53 Pa. Stat. § 13346
All cities of the first class shall allow and permit every member of such fire departments to have at least twenty-four consecutive hours of rest in every calendar week, and shall rotate the members of the fire departments on a regular schedule, except in emergency cases for the suppression of riots or tumults, or in times of war, pestilence, conflagration, or public celebrations, without diminution of the salary or compensation, fixed by ordinances or resolutions of such cities: Provided, however, That no vacation or suspension period of a member of the fire department shall be increased or reduced by reason of the fact that, during such period, such member, if working, would have been entitled to one or more rest days under the provisions of this act.
53 P.S. § 13346