FM Approved Pipe
FM Approved Pipe
FM standard specifies the design and performance specifications for steel pipe used in aboveground fire sprinkler systems planned and installed in accordance with FM Global Property Loss Prevention Data Sheets.
This Approval standard applies only to steel pipe in the NPS (Nominal Pipe Size) sizes 1/2, 3/4, 1, 1-1/4, 1-1/2, 2, 2-1/2, 3, 3-1/2, 4, 5, 6, 8, 10, and 12. NPS 12 pipe, for example, may be referred to as 12 in NPS or 12 in a pipe. Larger diameters of steel pipe may be considered on an individual basis. The use of NPS 1/2 and 3/4 pipe as valve trim, gauge connections, and other peripheral services is authorized. Steel pipe NPS 1 through 12 is approved for use in aboveground fire sprinkler systems. The sprinkler system’s water flow channel cannot be configured with pipe less than NPS 1. When examining metric-sized steel pipe for Approval, test standards corresponding to the equivalent or closest nominal diameter (DN) size must be applied.
Under this Standard, the steel pipe may be Approved for use in either wet or dry pipe sprinkler systems or both, but only for aboveground service.
Purpose of FM Approval
The FM Approval requirements for steel pipe used in aboveground fire sprinkler systems are specified in this standard.
Performance requirements, marking requirements, assessment of manufacturing facilities, audit of quality assurance systems, and a surveillance audit program are examples of FM Approval criteria.
Scope of FM Approved Pipe
FM approved pipe applies to a steel pipe that has been furnace welded, continuous butt-weld, or electric resistance welded. Other production processes, such as spiral welded or seamless pipe, may be assessed under this Standard if the objective of the Standard is satisfied.
This Approval Standard applies to “Specialty Tubulars” used with mechanical press connectors. “Specialty Tubulars,” like Schedule 5 steel pipe, are restricted to branch line service only after a transition fitting from steel pipe. When made in carbon steel, these “Specialty Tubulars” are restricted to diameters NPS 1 through 2, and NPS 1 through 4 when manufactured in stainless steel.
Dimensions and Sizes of FM Approved Sprinkler Pipe
Marking for FM Approved Sprinkler Pipe
Each length of FM sprinkler pipe must be permanently and continuously marked with the minimum information listed below:
- Name of manufacturer
- Nominal pipe sizes and length
- Schedule or model reference
- Working pressure
- Heat number
- FM approval certification mark
- Steel Grade
Markings must be painted, inked, or laser printed at regular intervals on the outside surface of each length of pipe. The distance between the end of one complete marking and the beginning of the next shall not be greater than 12 inches (300 mm).
Requirements of FM Approved Sprinkler Pipe
- Meet the stipulated performance, safety, and quality requirements for property conservation.
- If the steel pipe has a manufacturer-applied internal coating and is intended for use in a hybrid sprinkler system, this standard requires chemical compatibility testing with all FM Approved plastic pipes and fittings.
About FM Approved Pipe
FM-approved pipes refer to the pipes that have been approved for use in sprinkler systems that operate automatically. Unless otherwise specified in specific listings, the pressure rating is 175 psi (1205kPa), and use is limited to wet-pipe systems.
The American Society for Testing and Materials (ASTM) Standards are also taken into consideration when granting FM Approvals, in addition to certain particular FM Approvals criteria. Schedule 40 pipe is manufactured in accordance with ASTM A53 and A135 standards, whereas Schedule 10 pipe is manufactured in accordance with ASTM A135. The pipe that complies with ASTM A795 is also acceptable.
It is usually only possible to connect pipes of the “standard-weight” Schedules 30 or 40 by the use of threading or cut-grooving techniques. Roll-grooving is often used to link schedule 10 pipes together. A pipe with a “light wall” wall is non-threadable and has a dimension that is near to Schedule 5 but has a wall thickness that is not standard. “Thin wall” pipe is threadable and has a dimension that is comparable to Schedule 10 but has a wall thickness that is not industry standard. Steel pipeline products have a broad range of life expectancies, which are determined by factors such as water conditions, pipe material, as well as wall thicknesses. When purchasing pipe items, it is important to take these considerations into account. The approval of any piping product does not imply that it will perform in the field with the same lifetime as any of the pipe schedules or materials listed in this introductory section.
In the absence of a specific listing, every FM Approved pipe is appropriate for connecting by welding or by FM Approved plain-end fittings. During the welding process of pipe goods, strict adherence to established welding processes and the usage of welders who have been qualified under these procedures are required to occur. Pipe with different schedules or with odd junction designs may be FM Approved if it can be shown that it provides equal performance to the standard goods. Individual pipe fittings and couplings may be approved for use with certain schedules of pipe or at specified pressure ratings, depending on the approval process. It is important to exercise care when determining if a particular pipe fitting or coupling is FM Approved for use on a certain schedule of pipe and whether the rated operating pressures are compatible. In all situations, it is necessary to adhere to the installation instructions provided by both the pipe maker and the pipe fitting or coupling manufacturer.