This specification covers flat-bottom, upright, cylindrical tanks molded in one-piece seamless construction by rotational molding. The tanks are molded from polyethylene for above ground, vertical installation and are capable of containing aggressive chemicals at atmospheric pressure. This specification does not cover the design of vessels intended for use at pressures other than atmospheric pressure. Furthermore, this specification does not cover the design of portable tanks and is not for vessels intended for use with liquids heated above their flash points in continuous service. Special design considerations not covered in this specification shall be given to vessels subject to superimposed mechanical forces, such as seismic forces, wind load or agitation; to vessels subject to service above specified temperature; and vessels subject to specified superimposed pressure of water. Low-temperature impact test shall be performed on rotational-molded polyethylene tanks. The test method is used on tanks molded from both the crosslinked and non-crosslinked polyethylenes. Dart drop impact test shall be performed to determine the quality of the tank. O-xylene-insoluble fraction or gel test shall be performed on crosslinked polyethylene. Visual inspection and water test shall also be performed on the samples.

1.1 This specification covers flat-bottom, upright, cylindrical tanks molded in one-piece seamless construction by rotational molding. The tanks are molded from polyethylene for above ground, vertical installation and are capable of containing aggressive chemicals at atmospheric pressure. Included are requirements for materials, properties, design, construction, dimensions, tolerances, workmanship and appearance. Tank capacities are from 1900 L (500 gal) up.

1.2 This specification does not cover the design of vessels intended for use at pressures other than atmospheric pressure. Furthermore, this specification does not cover the design of portable tanks. It is also not for vessels intended for use with liquids heated above their flash points, or temperatures above 66°C (150°F) for Type I tanks and 60°C (140°F) for Type II tanks for continuous service. NFPA Standards 30 and 31 shall be consulted for installations that are subject to the requirements of these standards.

1.3 Special design considerations not covered in this specification shall be given to vessels subject to superimposed mechanical forces, such as seismic forces, wind load or agitation; to vessels subject to service temperature in excess of 23°C (73.4°F); and vessels subject to superimposed pressure exceeding 25.4 cm (10 in.) of water or 2.5 × 10⁻³ MPa (0.36 psi).

1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.5 The following precautionary caveat pertains only to the test methods portion, Section 11, of this specification: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.