49 CFR § 178.940 - Standards for flexible Large Packagings.
(1) 51H flexible plastics.
(2) 51M flexible paper.
(b) Construction requirements for flexible Large Packagings are as follows:
(1) The strength of the material and the construction of the flexible Large Packagings must be appropriate to its capacity and its intended use.
(2) All materials used in the construction of flexible Large Packagings of types 51M must, after complete immersion in water for not less than 24 hours, retain at least 85 percent of the tensile strength as measured originally on the material conditioned to equilibrium at 67 percent relative humidity or less.
(3) Seams must be stitched or formed by heat sealing, gluing or any equivalent method. All stitched seam-ends must be secured.
(5) For plastic flexible Large Packagings, if necessary, protection against ultraviolet radiation must be provided by the addition of pigments or inhibitors such as carbon black. These additives must be compatible with the contents and remain effective throughout the life of the Large Packaging. Where use is made of carbon black, pigments or inhibitors other than those used in the manufacture of the tested design type, retesting may be omitted if the carbon black content, the pigment content or the inhibitor content do not adversely affect the physical properties of the material of construction.
(6) Additives may be included in the composition of the material of the Large Packaging to improve the resistance to aging, provided they do not adversely affect the physical or chemical properties of the material.
(7) When flexible material Large Packagings are filled, the ratio of height to width must be no more than 2:1.
(c) Flexible Large Packagings:
(1) May not have a volumetric capacity greater than 3,000 L (793 gallons);
(2) May not have a volumetric capacity less than 56 L (15 gallons); and
(3) Must be designed and tested to a capacity of not less than 50 kg (110 pounds).