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Energy Savings En-Coded

Mark Ohrenschall
Con.Web, October 29, 2003

Oregon's Revised Commercial Energy Code
Close to 10 Percent More Efficient than Prior Version

Oregon's newly revised energy code for commercial buildings is close to 10 percent more stringent in efficiency requirements than before, according to officials.

The changes, effective Oct. 1, help make Oregon's non-residential code one of the most energy efficient in the nation, said Jeff Harris of the Northwest Energy Efficiency Alliance, who serves on the energy committee of the state Building Codes Structures Board.

This also signifies a shift in how some additional energy efficiencies will be gained in new non-residential buildings. "In this code change cycle, to get more savings out of the code, we're having to go into more complicated things like controls. A lot of simple equipment widget efficiency upgrades have been made," Harris told Con.WEB.

The revised code has controls provisions for demand control ventilation, air temperature resets and HVAC system start-ups in large buildings, daylighting for classrooms and atriums, exterior lighting, air-supply dampers and hydronic systems.

Other new aspects cover HVAC requirements for hospitals, laboratories, computer rooms and thermally sensitive equipment; use of economizers; reduced lighting power densities; and new minimum efficiency levels for distribution transformers.

Building commissioning narrowly missed inclusion in these code changes, which stem partly from former Gov. John Kitzhaber's call for consideration of energy code improvements, in the wake of the 2000-2001 energy crisis.

Another driving force is a federal requirement for states to adopt energy codes similar to or more rigorous than the latest ASHRAE/IESNA national standards, according to Alan Seymour of the Oregon Department of Energy.

Changing the Code

Seymour said many building professionals wonder if Oregon's new code exceeds ASHRAE/IESNA Standard 90.1-1999, which also functions as an energy benchmark for the increasingly popular LEED (Leadership in Energy and Environmental Design) green building standards. It does in many, but probably not all respects, he said.

Harris credited ODOE (formerly Oregon Office of Energy) as a leading force in the code review, supported by Alliance funding.

"When we developed those changes, we tried to involve representatives of the design community in putting those together," said Seymour. The process covered two-plus years of stakeholder and public review of the code revisions. They affect building plans submitted for permitting on or after Oct. 1, for all structures except single- and two-family dwellings.

Although no one has quantified potential energy savings from the new code, Harris said the changes probably exceed the former requirements by 5 percent to 10 percent. Seymour thinks it could be in the 10-percent range.

"It's maybe not quite as significant [in energy savings] as the code changes in Washington in '94 and Oregon in '96," said Harris. But it is noteworthy "in terms of the areas it's moving into," such as controls for daylighting and demand control ventilation; he called those "quite significant as first steps," though perhaps not yielding big immediate energy savings.

The code revisions were not especially resisted by building and development practitioners, according to Harris, but government building inspectors had some concerns. "The building officials felt very strongly that these controls provisions are not enforceable from their perspective," he said. That's one reason why controls requirements are separate for larger buildings, which generally involve professional engineers obligated to meet ASHRAE standards. "The designers themselves will be enforcing this," according to Harris.

A similar principle applies to equipment requirements, such as distribution transformers. "In theory, somebody could put something in that does not comply," said Harris, but that could raise liability issues and potentially harm the business reputation of vendors.

Energy codes are evolutionary, reflecting changes in building practices. "These [code changes] build on each other," he said. "We hope it'll be the foundation for future code changes."

As it is, Oregon's non-residential energy requirements are "right up there as one of the best codes in the nation," according to Harris--probably less stringent than the city of Seattle, but "in some ways a move beyond the current Washington state code." (See Con.WEB, Dec. 20, 2001, for a story on Washington's upgraded energy code.)

Mechanical, Envelope, Lighting System Requirements

Revisions to Oregon's non-residential energy code affect mechanical, envelope and lighting systems in new buildings.

In the HVAC realm, controls are a major focus. "A lot of these code provisions are now targeted toward systems-level design and controls, which are traditionally hard to do in code," said Harris. "The code is now split into two sections: simple, prescriptive requirements are in one portion and more complicated things that only apply to large, complex buildings are in a separate section."

The revised code mandates controls for: reducing outside air in partially occupied spaces served by larger HVAC systems; resetting supply-air temperatures in response to building loads or outside air temperature, in multiple-zone HVAC systems; shutting off conditioned- and outside-air supply to different zones in the same building; varying HVAC system start times to meet temperature setpoints at time of occupancy; resetting supply water temperatures according to building loads or outside air temperature, for large chilled and hot water systems; damper closings for certain applications; and certain hydronic systems.

Also in the code are new economizer mandates ("We made an attempt to clarify economizer requirements for special situations," said Harris); airflow reductions for large-volume fan systems; and expanded applications for variable-speed drives for fan and pump motors.

A substantial new addition is the inclusion of hospitals, laboratories, computer rooms and thermally sensitive equipment in HVAC requirements. "We felt it was appropriate to exempt [them] from certain requirements, but certainly not everything," said Seymour (some specific exceptions are provided in the new code).

Air-transport energy requirements are proving a challenge for designers of those building types, according to Seymour and Harris. "This will require significant changes and will result in some significant enegy savings," said Harris, although he added that this specific mandate may be loosened slightly in the near future.

Richard Beam, corporate utility manager for Providence Health System and an Alliance board member, described the code revisions as an important advance that reflects Oregon's attention to energy efficiency.

"Any time that we can upgrade the code here in Oregon to allow us to achieve more energy efficiency in our facilities, it's a good thing. We're happy to see the bar raised," said Beam, adding with a laugh, "I don't know if the financial people are. Those of us in facilities are."

Non-HVAC features of the revised code include daylighting controls for classrooms and atriums with either window-to-wall ratios higher than 50 percent or with skylights. "We felt at the . . . energy committee that daylighting controls as a code requirement were not ready for prime time for all buildings," but they could be unobtrusively applied in those specific applications "as a first step toward a more inclusive daylighting controls in code," said Harris.

Also new are reduced lighting power densities (down to 1 watt per square foot in offices), which Harris said should save considerable energy; minimum efficiency levels for distribution transformers; more stringent shading coefficent requirements for skylights; and occupany sensor requirement specifications.

Perhaps the most notable omission from these code revisions is building commissioning, which fell short by one vote at the Building Codes Structures Board. This would have been particularly helpful in ensuring controls work as intended, Harris said. He predicted commissioning eventually would make it into Oregon's code, as it has in Seattle and Washington. He also noted that commissioning as a code requirement doesn't address post-occupancy performance of building systems.

Related Sites:
Oregon non-residential energy code changes

by Mark Ohrenschall
Energy Savings En-Coded
Con.Web - October 29, 2003

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