1.1This specification provides design and construction criteria for large diameter flanges sizes 14 NPS to 144 NPS, for use in high temperature (1000 °F), low pressure service (25 psig), such as internal combustion engine exhaust and forced ventilation systems.

1.2The values stated in inch-pound units are to be regarded as standard. No other units of measurement are included in this standard.

1.3This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.