(MENAFN- Arab News) The Jeddah Mayoralty carried out a comprehensive and integrated assessment of the quality of concrete in 49 factories, in which 12 failed to pass the evaluation, according to a government official. "The survey found that seven factories had poor equipment, in terms of laboratory equipment and cooling system," the source said. Stating that the 12 factories were removed from the ranking list after their failure to pass the quality tests, the official said, "Samples were not taken from four factories as they did not comply with the regulations of the ministry." Most of the factories in Jeddah fell short of the required number of concrete blenders. "The assessment report also included a classification of the factories in terms of their quality and output," the official explained. The mayoralty conducts evaluations every six months, however the officials urged consumers to exercise caution and requested the opinion of experts to ensure the soundness and safety of the concrete material to avoid complications in construction projects. Outlining the method to conduct an experiment or a test on the quality of concrete, the official said: "The consumer or factory should take three cubic samples, preserve them at the same site for 24 hours, then move it to the factory and try to break the first one on the seventh day, the second after two weeks, then the last after 28 days to examine its quality." According to Saudi standards, the temperature of the concrete when casting should not exceed 35 centigrade and no water should be added during the procedure.