Domino effects

Knock-on Effects Plants should be designed so that those incidents that do occur do not produce knock-on or domino effects. This can be done, for example, by ... 

Natural rubber is composed of polymerized isoprene units. When rubber is under tension, ozone attacks the carbon-carbon double bond, breaking the bond. The broken bond leaves adjacent C = C bonds under additional stress, eventually breaking and placing shll more stress on surrounding C = C bonds. This "domino" effect can be discerned from the structural formulas in Fig. 9-4. The number of cracks and the depth of the cracks in rubber under tension are related to ambient concentrations of ozone. 

Fires Pyrolysis products Combustion products Vaporization Through domino effects... 

Keep flammable chemicals apart from oxidizing agents Design layout to avoid domino effects/fire spread Segregate empty and full containers... 

Equipment Failures Safety system Ignition Sources Furnaces, Flares, Incinerators, Vehicles, Electrical switches. Static electricity, Hot surfaces. Cigarettes Human Failures Omission, Commission, Fault diagnosis. Decisions Domino Effects Other containment failures. Other material release External Conditions Meteorology, Visibility... 

Ammonium nitrate is made at Fisons Ltd and stored in solution in two heated tanks to prevent ciystalization. One tank holds 3,100 tonnes and the other 6,200 tonnes of 92% aqueous ammonium nitrate solution. Trains laden with oil refinery products from the Mobil and Shell refineries pass the factory on a near embankment. A derailment could spill and ignite hydrocarbons from a rail tank car to explode an ammonium nitrate storage tank. Suggestions were made to mitigate or prevent such a domino effect... 

Reflux drum Mixer or stirrer Breathing apparatus (BA) Slip-plate Refrigeration plant Knock-on (or domino effects) Nonreturn valve Blinded... 

Tlie importance of when to correct/replace a broken bag will depend on tlie type of collector and tlie resultant effect on outlet emissions. In inside bag collection types of collectors, it is very important tliat dust leaks be stopped as quickly as possible to prevent adjacent bags from being abraded by jet streams of dust emitting from tlie broken bag. Tliis is called tlie domino effect of bag failure. Outside bag collection systems do not liave tliis problem, and tlie speed of repair is delennined by wlietlier tlie outlet opacity litis e.xceeded its limits. Often, it will take several broken bags to create an opacity problem mid a convenient maintenance schedule can be employed instead of emergency maintenance. ... 

Besides these special physical properties, hydrogen-bonded liquid water also has unique solvent and solution properties. One feature is high proton (H ) mobility due to the ability of individual hydrogen nuclei to jump from one water molecule to the next. Recalling that at temperatures of about 300 K, the molar concentration in pure water of H3O ions is ca. 10 M, the "extra" proton can come from either of two water molecules. This freedom of to transfer from one to an adjacent "parent" molecule allows relatively high electrical conductivity. A proton added at one point in an aqueous solution causes a domino effect, because the initiating proton has only a short distance to travel to cause one to pop out somewhere else. 

In addition to effects on the concentration of anions, the redox potential can affect the oxidation state and solubility of the metal ion directly. The most important examples of this are the dissolution of iron and manganese under reducing conditions. The oxidized forms of these elements (Fe(III) and Mn(IV)) form very insoluble oxides and hydroxides, while the reduced forms (Fe(II) and Mn(II)) are orders of magnitude more soluble (in the absence of S( — II)). The oxidation or reduction of the metals, which can occur fairly rapidly at oxic-anoxic interfaces, has an important "domino" effect on the distribution of many other metals in the system due to the importance of iron and manganese oxides in adsorption reactions. In an interesting example of this, it has been suggested that arsenate accumulates in the upper, oxidized layers of some sediments by diffusion of As(III), Fe(II), and Mn(II) from the deeper, reduced zones. In the aerobic zone, the cations are oxidized by oxygen, and precipitate. The solids can then oxidize, as As(III) to As(V), which is subsequently immobilized by sorption onto other Fe or Mn oxyhydroxide particles (Takamatsu et al, 1985). 

Domino effects eliminated so that adverse events are self-terminated and do not initiate new events. 

Segregation is practised to allow for housekeeping, construction and maintenance requirements and to reduce the risk of an accident resulting in a domino effect , e.g. from a fire, explosion or toxic release. For very toxic substances, e.g. prussic acid (HCN) or tetraethyl lead, this may involve isolating the entire manufacturing operation in a separate unoccupied building or sealed-off area. 

These mirror those at fixed installations, but loss of containment due to the triggering event can occur anywhere en route. Thus accidents may occur in populated or environmentally sensitive locations, or where domino effects are less easily controlled. Common risks are also associated with all vehicular movements and mechanical/manual loading/unloading activities. 

J Temperature cycling tions Domino effects Missile effects... 

Simpler plants are friendlier than complex plants because they provide fewer opportunities for error and because they contain less equipment that can cause problems. Often, the reason for complexity in a plant is the need to add equipment and automation to control the hazards. Simplification reduces the opportunities for errors and misoperation. For example, (1) piping systems can be designed to minimize leaks or failures, (2) transfer systems can be designed to minimize the potential for leaks, (3) process steps and units can be separated to prevent the domino effect, (4) fail-safe valves can be added, (5) equipment and controls can be placed in a logical order, and (6) the status of the process can be made visible and clear at all times. 

The indexes can be used to identify those units which require the highest priority for attention from a viewpoint of safety review. They are also useful in designing layout and spacing of equipment in process plants to avoid domino effects following an incident [2,3,252-254]. 

Domino effect An incident which starts in one piece of equipment and affects other nearby items, such as vessels containing hazardous materials, by thermal blast or fragment impact. This can lead to escalation of consequences or frequency of occurrence. This is also known as a knock-on effect. 

Preventing domino effects that could have even more severe consequences... 

Domino effects—The triggering of secondary events, such as toxic releases, by a primary event, such as an explosion, such that the result is an increase in consequences or area of an effect zone. Generally only considered when a significant escalation of the original incident results sometimes known as a knock on event. 

This effect should be distinguished from the bodily aspects of addiction. In the reformed alcoholic a single drink can have a purely physiological effect that will, in fact, trigger off an irresistible desire for more. The domino effect is all in the mind. 

Fire, fire spread, fireballs, radiation Explosion, secondary explosion, domino effects Noise, smoke, toxic fumes, exposure effects Collapse, falling objects, fragmentation... 

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