37 Tex. Admin. Code § 259.768
Adequate illumination shall be provided throughout the cells and day rooms. An illumination level of 20 foot candles shall be provided at mirrors and tables. Master light controls for cells and day rooms and electrical conduit shall be out of reach of inmates. Inmates should be capable of controlling some lighting; override capability shall be provided. Security detention type lighting shall be provided in inmate housing areas and vandal resistive lighting provided within inmate occupied areas. Night lights sufficient to permit continuous observation shall be provided. Control areas and means of egress shall be continuously illuminated. Exteriors of buildings and all entrances shall be lighted sufficiently to observe approaching persons.
37 Tex. Admin. Code § 259.768