200 likes | 219 Views
Learn how to lessen the risk of hazardous release incidents through mitigation and enhance emergency response to reduce impact. Discover preventive measures and containment strategies to manage hazardous materials effectively.
E N D
Release Prevention & Mitigation Release mitigation is defined as “lessening” the risk of a release incident by acting on the source (at the point of release) Preventive Measures: reducing the likelihood of an event which could generate a hazardous vapour cloud; or Protective Measures: reducing the magnitude of the release and/or the exposure of local persons or property.
Release Prevention & Mitigation Hazard Inherent Safety Measures Choice of Technology 1 - Process Design Initiating Event Safety System, Redundancy, Training 2 - Layer of Protection Moderation, Containment, neutralize, water curtain 3 - Containment Release of Material Remote siting evacuation plan 4 - Evacuation Exposure Medical Treatment Consequence 0 – Process Safety Management
2 - Release Prevention through Layer of Protection Shutdown System Relief System Five Hierarchy of Independent Protection Layers (IPL) Safety Interlock System Alarm System Basic Process Control System Process
Release mitigation involves Detecting the release as quickly as possible; Stopping the release as quickly as possible; and Invoking a mitigation procedure to reduce the impact of the release on the surroundings. Reduce the amount of vapour formed/release Once a release is in vapour form, the resulting cloud is nearly impossible to control. Reduce amount of liquid/solid formed/release Prevent dispersion & escalation of releases 3 – Containment
Foam • Foam is used to reduce the rate of evaporation • Foam acts by insulating the surface of the spill and preventing vaporization. • Any foam used must be suitable for the application; the wrong foam can do more harm than good. • Foam should be applied gently, possibly with continuous application or frequent reapplication.
Passive Fire Protection • Passive fire protection can limit fire spread and can ‘buy time’ in which the firefighting resources can be mobilized • One of the principal passive fire protection measures is fireproofing • Coatings • Insulation • Fire wall
Active Fire Protection • Active fire protection measures are also provided but are effective only when activated in response to a fire. • Combustible gas detection & Alarms • Emergency material transfer facilities: relief header leading to vent stack, flare stack, blowdown, drains etc • Firefighting agents: water, foam, dry chemicals, vaporizing liquids, inert gases, and other agents.
Ignition sources for vapor mixes • Electric sparks and arcs (from electrical circuits, motors, switches etc.); • Mechanical sparks (from friction and falling objects); • Static electrical sparks; • Lightning; • Flame (including flaring, boilers, smoking); • Hot surfaces (including hot work, hot processing equipment, electrical • equipment); • Heat of compression; • Chemical reactions (e.g. auto-ignition of oil-soaked lagging on hot piping); and • High energy radiation, microwaves, RF, etc.
Ignition of non-vapor mixes • Diesel Oil Mists - a dispersion of droplets with diameters <10 microns - such as might be produced when a saturated vapor condenses. It is significant because oil mists may be in a physical form that gives the lowest ignition energies. • Crude oil mists and crude oil-water mixtures - a significant number of reservoirs now produce high water cut fluids. Ignition of oil–water mixes are not well understood.
Static Electricity • Sparks resulting from static charge buildup (involving at least one poor conductor) and sudden discharge • Household Example: walking across a rug and grabbing a door knob • Industrial Example: Pumping nonconductive liquid through a pipe then subsequent grounding of the container
GROUNDING BONDING ControllingStatic Electricity
Bunds • A bund around a storage tank is generally designed to contain the contents of the tank. • A bund with a smaller floor area but higher walls presents a smaller surface to heat up and vaporize the liquid. • The higher wall also acts as a barrier to the flow of the vapor. • The provision of a bund facilitates the use in suitable cases of foam, which can effect a further large reduction in evaporation
Flare Ground Flare Elevated Flare