This appears to be a Plumbers & Steam Fitters Union Coin. The Building on the Obverse could be their Union Hall that was built or dedicated in 1972. Similar to a Military Challenge Coin. This is perhaps what the Union used at in the 70s to show proof of membership. Personally I believe it is just a dedication medal that was made to commemorate their new building. Googled it and discovered that the Union is based in Metairie, LA. (SE LA) Maybe someone from that area can give you more details