Local 537 opens its brand-new, state-of-the-art training facility and new headquarters in Dorchester.

Local 537 celebrates its 100th anniversary, promising to remain dedicated to the principles that founded and built this union.

The Refrigeration Fitters of Local 537 apply for and are granted a separate charter by the UA, creating Local 801. 801 operates until January 1958, when UA GP Peter Schoeman issues an order of consolidation to bring the two Unions together.

The UA General Office orders Helpers Local 635 to merge with Steamfitters Local 537, further bringing the Union structure to its present form.

The Boston Building Trades sees the greatest building boom to date with the construction of high-end hotels, theaters, and college dormitories.

Membership of Local 537 asks for a 50 cent per-hour wage increase, and receive a seven month lock-out that only ends when they return to work for a reduction in wages to 90 cents per hour.

AFL orders the UA and International Association to merge, creating the United Association of Plumbers, Gasfitters and Steamfitter Helpers.

The American Federation of Labor issues a charter to the United Association made up of Plumbers, Gasfitters, and Helpers.