PRODUCTS
STYLE D / DS
Assets
Style D & DS couplings incorporate the more noble, duplex-alloy construction, which although initially more expensive, offers the superior corrosion resistance and corresponding better longevity for highly corrosive environments compared to the Style B coupling which is constructed from 316 alloy. Consult Piedmont application engineering for guidance on the selection of metal alloy for your application.
Application
Applications can impose severe-duty factors in addition to the maximum continuous operating pressure rating. These additional design requirements must be considered in selecting the appropriate Piedmont coupling.
+ Advice
An example of a severe-cyclical duty consideration is piping in the immediate proximity of the discharge of reciprocating, positive displacement piston pumps including the energy recovery devices of this type used in the seawater desalination industry.
Piping components, including grooved end pipe couplings, can be subjected to severe cyclical duty in industrial and desalination plants and engineers and designers need to assure that piping system pulsations and axial displacements are adequately provided for in the piping system design, particularly geometry.
Piping system displacements impart compressive and tensile loads in addition to the axial and hoop stresses arising from both continuous operating pressure and localized pulsation conditions. Displacement loads from reciprocating pumping devices impose additional stresses and require greater strength of the piping-joint components compared to piping components throughout the remainder of a plant at similar pressure, but not subjected to these additional loads. Contact Piedmont for assistance during the early stages of such designs.
Features
Pressure Rating
1200 psi (82 bar) with schedule 40s pipe (special alloys) with cut groove only – all sizes.
+ Duplex (Style D)
Duplex stainless steel is highly resistant to chloride corrosion because of its metallurgy and microstructure. Used for high pressure couplings for seawater installation our duplex alloy is made of two metallurgical phases with each their role to play in the efficiency of the couplings.
Duplex 2205 is also available upon request. We highly recommend duplex for sea water corrosive applications.
• Austenite for nobility
• Ferrite for strength
The two phases are homogenized to form a metallic composite analogue to epoxy/glass composite. Our duplex is highly resistant to corrosion and offers twice the tensile and yield strength compared to stainless steel 316. Our duplex alloy is CE8MN and offers better mechanical properties when compared to conventional 316L stainless steel.
+ Super Duplex (Style DS)
Our couplings can also be produced using a Super Duplex material, which offers even higher corrosion resistance than duplex, and is very similar to alloys 2507 and Zeron 100 which are commonly used for seawater piping.
Made of Super Duplex stainless steel CE8MN alloy, our couplings are austenitic-ferritic stainless steel and highly resistant to chloride stress corrosion. Super Duplex grade of stainless also offers higher strength and better mechanical properties than duplex stainless steel.
As an option, these couplings can be specified with CE3MN Super Duplex material, which offers a slightly higher Pitting Resistance Equivalent Number (PREN).
Hardware
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- Housing
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- Duplex & Super Duplex stainless steel type CE8MN, conform to ASTM A-890 Grade 2A. Piedmont also offers this coupling style in CE3MN (Grade 5A) for even higher corrosion resistance. Other alloys are also available, contact Piedmont for details.
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- Housing
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- Gaskets
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- EPDM rubber, suitable for hot and cold water service. Two shapes of gaskets available: C-shaped or Flush-fit. NSF/ANSI 61 approved for drinking water system components. Not suitable for petroleum service.
EPDM peroxide cured gaskets available upon request (for special applications such us chloramines, etc.)
- EPDM rubber, suitable for hot and cold water service. Two shapes of gaskets available: C-shaped or Flush-fit. NSF/ANSI 61 approved for drinking water system components. Not suitable for petroleum service.
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- Gaskets
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- Bolts/Nuts
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- Round / hexagonal head, oval neck, 316 stainless steel bolts conform to ASTM F-593, group 2, condition CW. Heavy hex silicon bronze nuts for sizes from ¾” to 3”, 316 stainless steel nuts for 4” and above. Washers are heavy pattern 316 stainless steel.
- Nuts are according to DIN-934 (ISO-4032). Washers are according to DIN-125 (ISO 7089). Hexagonal head bolts (DIN-931/933) also used in 6” – 20” couplings.
- Optional: Threaded rods (DIN-976) for sizes up to 6” available upon request / Inches series thread components available upon request.
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- Bolts/Nuts
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- Material
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- Standard: SS Duplex 2205 / S32205 as per ASTM A1082 (PREN>35). It is recommended to improve against chloride stress cracking, crevice and pitting bolts corrosion.
- Optional:
SS Super Duplex 2507 / S32750 or S32760 (Zeron-100) as per ASTM A1082 (PREN>40)
SS316L bolts & SS316 nuts & washers as per ASTM A276 (PREN>23) (up to 14”).
Silicon bronze nuts (ASTM B98 C65100) avoid the use of any additional antigalling paste on SS bolts.
Antigalling / antiseize dry lubricated bolts/rods & nuts (Gleitmo 615 or similar).
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- Material
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- Isolation washer (optional):
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- In addition to Duplex / Super Duplex material bolting upgrading, to improve against bolting crevice corrosion, some isolation neoprene washers are available upon request.
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- Isolation washer (optional):
Coatings (optional)
To improve against corrosion, couplings coatings components are available upon request:
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- Coated castings with epoxy primer plus polyurethane coating (other coatings available upon request).
- Coated hardware with fluoropolymer coats such as Xylan, Fluorokote or similar (Oil & Gas applications)
Quality
Standard Quality certificates
Piedmont is ISO 9001:2015 certified. The following quality certificates are provided with the order:
- EN10204 3.1 metallic components (castings, hardware)
- EN10204 2.2 certificate for EPDM gaskets
- EN10204 2.1 PO certificate of conformity
Quality tests (optional)
Several additional quality testing certifications with independent laboratories are available upon request:
| Optional test | Remarks |
|---|---|
| Hydrostatic proof test (1.5 x) | ASTM F1476 or ANSI AWWA C606 (in house) |
| Positive Material identification (PMI) | X-Ray fluorescent (XRF) |
| Dye penentrant test (DPT) | — |
| Corrosion test | ASTM G48 Method A ASTM 923 Method C ICG intergranular corrosion test (ASTM A262 Pract.B) |
| Metallographic / Micrographic analysis (incl. % Ferrite) | ASTM E562 |
| Bolts laboratory full analysis report | Grain flow, metallogr., hardness, etc. |
| Independent material and test certification (Oil & Gas applications) | EN10204 3.2 with GIS, SGS, Bureau Veritas, etc. |
| Magrographic / Macroetch alloy analysis | ASTM E340 |
| Impact (Charpy) test | ASTM A923 Method B or ASTM A370 |
| Hardness test | ASTM A370 |
| Ferroxyl test | ASTM A380 |
| Radiographic test | — |
| NORSOK qualified castings (Oil & Gas applications) | M-650 |
TABLE OF SPECIFICATION
| Style D/DS Specifications | |||||
|---|---|---|---|---|---|
| Nominal size | X | Y | Z | Aprx Weight | Pressure rating* |
| Inches | inches mm. | inches mm. | inches mm. | lbs. kgs. | PSI BAR |
| .75 | 1.91 48.5 | 3.04 77.2 | 1.68 42.7 | 0.81 0.37 | 1200 82 |
| 1.0 | 2.29 58.2 | 3.42 86.9 | 1.68 42.7 | 0.97 0.44 | 1200 82 |
| 1.25 | 2.50 63.5 | 3.65 92.7 | 1.71 43.4 | 1.08 0.49 | 1200 82 |
| 1.5 | 2.76 70.1 | 4.06 103.1 | 1.71 43.4 | 1.21 0.55 | 1200 82 |
| 2.0 | 3.24 82.3 | 4.38 111.3 | 1.85 47.0 | 1.92 0.87 | 1200 82 |
| 2.5 | 3.74 95 | 5.30 134.6 | 1.85 47 | 2.14 0.97 | 1200 82 |
| 3.0 | 4.48 113.8 | 6.03 153.3 | 1.85 47.0 | 2.64 1.20 | 1200 82 |
| 4.0 | 5.70 144.8 | 7.60 193.0 | 2.02 51.3 | 4.54 2.06 | 1200 82 |
| 5.0 | 7.22 183.4 | 9.50 241.5 | 2.02 51.3 | 9.30 4.23 | 1200 82 |
| 6.0 | 8.18 207.8 | 10.25 260.4 | 2.02 51.3 | 9.74 4.42 | 1200 82 |
| 8.0 | 10.89 276.6 | 13.44 341.5 | 2.34 60.7 | 24.50 11.10 | 1200 82 |
| 10.0 | 13.28 337.3 | 15.88 403.3 | 2.55 64.8 | 33.46 15.18 | 1200 82 |
| 12.0 | 15.28 388.1 | 17.38 441.4 | 2.55 64.8 | 34.82 15.80 | 1200 82 |
| 14.0 | 16.45 417.7 | 20.30 515.7 | 2.99 75.8 | 44.91 20.38 | 1200 82 |
| 16.0 | — | 20.86 529.8 | 2.94 74.7 | 76.56 34.73 | 1200 82 |
| 18.0 | — | 23.83 596.8 | 3.20 80.1 | 95.07 43.12 | 1200 82 |
| 20.0 | — | 27.08 687.8 | 3.2 80.1 | 109.55 49.69 | 1200 82 |
* Pressure rating when cut grooves and sch 40 pipes are used.
Note I: Working pressure ratings based upon generally accepted pressure piping design standards and testing in accordance with ASME Section VIII Division 1 pressure vessel test method.
Note II: It is allowed a single hydrostatic proof test at 1.5 x rating pressure before being put in operation at its rated pressure or less.
Images
NOTE
For the use of Style D couplings on cyclic axial displacement systems, please consult with Piedmont for design and installation guidance.
Quote request
Piedmont couplings are sold as a whole including the housing, the gasket, the bolts, nuts and washers when necessary. Please specify the coupling size and gasket type required.
Documents
Installation manual
Product Sheet – Style D-DS
CAD | STP – Style D 0.75
CAD | STP – Style D 1.0
CAD | STP – Style D 1.25
CAD | STP – Style D 1.5
CAD | STP – Style D 2.0
CAD | STP – Style D 2.5
CAD | STP – Style D 3.0
CAD | STP – Style D 4.0
CAD | STP-Style D-5.0
CAD | STP – Style D 6.0
CAD | STP – Style D 10.0
CAD | STP-Style D 12.0
Technical Drawing – Style D
Technical Drawing – Style D (16” & 18”)
Coupling pipe groove
- Standard cut groove profile according to AWWA C606 table 4 for sizes up to 16”.
- Cut groove according to Piedmont specifications for sizes 18” and 20”.
- Please refer to the Installation Manual for further details on maximum allowable pipe displacements and angular deflections, coupling end loads, and roll groove.
- For SWRO high pressure applications, Piedmont recommends our couplings to be installed on pipe, and/or connecting fitting alloys with high corrosion & crevice resistance such as UNS S32750 & S32760 super duplex, S31254 and N08367 (PREN ≥ 40 & CF ≥ 35).
- For the use on cyclic axial displacement systems, please support properly the output high pressure flexible hose to avoid excessive bending loads, displacements and deflections on the grooves. They should work coplanar to avoid couplings damages. Consult with Piedmont for guidance.
Spare parts
- Recommended: gaskets and hardware kits.
- Castings components also available upon request.
- Consumable parts needed for assembly: glycerine lubricant for gasket, and, if so needed, antiseize/antigalling lubricant for SS bolts & nuts threads.
Complementary products
End caps, grooved elbows, Tees, pups/nipples, and others complementary grooved products are available. Please contact Piedmont for details.
