Battery Street Tunnel sprinklers activate unexpectedly

SEATTLE – Department of Transportation crews will ask for help from a consultant to determine exactly what's causing sprinklers in the Battery Street Tunnel to go off unexpectedly.

Rick Rodda, assistant superintendent for bridge maintenance at WSDOT, said there's been five unplanned "events" involving the fire detection system since the beginning of the year. Now they'll turn to an expert in mercury switches to confirm those devices are what's failing and repair an aging system.

"It's surpassed its life expectancy and I think the crews are doing a great job holding it together," Rodda said. "It's spread out. It's not in one area, so something's starting to fail throughout and that's why we want to get a consultant on board that understands these types of switches."

Rodda said the problems have come in three different section, one on either end and another in a middle section of the tunnel.

WSDOT records show the structure was completed in 1954 and the fire detection system, for the most part, is about that age too with the exception of some repairs and upgrades. The Seattle Department of Transportation maintains the tunnel under an agreement with WSDOT. Rodda said, initially, there was going to be a $2 million rehabilitation project for the fire system in the tunnel.

"When it was decided to build a new tunnel, they thought it was best to save those dollars and let's try to maintain it because it's going to be torn down, and they didn't want to put $2 million into something that's going to be torn down in a few years," he said.

The new tunnel has been delayed because of problems with Bertha, the boring machine cutting the path for it.

"With that, we knew that we had failing systems and they put aside about $425,000 to maintain the fire system that was above regular maintenance for the systems that would've been replaced during the full contract," Rodda said.

So far, about $60,000 of that's been used.

The sprinklers went off again this past weekend, causing a backup for more than an hour.

"When it blocks a major arterial like that it causes havoc throughout the rest of the city," Rodda said.

He said despite the troubles with the fire system, the tunnel itself is fine.

"It is safe," he said. "It's a safe tunnel and we have had a couple anomalies in a couple pits, but we're working toward that solution to see what's going on with it."