After a major expansion in 2003, the Oregon Convention Center in Portland, Ore., doubled its size to become an 18-acre campus. The 350,000-square-foot expansion later received the Leadership in Energy and Environmental Design certification from the U.S. Green Building Council.

PORTLAND, Ore. - After a major expansion in 2003, the Oregon Convention Center in Portland, Ore., doubled its size to become an 18-acre campus.

The 350,000-square-foot expansion later received the Leadership in Energy and Environmental Design certification from the U.S. Green Building Council.

According to Bob Spier, director of the convention center's operations department, the entire expansion project was undertaken with LEED certification in mind. That means not just energy efficiency, but indoor air quality, recycling programs, exterior maintenance and interior cleaning.

While the original HVAC design for the expansion met the center's requirements, it was overbudget. The convention center turned to McKinstry Co., a Seattle-based design-build mechanical contracting firm, to make some changes.

Bill Goerlich, a senior engineer with McKinstry, worked with Oregon Air Reps, the local McQuay representative, to replace the custom air-handling units that were specified for the job with 23 McQuay Vision air-handling units to reduce the budget by 21 percent.

Besides coming in under budget, the Vision units also helped the convention center to achieve LEED certification, officials said. LEED is a set of performance standards for the "sustainable" operation of new and existing buildings.

To earn the designation, the design team reworked the fitting and streamlined the ductwork, which enabled the McQuay vision units to use lower-horsepower motors to reduce energy consumption. In part because of this change, the building's energy efficiency exceeds the Oregon state energy code by 30 percent.

"The modular units are configured at the factory to meet individual design specs," said Tony Larson, project manager with McKinstry. "In addition, the pieces are constructed so that they are never more than 80 inches long, so they can be shipped sideways on a semitrailer, keeping transportation costs under control."

To further increase efficiency, the units use "economizer" cooling for outside air, which is an Oregon code requirement. If the outdoor temperature is not too hot, as often is the case in Portland, Ore., then outside air is circulated in the convention center without mechanical cooling.

Thirteen of the 23 McQuay units, including the 90-square-foot air handler, are located directly above the ballroom at the convention center in a large mechanical room. So that operating noise and vibration from the units would not interfere with events in the ballroom, the design specified a noise criteria level of 35, approximately equivalent to 35 decibels. The Vision units are installed on large concrete bases with Neoprene vibration-isolation material.

Hospital fights outdoor air contaminants

VANCOUVER, British Columbia - Elevated mold counts from upcoming demolition projects at Canada's Vancouver General Hospital could have threatened patient health via the surgical center's outdoor air supply.

Four problems also further complicated the hospital's search for a solution. First, the two-story surgery unit building was scheduled for demolition in a few years, and retrofitting the building's antiquated air handlers would have been too expensive. Also, the building's negative air pressure had to be reversed.

The hospital also had budget constraints and a tight deadline because of the impending demolition projects.

Hospital officials looked for solutions from indoor-air-quality equipment manufacturer StrionAir, plus a consortium of Vancouver-based companies that included Stantec Consulting, Olympic International, as well as HVAC contractors K.D. Engineering and Advanced Sheet Metal.

"We identified the need to improve existing filtration to insure air quality was maintained inside the SDCC (surgical day care centre) building independent of outside air conditions," said Con Buzunis, executive director of facility planning at the 950-bed hospital.

Because of the environmental conditions, Stantec's project manager, Desmond Pattrick, determined the conventional 95 percent filter media in the building's three original air handlers would not meet the health care facility outdoor-air requirements of the American Society of Heating, Refrigerating and Air Conditioning Engineers.

Pattrick also advised that HEPA filters were too expensive and ultraviolet germicidal irradiation would only be partially effective in stopping or eliminating the anticipated high mold and other organic particulate counts from entering the building through the outdoor air supply.

Aside from the expense and an inability to kill bacteria, HEPA filtration was ruled out because of the significant airflow resistance it creates. Additionally, upgrading the supply air fans and motors was not cost effective. The resistance increases of up to 300 percent necessitate expensive booster fans and increase operational costs to maintain the specified airflows.

"HEPA filters are very effective in filtering out particulates, however the bacteria can stay alive in the system, producing gaseous toxins that can also cause problems," said Pattrick. "We would also have to create another centralized pre-air handler with 95-percent filters, carbon-charcoal filters, and then the HEPA filters. That's a dramatically expensive solution for a system that is only needed for a few years."

In the search for alternatives, Howard Porritt of manufacturer's representative Olympic International told Stantec about the StrionAir HVAC filtration system. This method employs mechanical filtration to capture particulates from 0.01 to 2 microns in size, and then kills any bacteria passing through the supply air side with a combination of electrostatics and ionization.

Instead of retrofitting all three air handlers with the StrionAir system, Stantec designed one universal galvanized sheet metal plenum to serve the three existing air handlers as well as an added 5,000-cfm makeup-air unit. An 18-unit StrionAir filter bank purifies air drawn through louvers on the two sides of the plenum.