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Gas cylinder regs take attention from oxygen generators

Oxygen cylinders grabbed attention after the ValuJet crash. Now hazardous materials packed in gas cylinders are generating plenty of attention at federal agencies.
FILED IN:  Machinery  > Inspection
Gas cylinder regs take attention from oxygen generatorsGas cylinder regs take attention from oxygen generators

Despite the burst of attention paid to oxygen generators because of their alleged role in the ValuJet crash in Florida it is really gas cylinders--totally different and considerably bigger and older than oxygen generators--that are center stage at the Research and Special Projects Administration (RSPA). This is the Dept. of Transportation (DOT) agency charged with assuring the safety of hazardous materials packaging. RSPA published a mildly-controversial narrow final rule on cylinder retesting in May and is about to unveil what doubtless will be a contentious mega-rule meant to "accommodate contemporary manufacturing technology...and make safety enhancements." This imminent rule when it becomes final will have a big impact on the price of new cylinders and the cost of retesting old ones. Safety requirements need to be updated. There are certainly some parallels between unheeded warnings about the Federal Aviation Administration's (FAA) hazmat program--for example a 1992 internal report by FAA's office of civil aviation security--and ignored recommendations on improvements to the RSPA cylinder rules. The National Transportation Safety Board (NTSB) made recommendations on cylinder safety after serious accidents in 1988 and 1993. Both the RSPA and the Compressed Gas Assn. (CGA) failed to implement any of them. Industry has its own cylinder spec change wish list. "We need to harmonize U.S. cylinder specs with international specs" explains David Sonnemann manager of DOT and Fleet Safety at Praxair Inc. one of the largest packagers of industrial gases in the U.S. "Now when we get a cylinder manufactured in Europe at one of our U.S. facilities we have to retest it to make sure it passes the DOT requalification standard. That represents an additional expense. "And if it doesn't pass the DOT test we have to scrap it or return it without refilling with product. That's another cost." The DOT requires cylinders to withstand a test pressure of five-thirds of the service pressure of the cylinder. The European standard is 11/2 times. DOT statistics estimate there are about 100 million cylinders in circulation in the U.S. Praxair alone owns five million cylinders which are refilled on average three or four times a year. The airline industry alone uses cylinders for about 350 tasks including providing emergency air to passengers a role that oxygen generators has begun to usurp. Jim Jones chief of the approvals branch at RSPA says a 747 has 350 different cylinders for various applications including tasks such as deploying the emergency exit chute and the emergency brakes. In all fairness the accident record for cylinders appears to be pretty good. There were 51 incidents between 1991-95 where the RSPA reported "packaging failure" as the cause of a hazardous materials accident. Those resulted in two major injuries 19 minor injuries no deaths and just $82 in damage. These statistics only cover cylinder accidents involving transportation. So an explosion of a propane cooking cylinder would not be included. The RSPA requires hazardous materials to be carried in cylinders that meet any of about 20 specifications. The cylinders have DOT numbers such as 3A 3AA 3HT (for airlines) and 4BA. DOT certifies independent inspection agencies who review the manufacture of every cylinder or batch of cylinders in the U.S. Those agencies in turn license "retesters." Depending on the cylinder and what it holds it must be retested generally every five or 10 years. The retesting rules needed to be cleaned up and ostensibly simplified because they were either misunderstood or ignored by too many retesters. But the proposal the RSPA surfaced on October 18 1995 went beyond simple "regulatory simplification" and suggested some fairly significant changes in the retest and inspection rules. For example the agency had proposed requiring every cylinder owner to have his cylinders restested by a company with a retester identification number (RIN). Some companies such as Tanner Industries Inc. which packs ammonia in large cylinders retests its cylinders itself via visual inspection. Tanner does this every five years instead of sending the cylinders out for hydrostatic retesting every 10 years. Visual retesting is legal as long as it is done by someone who is "competent." Dave Binder a compliance officer at Tanner says it is difficult to find a retest company who has large enough "water jackets" with which to test the large ammonia cylinders. Even if those retesters were conveniently located each retest can cost about $27/cylinder. There is also an additional cost because Tanner has to depressurize the cylinder and pull the valve before sending the cylinder to the retester. On the cylinder's return it has to be flushed and refilled sometimes with a lower value-added gas perhaps for agricultural use. Tanner might have to retest 10 or 20 cylinders a day based on the 100 to 200 they refill daily. In the final rule RSPA revised its proposal "to clarify that a person is not required to obtain a RIN if the person only performs visual inspections on DOT specification or exemption cylinders." Binder says "That's good for industry and it still maintains the safe transportation of hazardous materials cylinders." Replacing relief valves The RSPA also decided to turn down a request from the CGA that the agency require pressure relief valves on cylinders be replaced every 10 years. That would have applied to reclosable valves which are used almost exclusively on cylinders containing propane. Those valves cancost between $10 to $15. The CGA submitted data to RSPA to support its request. The National Propane Gas Assn. (NPGA) described that data as "woefully deficient." The RSPA apparently agreed. In the final rule it affirmed its belief that a number of pressure relief valves deteriorate over time and that most members of the regulated community recognize the need for periodic replacement of these valves. But it decided to eliminate the portion in the proposed rule that included a new reference to CGA Pamphlet S-1.1.1 paragraph which specifies the replacement or requalification of pressure relief valves on certain DOT cylinders every 10 years. It did say it would consider this issue in a future rulemaking which is likely to be the proposed cylinder spec rule that will surface later this year. Rex Greer president of Authorized Testing Inc. a major retester with offices in Phoenix Denver Salt Lake City and elsewhere says the new cylinder retesting rules tighten things up in some areas. "But in other instances the new rule makes things worse." Updating specs Those disputes though were nothing more than appetizers before the main meal: the long-overdue update of cylinder specifications. The RSPA is in the process of working behind the scenes with the CGA to publish a new proposed rule at the end of 1996 that will make significant changes in cylinder specifications for hazardous materials. The CGA's Ron McGrath says his association has already been through five or six drafts of proposed changes in three areas: high-pressure cylinder manufacturing low-pressure cylinder manufacturing and cylinder requalification. RSPA officials have reviewed these drafts and asked for additional information. McGrath says the CGA hopes the RSPA will use the CGA's final draft as the basis for the proposed rule. "We've tried to think of everyone's concerns so no one gets burned" he explains. "But when the proposed rule comes out everybody better look at it carefully." One of the things a final rule may do is group gases into categories so it is easier for cylinder users to select the least expensive cylinder. There will also be a push to approve new testing methods that do not require cylinder owners to clean a cylinder before having it requalified. This will save money. Are fines severe? Though RSPA statistics seem to indicate that cylinder accidents have been few and far between that is not because manufacturers and retesters are looking over their shoulders for RSPA inspectors. RSPA inspectors are on the job. They are just not meting out very big fines. Fines cannot be any greater than $25/instance. Bob Monniere the RSPA general counsel explains that RSPA is required to take into account a company's ability to pay and the effect a penalty will have on that company's ability to stay in business. RSPA enforcement actions during 1992-93 the most recent period available show no penalty over $10 with the overwhelming majority below $5. Companies typically paid fines of between $3 to $5 for using inaccurate hydrostatic retesting equipment. These kinds of testing failures led to the 1988 and 1993 cylinder-leak accidents in Florida and Iowa. The 1993 incident involved a leak of poisonous anhydrous hydrogen chloride gas from 3AA cylinders near Des Moines Iowa. The leak came through the threads between the cylinder neck and pressure relief valve. There was severe corrosion on the interior section of the tapered threads. After its investigation the NTSB recommended that RSPA require the CGA to amend one of its pamphlets to require the use of a thread gauge such as an L9 or equivalent to measure the interior section neck threads. Ron McGrath technical manager for the CGA says that pamphlet has not been changed to reflect the NTSB recommendation. "But we do have a task force working on the thread problem" he adds. c

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