"Before we exhausted (the smoke), we tried to inspect the natatorium, but the fire marshal couldn't see ahead more than a foot or two even with his flashlight," recalled Allison. "He had to keep a hand on my shoulder while he followed me through the pool area."

Exhaust Fan Clears The Way

With an abundance of individual power outages, tripped breakers, and broken circuits hampering operations, Andiorio manually turned on the exhaust fan feature of the 10,000-sq-ft natatorium's rooftop dehumidifier/air conditioner/heater, a Dry-O-Tron RS-150 by Dectron Internationale (Roswell, GA).

Within 15 minutes, the 5,000 cfm fan, which is sized and operated in conjunction with the outdoor air damper actuator, completely evacuated smoke from the 10,000-sq-ft pool room as well as the ill-fated locker room where the fire caused $225,000 in damages. Besides the pool area, the Dry-O-Tron also pulled smoke from the entire building (once doors and hallways were opened) and saved tens of thousands of dollars in potential smoke damage to the remainder of the recreation center.

In effect, Andiorio's project, which was designed by former Siemens engineer Jason Richards, P.E., passed the ultimate smoke bomb test. Smoke bomb testing is sometimes intentionally administered in sick buildings to visually reveal ventilation problems.

It was Richards and Andiorio that specified the factory-installed exhaust fan in the custom-manufactured Dry-O-Tron, but its intended use was not for smoke clearing during accidental fires. Instead, the two-speed fan operates at full capacity during heavily attended swim meets when the introduction of several hundred bodies, each that emit its own humidity and carbon dioxide, taxes a ventilation system. During nighttime hours however, the fan and outdoor damper are programmed for low-speed operation to conserve energy and save the YMCA money.

Air Quality Design Wins Praise

The 1997 retrofit replaced an aging air conditioning/heating air handler that unsuccessfully attempted indoor air quality and humidity control through a single wall supply. Consequently, years of excess chlorine-laden air wafting throughout the facility had permeated and corroded holes through the 40-year-old natatorium's cinder block walls and concrete decking. Siemens' remedy, which was a design/build performance contract for hvac and lighting, included more than the dehumidifier installation. Instead of just a wall grille supply, Richards' design included 4-ft-round spiral ceiling-hung ductwork. Its circular pattern and many take-offs equally distribute the air and eliminate the many dead air spaces the former hvac suffered.

"The Dry-O-Tron did its job, but the real credit goes to the engineer's indoor air quality design," said Ralph Kittler, vice president of sales, Dectron Internationale. "The circumstance of the fire and smoke was unfortunate, but it did prove the integrity of the indoor swimming pool's ventilation system and the effect its normal everyday operation has on swimmers and spectators. The system introduces the appropriate amount of outside air for homogenous air quality throughout the space, but also has an exhaust fan to dilute chemical gas buildup."

Siemens' retrofit design has been an "amazing improvement," according to Allison, over the previous ventilation system, which was specified before commercial dehumidifiers came on the hvac scene in the early 1970s. ES