There are five ways to purchase high-quality fire doors: The first method is to check the appearance. The high-quality steel / fire door shall be firmly welded and the welding points shall be evenly distributed; the external surface shall be painted flat and smooth; the product mark, quality inspection mark and quality certification (APPROVAL) mark shall be provided at the specified position. The qualified wooden fireproof door shall be complete without damage, with clean surface, no planed mark, burr and hammer mark; the corner cutting and joint shall be tight and flat. The second method is to use numbers. The overall dimension of qualified products shall be less than or equal to the overall dimension in the sample description, the door leaf thickness shall be greater than or equal to the door leaf thickness in the sample description, the door frame side wall width shall be greater than or equal to the door frame side wall width in the sample description, the overall dimension of fire-proof glass shall be less than or equal to the overall dimension of fire-proof glass in the sample description, and the fire-proof glass thickness shall be greater than or equal to The thickness of the fireproof glass in the sample description. The third method is to look at the sealing strip. The qualified steel and wood fire doors shall be provided with fire sealing strip, which shall be straight and free of arching, and shall have the qualified test report issued by the national testing agency. The fourth method is to estimate the weight. Generally, the fire doors with qualified quality are heavier, while those with very light quality must be fake products. The fifth call is to check the certificate. The fire door is a product incorporated into the type approval system. The type inspection is required before the product is sold. The general type inspection report describes the specification, size, composition, material and product photos of the sample in detail. When actually purchasing, the type inspection report shall be obtained from the manufacturer.