67 Pa. Code § 212.414 – Emergency work.

(a) General. Emergency work may be initiated without prior compliance with the traffic-control provisions specified by this subchapter, provided the foreman or lead worker implements all available safety measures, and the traffic control is brought into compliance with this subchapter as soon as possible. The foreman or lead worker may use flares as attention-getting and warning devices.
(b) Utility work. Emergency repair for utility work may be initiated under this section or repair to a utility facility undertaken under Chapter 459 (relating to occupancy of highways by utilities) to repair damage resulting from a vehicle crash or collision with the facility, a failed component or storm damage. Utility service connections or disconnections unrelated to a vehicle crash, a failed component, or storm damage must otherwise comply with this subchapter.
(c) Expediting emergency work. Emergency work may be completed without installation of work zone traffic-control devices required by this subchapter, if one of the following conditions is met:
1. (1) Review of the condition indicates that the emergency work can be completed in less time than it would take to install the temporary traffic-control devices, and the work or condition would not create a significant potential hazard.
2. (2) Temporary traffic control has been set up and it is found that additional traffic-control devices are desirable, but that it would take longer to obtain and install additional traffic-control devices than it would to complete the work.