The installation of which component is prohibited inside an elevator shaft?

The installation of gas piping inside an elevator shaft is prohibited due to safety concerns related to the potential for gas leaks and fire hazards. Elevators are enclosed spaces where flammable gases could build up, increasing the risk of explosion or fire if a leak were to occur. Additionally, the enclosed environment of an elevator shaft limits ventilation, making it difficult for any gas to disperse safely if there were a leak. This regulation is in place to ensure the safety of both the elevator system and the individuals who use it.

In contrast, electrical wiring, water supply lines, and HVAC ducts may be permitted in elevator shafts under certain conditions, as they are typically designed to minimize safety risks when properly installed according to code and best practices.