Shipyard Employment eTool
Initial Entry Testing >> Warning Signs and Labels
If atmospheric testing indicates a dangerous atmosphere in a space, this information must be posted at the point of entry (for example, "Not Safe for Workers" or "Not Safe for Hot Work"). [29 CFR 1915.11(b)] Some employers, however, require that all spaces are labeled. Warning signs and labels may include a sign, placard, or other form of written communication or pictographs, which can be perceived and understood by all workers. These include:
"Safe for Shipbreaking" requires that the compartment so designated shall meet the criteria of NFPA 306 4.3.4(a) to (4). The residual combustible materials designated shall not be capable of producing fire beyond the extinguishing capabilities of the equipment on hand. [NFPA 306]
Safe for Hot Work" denotes a space that meets all of the following criteria:
The oxygen content of the atmosphere does not exceed 22 percent by volume;
The concentration of flammable vapors in the atmosphere is less than 10 percent of the lower explosive limit;
The residues or materials in the space are not capable of producing a higher concentration than permitted by requirements 1 and 2 above, under existing atmospheric conditions in the presence of hot work, and while maintained as directed by the Marine Chemist or competent person; and
All adjacent spaces are cleaned, inerted, or treated sufficiently to prevent the spread of fire.
"Safe for Workers" denotes a space that meets the following criteria:
The oxygen content of the atmosphere is at least 19.5 percent and below 22 percent by volume;
The concentration of flammable vapors is below 10 percent of the lower explosive limit (LEL);
Any toxic materials in the atmosphere associated with cargo, fuel, tank coatings, or inerting media are within permissible concentrations at the time of the inspection; and
Any residues or materials associated with the work authorized by the Marine Chemist, Certified Industrial Hygienist, or competent person will not produce uncontrolled release of toxic materials under existing atmospheric conditions while maintained as directed.
"Not Safe for Workers" denotes a space an employee must not enter because the conditions do not meet the criteria for "Safe for Workers."
"Not Safe for Hot Work" denotes a space where hot work must not be performed because the conditions do not meet the criteria for "Safe for Hot Work."
"Enter with Restrictions" denotes a space where entry for work is permitted only if engineering controls, personal protective equipment, clothing, and time limitations are as specified by the Marine Chemist, Certified Industrial Hygienist, or shipyard competent person.