scope:

2.1 Cylinders and tubes for which procedures apply
The cleaning recommendations contained in this publication are intended for cylinders of water capacities from 0.5 L to 454 L and tubes up to 3000 L that are fabricated in accordance with specifications promulgated by the U.S. Department of Transportation (DOT) in the United States and the Canadian Transport Commission (CTC) or Transport Canada (TC) in Canada and are authorized for reuse [1, 2].¹

The references made in this publication, in general, apply equally to DOT specifications and regulations in the United States and TC specifications and regulations in Canada [1, 2].

In the United States new cylinders are prefaced by DOT and in Canada new cylinder specifications are prefaced by TC. Older United States cylinders are prefaced by ICC (Interstate Commerce Commission) and older Canadian cylinders are prefaced by CTC. Cylinders marked CTC/DOT or TC/DOT are authorized for service in both the United States and Canada. These procedures also apply to these cylinder specifications.

These recommendations do not apply to cargo tanks, portable tanks, or tank cars. As a result of their unusual sizes and unique designs, these tanks may require special techniques that can best be prescribed by the tank manufacturer.

2.2 Cylinders for which procedures are not applicable

 The cleaning recommendations contained in this publication are not intended for nonrefillable and/or composite cylinders.

2.3 Application of recommended guidelines

This publication provides general guidelines that shall be considered whenever a cylinder is being changed from one gas service to another.

This publication contains guidelines and some references to federal regulations that will be of assistance in determining whether a cylinder is qualified for use in a specific gas service.

It should be noted that these guidelines also apply to the preparation of new cylinders that are being placed into any gas service for the first time.

2.4 Gas property classification

For the purposes of this publication, the gases for which cylinder changes are most frequently desired have been separated into several classes. This separation takes into consideration the chemical and physical reactivity of the gases and of the contaminants that are most frequently encountered.

The recommendations in this publication may not be applicable to gases or mixtures that are not referenced in the classification paragraphs. Recommendations for the cleaning of cylinders that have contained such gases shall be obtained from the manufacturer of the gases.

2.5 Contaminant detection This publication describes the various tests and inspection procedures that are recommended for the detection of possible contamination or the presence of corrosion products.

These procedures are applicable to the change of cylinders from one gas service to another and also as routine prefilling procedures that may be applicable to all cylinders.

2.6 Contaminant removal

This publication contains detailed cleaning procedures that have been found to be satisfactory for the removal of various types of contaminants and corrosion products from the exteriors and interiors of cylinders.

Additional procedures that are developed by individual cylinder owners should be equally satisfactory as those given here for cylinders or should be compatible for use with cylinders of nonferrous construction.

¹ References are shown by bracketed numbers and are listed in order of appearance in the reference section.