BOS 108: 2013 ed.2

Description

This Botswana Standard specifies requirements for the design and manufacture of polyethylene storage tanks that are rotationally moulded in one-piece seamless construction. The tanks are for non-buried vertical installation and capable of containing water, liquids used in food and beverage manufacture and chemical solutions at atmospheric pressure. 1.1 This Standard does not provide design criteria for a)liquid contents heated above their flash points, b)liquid contents with service temperatures above 40 °C or the rated service temperature of the tankmaterial, c)superimposed pressure exceeding 0.25 m head of water, or 2.5 kPa above the maximum recommendedfill level, and d)superimposed mechanical forces, such as seismic forces, wind load or agitation. Where criteria in items (a) to (d) above apply, special design consideration shall be given. A tank shall have provision for overflow of contents. The tank material supplier shall be consulted where the anticipated service temperature of the liquid stored within the tank exceeds 40 °C. Tank design analysis andindependent verification shall be performed by qualified professional engineer(s) as defined in Clause 4.3. Material data used as a basis for the design may include ‘hydrostatic design stress data’ and/or ‘creep and creep rupture data’.