6.3.4 Where 300 series stainless steels are specified, integrally clad or weld overlaid construction shall be specified for pressure retaining components due to the risk of internal chloride stress corrosion cracking, either during operation or shutdown conditions. Exceptions to this are: • Cryogenic applications • Pressure vessels and heat exchangers where the maximum metal temperature does not exceed 140°F (60°C) (taking account of solar radiation, heat tracing or steam-out operations) • Pressure vessels and heat exchangers where the maximum design temperature precludes the use of integrally clad or weld overlay construction • Heat exchanger, steam generating boiler and fired heater tubes • Storage vessels for water, air, inert gases, chemicals and catalyst • Castings for rotating machinery casings • Seal reservoirs and lube oil systems associated with rotating machinery • Pipework components