Leaks chlorine

Figure 5.4. Emergency kit for chlorine leak repair. (Courtesy of the Chlorine Institute, Washington, D.C.)...

The most sophisticated system includes the basic system plus two scales, a gas mask, a diffuser corporation cock (to allow connection under water line pressure), a flow-pacing chlorine addition system, a flow meter, a booster pump and piping, and a chlorine leak detector. 

Eirst aid procedures should be developed and all personnel handling chlorine should be familiar with their application. These procedures should be posted in the chlorine area. Eire protection should be provided by class C fire extinguishers (for energized electrical equipment) and located in the area immediately adjacent to the chlorination room. Procedures should be developed to handle chlorine leaks from storage cylinders or application equipment. Periodically operating personnel should review these procedures in a hypothetical emergency situation. 

During a chlorine leak, the emergency response team was not totally familiar with the facility systems. Plant operators had to tell them how to isolate chlorine cylinders and how to reset alamis to determine if they were still detecting chlorine. (ORPS Report RL—PHMC-S W-1999- 0002)... 

Less suction and complete stoppage of suction fans can be very dangerous as any small quantity of chlorine leak can be inhaled by persons in the working area. Provide installed standby suction fans. 

In ease of aceidental release of chlorine gas, sueh as from a leaking cylinder or associated apparatus, evacuate the area and eliminate the source of the leak if this can be done safely. Full-face suppUed-air respiratory protection and protective clothing may be required to deal with a ehlorine release. Cylinders with slow leaks should be carefully removed to a fume hood or remote outdoor locations. Chlorine leaks may he detected by passing a rag dampened with aqueous ammonia over the suspected valve or fitting. White fumes indicate escaping chlorine gas. 

Drivers should park vehicles in safe locations, away from hazards such as falling objects and fire hazards. Should a vehicle be exposed to fire, it should be moved away as quickly as possible. Failing this, it should be cooled by a spray of water to avoid heating to the point of chlorine/steel combustion. Water, on the other hand, should never be used on a chlorine leak, because it will cause rapid corrosion. If a leak develops during transit, the vehicle should be taken to a remote spot and one of the emergency response organizations informed. The driver should on no account leave the vehicle unattended. 

After completion of all the above, the appropriate parts of the system are ready for the introduction of liquid chlorine. Leak tests should be repeated after these sections reach steady temperature. 

Operation under pressure would seriously aggravate the consequences of a chlorine leak in the cell room. Outdoor construction or the use of some of the practices associated with contained storage systems (Section 9.1.8.2C) would help to relieve the hazard. In any event, there would have to be a complete rethinking of many operating practices as well as major revisions in design. 

Chlorine is listed as a toxic and reactive highly hazardous chemical in Title 29 CFR Part 1910 of the U.S. Occupational Safety and Health Standards. The requirements for handling chlorine are well documented. Protective equipment is required to prevent inhalation and contact with eyes, skin, and clothing. Chlorine is often handled in confined areas to prevent accidental releases. These areas require continuous monitoring to detect chlorine leaks, air scrubbers. 

FIGURE 5.4 A CHEMTREC Emergency Services specialist (with an industry response team member) receives training in chlorine leak control. 

The chlorine leak occurred from one of two one-ton capacity chlorine tanks connected with a manifold at a water treatment plant. A room chlorine monitor and alarm signaled employees that a leak occurred at 4 50 a.m. on September 2, 1988. However, chlorine concentrations in the room were too great for employees to enter. The Morristown fire department was notified at 5 07 a.m. the fire department entered the room using self-contained breathing apparatus but was unable to cap the leak. The leak was described as a chlorine liquid jet escaping from the tank. The liquid dropped to the floor and vaporized. The chlorine corroded the electrical components, eventually starting a fire in the transformer room. Power to the plant was cut off at 7 a.m. Chorine hydrate slush began to build up in the area. At noon a team from the chlorine supplier arrived on site and capped the leak. Before the leak was capped, an estimated 2,400 to 3,000 pounds of chlorine had escaped. 

Officials at Pioneer Chlor Alkali Co., Inc. near Henderson, Nevada, investigated an accidental chlorine leak early one morning. The chlorine gas leak was detected by the air monitoring system about 1 10 a.m. and the 10 employees working at the time were evacuated by 2 30 a.m. As a precaution, many residents were evacuated until the chlorine gas dissipated later... 

KAZAN is a quantitative hazard analysis approach that can be used to estimate the probability of occurrence of a hazard given the probability of failure of various control systems and the probability of occurrence of various events that can lead to the hazard. The FMEA and KAZAN approaches are similar. The following example explains the principle behind KAZAN Consider a packed bed, countercurrent absorber used to absorb chlorine gas from an exit stream using alkali solution in a countercurrent manner. Chlorine enters the bottom of the bed and alkali is sprayed from the top. Chlorine could escape from the top exit of this absorber for several reasons a decrease in alkali concentration, insufficient alkali, excess chlorine in the inlet, leakage in the chlorine pipeline, and failure of the absorber column. If the probabilities of these possible failures are known, one could estimate the overall probability of chlorine leak. 

To find a leak, tie a cloth to the end of a stick, soak the cloth with ammonia liquor and hold close to the suspected area. A white cloud of ammonium chloride will indicate a chlorine leak. Never use water on a chlorine leak. The corrosive action will make the leak worse and the heat evolved will cause liquid chlorine to evaporate faster. 

If a chlorine leak occurs, authorized, trained personnel equipped with suitable respiratory protection should investigate. All other persons should be kept away from the affected area until the cause of the leak is discovered and corrected. If the leak is extensive, warn all persons in the path of the fumes. 

Do not spray water on a chlorine leak. To do so makes the leak worse because of the corrosive action of wet chlorine. When a leak occurs in equipment in which chlorine is being used, immediately close the chlorine container valve. 

The severity of a chlorine leak can be lessened by reducing the pressure on the leaking container. This may be done by absorbing and reacting chlorine gas from the container into caustic soda solution. Evaporation of some of the liquid chlorine cools the remaining liquid, reducing its pressure. 

Instruction to report to the proper authority all equipment failures and chlorine leaks. 

As soon as there is any indication of a chlorine release, immediate steps must be taken to correct the condition. Chlorine leaks always get worse if they are not promptly corrected. When a chlorine leak occurs, authorized, trained personnel equipped with respiratory and appropriate other PPE should investigate and take proper action. Personnel should not enter into atmospheres containing concentrations of chlorine in excess of the IDLH concentration (lOppm) without appropriate PPE and back-up personnel. Keep unnecessary personnel away and isolate the hazard area. Persons potentially affected by a chlorine release should be evacuated or sheltered in place as circumstances warrant. 

If fire is present or imminent, chlorine containers and equipment should be moved away from the fire if possible. If a nonleaking container or equipment cannot be moved, it should be kept cool by putting water on it. Water should not be used directly on a chlorine leak. Chlorine and water react forming acids and the leak quickly will get worse. However, where several containers are involved and some are leaking, it may be prudent to use a water spray to help prevent overpressure of the nonleaking containers. 

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