The goalkeeper was ordered off by referee Craig Charleston after Kilmarnock midfielder Borja Perez was brought down in the penalty area.
Substitute Jason Brown was unable to keep out Liam Kelly's subsequent spot-kick and the Kilmarnock midfielder added a late second for the visitors.
A club spokesman said: "The club can confirm they will be appealing the red card given to Jamie Langfield during the game with Kilmarnock on Saturday."







