1. Indefinite length (usual length)
Galvanized seamless steel pipes generally vary in length, which is called indefinite length within the scope of the standard. Indefinite length is also called normal length (through ruler). For example, the length of 159*4.5 galvanized seamless steel pipe is usually 8～12.5

2. Fixed length
Cut to a fixed size according to the order requirements is called fixed-length. When delivering according to the fixed-length length, the galvanized seamless steel pipe must have the length specified by the purchaser in the order contract. For example, if the contract states that the delivery is based on a fixed-length length of 6m, the delivered materials must be 6m long. Anything shorter than 6m or longer than 6m is not qualified. But in fact, it is impossible for the delivery to be all 6m long, so it is stipulated that a positive deviation is allowed, but a negative deviation is not allowed. (When the fixed length is less than 6m, the allowable deviation is expanded to +30mm; when the fixed length is greater than 6m, the allowable deviation is expanded to +50mm)

3. Times
The fixed size cut into integral multiples according to the order requirements is called double ruler. When delivering in multiple lengths, the length of the galvanized seamless steel pipe delivered must be an integer multiple of the length (called a single length) specified in the order contract by the purchaser (plus saw cut). For example, the buyer requires a single ruler length of 2m in the order contract, then the length is 4m when cut into a double ruler, and 6m when cut into a triple ruler, plus one or two cuts respectively. .
The amount of saw cut is specified in the standard. When the double ruler is delivered, only positive deviation is allowed, and negative deviation is not allowed.

4. Short ruler
The length is less than the lower limit of the indefinite length specified by the standard, but not less than the allowable shortest length is called short length. For example, the fluid transport steel pipe standard stipulates that 10% (calculated according to the number) of short-length steel pipes with a length of 2-4m are allowed per batch. 4m is the lower limit of indefinite length, and the shortest allowed length is 2m.