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General Requirements Shipbuilding Ship Repair Shipbreaking Barge Cleaning

Pre-Entry » Testing the Atmosphere
 
All confined spaces and many enclosed spaces require atmospheric testing before entry as well as periodic re-testing, depending on operations and conditions in and around the space.

OSHA specifies testing procedures. [1915.12] Those qualified to conduct these tests include: 		Atmospheric Testing
Figure 1: Take precautions when opening the covers to tanks.
The Shipyard Competent Person (SCP) or a Certified Marine Chemist (CMC) may conduct initial tank entry testing and/or hot work testing. However, if the space contains flammable or combustible liquids or gases, a Marine Chemist must issue a certificate before hot work begins. If the Shipyard Competent Person finds a toxic atmosphere above the OSHA Permissible Exposure Limit (PEL), additional testing by the certified marine chemist or certified industrial hygienist is required, and additional controls must be implemented to prevent excessive exposures. Controls typically include ventilation and personal protective equipment (PPE). [1915.12(c)(3)]


Sequence of Atmospheric Testing
The employer shall ensure that atmospheric testing is performed in the following sequence: [1915.12]
  1. Oxygen-deficient or-enriched atmospheres
  2. Flammable atmospheres
  3. Toxic atmospheres
Test records must be posted near the work being done and be available for inspection for a period of 3 months after work is completed (for OSHA, workers, supervisors, etc.).


Back to Top Back to Top 		Figure 1: Shipyard Competent Person testing a confined space before cold work.
Figure 2: Shipyard Competent Person tests a confined space before cold entry.


Safe Atmospheres
According to OSHA, the following are acceptable atmospheric conditions for entry:
  • Oxygen concentrations between 19.5 percent and 22.0 percent by volume. [1915.12]
  • Flammable gas and vapor concentrations less than 10 percent of the Lower Explosive Limits (LEL). [1915.12]
  • Toxic vapor, gas, and particulate concentrations less than the OSHA Permissible Exposure Limits (8-hour time weighted average PELs). [1915.12]
An employee may not enter a space in which the oxygen content by volume is less than 19.5 percent or more than 22.0 percent except for emergency rescue or for a short duration in order to install necessary ventilation equipment, provided:
  • The oxygen content within the space is monitored continually by volume. [1915.12(a)(3)]
  • Respiratory protection and other appropriate PPE and clothing are provided in accordance with the PPE section of 29 CFR 1915. [1915.12(a)(3)]
An employee may not enter a space in which the concentration of flammable vapors or gases is equal to, or greater than, 10 percent of the LEL, except for emergency rescue or for a short duration in order to install necessary ventilation equipment, provided:
  • No ignition sources are present.
  • The atmosphere in the space is monitored continuously. [1915.12(b)(3)]
  • Atmospheres at or above the upper explosive limit (UEL) are maintained. [1915.12(b)(3)]
  • Respiratory protection and other appropriate PPE and clothing are provided in accordance with the PPE section of 29 CFR 1915. [1915.12(b)(3)]
An employee may not enter a space in which the concentration exceeds a PEL or is IDLH, except for emergency rescue or for a short duration in order to install necessary ventilation equipment, provided:
  • The oxygen content within the space is monitored continually by volume. [1915.12(c)(3)]
  • Respiratory protection and other appropriate PPE and clothing are provided in accordance with the PPE section of 29 CFR 1915. [1915.12(c)(3)]
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Shipyard Competent Person (SCP)
Shipyard employers must designate competent persons who possess the following minimum criteria: [1915.7(c)]
  • Ability to carry out instructions and perform tests as directed by the Certified Marine Chemist.
  • Understanding of appropriate 1915 standards.
  • Knowledge about the structure, location, and spaces in which work is performed.
  • Ability to perform tests, calibrate and use test equipment, interpret test results, and maintain test records.
  • Ability to inspect, test, evaluate spaces, and determine the need for further evaluation by a CIH or CMC.
Figure 1: Shipyard Competent Person testing a confined space prior to cold work.
Figure 3: Shipyard Competent Person tests a confined space before cold work.
A Shipyard Competent Person (SCP) is qualified to perform the following tasks:
  • Visually inspect the following spaces and test to determine the atmosphere's oxygen content before initial entry into the spaces by an employee. [1915.12(a)(1)]
    • Spaces that have been sealed.
    • Spaces containing or that have previously contained combustible or flammable liquids or gases.
    • Spaces containing or that have previously contained liquids, gases, or solids that are toxic, corrosive, or irritating.
    • Spaces that have been fumigated.
    • Spaces that contain or that have previously contained materials or residues of materials that create an oxygen-deficient atmosphere.
  • Visually inspect spaces containing or that have previously contained combustible or flammable liquids or gases before initial entry into the spaces by an employee in order to:
    • Determine the presence of combustible or flammable liquids within these spaces, and
    • Test to determine the concentration of flammable vapors and gases within these spaces prior to entry by an employee. [1915.12(b)(1)]
  • Before initial entry by an employee, visually inspect spaces containing, or that have previously contained liquids, gases or solids that are toxic, corrosive, or irritating to:
    • Determine toxic, corrosive, or irritant residues within these spaces, and
    • Test air concentrations for toxic, corrosive, or irritant materials within these spaces. [1915.12(c)(1)]
  • Test spaces before hot work and ensure that no concentrations of flammable vapors equal to or greater than 10 percent of the LEL exist in the following spaces: [1915.14(b)]
    • Dry cargo holds.
    • Bilges.
    • Engine and boiler room spaces where a CMC or CGAP certificate is not required.
    • Vessels and vessel sections for which a CMC or CGAP certificate is not required.
    • Land side confined and enclosed spaces or other dangerous atmospheres which a CMC or CGAP certificate is not required.
  • Visually inspect and test each space certified as "Safe for Workers" or "Safe for Hot Work" as often as necessary to ensure that atmospheric conditions within the spaces is maintained within the conditions established by the certificate, after the certificate has been issued. [1915.15(c)]
  • Determine the flammability of preservative coatings on any surface before welding, cutting, or heating is performed. [1915.53(b)]
  • Test the atmosphere for explosive vapors in spaces in which the metals are coated with soft and greasy preservatives before and immediately after beginning welding, cutting, or heating. [1915.53(e)(1) and 1915.53(f)].
  • Visually inspect structural voids such as skegs, bilge keels, rudders, fair waters, masts, booms, support stanchions, pipe stanchions, and railings, and test them for the presence of flammable liquids or vapors before welding, cutting, heating or brazing. [1915.54(c)]
  • Calibrate and maintain test equipment. [1915.7(c)]
The Shipyard Competent Person (SCP) must complete the Competent Person Record, which must be posted. This record identifies conditions of spaces designated as "Safe for Hot Work" or "Safe for Workers." Spaces that are designated "Not Safe for Workers" or "Not Safe for Hot Work" or "Enter with Restrictions" must have warning signs and labels posted at the entrance of the space. [1915.16] The shipyard must maintain and make available a roster of shipyard competent persons. [1915.7(b)(2)(i)]


 Figure 2: Testing and visual inspection to maintain Marine Chemist Certificate.
Figure 4: Testing and visual inspection ensure atmospheric conditions within the space are maintained after the certificate is issued.

Figure 3: Rudder.
Figure 5: Rudder being visually inspected for structural voids.

Figure 4: Testing equipment.
Figure 6: Testing equipment.

Figure 5: Sample Competent Person Record of Inspection.
 Figure 7: Sample Competent Person Record.
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Certified Marine Chemist (CMC)
A Certified Marine Chemist is one who possesses a current Marine Chemist Certificate issued by the National Fire Protection Association. [NFPA 306: Control of Gas Hazards on Vessel Sections] The NFPA specifies training and certification requirements.

Tasks performed by the CMC include:
  • Testing for flammable, combustible, and toxic atmospheres before beginning hot work operations in spaces, adjacent spaces, and pipelines, which contain flammable or combustible liquids or gases. [1915.14(a)]
  • Testing to confirm that inerting of spaces containing flammable and combustible materials has been effective. [NFPA 306, Section 3-2.1]
  • Testing of spaces which are immediately dangerous to life and health (IDLH) or cannot be ventilated to comply with OSHA PELs until the space can be certifed "Enter with Restrictions" or "Safe for Workers." [1915.12(c)(3)]
  • Approving the use of inerting medium (such as nitrogen, carbon dioxide, etc.) and personally supervising the introduction of the inerting medium into the space. [NFPA 306, Section 3-2.1]
Marine Chemist certificates shall be posted and accessible nearby during the operations and available for inspection (such as for OSHA, workers, supervisors, etc.) for a period of 3 months after the completion of work. [1915.14(a)(2)]




 Figure 1: Marine Chemist testing confined space prior to entry.
Figure 8: Marine Chemist tests
confined space before entry.

 Figure 2: Marine Chemist certificate posted at entrance to space.
Figure 9: Marine Chemist certificate posted near the work area.
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Certified Industrial Hygienist (CIH)
An Industrial Hygienist (IH) has the appropriate training, education, and experience to recognize, evaluate, and control occupational and environmental health hazards. A Certified Industrial Hygienist (CIH) has met the requirements of the American Board of Industrial Hygiene (ABIH). Tests performed by the CIH include: Back to Top Back to Top Figure 1: Certified Industrial Hygienist (CIH).
Figure 10: CIH performing test in confined space.


Coast Guard Authorized Person (CGAP)
A Coast Guard Authorized Person is one who is authorized by the Coast Guard to conduct inspections for hot work, instead of a CMC. [1915.14(a) and 1915 Subpart B Appendix B]

Note: If a CMC is not available, the Coast Guard Captain of the Port can authorize personnel to perform this work.

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