Flexible Metal Hose Assemblies Technical Specification and Catalog
- PURPOSE
1.1 This technical specification defines the minimum requirements for design, materials, and manufacture of flexible metal hose assemblies (hereinafter referred to as assembly or assemblies). It shall be used in conjunction with a data sheet, supplied by Company, which provides the required design and service information for all applications except those covered by paragraph 1.2.
1.2 This specification, in Section 9 and Table 1, also tabulates a set of standard assemblies that may be used in a design without the need to provide a separate data sheet. Applications that do not conform to the design and service limitations in Section 9 are not standard and require a separate data sheet as in paragraph 1.1.
- SCOPE
2.1 This specification applies to assemblies used to provide flexibility in piping systems and may be used in association with gases and liquids at cryogenic, ambient, and elevated temperatures.
2.2 This specification shall be read in conjunction with GENERAL PIPING MATERIAL TECHNICAL PURCHASE SPECIFICATION.
2.3 The supplier shall engineer, fabricate, test, and ship assemblies according to the requirements in this specification, the data sheet, purchase requisition, and the Vendor Data Requirements document provided.
2.4 This specification does not apply to flexible metal hose that is used for trailer loading/unloading applications for which a hose is used to transfer fluid between storage and a conveyance (for example, trailer, cylinder, dewar).
- RELATED DOCUMENTS
3.1 Company Engineering Documents
Painting and Corrosion Protection of New Construction for Design Temperatures to 649°C (1200°F)
Shipment and Packing Specification for Equipment and Materials being Exported Directly by Vendors
GENERAL PIPING MATERIAL TECHNICAL PURCHASE SPECIFICATION.
Process Clean (Class B) Inspection and Acceptance Requirements
Oxygen Clean (Class AA) Inspection and Acceptance Requirements
3.2 American Society for Testing and Materials (ASTM)
A 183 Standard Specification for Carbon Steel Track Bolts and Nuts
A 312/A 312M Standard Specification for Seamless, Welded, and Heavily Cold Worked Austenitic Stainless Steel Pipes
3.3 American Society of Mechanical Engineers (ASME)
B16.5 Pipe Flanges and Flanged Fittings NPS 1/2 through NPS 24
B31.3 Process Piping
3.4 British Standards Institute (BSI)
BS 6501-1 Flexible metallic hose assemblies: Part 1, Specification for corrugated hose assemblies
- DESIGN, MATERIALS, AND MANUFACTURE
4.1 Except when a separate formal agreement already exists between Company and the supplier or when a standard flexible metal hose is being provided from Section 9 of this specification, a data sheet that details the specific design requirements for each assembly will be issued by Company.
4.1.1 Requirements specified on the data sheet take precedence over the requirements in this specification when there is a discrepancy.
4.2 Unless stated otherwise on the data sheet, assemblies shall be according to ASME B31.3 and BS 6501-1.
4.3 Materials of construction shall be suitable for the fluid service at the design temperature specified on the data sheet, taking into consideration the fluid service listed on the data sheet.
4.3.1 Unless otherwise specified on the datasheet, the bellows hose material shall be stainless steel Grade 316L, Grade 321, or better, for increased corrosion resistance. Grade 304 shall not be used.
4.3.2 If the data sheet specifies that the metal hose assembly will be exposed to environmental corrosive conditions, the bellows hose material shall be of a suitable alloy that will prevent or resist pitting or stress corrosion cracking.
4.4 Bellows convolutions shall be annular and fabricated from a longitudinally butt-welded or seamless tube.
4.5 Assemblies shall be fitted with a stainless steel braided wire covering around the metal bellows for purpose of pressure containment and stability of the hose.
4.5.1 Braiding shall be fabricated from materials that will be compatible with the service temperature, pressure, and operating environment. Unless otherwise stated on the data sheet, service temperature shall be equal to the design temperature of the assembly.
4.6 The bursting pressure of the assembly shall not be less than four times that of the design pressure.
4.7 Unless otherwise stated on the data sheet or purchase order, the assembly shall be suitable for service life of a minimum of 1000 thermal displacement and/or pressure cycles.
4.8 When flanged-end fittings are specified, they shall be supplied in accordance to ASME B16.5 or as specified on the data sheet.
4.8.1 Unless otherwise stated on the data sheet, the surface finish on gasket seating surfaces shall be 3.2 to 6.3 μm (125 to 250 μ in) average roughness.
4.8.2 Flange bolt holes shall straddle centerlines.
4.8.3 Strainer support holes: When specified on the data sheet, four additional holes of 6.35 mm (1/4 in) diameter shall be drilled through the downstream outlet flange. The holes shall be located on the flange bolt circle diameter, directly on the vertical and horizontal centerlines.
4.8.4 Slip-on flanges or plate flanges shall be double-welded (that is, welded to the pipe on both sides of the flange) unless the bellows is attached directly to the flange.
4.9 The supplier shall advise Company when liners or internal sleeves are required. Liners shall be designed to accommodate the following conditions when specified on the data sheet.
4.9.1 Unless the supplier can justify otherwise, the requirements for a liner shall be based on the design flow velocity multiplied by four when turbulence is present. Thickness of the liner shall be sufficient to prevent fatigue failure due to vibration from exposure to turbulent flow. Turbulence in the flow stream can be due to compressor nozzles or piping fittings such as elbows or tees within four pipe diameters upstream of the assembly.
4.9.2 The possibility of flow reversal due to compressor surge events is specified on the data sheet. When reverse flow is indicated, thickness of the liner shall be sufficient to prevent liner failure due to exposure to reverse flow. Unless otherwise justified by the supplier, the flow velocity of the reversed flow shall be two times the design flow velocity. If the flexible metal hose is within four pipe diameters “upstream” (during normal flow) of a fitting such as an elbow or tee or the suction nozzle of a compressor, the reverse-flow velocity shall be the design-flow velocity multiplied by eight.
4.9.3 Strainer clearance might be specified on the data sheet. When strainer clearance is indicated, the internal diameter of the downstream end of the liner on the outlet end of the assembly shall be no smaller than is shown on the data sheet for a distance of 40 mm (1 5/8 in) from the outlet flange end.
4.9.4 In oxygen or oxygen-enriched service (fluid with oxygen content greater than 25%), a liner fabricated of interlocked tubing is not permitted. Assurance of oxygen cleanliness is required, and friction in the interlocked parts is a potential ignition source.
4.10 Dimensional tolerances shall be as follows:
- Overall length ± 3 mm.
- For butt-welded end connections, out-of-roundness shall not exceed a 1% difference between the largest measured outside diameter and the smallest measured outside diameter after fabrication.
4.11 Finish
4.11.1 Unless specifically stated in the data sheet, all supplied or fabricated carbon steel parts shall be prime-painted in accordance with Company specification 4WEQ-6804 Rev. 3 as follows:
- Design Temperature less than or equal to 93°C (200°F): Apply only a prime coat using a zinc-rich primer (see Painting and Corrosion Protection of New Construction for Design Temperatures to 649°C (1200°F) Table 2, System 2 for material selection options).
- Design Temperature greater than 93°C (200°F): Paint in accordance with Painting and Corrosion Protection of New Construction for Design Temperatures to 649°C (1200°F), Paragraph 6.5.
4.11.2 Bellows and braiding shall be unpainted.
- IDENTIFICATION
5.1 Each assembly shall be supplied with a noncorrodible metallic tag that shall be permanently attached to the unit (wiring is unacceptable) and shall include the following:
5.1.1 The “Tag Information” specified on the data sheet.
5.1.2 • Supplier name
- Purchase order number
- Design temperature and design pressure
- As-built manufactured length (overall length in millimeters)
- Flow direction arrow, properly oriented (Note: In cases where the inlet and outlet of the flexible hose are identical and the unit can be installed in either direction without consideration of fluid flow direction, the flow arrow direction shall be arbitrarily selected, or the arrow shall point in both directions.)
- INSPECTION AND TESTING
6.1 Company will indicate on the purchase order or requisition whether on-site inspection is required by an Company representative. Documentation of testing and inspections shall be maintained by the supplier and be available to Company as required (see General Piping Material Technical Purchase Specification).
6.2 Proof test: All flexible metal hose assemblies shall be proof-tested in accordance with ASME B31.3 Appendix X, paragraph X302.2.3, but not less than 1.5 times design pressure as stated on the data sheet. The test may be hydraulic or pneumatic at the discretion of the fabricator, taking into consideration the safety of nearby personnel and facilities. The hose braiding shall carry the full proof test load.
6.3 Leak test: All flexible metal hoses shall be tested according to either of the following:
- Pneumatically tested for leaks at 1.1 times design pressure as stated on the data sheet by using air or nitrogen.
- Helium leak-tested at the design pressure [but not higher than 6 bar g (87 psig)] with a maximum detected leak rate not to exceed 10-5 atm.cm3.s-1.
6.4 All pressure-containing and load-bearing welds shall be 100% nondestructive tested (NDT). Longitudinal-seam welds shall be tested before forming the bellows corrugations.
6.5 Liners or sleeves shall not be fitted until after inspection for cleanliness by the Company inspector.
6.6 All pressure tests shall take place at the supplier’s works in the presence of an Company inspector.
- CLEANING AND PACKING
7.1 All assemblies shall be cleaned in compliance with the Company cleanliness specification stated on the data sheet or as required by Section 9. After cleaning, the open ends shall be plugged to prevent contamination.
7.2 Hoses shall be labeled “Cleaned for XXXXX,” for which XXXXX is the service as stated in the cleanliness specification (for example, joints cleaned to specification 4WPI-SW70003 shall be labeled: “Cleaned for Oxygen Service”). The appropriate cleanliness specification will be selected by Company from those listed in paragraph 3.1.
Note: This label is separate from the tag information required by Section 5, but shall be durable enough to withstand shipping and handling during installation.
7.3 Assemblies shall be protected from damage and corrosion during shipping by appropriate packaging or crating according to 4WGN-10001.
- DOCUMENTATION
8.1 At the time of quotation, the supplier shall submit the following information:
- Confirmed overall length of the assembly
- Proposed materials of construction
- Whether or not liners or sleeves are required
8.2 The supplier shall provide a general arrangement drawing that shows all of the following:
- Overall dimensions
- End preparation
- Bill of material that specifies materials of manufacture
- Weld details
- NDT requirements
- Tolerances
8.3 Additional drawing or data requirements, if any, will be stated on the Vendor Data Requirements document, attached to the purchase order.
8.4 The supplier shall be prepared to provide to Company, at no additional cost, weld qualification procedures for all welds and material certifications according to ASME B31.3 unless otherwise specified on the inquiry documents.
- STANDARD FLEXIBLE METAL HOSE ASSEMBLIES
9.1 Table 1 defines design requirements and Company model numbers for Standard Flexible Metal Hose Assemblies.
9.1.1 Section 9 constitutes the “data sheet” for Standard Flexible Metal Hose assemblies detailed in Table 1. Sections 1 through 8 apply to the design and fabrication of these assemblies.
9.1.2 When using a standard flexible metal hose, no modification of service conditions or physical parameters specified herein is allowed.
9.2 Tag Information: “Flexible Metal Hose Assemblies Technical Specification and Catalogue” Company code number (from Table 1)
Supplier’s name
Supplier’s model number
Purchase order or contract number
As-Fabricated length
“FLOW ORIENTATION: BI-DIRECTIONAL” Design pressure
Design temperature
9.3 Process and Design Information
9.3.1 Fluid Conveyed: Air, oxygen, nitrogen, argon, or other inert atmospheric elements in gaseous or liquid form.
9.3.2 Flow Velocity: Liquid velocity 5 m/s (16.4 ft/s) or less. Gas velocity 60 m/s (196 ft/sec) or less (see BS 6501-1, Appendix A). The Company specifier shall have evaluated effects of turbulence and surge according to paragraphs 4.9.1 and 4.9.2.
9.3.3 Design Temperature: Minimum design temperature shall be -196°C (-320°F). Maximum design temperature shall be +65°C (+150°F).
9.3.4 Test Pressure: 1.5 times the Design Pressure defined in Table 1.
9.3.5 Materials:
- Pipe: ASTM A312 TP304 (or equivalent approved in writing by Company before start of fabrication)
- Flanges: ASTM A183 Grade F304 (or equivalent approved in writing by Company before start of fabrication)
9.3.6 Installation Offset: Straight or parallel offset. Offset plus design movement shall not exceed Maximum Lateral Movement defined in Table 1.
9.3.7 Cleanliness Specification: Oxygen Clean (Class AA) Inspection and Acceptance Requirements.
Table 1
Code Number and Mechanical Requirements for Standard Flexible Metal Hose Assemblies
| Company Code Number | Nominal Size DN (NPS) mm (in) | End Connections (both ends) | Face-to-Face Dimension mm (in) | Maximum Lateral Movement mm (in) | Design Pressure bar g (psig) |
| FLEX40A | 40 (1.5) | BW Sch 10 | 350 (13.78) | +/- 29 (1.1) | 36.5 (530) |
| FLEX40B | 40 (1.5) | BW Sch 40 | 350 (13.78) | +/- 29 (1.1) | 36.5 (530) |
| FLEX40C | 40 (1.5) | ** RFSO 300# | 400 (15.75) | +/- 36 (1.4) | 36.5 (530) |
| FLEX40D | 40 (1.5) | ** RFSO 150# | 400 (15.75) | +/- 36 (1.4) | 17.5 (255) |
| FLEX50A | 50 (2) | BW Sch 10 | 360 (14.17) | +/- 18 (0.7) | 36.5 (530) |
| FLEX50B | 50 (2) | BW Sch 40 | 360 (14.17) | +/- 18 (0.7) | 36.5 (530) |
| FLEX50C | 50 (2) | ** RFSO 300# | 410 (16.14) | +/- 23 (0.9) | 36.5 (530) |
| FLEX50D | 50 (2) | ** RFSO 150# | 410 (16.14) | +/- 23 (0.9) | 17.5 (255) |
| FLEX650A | 65 (2.5) | BW Sch 10 | 410 (16.14) | +/- 24 (0.95) | 27 (395) |
| FLEX65B | 65 (2.5) | BW Sch 40 | 410 (16.14) | +/- 24 (0.95) | 27 (395) |
| FLEX65C | 65 (2.5) | ** RFSO 300# | 480 (18.9) | +/- 24 (1.3) | 27 (395) |
| FLEX65D | 65 (2.5) | ** RFSO 150# | 480 (18.9) | +/- 24 (1.3) | 17.5 (255) |
| FLEX80A | 80 (3) | BW Sch 10 | 510 (20.08) | +/- 43 (1.7) | 26.5 (385) |
| FLEX80B | 80 (3) | BW Sch 40 | 510 (20.08) | +/- 43 (1.7) | 26.5 (385) |
| FLEX80C | 80 (3) | ** RFSO 300# | 580 (22.83) | +/- 55 (2.2) | 26.5 (385) |
| FLEX80D | 80 (3) | ** RFSO 150# | 580 (22.83) | +/- 55 (2.2) | 17.5 (255) |
| FLEX100A | 100 (4) | BW Sch 10 | 580 (22.83) | +/- 50 (2.0) | 18.5 (270) |
| FLEX100B | 100 (4) | BW Sch 40 | 580 (22.83) | +/- 50 (2.0) | 18.5 (270) |
| FLEX100C | 100 (4) | ** RFSO 300# | 650 (25.59) | +/- 55 (2.2) | 18.5 (270) |
| FLEX100D | 100 (4) | ** RFSO 150# | 650 (25.59) | +/- 55 (2.2) | 17.5 (255) |
| FLEX125A | 125 (5) | BW Sch 10 | 700 (27.56) | +/- 61 (2.4) | 15.5 (225) |
| FLEX125B | 125 (5) | BW Sch 40 | 700 (27.56) | +/- 61 (2.4) | 15.5 (225) |
| FLEX125C | 125 (5) | ** RFSO 300# | 750 (29.53) | +/- 61 (2.4) | 15.5 (225) |
| FLEX125D | 125 (5) | ** RFSO 150# | 750 (29.53) | +/- 61 (2.4) | 15.5 (225) |
| FLEX150A | 150 (6) | BW Sch 10 | 810 (31.89) | +/- 74 (2.9) | 12 (170) |
| FLEX150B | 150 (6) | BW Sch 40 | 810 (31.89) | +/- 74 (2.9) | 12 (170) |
| FLEX150C | 150 (6) | ** RFSO 300# | 850 (33.46) | +/- 72 (2.8) | 12 (170) |
| FLEX150D | 150 (6) | ** RFSO 150# | 850 (33.46) | +/- 72 (2.8) | 12 (170) |
BW = butt-welded prepared end
RFSO = Raised Face Slip on flange
Shaded areas – pressure is limited by the flange.
** Note to the user: Not for use with spiral-wound gaskets without approval of the Company piping engineer.
Table 1 – Code Number and Mechanical Requirements for Standard Flexible Metal Hose Assemblies
| Company Code Number | Nominal Size DN (NPS) mm (in) | End Connections (both ends) | Face-to-Face Dimension mm (in) | Maximum Lateral Movement mm (in) |
Design Pressure bar g (psig) |
| FLEX200A | 200 (8) | BW Sch 10 | 880 (34.64) | +/- 74 (2.9) | 16 (235) |
| FLEX200B | 200 (8) | BW Sch 40 | 880 (34.64) | +/- 74 (2.9) | 16 (235) |
| FLEX200C | 200 (8) | ** RFSO 300# | 950 (37.40) | +/- 67 (2.7) | 16 (235) |
| FLEX200D | 200 (8) | ** RFSO 150# | 950 (37.40) | +/- 67 (2.7) | 16 (235) |
| FLEX250A | 250 (10) | BW Sch 10 | 950 (37.40) | +/- 75 (2.9) | 16 (235) |
| FLEX250B | 250 (10) | BW Sch 40 | 950 (37.40) | +/- 75 (2.9) | 16 (235) |
| FLEX250C | 250 (10) | ** RFSO 300# | 1050 (41.34) | +/- 75 (2.9) | 16 (235) |
| FLEX250D | 250 (10) | ** RFSO 150# | 1050 (41.34) | +/- 75 (2.9) | 16 (235) |
| FLEX300A | 300 (12) | BW Sch 10 | 1040 (40.95) | +/- 81 (3.2) | 11 (160) |
| FLEX300B | 300 (12) | BW Sch 40 | 1040 (40.95) | +/- 81 (3.2) | 11 (160) |
| FLEX300C | 300 (12) | ** RFSO 300# | 1150 (45.28) | +/- 83 (3.3) | 11 (160) |
| FLEX300D | 300 (12) | ** RFSO 150# | 1150 (45.28) | +/- 83 (3.3) | 11 (160) |
BW = butt-welded prepared end
RFSO = Raised Face Slip on flange
Shaded areas – pressure is limited by the flange.
** Note to the user: Not for use with spiral-wound gaskets without approval of the Company piping engineer.