 - 5 | Unoccupied storage areas, night lighting of hallways |
| Simple orientation for short occupancy | 5 – 7.5 – 10 | Restaurant dining areas,, inactive storage rooms, service elevators, stairways |
| Occasional, simple visual tasks | 10 – 15 – 20 | Auditoriums, passenger elevators, lobbies, corridors, pump island areas |
| Execution of visual tasks having high contrast or large size | 20 – 30 – 50 | Conference rooms, book stacks, active storage rooms, rough bench or machine work, simple inspections |
| Execution of visual tasks having medium contrast or small size | 50 – 75 – 100 | Mail sorting, reading poor copy, high contrast drafting, medium bench or machine work |
| Execution of visual tasks having low contrast or small size | 100 – 150 – 200 | Proofreading, low contrast drafting, difficult inspection |
| Execution of visual tasks having low contrast and small size for a long period of time | 200 – 300 – 500 | Very difficult assembly, inspection, or machine work |
| Execution of sustained and exacting visual tasks | 500 – 750 – 1,000 | Exacting assembly or inspection, extra-fine bench or machine work |
| Execution of special and exacting visual tasks having low contrast and small size | 1,000 – 1,500 – 2,000 | Surgical procedures |
Source: Illuminating Engineering Society of North America
| Application | Foot-candles (fc) |
|---|---|
| Building Exteriors | |
| Entrances (active) | 5 |
| Entrances (inactive) | 1 |
| Critical Areas | 5 |
| Building & Monuments | |
| Bright Surroundings, Light Surfaces | 15 |
| Bright Surroundings, Dark Surfaces | 50 |
| Dark Surroundings, Light Surfaces | 5 |
| Dark Surroundings, Dark Surfaces | 20 |
| Bulletin Boards & Signs | |
| Bright Surroundings, Light Surfaces | 50 |
| Bright Surroundings, Dark Surfaces | 100 |
| Dark Surroundings, Light Surfaces | 20 |
| Dark Surroundings, Dark Surfaces | 50 |
| Loading Docks | 20 |
| Parking Facilities | |
| Open, Low Activity | 0.5 |
| Open, High Activity | 2 |
| Covered, General Parking | 5 |
| Covered Ramps | 10 |
| Covered, Entrances | 50 |
| Roadways | |
| Roadways | 1 |
| Storage Yards | |
| Active | 20 |
| Inactive | 1 |
| Walkways | |
| General | 0.5 |
| Stairways | 4 |
Source: Illuminating Engineering Society of North America