The company started in 1929 as Standard Sanitary Corporation
The company was rebranded American Standard upon merger with American Radiator.
This logo is hard to see as it was usually awkwardly placed on the lower left-hand side of this brand's bathroom fixtures. The one with the block was used until 1984, and was just used with the text in 1985-1988.
1984–2013 (North America). 198?–2016 (Asia Pacific)
In 1984-1988 it was a secondary. This officially replaced it in 1988.
2013–present (North America)
In August 2013, American Standard unveiled a new logo designed by Sterling Brands.
2017–present (Asia Pacific)
A new logo for American Standard in Asia Pacific was used from January 1, 2017.