CMC - Certified Marine Chemist Confined Space Entry Requirements Questions and Answers 1 — Questions and Answers
Question 1: According to OSHA 29 CFR 1915 Subpart B and NFPA 306, what is the correct order for atmospheric testing in a confined space prior to entry?
- Flammability, oxygen content, then potential toxic contaminants.
- Oxygen content, flammability, then potential toxic contaminants. (Correct answer)
- Potential toxic contaminants, oxygen content, then flammability.
- Oxygen content, potential toxic contaminants, then flammability.
Correct answer: Oxygen content, flammability, then potential toxic contaminants.
The correct and safest procedure is to test for oxygen content first, as many combustible gas meters require sufficient oxygen to function correctly. Flammability is tested next, as it poses an immediate risk of fire or explosion. Finally, potential toxic contaminants are tested for, as their presence could be masked by other hazards.
Question 2: A Marine Chemist is called to certify a fuel oil cargo tank for hot work. The tank has been cleaned and ventilated. What is the maximum permissible Lower Explosive Limit (LEL) reading for the chemist to issue a 'Safe for Hot Work' certificate?
- Less than 10%
- Exactly 0% (Correct answer)
- Less than 5%
- Less than 1%
Correct answer: Exactly 0%
For a space to be certified 'Safe for Hot Work' under NFPA 306, the concentration of flammable vapors must be 0% of the Lower Explosive Limit (LEL). For a space to be 'Safe for Workers', the concentration must be below 10% of the LEL.
Question 3: A shipyard competent person has been monitoring a space certified as 'Safe for Workers' by a Marine Chemist. If a change in conditions occurs, such as the introduction of a cleaning solvent, which of the following actions is required?
- Continue work as long as the original certificate is posted.
- Ventilate the space for 30 minutes and then resume work.
- Stop all work, re-evaluate the space, and potentially void the certificate. (Correct answer)
- Record the new solvent on the existing certificate and proceed.
Correct answer: Stop all work, re-evaluate the space, and potentially void the certificate.
Any change in the conditions of a space under which a Marine Chemist's certificate was issued invalidates that certificate. Work must be stopped, and the space must be re-evaluated to ensure it is safe for the intended operations.
Question 4: Under which of the following scenarios is a Marine Chemist's certificate MANDATORY before hot work can begin?
- Welding on a new steel plate in a fabrication shop.
- Grinding on a handrail on the open main deck.
- Welding on a bulkhead immediately adjacent to a tank that previously contained diesel fuel. (Correct answer)
- Replacing a pipe in the engine room's bilge, which contains only water.
Correct answer: Welding on a bulkhead immediately adjacent to a tank that previously contained diesel fuel.
OSHA regulations (29 CFR 1915.14) and NFPA 306 require a Marine Chemist or a U.S. Coast Guard authorized person to test and certify a space as 'Safe for Hot Work' when the work is performed on surfaces immediately adjacent to spaces that have contained combustible or flammable liquids or gases.
Question 5: A Marine Chemist's certificate for a confined space specifies 'Enter with Restrictions.' Which of the following best describes what this designation implies?
- The space is safe for entry but not for any type of work.
- Entry is prohibited until the space is re-certified as 'Safe for Workers'.
- Entry is permitted only if specific controls like continuous ventilation or PPE are used. (Correct answer)
- Only a certified Marine Chemist is permitted to enter the space.
Correct answer: Entry is permitted only if specific controls like continuous ventilation or PPE are used.
The designation 'Enter with Restrictions' means that entry for work is allowed, but only under specific conditions stipulated by the Marine Chemist. These restrictions could include requirements for continuous mechanical ventilation, specific personal protective equipment (PPE), atmospheric monitoring, or time limitations.
Question 6: Which of the following standards is the primary document a Certified Marine Chemist applies when evaluating gas hazards on vessels?
- OSHA 29 CFR 1910.146 - Permit-required confined spaces
- NFPA 70 - National Electrical Code
- NFPA 306 - Standard for the Control of Gas Hazards on Vessels (Correct answer)
- IMO SOLAS - Safety of Life at Sea Convention
Correct answer: NFPA 306 - Standard for the Control of Gas Hazards on Vessels
NFPA 306 is the foundational standard for Marine Chemists. It provides the detailed requirements for testing, inspecting, and certifying that spaces on marine vessels are safe for entry or hot work by controlling gas hazards.
CMC - Certified Marine Chemist Confined Space Entry Requirements Questions and Answers 1
According to OSHA 29 CFR 1915 Subpart B and NFPA 306, what is the correct order for atmospheric testing in a confined space prior to entry?