1960 | Company name changes from Pentalent Engineering Company to Thermo-Systems Engineering Co.

1961 | The company moves from its first location in the basement of co-founder Mike Fingerson’s house to a storefront on Hennepin Avenue in Minneapolis, Minnesota.

1967 | TSI moves to a 10,000 square foot leased property on Cleveland Avenue in Roseville, Minnesota.

1971 | TSI starts work on a project to design a wind speed velocity sensor—or anemometer—that is sensitive to low winds and winds in a low-density atmosphere. Of the 60 anemometers created for NASA, six went on to Mars, installed on the Viking spacecraft.

1976 | Company officially becomes TSI Incorporated.

1976 | Employee Charlie Johnson’s idea for renaming the street where TSI resides is unanimously approved by the Village of Shoreview. He suggested “Cardigan Road,” to replace Industrial Boulevard. Cardigan Junction was the name of a nearby railroad station dating back to 1888.

1976 | TSI builds a 32,000 square foot building on 7.5 acres in Shoreview, Minnesota. In 1980, TSI adds 52,000 additional square feet. In 1996, another 56,000 square feet are added, for a total of 140,000 square feet and over 13 acres.

1986 | TSI acquires Handar of Sunnydale, California.

1987 | TSI’s single most successful product, the PortaCount Respirator Fit Tester, launches. In 1993, the product is packaged for military use for the U.S. Army and U.S. Marines.

1988 | In 1988, DICKEY-john was purchased by Churchill Industries. DICKEY-john now operates as a division of TSI Incorporated.

1993 | TSI acquires Transducer Research Incorporated.

1993 | TSI Co-Founder, Chairman, and CEO Dr. Leroy Fingerson is elected to membership in the National Academy of Engineering for his work on flow instrumentation—including research, development, design, and manufacturing

1995 | TSI acquires Alnor Instrument Company of Chicago, Illinois. TSI acquires Aerometrics, Inc. of Sunnyvale, California.

1995 | TSI receives its first contracts to develop and produce Aerodynamic Particle Sizer instruments for the U.S. Army and the Canadian Army. These instruments detect the presence of biohazard materials in the air.

1996 | TSI acquires Zimmer GmbH of Rossdorf, Germany.

1997 | TSI acquires Target Systems of Salt Lake City, Utah.

1998 | TSI Board of Directors and co-founder Mike Fingerson endow a faculty Chair in the Mechanical Engineering department at the University of Minnesota. 

1998 | TSI acquires Amherst Process Instruments, Inc. of Amherst, Massachusetts.

1999 | TSI acquires assets of MESACON GmbH of Dortmund, Germany.

1999 | TSI acquires the stock, assets and operations of Environmental Systems Corporation. ESC, located in Knoxville, Tennessee.

2005 | TSI acquires instrument-production lines owned by Airflow Developments Ltd., of High Wycombe, England. TSI acquired the Test Instruments portion of ADL's business, including manufacturing, assembly, and sales and service operations.

2008 | TSI opens TSI Instruments India Private Limited in Bangalore, India.

2008 | TSI acquires Adams Instruments, certain assets of Mesacon GmbH, Facility Monitoring Systems, Ltd. of Malvern, England, and SystemPlus Technology Pte Ltd. of Singapore. 

2009 | TSI acquires certain assets of Particle Metrics Incorporated from Research Electro-Optics, Inc. of Boulder, Colorado.

2010 | TSI acquires Quant Technologies, LLC of Minneapolis, Minnesota

2012 | TSI acquires the laser induced breakdown spectroscopy (LIBS) technology and product line from Photon Machines Corporation of Redmond, Washington.

2014 | TSI acquires the business assets and Raman spectroscopy technology of Enwave Optronics, Inc. of Irvine, California.

2016 | TSI acquires MSP Corporation of Shoreview, Minnesota. 

2018 | TSI endows the Benjamin Y.H. Liu - TSI Applied Technology Chair in Mechanical Engineering, recognizing University alumnus Dr. Benjamin Liu. Read about the Liu-TSI endowed chair.

2018 | TSI's Future Industrial Hygiene and Safety Leaders Program launches in partnership with the American Industrial Hygiene Association (AIHA) and the American Industrial Hygiene Foundation (AIHF). Read about the Future Industrial Hygiene and Safety Leaders Program.

2018 | TSI acquires Quest Personal Safety Division products, including Dosimeters, EVM Environmental Monitors, Heat Stress Monitors, and Sound Level Meters from 3M. Read more about this acquisition.