ISO 11117:2008 has been published, but I don't have access to it without buying it first. The abstract of it that I've seen states that the ISO standard does NOT have all the info needed to certify the valve cap for lifting.
If anyone has access to this ISO standard, perhaps you could find some statement there as to why it's a bad idea to lift a cylinder by the valve protection cap.
I'm also gonna ask our riggers in the shipyard about it- perhaps they have some written evidence to share....
TL =96 I=92m not in the trade, so I haven=92t gotten a copy of ISO 11117 to read (too expensive for me). However I found a link to a copy of ISO
9809-3 relating to the manufacturing of refillable seanless steel gas cylinders. It was probably left on the internet as a mistake, however, here is the link:
Here=92s an excerpt about the =93neck rings=94:
7.7 Neck-rings When a neck-ring is provided, it shall be of material compatible with that of the cylinder and shall be securely attached by a method other than welding, brazing or soldering. The manufacturer shall ensure that the axial load to remove the neck ring is greater than 10 times the weight of the empty cylinder and not less than 1 000 N, and that the torque to turn the neck-ring is greater than 100 Nm.
Appendix 4 has provisions for repairing the neck rings if they fail due to torque.
I think that this ISO prohibits welding, brazing or soldering the neck rings because it would create a HAZ (heat affected zone) on a pressure vessel requiring more testing to qualify the vessel for its intended use.
I found another reference that says that the neck rings are =93press fit=94 or =93peened=94 on. See 22.214.171.124.1 Neck flanges:
Stoody Industrial repairs and re-certifies compressed gas cylinders. Here=92s another link* regarding this topic: (See page 3):
One of their services is a charge for replacing/installing the neck collar:
Here is a letter to the government from American Cap Co. asking if they are required to stamp their products (protective valve caps) showing that they passed government regulations (at the time of manufacturer):
Here=92s a link to the same manufacturer=92s website showing what specifications (including ISO 11117) they meet:
In industry, things used for lifting are usually stamped with the manufacturer=92s name, serial #, load limit, etc, and usually require periodic inspection. To my knowledge, valve protection caps are unstamped and do not require periodic testing. They have no serial number and no system for tracking them so they can be retired when they no longer meet their original design specifications.
Many DOT tests are performed on samples from lots taken at the time of manufacturing. Compressed gas cylinders are required to undergo periodic testing to ensure that the pressure vessel is still safe (i.e. DOT 3AAX every 5 yrs) and the threads are visually inspected. Some companies use thread inspection gauges for this.
Valve protection caps are designed to protect the valve when a cylinder is dropped from the height of about 6 feet in a way that could cause the valve maximal damage and dissipate gas to prevent the cylinder from becoming a missile should the valve break.
Lifting a compressed gas cylinder by its protective gas cap is a silly and dangerous idea. You=92re risking your company or yourself an expensive lawsuit should an accident happen. Generally I admire people who think for themselves and many things that are considered dangerous CAN be done. That doesn=92t mean it=92s worth the risk.
*This Stoody publication was interesting to read. I didn=92t know that the =93MC=94 and =93B=94 series acetylene tanks stood for =93Motorcycle=94 = and =93Bus=94.