Just How Hot Is It in Metro's Underground Stations?

(By Melina Mara -- The Washington Post)
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Sunday, August 16, 2009

Is it hot down there, or is it just you? This summer has not been unusually warm -- not for Washington -- but many Metro riders have been waiting an unusually long time for trains. While simmering about that, they also have extra time to notice the heat in the underground stations. On Monday and Tuesday, I visited 18 stations and took readings with a digital air thermometer. I picked stations on all five lines that would represent a variety of cooling challenges.

Measure by Measure

Turn on your home air conditioner, throw open the doors and windows, and invite all the neighbors in. Every once in a while, drive a car through the living room.

This is something like the challenge Metro faces in cooling the underground stations, where wide-open entrances, hundreds of passengers and frequent train arrivals draw in the heat.

Paul C. Gillum Jr., Metro's director of plant maintenance, says the goal is to have station temperatures at about 85 degrees when the outdoor temperature is 91. By that standard, my spot-check showed Metro is doing well overall. Average temperatures in the 18 stations were in the mid-80s when the outside air was in the mid-90s. But some were much better than others.

Metro Center has drawn the most complaints from riders this summer, but many contend that their stations can beat any other station when it comes to heat. On Monday afternoon, when the outdoor temperature ranged between 94 and 97, I started my survey at Union Station. Summer after summer, this station draws many complaints -- and rightly so. Just beyond the platform, the Red Line tunnel rises to greet the hot, heavy air outside.

Travelers waiting on the platform get a blast of the tropics as incoming trains push the outdoor air inside. This is where I expected the Gridometer to spike, and I wasn't disappointed: 89.6 at 2:33 p.m.

The next big target was Metro Center, where the two chillers broke down in mid-May. It's hard to imagine a worse spot for that: Metro Center is a big transfer station on two levels, with thousands of people walking in from wide-open entrances and trains from three lines generating heat. But stepping off a Red Line train, I encountered a mild breeze and a low hum.

The transit authority had repaired one of the chillers and placed large fans and a few Port-A-Cool air conditioners along the platforms. It was 84.4 degrees on the Red Line platform at 3 p.m. Downstairs on the Blue and Orange Line platform, it was 81.3 degrees at 3:12 p.m.

A reader on the Get There blog urged me to get back to Metro Center during the evening rush and take another reading. I got there at 5:12 p.m. Tuesday and got a reading of 86.5 degrees on the crowded Red Line platform. (It was 84.4 on the Blue-Orange platform at 5:16 p.m.) On Tuesday, Metro had just replaced the second chiller and was getting it back in operation.

The coolest reading over the two days was at Forest Glen, which came in at 79 degrees at 6:23 p.m. Monday. Forest Glen is a portal station, like Union Station, but nowhere near as close to the outdoor tracks. Also, it's the deepest in the rail system, at about 200 feet, and passengers connect with the surface by elevators rather than escalators. The station is newer than most others and has a more modern cooling system, notes Randy Grooman, Metro's superintendent for equipment maintenance.

On Tuesday afternoon, when the outdoor temperature was 90 to 93 degrees -- slightly cooler than Monday -- I focused on the Orange and Blue line stations, once again selecting a variety of station types. At Stadium-Armory, a portal station, I got a reading of 86.4 degrees at 2 p.m., but at Capitol South, deeper into the tunnel, the temperature was 85.6 degrees at 2:10 p.m. Way out west in Ballston, another portal station that is the source of many rider complaints about heat, it was 87.1 degrees at 4:09 p.m.

Simmering above all other stations, though, were these two: McPherson Square at 3 p.m. and Pentagon City at 4:30 p.m. Each produced a reading of 90 degrees. Neither had the chiller challenges of Metro Center, but they are part of an aging system in which lots of parts need to be repaired or replaced.

Beating the Heat

"We check the system every day," Gillum said. "We try to run everything wide-open." But even when all the air-cooling equipment is functioning at maximum capacity, it still is not cool. "It's not designed to be like an office environment," he noted. If something breaks down, like the chillers at Metro Center, Gillum's plant maintenance staff will fix it. Another chiller, at Congress Heights, is out of action now. The parts are on order, and the chiller should be back in service the week of Aug. 16.

The maintenance staff can offer some temporary relief at stations by deploying big fans and portable air conditioners to the underground platforms. But the platforms weren't built to easily accommodate movable, plug-in devices.

The cooling system for any station is a complex network of chiller plants at outdoor locations and chilled water air-conditioning units in stations connected by water pipes and ductwork. That equipment gets old and stressed, operating less effectively at some stations. Pentagon City, for example, has a problem with its ductwork. Over three decades, water had penetrated and is starting to dissolve the metal. Cooling coils in stations can become less effective as they get coated with brake dust from the trains.

Metro has a program to upgrade the old equipment. It is overhauling chillers at 17 plants that feed chilled water to the underground stations. That program began last year and is scheduled to continue through 2011. Meanwhile, the chilled water air-conditioning units in nine stations are being replaced. That program is scheduled to be done early next year. Capitol South, Potomac Avenue and Farragut West are some stations where travelers should be feeling the benefits now.

-- Robert Thomson

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