Welding Booth In a Building With a Wood Roof

[ajc2014]

I work at an old manufacturing building with wood purlins and wood decking roof supported by steel trusses, steel columns and brick and block walls. We are interested in putting a permanent welding booth in this area. The area already has proper ventilation drops and a welding curtain. I am recommending to add a corrugated metal roof supported by steel channels hanging from the existing trusses (approximately 5' below the trusses) with additional sprinkler (water) heads new lighting etc.

I have investigated NFPA and OSHA and have not found anything specific to this project. I was designing the sprinkler system based on an Ordinary Hazard - 2 per NFPA.

Is this appropriate for my situation? Are there any code documents I have not taken into consideration?

thanks for any help in advance.

 

[LCREP]

Check out NFPA 51B Hot Work, also see FM data sheet 10-3. FM provides a lot more info. Basically the walls and floors need to be noncombustible and if in the open use noncombustible curtains to prevent the hot slag from leaving the area. The fm data sheets are free to view and download. I agree ordinary hazard sprinkler protection is adequate for the hazard.

From FM below a lot more is in the data sheet.

2.2.2.3 When possible, relocate hot work to a suitably arranged and isolated fixed hot work station. Locate fixed hot work in noncombustible buildings or combustible building areas with secured and sealed 1 hr fire rated noncombustible barriers over combustible floors, walls and ceilings. Maintain the fixed hot work station free of combustible materials and isolate it from surrounding combustible occupancies with physical non-combustible enclosures or open space of at least 35 ft (11 m). Provide manual fire extinguishers throughout the fixed hot work station.

3.1.3 Alternative to the 35 ft (11 m) Rule
An alternative to the 35 ft (11 m) rule is to physically isolate the hot work operation from adjacent combustible occupancies or construction using properly fire rated FM Approved welding curtains and/or FM Approved welding blankets. ‘‘Boxing’’ the hot work operation can be accomplished through vertically suspending welding curtains or welding blankets around the hot work extended at least 15 ft (4.6 m) above the highest elevation of the hot work or to the bottom of a solid/smooth ceiling/roof and extending to floor.
When boxing is used in buildings with structural members that create an open space between the top of the member and the floor or roof above, this space should be sealed to prevent liberation of sparks/spatter/ slag through the open space. The lower elevation of the boxing materials should overlap onto the floor at least 6 in. (152 mm) and this layer should be constructed of a FM Approved welding blanket. The process of boxing the hot work hazard requires a proper understanding of the limitations of the FM Approved welding curtains or FM Approved welding blankets being used.
FM Approved welding curtains should be used only as vertical barriers for hot work operations. Where these curtains are required to extend onto the floor in the hot work area, the bottom 2 ft (0.6 m) of the curtains should be constructed of noncombustible FM Approved welding blanket material. FM Approved welding curtains are typically constructed of translucent plastic materials that are combustible and will fail under extended exposure to severe hot work in positions other than the vertical.
Where severe hot work (torch cutting, arc stick welding) will be conducted and the area beneath this activity needs to be protected against the hot work, FM Approved welding pads should be provided.

https://www.fmglobal.com/fmglobalregistration/Downloads.aspx