Smoke and Toxic gas dispersion analysis study is used to evaluate the quantity of material that is released to atmosphere and to identify the risk and hazards associated with the dispersed material. Dispersion study is carried out for various purpose. One of them is to identify the potential leak that occur in the facility and to take mitigating measures like Gas detector placing etc. Another is to evaluate the Risk of personnel who work near the Gas release places like Vent, PSV. In order to identify the proper location and height of vent that releases smoke or gas to atmosphere.
Significance of Smoke and Toxic Gas Dispersion study
The main objective of Smoke and Toxic gas dispersion study in a process plant.
- To estimate quantity of consignment release from the potential leak source and vents to atmosphere.
- To estimate potential hazards and subsequent effects of fire, explosion, toxicity etc. whichever and wherever is applicable.
- To identify hazards and risks and how they could materialize.
- To recommend suitable height for the open vents
Why Smoke and Toxic gas dispersion study
Release of hazardous materials,
- To evaluate Gas dispersion in the facility
- To identify Flame Geometry
- Evaluation of Thermal Intensity
- Overpressure magnitude identification and assessment
- Smoke or toxic cloud generation and engulfment
- Structural failure / damage
- Equipment damage
- Personnel evacuation
Benefits of Smoke and Toxic gas dispersion study
- Determination of size of the hazard that is associated with the released fluid
- Comparison of the physical effects model with the impact criteria
- Evaluation of the effect distances of the released consignment from vent scenarios and their impact on dispersion
Smoke and Toxic gas dispersion analysis Study report provides the details for the credible events the following information has been identified
- Isotherms for thermal radiation for each type of incident.
- Isopleths for flammable gas concentrations at various LFL for each type of incident.
- Isopleths for blast overpressure events,
- Assessment of BLEVE prone vessels comprising; their time to failure when subject to a jet fire; their time to failure when subject to a pool fire; consequence in terms of stored energy release, radiation of fire ball and explosion
- Maximum range of missiles and penetration capabilities for any component or fragment potentially turned into a projectile by the identified credible explosion events
- DNV GL, PHAST-RISK (Safety)
- United States Environmental Protection Agency (US EPA), 1985. Good Engineering Practice Stack Height. EPA 401 KAR 50:042.
- CPR 18E – Committee for Prevention of Disasters, Netherlands
- TNO Purple Book, Guidelines for Quantitative Risk Assessment, 2005
- Methods for determination of possible damage – CPR 16E [Green Book]