As FlyingDoctorwu suggested, I can confirm that it was the Chesapeake Club which is on your left (and slightly behind you) as you clear international security at the E pier of BWI.

The line for security was very short when I arrived about 2 hours before the flight but the infrared scanner had problems reading my mobile BP. In fact, they had to turn it on especially for me.

I also noted that they had a full body scanner which I've never seen before on my travels.

Full trip report to follow.