When installing fire-resistant cable trays indoors, the short span of the tray supports and hangers is generally 1.5m to 2m, and the long span can be 3m, 4m, or 6m. When installing fire-resistant cable trays outdoors, the spacing between outdoor columns is generally 6m. The filling rate of cables inside the fire-resistant cable tray cannot exceed the specified value of relevant standards and specifications. The filling rate of power cables is generally 40% to 50%, and the filling rate of control cables is generally 50% to 70%. In addition, a development margin of 10% to 25% needs to be reserved for fire-resistant cable trays.
The bridge standard defines the scope of application of the bridge, including reference standards, definitions, model codes, requirements, test methods, and inspection specifications. The bridge frame standard defines the normative reference documents, structural requirements, markings, transportation, and storage of bridge frames. The cable tray standard specifies the manufacturing, engineering design, and construction of cable trays. When cable tray manufacturers produce cable trays, in addition to complying with this national standard, they should also comply with the provisions of other existing cable tray standards.
Fireproof cable trays crossing different areas on the same floor should be sealed with fireproof sealing. Fireproof sealing should be done at cable shafts crossing different floors, and fireproof sealing should be done at crossing holes and openings.

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