The premise of achieving higher levels of building performance is to provide indoor environments that are most conducive to high worker productivity, to increase the longevity of the property, and to deliver these in an optimally cost effective manner. Protection of property includes assets such as wood furnishings, art, archives where applicable, as well as minimizing detrimental effects of mold growth and material corrosion and decay.

• Baseline: Control of dry bulb temperature range, allowing for seasonal and unoccupied setpoint adjustment.
• ★: Adds the provision of control of surface temperatures surrounding the occupants to limit the detrimental effects of radiant temperature asymmetry, as well as decreasing the size of control zones, so that fewer personal preferences are subject to a common environment. Control of surface temperatures is to be done passively, such as better R-values in materials, and synergistically, through intentional delivery of heating and cooling media (air, water, electricity, refrigerant) to offset undesirable surface temperatures. Better adaptation to individual preferences is necessary to achieve the goal of lower PPD (predicted percentage of dissatisfied).
• ★★: Adds Building Automation System (BAS) control of surface temperatures to reduce the detrimental aspects of radiant temperature asymmetry on occupants and allow for space air dry bulb temperature reset from the baseline parameters.
• ★★★: Additionally allows for occupant control of the surface temperatures within optimized limits determined by a BAS.

Humidity is one of several determining factors of an acceptable environment, but the limits for occupant comfort and productivity are much more widespread than the humidity limits required for asset protection and longevity. ASHRAE Standard 55-2010 “Thermal Environmental Conditions for Human Occupancy” does not require a lower limit of humidity with respect to maintaining an acceptable environment. Increasing levels of indoor environmental performance as impacted by the discrete attribute of humidity are defined as follows.

• Baseline: Provide a maximum indoor dew point limitation, applicable to all times and seasons.
• ★: Adds the provision of Class C control and seasonal setpoint adjustment for the preservation of "medium vulnerability" woodwork; this does not necessarily require humidification equipment.
• ★★: Upgrades to the provision of Class B control and seasonal setpoint adjustment for the preservation of "high vulnerability" woodwork. No archival storage of fabrics, books, film, or photos is considered.
• ★★★: Upgrades to the provision of Class A control and seasonal setpoint adjustment for the preservation of "high vulnerability" woodwork, through which also allows a small risk to archival storage items such as fabrics, books, film, or photos.

Air movement is discussed under the temperature attribute, because the amount and control of air movement directly affects the level of temperature control required to maintain a comfortable and productive environment. Levels of indoor environmental performance as impacted by the discrete attribute of air movement are defined as follows.

• Baseline: Less than 40 fpm air speed at the occupied level.
• ★: Group occupant controlled air speed at the occupied level adjustable between 20 and 150 fpm, but subject to not more than six occupants per control zone so that 1) fewer occupants are dissatisfied with their environment, and 2) space temperatures can be reset upward for overall energy savings in the cooling mode, and internal heat recovery in transitional seasons.
• ★★: Individual occupant controlled air speed at the occupied level adjustable between 20 and 150 fpm, adapting to individual preferences to achieve the goal of lower PPD.
• ★★★: Continues ★★ performance; no further enhancement.

Pressure is a factor contributing to longevity of the property, and the resultant indoor air quality. Under ordinary conditions, the relatively small orders of magnitude of air pressure experienced in and immediately around a facility do not usually create uncomfortable indoor environments. Control of space pressurization is important, in overall facility operations, to manage moisture, water vapor, airborne contaminants, and the consequent effects of mold growth. Levels of building performance as impacted by the discrete attribute of pressure are as follows.

• Baseline: Manage the differential flow rates of building outdoor air and exhaust air by the HVAC equipment, reset as determined by the pressure differential of each floor’s interior space with the outdoor.
• ★: Maintain building perimeter zones at 0.02”w.c. positive with respect to outdoor, with control zones no larger than per exposure and per three floors in height. Return air plenums require isolation near the perimeter. Note: The architectural design cannot locate negative pressure spaces at building perimeter.
• ★★: Provide envelope cavities at 0.02”w.c. positive with respect to interior occupied space when outside temperature drops below the dew point of inside air.
• ★★★: Continue the ★★ performance with the exception that mandatory negative pressure spaces are allowed at building perimeter when provided with active envelope cavity pressurization at 0.02”w.c. positive with respect to the environment with greater dew point.

Ventilation is one of the key elements (along with source control and air cleaning) to achieving acceptable indoor air quality. Source control alone is not sufficient because it is impossible to eliminate all off-gassing materials in the built environment and people are also a source of pollutants (bioeffluents). Hence, ventilation is required in all occupied spaces. ASHRAE Standard 62.1 is the consensus standard prescribing ventilation requirements in the U.S. It has been integrated into the two major U.S. model codes, the International Mechanical Code and the Uniform Building Code. Ventilation rates higher than Standard 62.1 rates have been shown in several studies to reduce sick building syndrome symptoms and reduce absenteeism.

• Baseline:
  • Ventilation rates shall comply with Standard 62.1-2010 using the Ventilation Rate Procedure. (The IAQ procedure is not practical since it is not possible to identify all pollutants, their source strengths, and their maximum acceptable concentrations.)
  • All variable air volume systems shall include devices to measure and control minimum outdoor air flow.
• ★
  • Comply with the baseline requirements
  • Comply with all LEED 3.0 Indoor Environmental Quality credits for building materials including EQ Credit 4.1 (Low-Emitting Materials - Adhesives and Sealants), EQ Credit 4.2 (Low-Emitting Materials-Paints and Coatings), EQ Credit 4.3 (Low-Emitting Materials-Flooring Systems), EQ Credit 4.4 (Low-Emitting Materials-Composite Wood and Agrifiber Products)
• ★★
  • Breathing zone outdoor air ventilation rates for private and open office spaces shall be equal to or greater than a total of 20 cfm/person.
  • Comply with all LEED 3.0 Indoor Environmental Quality credits for building materials including EQ Credit 4.1 (Low-Emitting Materials - Adhesives and Sealants), EQ Credit 4.2 (Low-Emitting Materials-Paints and Coatings), EQ Credit 4.3 (Low-Emitting Materials-Flooring Systems), EQ Credit 4.4 (Low-Emitting Materials-Composite Wood and Agrifiber Products)
  • All systems shall include devices to measure and control minimum outdoor air flow.
• ★★★:
  • Comply with ★★ requirements
  • Breathing zone outdoor air ventilation rates for all private and open office spaces shall be equal to or greater than a total of 30 cfm/person.
  • Provide an occupant indoor air quality survey in the POE.

Filtration and air cleaning can improve indoor air quality by removing contaminants from ventilation air. It is particularly effective in areas where outdoor air quality is poor. Particulate filtration can also improve air quality by reducing dirt on surfaces that can support microbial growth such as cooling coils.

• Baseline:
  • Provide minimum MERV 6 filters upstream of all cooling coils and other devices with wetted surfaces per Standard 62.1-2010 Section 5.8
  • Provide minimum MERV 6 filters on all ventilation outdoor air intakes where the national standard for PM10 is exceeded per Standard 62.1-2010 Section 6.2.1.1
  • Provide minimum MERV 11 filters on all ventilation outdoor air intakes where the national standard for PM2.5 is exceeded per Standard 62.1-2010 Section 6.2.1.2
• ★
  • Comply with baseline
  • Provide minimum MERV 8 filters upstream of all coils and any devices with wetted surfaces
• ★★
  • Comply with ★
  • Provide minimum MERV 13 filters on all air supply systems supplying any percentage of outdoor air. Prefilters are not mandatory.
• ★★★:
  • Comply with ★★
  • Provide ultra-violet germicidal irradiation (UVGI) for cooling coils and other devices with wetted surfaces.

Acoustics in the workplace can affect productivity and excessive noise can also cause sick building symptoms. Cross-talk in open offices can also be a detriment to worker productivity. However, there is no evidence to suggest that these factors are improved with lower sound pressure levels. Hence requirements are to simply meet the industry standard Room Criteria (RC) levels for all levels.

• Baseline:
  • Design all systems so that space RC is equal to or less than those listed in 2011 ASHRAE Applications, Chapter 48, Noise and Vibration Control, Table 1, Design Guidelines for HVAC-Related Background Sound in Rooms
• ★
  • Comply with baseline requirements
• ★★
  • Comply with baseline requirements
  • Provide sound masking in open office spaces.
  • Confirm design sound levels are achieved through field measurements in accordance with ASTM E336 "Field Measurement of Sound Insulation in Buildings
• ★★★:
  • Comply with ★★ requirements
  • Provide an occupant indoor acoustical survey in the POE.

The goal of operational efficiency is to maximize HVAC system energy efficiency in order to reduce HVAC energy consumption and costs. Annual HVAC energy consumption is impacted by many other factors in the building including building envelope, lighting, and equipment loads. This metric focuses strictly on the HVAC equipment and system efficiencies by utilizing industry standards for the various levels of efficiency.

• Baseline:
  • HVAC equipment efficiencies shall comply with the minimum efficiencies shown in ASHRAE Standard 90.1-2010
  • HVAC fan energy consumption shall not exceed that allowed by ASHRAE Standard 90.1-2010 Fan System Power Limitation Requirements
  • Building HVAC energy performance shall not exceed that allowed using ASHRAE Standard 90.1-2010 Appendix G
• ★
  • HVAC equipment efficiencies shall comply with the minimum efficiencies shown in ASHRAE Standard 90.1-2010
  • HVAC fan energy consumption shall be 5% less than that allowed by ASHRAE Standard 90.1-2010 Fan System Power Limitation Requirements
  • Building HVAC energy performance shall be 10% below that allowed using ASHRAE Standard 90.1-2010 Appendix G
  • Provide energy sub-metering for at least 80% of the building HVAC energy
• ★★
  • HVAC equipment efficiencies shall comply with the minimum efficiencies shown in ASHRAE Standard 189.1-2011
  • HVAC fan energy consumption shall not exceed that allowed by ASHRAE 189.1-2011 Fan System Power Limitation Requirements
  • Building HVAC energy performance shall be 15% below that allowed using ASHRAE Standard 189.1-2011 Section 7.5.2
  • Provide energy sub-metering for at least 90% of the building HVAC energy
• ★★★:
  • HVAC equipment efficiencies shall meet the maximum efficiency required by Tier 2 Energy Star or ASHRAE Standard 189.1-2011 minimum efficiencies
  • HVAC fan energy consumption shall be 5% less than that allowed by ASHRAE 189.1-2011 Fan System Power Limitation Requirements
  • Building HVAC energy performance shall be 30% below that allowed using ASHRAE Standard 189.1-2011 Section 7.5.2
  • Provide energy sub-metering for 100% of the building HVAC energy

The goal of maintainability is to provide equipment and systems that are easily and cost-effectively maintained to achieve acceptable thermal comfort, energy efficiency, and indoor air quality through the life of the building. This metric uses various important maintenance objectives to determine how easily the HVAC systems can be maintained.

The maintainability metric is based on the area density of HVAC motors, air handler locations, accessibility for part replacement, motor and filter accessibility, and whether a predictive maintenance system is implemented in the design and construction.

Accessible is defined as providing access for maintenance, repairs, removal, and replacement of equipment and valves.

Easily accessible is defined as accessible in mechanical spaces or with a maximum 12-foot ladder.

Equipment requiring frequent service shall not be installed in occupied rooms or above ceilings in work areas unless it is unavoidable due to space configuration. When such installation is unavoidable, efforts shall be made to locate frequently serviced equipment in the traffic areas of the occupied space.

HVAC systems shall be designed in accordance with the following maintainability principles:

• Systems shall be selected with minimal mechanical components requiring service and maintenance.
• System components requiring frequent service and maintenance shall be located in equipment rooms or service areas, and not above suspended ceilings or in occupied spaces.
• Clear and safe access shall be provided for servicing, removal, and replacement of equipment.
• Sufficient instrumentation shall be specified for measuring, indicating, monitoring, and operating at part load as well as full load.
• Equipment shall be selected for long-term durability, reliability, maintainability, and serviceability.

The goal of operability is to provide equipment and systems that are easily operated by personnel with a reasonable level of training for similar activities. This includes minimizing the need for extensive special training of operators and providing adequate redundancy of major equipment to maintain HVAC operations in the event of equipment failure.

The operability metric evaluates ease of operation for the HVAC systems with high-performance systems being easily operated. The control sequence complexity is also used in this metric to encourage control sequences that are easy for the average operator to understand.

Instrumentation and test ports shall be provided for measuring temperatures and pressures at each piece of HVAC equipment.

The goal of this metric is to encourage extended service life on HVAC equipment. Service life is a function of equipment materials and construction and the environment with which the equipment is operated. The design shall document the basis of anticipated HVAC equipment service life.

Major HVAC equipment evaluated in the service life metric includes chillers, cooling towers, boilers, and air handlers.

The attribute of energy performance considers the whole building synergistically and measured with respect to both energy utilization (consumption) and carbon emissions (total or source) on an annual basis.

Federal law requires minimum levels of performance for Federal facilities and total portfolio performance for Federal agencies. The related attribute of energy cost is required to be reported for LEED certification, and this may be a driving requirement in terms of systems selection, particularly thermal storage and demand peak shaving/load offset.

Energy cost, however, is not a direct report as it is possible to decrease energy consumption without a corresponding decrease in the annual cost of energy. It is possible to decrease the annual energy cost while experiencing an increase in annual energy consumption through technologies such as thermal storage. Because this would be counter to the goals of the Federal mandates, it is for this reason that only energy consumption and carbon emissions are to be measured here.