When populating the board with components, the components themselves also can carry various ionic/conductive contaminants to your assembly including cutting oils/fluids, biocides, and corrosion preventatives. A simple example is table salt (sodium chloride), composed of a single positive sodium cation (Na) which lacks one electron, and a negatively charged chloride anion (Cl), which has an extra electron. These electrostatic forces are composed of positively charged cations and negatively charged anions. Ionic compounds are held together by electrostatic forces - the compound itself has a zero net charge. Ionic contaminants are remains of flux that are left behind during the assembly process. In this article, we will concentrate largely on the ionic contamination sources. There are essentially two broad categories of PCB contamination, ionic and nonionic. I can’t speak to every potential quality control problem that can creep into a PCB assembly process, but contamination continues to be an underlying issue in many PCB reliability problems.
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The design was prototyped and thoroughly tested, and yet, it has problems once in full production. William Andrews, a spokesman for the department, said that until the tests were completed today, it would not be known how seriously the firefighters had been exposed to PCB's, if at all.Whether it's a catastrophic failure or a latent field failure, nothing is more frustrating and expensive than when a circuit board stops functioning. The city's Department of Environmental Protection was called to the station to test the levels of PCB's in the oil and soil under the railroad car that burned. Later, he conceded, the environmental department tests showed the gravel area around the transformer had concentrations of PCB's of 450 parts per million. Spinnato said, ''We contacted Con Ed and were told that this transformer had been drained of PCB oil and was safe.'' Answering the union charges about the fire Sept. Spinnato denied the union charges about the two past fires, saying all procedures were followed and were adequate. Boyle continued.įire Commissioner Joseph E. ''We need a mobile decontamination unit to wash the men and transport them back to their stations for new equipment and uniforms,'' Mr. He said there was only one shower for the nearly 30 firefighters who were exposed, and ''we've got 6 rigs, 30 men and a firehouse tied up for hours and hours because of this.'' Boyle, president of the Uniformed Firefighters Association. ''They followed safety procedures in the Grand Central fire, but the procedures are so inefficient we're going to have to come up with some improvements,'' said James J. They also charged that at another Con Edison transformer fire Monday night in Maspeth, Queens, the procedures were followed but proved to be chaotic and inefficient.Īfter they learned of the Grand Central fire, the union officials said it, too, pointed up the inefficiency of the department's procedures. 24, the department failed to follow its own safety and decontamination procedures and two firefighters were exposed to high levels of the chemical. Union officials charged that during a transformer fire at a Consolidated Edison plant in the Flatbush section of Brooklyn Sept. She said the second fire in the car broke out as it was being towed to the East Yard in the terminal for repairs.Įarlier yesterday morning, before the Grand Central fire broke out, union officials scheduled a news conference on the steps of City Hall to protest the way the Fire Department has been handling fires involving PCB's. She said she did not know why the car was on Track 25, or what its origin or destination was. on Track 25 in the terminal, and had been quickly extinguished by railroad workers. She said the first fire in the car had been at 9:10 A.M. It was the second fire in that rail car yesterday, according to Susan Gilbert, a Metro-North spokesman. in the undercarriage of the railroad car, near the car's transformer, which once contained a PCB-laden oil, fire officials said. Twenty-eight men were examined by department doctors and then sent home at about 6 P.M., fire officials said. The firefighters and the six fire trucks at the scene were quarantined for up to five hours hours yesterday as the department began decontamination procedures - a soapy shower and the confiscation of the firefighters' clothes.Īt the same time, union officials protested the way the Fire Department has been handling fires that involve PCB's, or polychlorinated biphenyls, potent cancer-causing agents formerly used in the insulation of electrical transformers. A fire broke out in the undercarriage of an empty Metro-North Commuter Railroad car in Grand Central Terminal yesterday, and after it was put out more than two dozen firefighters were examined for PCB contamination.
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