Cylinder inspection, requalification a vital public safety measure

March 29, 2021 By    

There are an estimated 60 million portable grill cylinders throughout the U.S. and thousands of reseller facilities with personnel that must be trained to identify unsafe cylinders before filling them. The high rate of turnover increases the risk that many are not trained properly. Many marketers address that challenge by providing and tracking the training themselves, including a contractual obligation that reseller customers inform them of any turnover to avoid training gaps.

Training requirements

At a minimum, all persons dispensing propane into portable cylinders and/or requalifying those cylinders must be trained on:

  • Understanding the regulations, routine inspections and operation of the dispensing equipment.
  • Damage criteria such as physical cylinder integrity; bulges; corrosion; dents; neck, valve or attachment damage; distortions; cuts; gouges or digs. Cylinder sleeves must also be removed so the cylinder can be inspected for unsafe amounts of rust or corrosion. Face seals must also be inspected for signs of damage.
  • Filling containers to their proper levels and preventing them from being overfilled.
  • Maintaining the security of the propane dispenser and transfer area to control ignition sources and prevent tampering or release of propane.

Shutting down and securing the dispenser in the event of an emergency.

Requalifying cylinders

Those who visually requalify cylinders require additional knowledge and hands-on training, and must obtain a requalification inspection number (RIN) from the U.S. Department of Transportation (DOT).

For more comprehensive information, the Propane Education & Research Council’s “Cylinder Requalification” training is an excellent resource and includes the four parameters of inspection and requalification:

1. Prepare: During the first step of the requalification process:

  • Verify cylinder date requirements.
  • Prepare the cylinder for inspection.
  • Gather required inspection forms.

Visual requalification documentation includes:

  • Date of requalification.
  • Cylinder size.
  • Cylinder serial number.
  • DOT specification or special permit number.
  • Marked pressure.
  • Manufacturer’s name or symbol.
  • Owner’s name or symbol if present.
  • Result of the visual inspection.
  • Cylinder disposition, with the reason for any repeated test, rejection or condemnation.
  • Legible identification of the test operator.

2. Inspect: Inspect the entire cylinder thoroughly for signs of any damage criteria mentioned above. If visual inspection reveals signs of corrosion, the cylinder should be emptied and weighed to compare to marked tare weight. Charts are used to determine the allowable limits of damage criteria, such as corrosion or gouges, to guide whether the cylinder should be refilled, rejected or condemned.

3. Leak test: Test the cylinder for leaks by charging the cylinder with propane vapor and using a suitable leak detector solution or device. After a cylinder has passed the visual inspection, the cylinder must be tested for leaks. If the cylinder continues to leak through a threaded appurtenance even after initial adjustments are made, it must be rejected. If the cylinder is leaking from somewhere other than the threaded opening, it must be condemned.

4. Process: Identify the cylinder as OK (return to service), RM (reject) or SC (scrap/condemn), and make sure your documentation is complete. Rejected cylinders must be tested and repaired before they can be refilled.

Document, document, document

Cylinders deemed unsafe may not be filled. This may trigger unhappy customers, so it is important to explain your actions.

You do not have the legal authority to confiscate an unsafe cylinder, and the customer may take it elsewhere. It’s therefore critical that all inspection forms are properly documented, including customer discussions, in the event of an incident involving a cylinder that you rightly refused to fill.


Stuart Flatow spent 18 years as the Propane Education & Research Council’s vice president of safety and training before stepping down in February 2019. 

NOTE: The opinions and viewpoints expressed herein are solely the author’s and should in no way be interpreted as those of LP Gas magazine or any of its staff members.

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