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ConstructionPro Week, Volume: Construction Advisor Today - Issue: 46 - 03/11/2010

Comment Period Closes Next Month for Another 23 Addenda to Standard 189.1

The comment period for 13 proposed addenda to Standard 189.1, Standard for the Design of High-Performance Green Buildings Except Low-Rise Residential Buildings, will end April 4. Comments for another 10 proposed addenda will be accepted through April 19.  The comment period for the following proposed addenda is scheduled to close April 4:

 

Addendum b -- This addendum would change the height of illuminance calculations required for the performance option of daylighting simulations from three feet to 2.5 feet to coincide with standard industry practice.

 


Addendum bb -- This addendum would update the building envelope requirements for opaque elements and fenestration in Standard 90.1-2007 and associated text and appendix changes that relate to the prescriptive criteria tables. The text changes related to the ISC are in Appendix A and Appendix C.

 

Addendum bf -- This addendum would place performance requirements for air leakage of the opaque envelope. Performance requirements have existed on fenestration and door products to date, but evidence suggests that the opaque envelope is the source of most air leakage in buildings and that the cause is a lack of attention in the design, construction, and enforcement process due to the absence of performance criteria.

 

Addendum bz -- This proposed revision addresses the comments received during the first public review calling for clarification of the requirements to reduce misinterpretation of the proposed monitoring requirements. The committee still finds merit in the requirement for monitoring at this level of detail.

 

Addendum ce -- Proposed changes in this addendum are intended to clarify the requirements and avoid conflicts with other existing requirements for lighting space control.

 

Addendum cs -- This proposed change originated with a continuous maintenance proposal to address information received on addendum bs after the public review period closed and which the subcommittee found to have merit. "The change from a list of exemptions that may not be incomplete to a set of spaces where the control is required eliminates many potential practical application issues (that tends to reduce compliance) while still retaining the requirement in those spaces expected to provide the vast majority of savings," according to ASHRAE.

 

Addendum cu -- This addendum would control the "night lights" that are part of the emergency system when there are no occupants in the space. "This has definite energy savings and is not prohibited by the electrical codes. There is nothing in the National Electric Code that dictates that emergency lighting be on when normal power is present or the building is unoccupied."

 

Addendum cv -- A Continuous Maintenance Proposal was submitted that indicated there is substantial energy waste in many service water booster systems. Service water (domestic water) booster pump systems can waste substantial energy in three ways, according to ASHRAE:

 

  • It is common to boost pressure beyond the pressure needed under most conditions and then to reduce that pressure with one or more pressure-reducing valves.
  • Even relatively efficient systems incorporating variable speed drives may be controlled in ways that require the pumps to run even when there is no service water flow.
  • The pressure maintained may be more than needed during low-flow conditions when there is less piping pressure loss to account for.

Locating the pressure sensor near the critical fixture (usually at the highest floor of the building) conserves energy by minimizing the setpoint during non-peak conditions. The same requirement exists in the fan power and cooling pump energy requirements. In booster systems, however, the economics are somewhat different because of the high lift pressure even when flow rates are low.

 

Economic analysis:

 

  • Mounting the pressure sensor remotely showed net LCC improvements with a scalar of 7 (acceptable for a 14-year life) for the minimum pump size covered when compared to a simple fixed-pressure discharge setpoint. The scalar, however, was not met when compared to systems with a discharge sensor and even simple pressure reset logic.
  • Having the pump turn off when there is no demand is a standard feature on most units, provided that the startup procedures are followed, so there is no need for cost justification.
  • Eliminating the PRV potentially increases first cost because one or more of the following features will be used in lieu of the PRV to provide adequate control of the system pressure: variable speed drives; multiple smaller pumps; and larger pressure tanks.
Research of actual costs, however, showed that the least expensive option is often the variable speed driven design without a PRV. The cost of the VFD is offset by eliminating the PRV and reducing the size of the bladder tank. Therefore, economic analysis was not required for this provision.

 

Addendum cw --  These proposed changes address corrections and clarification necessary to Section 11, Table 11.3.1, Section 11, Service Hot Water Systems. Currently, the budget building design (Column B) for the energy cost budget (ECB) instructs the user to apply identical system type and efficiency for the service hot water systems in the budget building design and in the proposed building design. This contradicts Section 11.32 (b), which states that the minimum efficiency of the service hot water system of the budget building design shall be per Section 7.4 ( or 7.4.2), which refers to table 7.8. The current approach also does not allow any credit for better than the minimum efficiency requirements as listed in table 7.8. By correcting this contradiction and changing the current description, there is a possibility that the proposed building design service hot water system will not be listed in table 7.8. This will not allow the user to select the system type and specify the minimum efficiency of the budget building design service hot water system. Under these circumstances, the user is instructed to use identical service hot water system (and efficiency) in both the budget building design and the proposed building design. This approach is also consistent with Section 11.3.2 (a), which refers only to HVAC systems.

 

Addendum cx -- This addendum would allow a 40 percent window wall area path within the prescriptive tables 5.5-1 through 5.5-8.

 

Addendum cz -- This proposed change would incorporate bi-level control for parking garages to reduce the wasted energy associated with unoccupied periods for many garages and allow an exception for lighting in the transition (entrance/exit) areas to accommodate IES recommendations. The IES Recommended Practice for Parking Facilities, RP-20 includes a recommendation for a daylight transition zone to allow for eye adaptation going to/from daylight conditions and the interior of a parking facility. Because some parking facilities will have much more daylight available than others, it is very difficult to determine an appropriate LPD (watts per square foot allowance). An exception for this specific small area in a parking garage is the most straightforward way to allow for this recommended practice. Several case studies have been conducted by the California Lighting Technology Center (CLTC) of motion-sensing bi-level lighting controls for outdoor lighting. The CLTC measured lighting control savings of 42 percent in parking garages (http://cltc.ucdavis.edu/content/view/354/287/). CLTC also conducted a life-cycle savings analysis and showed that this type of control was cost effective with simple paybacks under five years. The University of California has a sample specification for these types of controls and is implementing this control across their campuses. Campus police have indicated that they like this type of control as they can readily identify occupancy in spaces at night. Bi-level controls are compatible with various small (< 175 W) wattage sources used in parking garages including ceramic metal halide, fluorescent, light-emitting-diode, and induction lighting.

 

Addendum da -- "The benefits of ventilation to the health and well being of building occupants is well documented and widely accepted. Minimum ventilation rates for buildings are generally established by local code and or a rating authority (i.e., Leadership in Energy and Environmental Design certification). In cases where building owners make conscious decisions to provide ventilation in excess of the minimum required for the health of building occupants, they need to understand the energy implication of this decision. Building owners and designers must make balanced decisions regarding indoor air quality and energy efficiency. The intent of this addendum is to establish that an Appendix G baseline shall be based on the minimum ventilation requirements required by local codes or a rating authority and not the proposed design ventilation rates."

 

Addendum dc --  "The conditions and common practice that existed to create the need for this requirement on tandem wiring are no longer practiced primarily with the new federal efficacy requirements and products available on the market."

 

The comment period for the following proposed addenda is scheduled to close April 19:

 

Addendum a -- This addendum would change the daylighting definitions to coincide with those in Standard 90.1 to facilitate consistent use of these terms. Some changes are semantic such as changing from daylight zone to daylight area and changing from adjacent to vertical fenestration to primary sidelight area. For the daylight area under skylights and under roof monitors, geometric relationships between obstructions heights and distances from glazing are provided to allow daylight areas to extend beyond obstructions where appropriate. Clerestory was deleted because roof monitor sufficiently describes roof elements other than skylights. The changes to toplighting are not substantive but are proposed to use the same text as 90.1 to ensure consistent use. Effective aperture has been replaced with sidelighting effective aperture again to coincide with 90.1. For background documentation on the analysis used to derive sidelighting effective aperture, access website http://www.h-m-g.com/ASHRAE_Daylighting.

 

Addendum bu -- Regarding modification to the new table column two heading, ASHRAE believes that the rating conditions of the equipment should not be mentioned specifically in Standard 90.1 and that the reference to ASHRAE 127 is sufficient. This would allow for the rating conditions for equipment regulated by 90.1 to be automatically upgraded if ASHRAE 127 is revised in the future without needing to "officially" amend this standard. Regarding new computer room exceptions, additional exceptions were proposed to be added for mission-critical facilities in response to some public comments.

 

Addendum cd -- Under this addendum, ASHRAE believes that this second public review provides more clearly written requirements to better match business operation.

 

Addendum cn -- This change would add two versions of a combined advanced control to the control incentives table. These control system combinations involve personal workstation control and workstation-specific occupancy sensors for open office applications. The control incentive would apply only to the particular controls when they are applied in open office areas. This advanced new technology is not yet widely used, but ASHRAE believes its inclusion in the incentive table would encourage this advanced control use and its energy savings in open office areas. "Occupancy type control is very effective but also very difficult to apply in open office areas. This control makes that possible in specific workstation arrangements. A study for BC Hydro Energy Smart Office installation, 'Energy Saving Lighting Control Systems for Open-Plan Offices: A Field Study (Galasiu, Newsham, Suvagau, Sander),' published in Leukos July 2007, broke down the energy savings by individual control strategies for this type of workstation-specific lighting system. The conclusions showed a savings of 46 percent made up of 11 percent for individual dimming if used alone and a saving of 35 percent for individual occupancy sensors if used alone."

 

Addendum co -- Five years ago, ASHRAE approved amendments to Standard 90.1 (addendum g to ASHRAE 90.1-2004) which increased the minimum energy efficiency standards of commercial air-cooled air conditioners and heat pumps greater than 65,000 British thermal units (Btu/h). EER and COP (at 47 degrees Fahrenheit) were amended, with new levels taking effect last January. However, Addendum g left unchanged the minimum energy-efficiency standards for water and evaporatively cooled commercial air conditioners as well as air cooled, water, and evaporatively cooled condensing units listed in Table 6.8.1A. In 2007, addendum s to ASHRAE 90.1-2007 replaced all part load IPLV values in Table 6.8.1A (at the exception of condensing units) with new part load IEER. This proposal would make three major amendments to Table 6.8.1A. 

 

First, it would update EER and IEER values for all condensing units and water and evaporatively cooled air conditioners with cooling capacities greater than 65,000 Btu/h. Depending on the cooling capacity, the new EERs and IEERs are between 5 percent and 13 percent higher than the values they are replacing. Second, the proposal would establish a separate product class for evaporatively cooled air conditioners with different energy-efficiency standards. While water and evaporatively cooled air conditioners have been listed in one product category with the same energy-efficiency standards since 1989, differences in how the two products are rated per AHRI standard 340/360 dictate a separate product class with different minimum EERs and IEERs.

 

A closer look at AHRI standard 340/360 shows that at cooling capacities greater than 135,000 Btu/h, cooling tower fan motor and circulating water pump motor power inputs are not taken into account in the energy-efficiency calculation for water cooled air conditioners while the power input for the evaporative condenser fan and re-circulating water pump is included in the EER calculation for evaporatively cooled air conditioners. As such, the new proposed EERs and IEERs for evaporatively cooled units are slightly lower than water cooled units. Third, the proposal would replace the IPLV descriptor for condensing units with the new IEER metric and amend the EERs with more stringent values. The new EER and IEER levels would become effective in June of next year.

 

Addendum cp -- Variable refrigerant fow (VRF) systems are variable-speed, multi-split air conditioners and heat pumps used in many buildings covered by ASHRAE 90.1. Some of the heat pump systems are capable of heat recovery operations, providing simultaneous heating and cooling. Although VRF systems were introduced in Japan and Europe more than 20 years ago, they are just beginning to penetrate the U.S. market. In the past five years, the U.S. demand for VRF systems has increased significantly, prompting the need to establish minimum energy-efficiency requirements for these products. 

 

This proposal would establish, for the first time in Standard 90.1, efficiency requirements for VRF air conditioners and heat pumps, including heat pumps that use a water source for heat rejection. Including these values would ensure that Standard 90.1 is up-to-date and recognize a new technology. The cooling EERs and heating COPs are proposed for a full range of product cooling capacities at standard rating conditions listed in AHRI Standard 1230. The AHRI standard was first published last November and contains test procedures for such equipment. 

 

In addition, AHRI is developing a certification program for this equipment and expects to launch it later this year. The proposed SEER, HSPF, EER, and COP levels are identical to the minimum efficiencies for conventional ducted air cooled air conditioners and applied heat pumps listed in ASHRAE 90.1. The only exception is for VRF Heat Pumps with Heat Recovery capability; the EER and IEER values would be 0.2 lower due to the pressure drop in the refrigerant system to achieve heat-recovery operation. Higher IEER levels are being proposed as these products are primarily designed to operate in zoning applications and at partload conditions. The first phase of IEER values would become effective immediately while the second phase would take effect in July 2012.

 

Addendum cq -- This section of the standard has not been revised since 1999. This addendum is based on economic analysis using the current scalar value. The detailed analysis divided ducts into many categories of duct type and location; however, analyzing the results showed that nearly all categories were economically justified at seal class A, which allowed eliminating two tables while reducing energy use.

 

Addendum cr -- This addendum would modify unmet load hour definition, Section 11.3.2i, Table 11.3.1, Section G3.1.2.2, Table G3.1, and add new Section G3.1.2.3. The definition for an unmet load hour is currently lacking a throttling range or limit to the setpoint. It was decided that the baseline and proposed should have the same thermostat throttling range. "This required additional language in the unmet load hour definition as to how throttling range effects determination of an unmet hour along with additional language in Table 11.3.1 and Table G3.1, Design Model sections. It was also discussed to remove the requirement that the proposed unmet hours be no more than 50 greater than baseline unmet hours.

Several LEED reviewers commented to the EA TAG that they had required an analysis to be modified to meet the 50-hour limit, which proved very difficult to do and resulted in no appreciable differences in the results as long as the 300-hour total limit on loads not met was not violated. It appears to be a burdensome requirement that does not result in a better or more accurate accounting of savings. Section 11.3.2i was revised to require both the proposed and baseline unmet hours be no greater than 300 in both the baseline and proposed. This is the same language used for unmet hours in Appendix G. Lastly, it was decided to remove the language allowing modification of the system coil capacities to reduce unmet hours as needed. The consensus of the ECB subcommittee and of other modelers was that loads not being met were almost never a result of undersized equipment but rather some other fundamental flaw in the model."


Addendum ct -- In proposing this addendum, ASHRAE asserted that the original sidelighting requirements were based on conservative analysis completed by H-M-G (Jon McHugh), which resulted in a sidelighting area of 1,000 square feet. The analysis has been re-run with revised but still conservative up-to-date cost data for sensors and daylighting controls installed in smaller spaces. "These results show cost-effective sidelighting at a threshold of 299 square feet. The 2010 standard will require occupancy sensor control in office spaces up to 250 square feet. Therefore, to cover all office environments where energy savings is available, [we are] proposing a slightly aggressive 250 threshold for daylighting."

 

Addendum cy -- This addendum would make several revisions to the economizer requirements in Section 6.5.1 and Section 6.3.2. "With increased envelope insulation levels and higher internal plug loads, we are seeing commercial buildings operating in cooling at lower ambient temperatures. This allows for greater air and water economizers to be used instead of mechanical cooling. Using the ASHRAE benchmark building models, we have conducted a detail energy and economic analysis and have found that requirements for the use of economizers can be justified in additional zones including 2a, 3a, and 3b. We have also found that the threshold limit on the size of the unit above which economizers are required can be decreased from 135,000 and 65,000 Btu/h to 54,000 Btu/hr. Integrated economizers allow for the use of economizers and mechanical cooling to meet the cooling loads of the building.

With advanced controls for economizers, it is now possible to eliminate the exception 6.5.1.3c, which exempted zones 1, 2, 3a, 4a, 5a, 5b, 6, 7, and 8 from using integrated economizers. The results of the analysis showed a market volume weighted average cooling energy savings for the HVAC system cooling power of 24 percent for the small office, 22.1 percent for a large office, and 33 percent for a hospital. As part of this change proposal, we have also updated the table 6.3.2, which allows for the elimination of economizers through the use of higher-efficiency HVAC equipment. The table has been modified to reflect the new ASHRAE benchmark building models and to expand the table to allow it to be used for any type of HVAC system and not just Unitary air cooled equipment currently covered by the table."


Members Being Sought for Committee

 

In addition, members are being sought for the committee developing the standard. Slots will open July 1.

 

When asked which specific areas of the green building community the new members will represent, ASHRAE Communications Manager Jodi Scott told GBI, "It is an open call for membership. The areas represented will entirely depend on who submits what application. A decision has also not been made to determine how many positions are open. The plan is to expand the size of the committee. It will depend on how many qualified applicants submit completed applications by the deadline.

 

"Our goal is to end up with a balanced committee that represents all interest categories including, but not limited to, environmental groups, designers, engineers, architects, utilities, builders, code officials, building owners, and user, etc."

 

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