This standard is issued under the fixed designation A 688/A 688M; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript epsilon ( ュ) indicates an editorial change since the last revision or reapproval.
1.Scope
1.1 this specification2 covers welded austenitic stainless steel feedwater heater tubes including those bent, if specified, into the from of U-tubes for application in tubular feedwater heaters.
1.2 The tubing sizes covered shall be 5/8 to 1 in. [15.9 to 25.4 mm] inclusive outside diameter, and average or minimum wall thicknesses of 0.028 in. [0.7 mm] and heavier.
1.3 the values stated in inch-pound units are to be regarded as the standard.
