About this chapter: Chapter 35 covers requirements for safety in welding and other types of hot work by reducing the potential for fire ignitions that usually result in large losses. Several different types of hot work would fall under the requirements found in Chapter 35, including both gas and electric arc methods and any open-torch operations. Many of the activities of this chapter focus on the actions of the occupants.
Hot work shall only be conducted in areas designed or authorized for that purpose by the personnel responsible for a hot work program. Hot work shall not be conducted in the following areas unless approval has been obtained from the fire code official:
- Areas where the sprinkler system is impaired.
- Areas where there exists the potential of an explosive atmosphere, such as locations where flammable gases, liquids or vapors are present.
- Areas with readily ignitable materials, such as storage of large quantities of bulk sulfur, baled paper, cotton, lint, dust or loose combustible materials.
- On board ships at dock or ships under construction or repair.
- At other locations as specified by the fire code official.
Visible hazard identification signs shall be provided where required by Chapter 50. Where the hot work area is open to persons other than the operator of the hot work equipment, conspicuous signs shall be posted to warn others before they enter the hot work area. Such signs shall display the following warning:
HOT WORK IN PROGRESS
A fire watch shall be provided during hot work activities and shall continue for not less than 30 minutes after the conclusion of the work. The fire code official, or the responsible manager under a hot work program, is authorized to extend the fire watch based on the hazards or work being performed.
Exception: Where the hot work area has no fire hazards or combustible exposures.
A pre-hot-work check shall be conducted prior to work to ensure that all equipment is safe and hazards are recognized and protected. A report of the check shall be kept at the work site during the work and available upon request. The pre-hot-work check shall determine all of the following:
- Hot work equipment to be used shall be in satisfactory operating condition and in good repair.
- Hot work site is clear of combustibles or combustibles are protected.
- Exposed construction is of noncombustible materials or, if combustible, then protected.
- Openings are protected.
- Floors are kept clean.
- Exposed combustibles are not located on the opposite side of partitions, walls, ceilings or floors.
- Fire watches, where required, are assigned.
- Approved actions have been taken to prevent accidental activation of suppression and detection equipment in accordance with Sections 3504.1.8 and 3504.1.9.
- Fire extinguishers and fire hoses (where provided) are operable and available.
The storage or use of a single cylinder of oxygen and a single cylinder of fuel gas located on a cart shall be allowed without requiring the cylinders to be separated in accordance with Section 5003.9.8 or 5003.10.3.6 when the cylinders are connected to regulators, ready for service, equipped with apparatus designed for cutting or welding and all of the following:
- Carts shall be kept away from the cutting or welding operation in accordance with Section 3505.5 or fire-resistant shields shall be provided.
- Cylinders shall be secured to the cart to resist movement.
- Carts shall be in accordance with Section 5003.10.3.
- Cylinder valves not having fixed hand wheels shall have keys, handles or nonadjustable wrenches on valve stems while the cylinders are in service.
- Cylinder valve outlet connections shall conform to the requirements of CGA V-1.
- Cylinder valves shall be closed when work is finished.
- Cylinder valves shall be closed before moving the cart.
Signs shall be posted for oxygen manifolds with service pressures not exceeding 200 psig (1379 kPa). Such signs shall include the words:
DO NOT CONNECT HIGH-PRESSURE CYLINDERS
MAXIMUM PRESSURE 250 PSIG
- Use alternative methods to avoid hot work where possible.
- Analyze the hazards prior to performing hot work, identify the potential hazards and the methods of hazard control.
- Hot work shall conform to the requirements of the code or standard to which the container was originally fabricated.
- Test the immediate and surrounding work area with a combustible gas detector and provide for a means of continuing monitoring while conducting the hot work.
- Qualified employees and contractors performing hot work shall use an industry-approved hot work permit system to control the work.
- Personnel shall be properly trained on hot work policies and procedures regarding equipment, safety, hazard controls and job-specific requirements.
- On-site safety supervision shall be present where hot work is in progress to protect the personnel conducting the hot work and provide additional overview of site-specific hazards.