Gas discharges are classified into which two general types of releases?

• A. Acute and Chronic
• B. Flash and Non-Flash
• C. Instantaneous and Continuous
• D. Primary and Secondary

Answer: (C)

Gas discharges are fundamentally about how long the release lasts. The two general types are instantaneous releases, which happen in a rapid, one-time surge of gas, and continuous releases, which persist as a leak over an extended period. This time pattern matters for hazard assessment: an instantaneous release can produce a sharp, short-lived plume that dissipates quickly, while a continuous release maintains exposure and hazard over time, potentially affecting a larger area for longer. Other terms you might see in different contexts—such as acute vs chronic (health effects), flash vs non-flash (ignition or vapor behavior), or primary vs secondary (sources or stages in a release)—don't describe the duration of the release itself.