Securing entry doors with an upper transom is not inherently different than any other door or window. Transom windows have the added benefit of being located out of reach and are difficult to access in the first place, in contrast to single or double sidelights. Nevertheless, depending on the size and shape of your transom, you may wish to select additional security measures.

For inoperable transoms, an exterior layer of laminated safety glass will dramatically increase the difficulty of breaking the glass. It consists of two panes with a layer of polyvinyl butyral (PVB) or ethylene-vinyl acetate (EVA) sandwiched between them. 

This is the same type of glass used in automobile windshields that remains intact when impacted and produces a spider web like pattern. For operable transoms with a tilt only function, laminated safety glass is also recommended in addition to concealed hinges and multiple locking points.