DC 304

Question 1

Hot Work Definition

Answer 1

Hotwork is any operation which involves flame, spark or temperatures in excess of 205°C (400°F) in the presence of flammables or flammable atmospheres. Hotwork can be caused by such things as riveting, grinding, abrasive blasting, drilling, welding and flame cutting, lighted cigarettes, static sparks, electric cooking apparatus, welding heaters and space heaters, non-explosion-proof lights, paint chipping, deck grinding, chiseling, hammering or electric motors.

Question 2

108.2 Discuss precautions that must be observed prior to performing hot-work operations?

Answer 2

• Any hot work operation can start a fire in combustible materials. It is the responsibility of the hot worker and the hot worker’s supervisor to take precautions to prevent fires caused by the exposure of combustibles to the effects of hot work.
• Do not perform hot work when flammable liquids or flammable atmospheres are present without specific instructions from the Gas-Free Engineer. For hot work in proximity to flammable liquids or flammable atmospheres, use NSTM Chapter 74, Gas Free Engineering.
• Remove explosive materials, flammable liquids, or vapors, and take suitable precautions against the re-accumulation of such materials.
• Where practicable, relocate all combustibles at least 35 feet from the work site. Where relocation is impracticable, protect combustibles with metal or guards and curtains constructed of MIL-C-24576 material. Tighten edges of covers at the deck to prevent sparks from going under the covers. This precaution is also important at overlaps where several covers are used to protect a large pile of combustibles.
• When hot work is done near decks, bulkheads, partitions, or overheads of combustible construction, take precautions to prevent ignition.

Question 3

108.3 Discuss the procedures that must be completed before performing hot work in/on the following:

Answer 3

Boundaries;
When hot work is performed on fuel tanks, associated vent spaces or other spaces containing flammables (i.e., paint lockers, flammable liquid storerooms), the adjacent spaces above, below and on all sides (boundary spaces) are first inspected and tested,

Question 4

What do you do Pipes, tubes, and coils prior to hot work starting?

Answer 4

When performing hot work, hollow connections to a space can present the same hazards as the space.
• Pipes, tubes, coils or similar items that service, enter or exit a confined space are flushed, blown, purged or otherwise cleaned and certified Safe for Hot Work before the performance of hot work on such items. If not treated and certified, the certificate for the space is marked Not Safe for Hot Work.
• Valves to pipes, tubes or similar items are closed and the pipes blanked off and tagged out following the provisions of the Ship’s Tagout Bill, to prevent inadvertent discharge or backflow of materials into the space.

Question 5

what about insulation before the start of hot work?

Answer 5

Remove insulation -
Remove insulation from the area of hot work.
Wet down insulation -
Wet down non-removable insulation with water then cover the insulation with water-soaked, fire-retarding cloth.
Station a fire watch -
Station a fire watch with a proper extinguishing agent

Question 6

What do you do for post hot work procedures?

Answer 6

After completing a hot work operation, fire watches remain on station for a minimum of 30 minutes to ensure the area is cool to the touch and that no smoldering embers remain.

Question 7

What about the Gas free certificate?

Answer 7

Prior to conducting hotwork, the Gas Free Engineer (GFE) will need to complete a Gas-Free Certificate. Copies of the certificate will need to be posted at each entrance of the space where the hotwork will be performed.