Hot Work in Occupied Buildings

Plumbers soldering in an apartment, fitters welding in a hospital mechanical room, and contractors cutting steel in an open store all bring fire risk into buildings full of people. Careful planning protects both the building and everyone in it.

• Plumbers
• Welders & fabricators
• Maintenance
• Facility managers

Plan with the building

• Get a hot work permit from the building owner or facility manager
• Ask whether there’s a safer alternative, like press fittings, mechanical connections or cold cutting
• Schedule work when the area is empty, if possible
• Coordinate smoke detectors and alarms with the facility; cover or bypass only the detectors in the work area, only as long as needed
• Confirm sprinklers are working in the area
• Keep exits and corridors clear

Protect the area

• Move combustibles 35 feet away or cover them with fire-resistant blankets. See Grinding & Cutting Sparks.
• Use heat shields behind solder joints near wood, insulation and drywall.
• Check the other side of walls, floors and ceilings for combustibles.
• Use welding screens to protect occupants from arc flash.
• Keep an extinguisher within reach.

Fumes and smoke

• Welding, brazing and burning-off coatings make fumes and odors that can travel through HVAC systems and cause complaints or health problems.
• Use local exhaust, and work with facility staff to close off or adjust ventilation for the area.
• Be especially careful in hospitals, schools and nursing homes.

After the work

Permit essentials

• Location and type of hot work
• Precautions checked: combustibles, openings, sprinklers, extinguishers, detectors
• Fire watch name and time
• Final check signed off

See Hot Work Permits and Fire System Impairments.

Last updated: October 2, 2026