4 ms·

The default seems to be 4 years visual inspection and 10 years periodic pressure-testing in France (I suspect it's general air compressor). https://www.legifran

The default seems to be 4 years visual inspection and 10 years periodic pressure-testing in France (I suspect it's general air compressor). https://www.legifrance.gouv.fr/jorf/id/JORFTEXT000036128632 https://www.legifrance.gouv.fr/jorf/id/JORFTEXT000036128632 I don't have time to read all of that. Skiming, I see the manufacturers have a wide latitude to create their custom maintenance schedule. Interesting detail, the thresholds for inspections are given in uncompressed volume (pression*compressed volume), I guess it's directly proportional to stored energy. I would expect a more relaxed inspection schedule in this instance because there is no significant cyclical loading of the pressure vessel, and since there is no water ingress, internal corrosion should be fine. Vibrations taken as cyclical loading can be swallowed in the bathtub curve, since you get 30000 cycles in the first second, and very little variation of stress at each cycle. edit: - appendix 1 if the vessel has non-corosive gas and not been de-pressurized, internal inspection is not required. Internal visual inspection only if re-pressurizing it and last visual inspection is more than 4 years old. - you seem to be able to replace the water pressure proofing test by an untrasound test under pressure with the nominal gas, but the document describing the procedure ("Guide des bonnes pratiques pour le contrôle par émission acoustique des équipements sous pression") seems to be behind a paywall, so I don't know if it's done at nominal pressure or if you need to open the vessel

bluGill 4y ago
Different pressure vessel materials have different characteristics. Just changing the alloy can make a major difference. Since there are thousands of alloys, and new ones are developed once in a while, it would be inappropriate for the law the create one inspection schedule. Plain steel corrodes, so an inspection that it isn't corroded should be done once in a while. Plain aluminum doesn't corrode, so a visual inspection won't find anything, but the fatigue characteristics means that you need to count cycles and stop using it after some number of cycles. There are many other elements that can be used for pressure vessels (though iron and aluminum are most likely), and you can alloy them in different ways. Of course there is more than visual inspection, sometimes ultrasound and x-ray inspections are done, each will show different things, and each requires different training to do.
jaclaz 4y ago
In Italy, for fire extinguishers, there is a "new" norm (2013) UNI 9994-1:2013 that essentially prescribes for them an overall lifetime (besides the need for periodical inspection/maintenance/recharging/re-certification) of 18 years, i.e. anything manufactured in a given year, 18 years later must be replaced with a new unit. For other pressurized tanks, I believe a line is drawn at 12 kg/cm2 (it depends also on size, those smaller than 25 lt are excluded), those up to that pressure have periodical visual and pressure tests (every 2, 3 or 4 years depending on a number of factors), those above that have additionally those (ultrasound) checks for the integrity every 10 years, but the norms are complex, no idea which specific ones may apply to this thing here.

bluGill 4y ago

Different pressure vessel materials have different characteristics. Just changing the alloy can make a major difference. Since there are thousands of alloys, and new ones are developed once in a while, it would be inappropriate for the law the create one inspection schedule. Plain steel corrodes, so an inspection that it isn't corroded should be done once in a while. Plain aluminum doesn't corrode, so a visual inspection won't find anything, but the fatigue characteristics means that you need to count cycles and stop using it after some number of cycles. There are many other elements that can be used for pressure vessels (though iron and aluminum are most likely), and you can alloy them in different ways. Of course there is more than visual inspection, sometimes ultrasound and x-ray inspections are done, each will show different things, and each requires different training to do.

jaclaz 4y ago

In Italy, for fire extinguishers, there is a "new" norm (2013) UNI 9994-1:2013 that essentially prescribes for them an overall lifetime (besides the need for periodical inspection/maintenance/recharging/re-certification) of 18 years, i.e. anything manufactured in a given year, 18 years later must be replaced with a new unit. For other pressurized tanks, I believe a line is drawn at 12 kg/cm2 (it depends also on size, those smaller than 25 lt are excluded), those up to that pressure have periodical visual and pressure tests (every 2, 3 or 4 years depending on a number of factors), those above that have additionally those (ultrasound) checks for the integrity every 10 years, but the norms are complex, no idea which specific ones may apply to this thing here.