Disposal systems should include equipment to prevent the infiltration of hazardous levels of air. This objective is normally achieved by using a flow of purge gas through the entire disposal system. The required flow rate of purge gas can be significantly decreased by the installation of a purge reduction seal.
The following sections provide a brief summary of purge gas flow requirements and of purge reduction and flare seals. See API Recommended Practice 521 for further discussion of these topics.