3D
Gas detection and enclosed spacesStart here
Gas detection, enclosed spaces and calibration
Use and calibrate gas meters, and run an enclosed space entry that brings everyone back out.
6 lessons1 h 30 minIntroductory
Topic · free courses
Gas detection and enclosed space entry courses
Why enclosed spaces kill, how to test the air with a portable gas meter, and the permit, testing and rescue steps that make an entry safe.
- 1 course, 6 lessons
- About 1 h 30 min in all
- Free certificate
The course
3D
The 6 lessons
- Why enclosed spaces kill: the numbers behind the rules Open to all
- Portable atmosphere testing instruments under SOLAS XI-1/7
- Bump tests, calibration and calibration certificates
- Fixed gas detection on tankers, gas carriers and in pump-rooms
- Entering an enclosed space step by step: permit, testing and rescue
- Chemical and gas-tight suits: carriage, inspection and leak testing
What you will be able to do
- Explain why oxygen-poor and toxic atmospheres kill so quickly in tanks and holds
- Test the air in an enclosed space at every level before and during an entry
- Bump test and calibrate a gas meter and read its calibration certificate
- Follow an entry permit step by step, with the attendant and the rescue plan in place
- Inspect and leak test chemical and gas-tight suits
Questions people ask
Is a space with an open hatch safe?
No. MSC.581(110) warns that an open door or hatch may wrongly be taken as a sign of safe air, and recommends an attendant or a physical barrier with a warning sign. Holds whose hatches have been open for some time can still hold unsafe air, especially in access trunks.
Why do so many senior officers die?
InterManager’s data shows about two thirds of the dead (where rank was known) were masters, chief engineers, chief officers and second engineers. They are the people who check spaces, sign permits and react first in an emergency, often under time pressure, which MSC.581(110) names as a cause of many accidents.
If oxygen reads 19%, is the space safe?
Not by the IMO recommendation. MSC.581(110) asks for a steady 20.9% oxygen, and anything less, or any trace of flammable or toxic gas, means treating the space as unsafe. With organic cargoes, carbon dioxide can already be dangerous while oxygen still looks acceptable.
Does a single four-gas meter satisfy SOLAS XI-1/7?
Legally one instrument can, since the rule says “instrument or instruments”. In practice you also need a calibrated spare for when it is out of service, and MSC.581(110), the chemical tanker and gas carrier rules and some flags expect two. Some flags require an alternative instrument on board while one is ashore for calibration.
Can the personal detector worn by the entrant be used for the pre-entry test?
Circ.1477 treats them as different jobs. The pre-entry instrument samples remotely through a hose from outside; a personal detector warns its wearer once inside. Some flags accept that the same model may do both roles, but the pre-entry test must still be done from outside, before anyone enters.