ASME PCC-1:2010 pdf free download – Guidelines for Pressure Boundary Bolted Flange Joint Assembly
(a) Examine the gasket contact surfaces of both mat- ing joint flanges for compliance with recommended sur- face finish (see Appendix C) and for damage to surface finish such as scratches, nicks, gouges, and burrs. Indica- tions running radially across the facing are of particular concern. Refer to Appendix D for guidelines covering recommended limits on gasket contactsurface imperfec- tions and their locations.
(1) It is recommended that surface-finish compara- tor gages be available to joint assembly personnel.
(2) Report any questionable imperfections for appropriate disposition. If weld repair of imperfections is deemed to be required, see ASME PCC-2, Article 3.5 for repair considerations. Appendix C provides recom- mended final surface finishes.
(b) When working with problematic or critical service [see Note (1) of Table 3] flanges of large diameter with leak histories or suspect fabrication, it is recommended to check gasket contact surfaces of both joint flanges for flatness, both radially and circumferentially. This may be accomplished in many cases using a machinist’s straight edge and feeler gages, but using a securely mounted run-out gage or field machining equipment capable of providing accurate total indicator readings may be nec- essary when tolerances need to be tight. Appendix D provides flatness tolerance recommendations. If weld repair is deemed to be required to achieve the required flatness, see ASME PCC-2, Article 3.5 for repair considerations. Appendix C provides recommended final surface finishes.
(c) Examine bolt 2 and nut threads and washer faces of nuts for damage such as rust, corrosion, and burrs; replace/correct any damaged components. Likewise bolt/nut combinations for which the nuts will not turn freely by hand past where they will come to rest after tightening should be replaced/corrected; this includes tapped hole threads. (See ASME PCC-2, Article 3.3 that covers repair of damaged tapped hole threads.) If sepa- rate washers are scored or cupped from previous use, replace with new through-hardened washers 3 (surface-hardened washers are not suitable). The condi- tion of previously-used bolts/nuts has a large influence on the performance of a bolted joint assembly. The fol- lowing guidelines relating to the reuse of bolts/nuts are offered for consideration.
(1) When using bolts and nuts of common grade as fasteners, the use of new bolts and nuts up to 1 1 ⁄ 8 in. diameter is recommended when bolt load-control meth- ods such as torque or tension are deemed necessary (see Appendix N). For larger bolt diameters, it is recom- mended that the cost of cleaning, deburring, and recon- ditioning be compared to the replacement cost and considered in the assessment of critical issues of the assembly. When assessing the cost, consider that work- ing with and reconditioning fasteners in the field may be more expensive than the cost of replacement and that the results ofreconditioningcan be unpredictable. When coated bolts are used, the remainingcorrosionprotection and self-lubricating functions are additional considera- tions with respect to continued use or replacement. See Notes (2) and (3) of Table 1M/Table 1, and paras. 7(e) and 7(f).