For more information, call the Baltimore Area Convention and Visitors Association at (410) 659-7300 or (800) 343-3468 outside Maryland.
* July 28-31 Great American Firehouse Exposition & Muster, professional educational and information sessions, exhibits, sales and trade show, parade and collectors flea market, Baltimore Convention Center. Contact: Barbara Schubnel at 244-1075. Expected attendance: 10,000.
* Aug. 3-7 Avalon Hill Game Co., Hunt Valley Inn. Contact Donald Greenwood, 4517 Harford Road, Baltimore, Md. 21214. Expected attendance: 1,000.
* Aug. 5-7 International Association of Exposition Management, regional conference, Hyatt Regency. Contact: Patricia Van Buren, One College Park, 8910 Purdue Road, Indianapolis, Ind. 46268. Expected attendance: 350.
* Aug. 10-15 American Pet Products Manufacturers Association, Hyatt Regency. Contact: Jules Schwimmer, 511 Harwood Building, Scarsdale, N.Y. 10583. Expected attendance: 1,800.
* Aug. 19-21 Baltimore Summer Antiques Fair, Convention Center. Open to the public. Contact: Frank Farbenbloom, Box 1400, Rockville, Md. 20850. Expected attendance: 5,000.
* Sept. 1-5 Baltimore Philatelic Society exposition, Hunt Valley Inn. Contact: Kalman Illyefalvi, 8207 Daren Court, Baltimore, Md. 21208. Expected attendance: 1,000.
For more information, call the Washington, D.C. Convention and Visitors Association at (202) 789-7000.
* July 27-Aug. 4 National Concrete Masonry Association, Omni ++ Shoreham Hotel. Contact: Mildred Fitzgerald (202) 829-6100. Estimated attendance: 600.
* July 30-Aug. 2 National Speakers Association, annual meeting, Washington Hilton. Contact: Karolyn Kirburz (602) 968-2552. Estimated attendance: 1,400.
* Aug. 2-4 International Association of Refrigerated Warehouses, Loew's L'Enfant Plaza. Contact: Mike Shaw (301) 652-5674. Estimated attendance: 250.
* Aug. 3-7 Sir Speedy Inc. annual meeting, Washington Hilton. vTC Contact: Marci Hanover (714) 472-0330. Attendance: 500.