What is the weight error standard of bulk cement? Is there a national standard in this respect? The error between the weighing figure of our factory and the invoice figure of the manufacturer is 400 kg. Composite Portland Cement (GB 12958- 1999) is a national compulsory cement standard. Article 9. 1 of the standard stipulates that cement can be bagged or bulk, and the net content of cement in each bag is 50kg, which shall not be less than 98% of the marked quality; The total mass of 20 bags randomly selected shall not be less than 1000kg. Other packaging forms are determined by both the supplier and the buyer, but the quality requirements of the packaging bags must conform to the above principles. So unless both parties to the contract agree, each bag is 50 kilograms. Cement packaging bags play an important role in protecting cement quality. Therefore, the state has formulated mandatory standards, which require that the mass per unit area of multi-film plastic woven bags should be ≥ 90g/m2, the thickness of multi-film layers should be ≥ 0.025mm, the mass per unit area of the whole bag should be not less than 1 10g/m2, and the ratio of the breaking force of the substrates should be more than 650M in the horizontal direction. 1996 the relevant state departments issued a document to explicitly eliminate plastic woven cement bags without film covering and inferior cement bags with grade 2 and grade 2. The harm of inferior cement packaging bags mainly includes the following three aspects: First, the quality of cement cannot be guaranteed. According to the test results of the influence of moisture-proof performance of plastic woven cement packaging bags on cement quality, under the same environment, the cement packaged in inferior plastic woven bags and standard paper bags will be stored for 14d, and the cement strength packaged in inferior plastic woven bags will decrease by 40%, which will inevitably bury hidden dangers for the quality of construction projects. However, the quality of cement packed in paper bags has basically not changed. Second, inferior plastic-coated cement packaging bags are hard to bear the pressure, and the breakage rate is often as high as 50%. In the process of filling and transportation, ash leakage is serious, which pollutes the environment. Each bag weighs about 3 ~ 5 kilograms, which leads to inaccurate cement proportioning measurement in the construction site and affects the quality of construction projects. Third, inferior plastic woven cement packaging bags are flooding, causing serious white pollution. Each plastic woven cement packaging bag should use 50g of chemical materials that are difficult to degrade for one or two hundred years. After use, it will be discarded, scattered all over the mountains, rushed into rivers, blocked rivers, and fell into fields, which will destroy soil structure and affect plant growth. Incineration will produce a lot of toxic and harmful gases, which will do great harm to the environment. Relevant departments will rectify cement packaging bags, vigorously promote non-woven extensible cement packaging paper bags, and resolutely investigate and deal with inferior cement bags such as non-standard plastic woven cement bags and second-class cement bags without film covering. Cement storage adopts the standard cement bag of retractable paper recommended by the state. The cement strength is unchanged, there is no leakage during transportation, and it will not pollute the air and the environment. Paper bags can be recycled, which is an international "green packaging" for cement.