Gaskets & Fasteners
Naftaar International FZE is a UAE-based stockist and global supplier of industrial gaskets and bolting fasteners for pipe flange joints — supplying oil & gas, petrochemical, power, water, and industrial projects in UAE, Oman, Saudi Arabia, Qatar, Kuwait, Bahrain, India, Africa, and worldwide from our UAQ Free Trade Zone facility.
Gaskets & Fasteners for Every Piping Application
Naftaar International FZE stocks and supplies a comprehensive range of pipe flange gaskets and bolting fasteners for the oil & gas, petrochemical, power generation, water treatment, offshore, and industrial construction sectors. We supply to projects and procurement teams across UAE, Oman, Saudi Arabia, Qatar, Kuwait, Bahrain, Iraq, India, Pakistan, Africa, and worldwide from our UAQ Free Trade Zone warehouse.
Our gasket range covers spiral wound gaskets (SWG), ring type joint (RTJ) metallic gaskets, kammprofile grooved gaskets, compressed asbestos-free fibre (CAF/CNAF) sheet gaskets, PTFE envelope and full-face gaskets, and corrugated metal gaskets — all to ASME B16.20 and B16.21. Our fastener range includes ASTM A193 Grade B7 stud bolts, ASTM A194 Grade 2H heavy hex nuts, alloy steel bolts, stainless steel fasteners, and complete flange joint bolt sets for all ASME pressure classes.
Ready Stock UAE
Complete range of pipe flange gaskets for all ASME pressure classes — spiral wound (SWG), ring type joint (RTJ), kammprofile, PTFE, CAF/CNAF, full-face, and corrugated metal gaskets. All to ASME B16.20 and B16.21. Supplied to UAE, Oman, Saudi Arabia, Qatar, and worldwide.
Complete Joint Sets
Full range of pipe flange bolting — double-end stud bolts (ASTM A193 B7), heavy hex nuts (ASTM A194 2H), hex head cap screws, and complete flange bolt sets for all ASME B16.5 pressure classes from 150 to 2500. Metric and imperial. Zinc-coated, plain, and PTFE-coated options.
Why Source from Naftaar UAE
Extensive inventory of SWG gaskets (Class 150–1500, all standard NPS sizes) and ASTM A193 B7/A194 2H stud bolt sets for all ASME B16.5 flange sizes. Immediate dispatch for shutdown, maintenance, and urgent project requirements.
Same-day dispatch · UAE FTZEfficient logistics from UAQ Free Trade Zone to Oman (Muscat, Sohar), Saudi Arabia (Jubail, Yanbu, Dammam), Qatar (Doha, RasLaffan), Kuwait, Bahrain, and Iraq — with full export documentation and customs clearance.
Oman · KSA · Qatar · Kuwait · India · AfricaWe supply complete flanged joint packages — gaskets + stud bolts + nuts — for any flange size, class, and material combination. Eliminates multiple sourcing from different vendors and ensures dimensional compatibility.
One-stop joint supplyAll gaskets supplied with manufacturer test certificates (MTC). All fasteners supplied with ASTM material test certificates including chemical analysis and mechanical test results. EN 10204 3.1 documentation standard.
EN 10204 3.1 · ASTM MTCRTJ gaskets in soft iron, 5Cr, SS316, Inconel 625, Duplex S31803 and Monel. Fasteners in ASTM A320 L7 (low-temp), A193 B8M (SS316), Duplex, Inconel 625, and Hastelloy C-276 for extreme service conditions.
Inconel · Duplex · Low-Temp · NACENon-standard sizes, special materials, and custom gasket shapes available on request. Kammprofile gaskets in custom diameters for heat exchangers. Special bolt lengths and thread forms for non-standard flange arrangements.
Custom fabrication available🔴 UAE Stock — SWG Gaskets & A193 B7 / A194 2H Bolt Sets for Immediate Supply
Naftaar maintains ready stock of spiral wound gaskets (SWG) in SS304 winding with graphite filler for Class 150, 300, 600, 900, and 1500 — all standard NPS sizes ½″ to 24″ — and ASTM A193 B7 stud bolt sets with A194 2H heavy hex nuts for all ASME B16.5 flange sizes and pressure classes. Complete flange bolt kits (studs + 2 nuts per stud) are available pre-packed for all common flange sizes. Contact sales@naftaar.com for same-day quotation and availability confirmation. We supply to UAE, Oman, Saudi Arabia, Qatar, Kuwait, Bahrain, India and worldwide.
Pipe Flange Gaskets — All Types
The correct gasket selection for a pipe flange joint is critical to maintaining leak-tight integrity throughout the design life of the piping system. The wrong gasket — incorrect material, incorrect type, or incorrect seating stress — leads to premature leakage, process downtime, and potential safety hazards. Naftaar supplies all standard gasket types for every application and pressure class.
01 — Spiral Wound Gaskets (SWG)
The spiral wound gasket (SWG) is the most widely used semi-metallic gasket in the oil & gas and process industries. It is manufactured by spirally winding a metallic strip (winding ring, typically SS304 or SS316) and a filler strip (graphite or PTFE) together — creating an alternating metallic and non-metallic layer structure. The V-profiled metallic winding provides resilience and recovery as the bolt load is applied, while the filler provides sealing. SWGs are typically specified per ASME B16.20.
Spiral wound body with solid inner ring (cage ring) and outer guide ring. The inner ring prevents inward buckling of the winding under high bolt loads and limits gasket blow-out. Standard type for most process flanges (Class 300–2500). Colour-coded inner ring identifies winding material.
Class 300–2500 · ASME B16.20 · StandardSpiral wound body with outer guide ring only — no inner ring. Suitable for Class 150 and 300 where bolt loads are lower and inward buckling risk is reduced. Most economical SWG type. Outer ring aligns gasket within the raised-face bolt circle.
Class 150–300 · Lower Bolt Load ServiceFull inner and outer ring construction — the premium SWG type. Inner ring prevents blow-in; outer ring aligns and prevents blow-out. Required by many oil company specifications for all hydrocarbon flange joints. Provides maximum resilience and sealing reliability.
Premium · All Classes · Recommended for HC serviceSpecial SWG configuration for shell-and-tube heat exchanger girth flanges — larger OD than standard pipe flanges, with multiple bolt circles and special materials for high-temperature and high-differential-pressure service. Kammprofile preferred for HX in many specifications.
Heat Exchanger · Special OD · High ΔPFlexible graphite filler between metallic windings — excellent high-temperature sealing (-200°C to +550°C), fire-safe, low seating stress. Standard for process plant and refinery flanges. Graphite filler colour code: olive/green on winding ring label.
-200°C to +550°C · Fire Resistant · StandardPTFE (virgin or reinforced) filler between metallic windings. Non-reactive with almost all chemicals — suitable for aggressive chemicals, caustic, acids, and food/pharmaceutical service where graphite contamination is unacceptable. Lower temperature range than graphite (-100°C to +200°C).
-100°C to +200°C · Chemical Resistant · Clean Service| Component | Material Options | ASTM/Grade | Temp Range | Application / Note |
|---|---|---|---|---|
| Winding Strip | 304 SS (standard) | ASTM A240 TP304 | -200°C to +650°C | Standard for carbon steel flanges; most economical |
| Winding Strip | 316L SS | ASTM A240 TP316L | -200°C to +870°C | Better corrosion resistance; recommended for SS flange systems |
| Winding Strip | 310 SS | ASTM A240 TP310 | -200°C to +1000°C | Very high temperature furnace/radiant service |
| Winding Strip | Alloy 20 / Incoloy 825 | UNS N08020 / N08825 | -200°C to +500°C | Sulphuric acid, phosphoric acid, corrosive chemical service |
| Winding Strip | Inconel 625 | UNS N06625 | -200°C to +980°C | Sour gas (H₂S), seawater, cryogenic — maximum corrosion resistance |
| Winding Strip | Hastelloy C-276 | UNS N10276 | -200°C to +1040°C | Extremely corrosive media — HCl, H₂SO₄, chlorine service |
| Filler | Flexible Graphite | — | -200°C to +550°C | Standard; fire resistant; excellent sealing; not for oxidising acids |
| Filler | PTFE (Virgin) | — | -200°C to +200°C | Universal chemical resistance; food/pharma; lower temp limit |
| Filler | Mineral Fibre / Ceramic | — | up to +1100°C | Ultra-high temperature — furnace connections, boiler manholes |
| Inner Ring | CS / SS304 / SS316 / Inconel | Various | — | Material matched to process fluid compatibility requirements |
| Outer Guide Ring | CS / SS304 / SS316 / Inconel | Various | — | Typically CS for CS flange systems; SS for SS/corrosive service |
| Winding Material | Inner Ring Colour | Outer Ring Marking | Application |
|---|---|---|---|
| 304 Stainless Steel | Yellow (inner ring) | Yellow stripe + grade marking | Standard CS and SS piping; most common |
| 316 Stainless Steel | Green (inner ring) | Green stripe + grade marking | Corrosive service, chemical, SS pipe systems |
| 321 Stainless Steel | Orange (inner ring) | Orange stripe + grade | High-temperature stabilised SS service |
| 347 Stainless Steel | Blue (inner ring) | Blue stripe + grade | High-temp Nb-stabilised service, refinery |
| Alloy 20 | Brown (inner ring) | Brown stripe | H₂SO₄ and phosphoric acid service |
| Inconel 625 | Grey (inner ring) | Grey stripe | Sour gas, seawater, extreme corrosion |
| Monel 400 | Pink (inner ring) | Pink stripe | HF acid, seawater, reducing acid service |
Note: Colour codes per ASME B16.20. Always verify against the stamped material identification on the gasket outer ring and confirm with MTC. Filler material (graphite vs PTFE) is additionally identified by separate colour stripe or labelling.
02 — Ring Type Joint (RTJ) Metallic Gaskets
Ring Type Joint (RTJ) gaskets are solid metal rings — octagonal or oval cross-section — that seat in precision-machined grooves in RTJ pipe flanges. When the flange bolts are tightened, the metal ring deforms plastically into the groove surfaces, creating a high-integrity metallic seal. RTJ gaskets are typically required for Class 600 and above in oil & gas service, and are standard for all offshore, subsea, and API 6A wellhead applications. Covered by ASME B16.20.
The preferred RTJ ring profile — octagonal cross-section provides better contact area than oval, and achieves a tighter seal at lower bolt loads. Recommended for all new designs. Contact on two seating faces of the RTJ groove. ASME B16.20 designation: R-ring (for standard RTJ flanges).
Preferred · Better Seal · ASME B16.20Oval cross-section RTJ ring — the original ring joint design. Contact on two points of the RTJ groove. Slightly lower performance than octagonal but fully interchangeable with octagonal in the same groove. Still widely used in legacy piping systems and some operator specifications.
Legacy · Interchangeable with OctagonalSpecial cross-section RTJ ring for API 6A type BX groove flanges used at very high pressures (5000–20000 psi WP). The BX ring seals radially against the groove walls and axially against the groove bottom — providing self-energised sealing action at extreme pressures. Used exclusively with API 6A BX groove flanges.
API 6A · 5000–20000 psi WP · WellheadPressure-energised RTJ ring for API 6A type RX groove flanges. As internal pressure increases, the ring is pushed outward against the groove walls — increasing sealing load with increasing pressure. Used for Class 900–2500 API applications where positive sealing under all conditions is required.
API 6A RX Groove · Class 900–2500 · Pressure Energised| Material | Max Hardness (HBW) | ASTM Spec | Temp Range | Pressure Classes | Application |
|---|---|---|---|---|---|
| Soft (Low Carbon) Iron | 90 HBW max | ASTM A108 | -29°C to +425°C | Class 150–600 | Standard for CS flanges in non-corrosive service — most common RTJ material |
| 5Cr (Grade F5) | 130 HBW max | ASTM A182 F5 | -29°C to +620°C | Class 150–2500 | Alloy steel (P5/P9) high-temperature flange systems — refinery service |
| SS 304 / 304L | 160 HBW max | ASTM A182 F304/304L | -196°C to +815°C | Class 150–2500 | Corrosive service — must be softer than the RTJ flange groove material |
| SS 316 / 316L | 160 HBW max | ASTM A182 F316/316L | -196°C to +870°C | Class 150–2500 | Corrosive and marine service; pairs with SS316 RTJ flange groove |
| Duplex S31803 | 250 HBW max | ASTM A182 F51 | -46°C to +315°C | Class 150–2500 | Offshore and seawater RTJ connections — pairs with duplex or CS RTJ flanges |
| Inconel 625 (N06625) | 241 HBW max | ASTM B564 N06625 | -196°C to +980°C | Class 150–2500 | Sour gas, HPHT, subsea — maximum corrosion resistance for critical joints |
| Monel 400 (N04400) | 150 HBW max | ASTM B164 N04400 | -196°C to +480°C | Class 150–2500 | HF acid, reducing acid service, seawater — where SS is susceptible to SCC |
⚠️ Critical Rule — RTJ Ring Must Always Be Softer Than the Flange Groove
When selecting an RTJ ring material, the ring must always be softer than the material of the RTJ groove in the mating flanges. If the ring is harder than the groove, the ring will deform the groove during tightening — destroying the seating surface. For CS (A105N) RTJ flanges, use soft iron or 5Cr rings. For SS316 RTJ flanges, use SS316 rings (max 160 HBW). For Duplex/Super Duplex RTJ flanges, Inconel 625 rings (max 241 HBW) are acceptable — confirm groove hardness with the flange MTC.
03 — Other Gasket Types
A solid metal core (CS, SS, or alloy) with concentric serrations machined into both faces, covered with a facing layer of flexible graphite or PTFE. The serrations bite into the facing material to create a high-unit-seating-stress seal. More reliable than SWG; lower seating load than RTJ. Preferred for heat exchanger bonnet flanges, large bore critical joints, and where SWG reliability is insufficient.
ASME B16.20 · All Classes · HX / Critical JointsCut from PTFE (polytetrafluoroethylene) sheet. Available as full-face (for flat-face flanges) or ring-type (for raised-face). Excellent chemical resistance — compatible with almost all process fluids. Soft, conformable seal requiring low seating stress. Limited to Class 150–300 and temperatures below 200°C (260°C with modified PTFE).
Class 150–300 · Universal Chemical ResistanceSheet gasket material manufactured from compressed synthetic mineral fibres, fillers, and rubber binder — asbestos-free replacement for traditional compressed asbestos fibre gaskets. Available in full-face and ring gasket configurations to ASME B16.21. Used for lower-pressure utility, water, and non-critical process service where SWG is over-specified.
Class 150–300 · Non-Asbestos · General UtilityA thin corrugated metal sheet (SS or CS) with or without facing material. The corrugations provide elastic recovery when the bolt load is applied. Used for high-temperature, high-pressure service where full metallic sealing is required without the groove machining needed for RTJ. Common in hydrogen and high-temperature process plant.
Metallic · High Temp / Pressure · No Groove RequiredEPDM, NBR (Nitrile), Neoprene, or Viton elastomeric sheet gaskets for water, HVAC, and low-pressure utility flanges. Full-face configuration for Class 150 flat-face flanges. Low seating stress required. Not for high-temperature or hydrocarbon service. Common in water treatment, irrigation, and building services.
Water / HVAC · Class 150 · Low Seating StressPure flexible graphite sheet cut to ring or full-face shape. Excellent high-temperature sealing — used for steam flanges, heat exchanger bonnets, and high-temperature process connections where organic gasket materials fail. Conforms to irregular surfaces under bolt load. Reinforced graphite with metal insert for higher pressure classes.
High Temp Steam · Reinforced Options · HX BonnetsPipe Flange Bolting — Complete Range
Pipe flange bolting must be matched to the flange material, gasket type, pressure class, and service conditions. Using incorrect bolting material — too weak, too brittle, or non-NACE compliant — in a pressure-containing flange joint is a serious safety risk. Naftaar supplies all standard flange bolting specifications for ASME B16.5 flanges and API valve connections.
01 — Stud Bolts (Double End / Full Thread)
The standard bolting for ASME B16.5 pipe flanges is the double-end stud bolt — a fully threaded rod with a heavy hex nut at each end. The stud bolt passes through the bolt holes in both flanges, and the nuts are tightened to compress the gasket. ASTM A193 Grade B7 (chromium-molybdenum alloy steel) is the standard stud bolt material for carbon steel flanges in process service up to 426°C.
| Stud Bolt Spec | Grade | Material | Min Yield (MPa) | Min UTS (MPa) | Temp Range | Mating Nut | NACE OK | Application |
|---|---|---|---|---|---|---|---|---|
| ASTM A193 | Grade B7 | Cr-Mo Alloy Steel (4140) | 724 | 861 | -45°C to +450°C | A194 Grade 2H | Yes ≤35 HRC | Standard for all ASME B16.5 CS flanges — universal service |
| ASTM A193 | Grade B7M | Cr-Mo Alloy Steel (modified) | 552 | 724 | -45°C to +450°C | A194 Grade 2HM | Yes — NACE grade | Sour service (H₂S) — hardness controlled max 235 HBW |
| ASTM A320 | Grade L7 | Cr-Mo Alloy Steel (impact tested) | 724 | 861 | -100°C to +400°C | A194 Grade 7 | Yes ≤35 HRC | Low-temperature flanges — LNG, cryogenic, sub-zero service |
| ASTM A193 | Grade B8 (Class 2) | 304 Stainless Steel | 552 | 724 | -200°C to +815°C | A194 Grade 8 | Yes | Austenitic SS flange systems — corrosive/chemical service |
| ASTM A193 | Grade B8M (Class 2) | 316 Stainless Steel | 552 | 724 | -200°C to +870°C | A194 Grade 8M | Yes | SS316 flange systems; marine, offshore utilities |
| ASTM A193 | Grade B16 | Cr-Mo-V Alloy Steel | 758 | 1000 | -45°C to +540°C | A194 Grade 7 | Limited | High-temperature flanges above 450°C — power plant, P91 systems |
| ASTM A307 | Grade B | Carbon Steel (galvanised) | 248 | 414 | — | A563 Grade C | No | Low-pressure Class 150 water, HVAC, utility service |
| Special | Alloy 625 (Inconel) | UNS N06625 | 414 | 827 | -200°C to +980°C | Inconel 625 nuts | Yes | HPHT sour service, subsea, seawater flanges — maximum corrosion resistance |
02 — Heavy Hex Nuts & Other Fasteners
Standard nut for ASME B16.5 flange bolting — paired with A193 B7 stud bolts. Manufactured to ASME B18.2.2. Higher dimensions than standard hex nuts (larger across-flats and greater height) — providing greater bearing area and reduced thread stripping risk. Always supplied 2 per stud (one each end).
ASTM A194 Gr 2H · ASME B18.2.2 · CS StandardNACE-grade heavy hex nut for sour service — manufactured from A194 Grade 2HM material with controlled hardness (max 235 HBW). Paired with A193 B7M stud bolts for H₂S sour environments per NACE MR0175 / ISO 15156.
ASTM A194 2HM · NACE MR0175 · Sour ServiceAustenitic stainless steel heavy hex nuts — Grade 8 (304 SS) or Grade 8M (316 SS) — paired with A193 B8/B8M stud bolts for stainless steel flange systems, chemical service, and corrosive environments. ASME B18.2.2 dimensions.
ASTM A194 Gr 8 / 8M · SS Flanges · ChemicalAlternative to stud bolts for some flange applications — hexagonal head bolt with partial or full thread used for smaller-bore Class 150 flanges where access for nut tightening on both ends is limited. ASME B18.2.1 / DIN 931 / DIN 933.
ASME B18.2.1 · Class 150/300 Small BoreUsed under nut or bolt head where the flange face is soft (e.g., GRP or HDPE flanges) to distribute the bearing load. Also used in structural connections. Not typically used in standard ASME B16.5 pipe flange connections.
ASME B18.22.1 · Structural / Non-Metallic FlangesA193 B7 stud bolts with PTFE (Teflon) coating for reduced friction during tightening — allowing more accurate bolt load from a given torque, and providing corrosion protection in external environments (offshore, marine). PTFE coating reduces the torque required for a given bolt preload.
A193 B7 + PTFE Coat · Offshore / Accurate TorqueStud bolt length is calculated as: flange thickness × 2 + gasket thickness + 2 × (nut height + washer thickness if used) + 3 thread pitches protruding each end. For standard ASME B16.5 flanges with SWG gaskets, typical stud bolt dimensions are:
| NPS | Cl.150 Bolt Dia | Cl.150 No. Bolts | Cl.150 Bolt Length (mm) | Cl.600 Bolt Dia | Cl.600 No. Bolts | Cl.600 Bolt Length (mm) | Cl.900 Bolt Dia | Cl.900 Bolt Length (mm) |
|---|---|---|---|---|---|---|---|---|
| ½" | ½" | 4 | 70 | ½" | 4 | 95 | ¾" | 130 |
| 1" | ½" | 4 | 80 | ⅝" | 4 | 115 | ⅞" | 160 |
| 2" | ⅝" | 4 | 100 | ¾" | 8 | 140 | 1" | 190 |
| 3" | ⅝" | 4 | 115 | ¾" | 8 | 155 | 1⅛" | 220 |
| 4" | ⅝" | 8 | 120 | ¾" | 8 | 170 | 1¼" | 250 |
| 6" | ¾" | 8 | 140 | ¾" | 12 | 190 | 1¼" | 290 |
| 8" | ¾" | 8 | 155 | ¾" | 12 | 215 | 1⅜" | 340 |
| 10" | ⅞" | 12 | 180 | 1" | 16 | 250 | 1½" | 385 |
| 12" | ⅞" | 12 | 195 | 1" | 20 | 270 | 1⅝" | 420 |
| 16" | 1" | 16 | 220 | 1⅛" | 20 | 315 | 1⅞" | 490 |
| 20" | 1⅛" | 20 | 260 | 1¼" | 24 | 370 | 2" | 560 |
| 24" | 1¼" | 20 | 295 | 1¼" | 24 | 410 | 2⅛" | 630 |
Lengths shown are approximate for standard SWG gaskets with standard weld neck or slip-on flanges. Lengths vary with gasket thickness, flange type (bolted bonnet valves, pressure seal bonnets), and thread pitch. Contact Naftaar for specific bolt length calculations for your project.
Gasket & Fastener Technical Data
| NPS | Pipe OD (mm) | Cl.150 SWG OD (mm) | Cl.300 SWG OD (mm) | Cl.600 SWG OD (mm) | Cl.900 SWG OD (mm) | Cl.1500 SWG OD (mm) | Bore ID (mm) | Thickness (mm) |
|---|---|---|---|---|---|---|---|---|
| ½" | 21.3 | 36.5 | 41.3 | 41.3 | 41.3 | 41.3 | 22.4 | 4.5 |
| 1" | 33.4 | 52.4 | 57.2 | 57.2 | 57.2 | 57.2 | 35.1 | 4.5 |
| 2" | 60.3 | 83.3 | 88.9 | 88.9 | 88.9 | 95.3 | 62.0 | 4.5 |
| 3" | 88.9 | 114.3 | 120.7 | 130.2 | 130.2 | 133.4 | 90.5 | 4.5 |
| 4" | 114.3 | 146.1 | 152.4 | 158.8 | 168.3 | 174.6 | 116.0 | 4.5 |
| 6" | 168.3 | 203.2 | 211.1 | 220.5 | 228.6 | 244.5 | 170.0 | 4.5 |
| 8" | 219.1 | 254.0 | 266.7 | 285.8 | 285.8 | 295.3 | 221.0 | 4.5 |
| 10" | 273.1 | 311.2 | 323.9 | 342.9 | 349.3 | 358.8 | 274.6 | 4.5 |
| 12" | 323.9 | 368.3 | 381.0 | 393.7 | 406.4 | 419.1 | 325.4 | 4.5 |
| 16" | 406.4 | 457.2 | 469.9 | 482.6 | 508.0 | 520.7 | 407.9 | 4.5 |
| 20" | 508.0 | 558.8 | 577.9 | 590.6 | 603.3 | 635.0 | 509.6 | 4.5 |
| 24" | 609.6 | 660.4 | 679.5 | 698.5 | 720.7 | 749.3 | 611.2 | 4.5 |
OD dimensions shown are for the spiral wound body (winding ring). Outer guide ring OD is larger (aligns with bolt circle). Inner ring bore matches pipe bore. Standard thickness 4.5mm (compressed to ~3.2mm). Contact Naftaar for full B16.20 dimension tables for all pressure classes.
| NPS | Class 150 Ring No. | Class 300 Ring No. | Class 600 Ring No. | Class 900 Ring No. | Class 1500 Ring No. | Class 2500 Ring No. |
|---|---|---|---|---|---|---|
| ½" | R-11 | R-11 | R-11 | R-11 | R-11 | R-12 |
| 1" | R-16 | R-16 | R-16 | R-16 | R-16 | R-18 |
| 2" | R-22 | R-22 | R-22 | R-23 | R-24 | R-26 |
| 3" | R-31 | R-31 | R-31 | R-33 | R-35 | R-37 |
| 4" | R-37 | R-37 | R-38 | R-40 | R-42 | R-44 |
| 6" | R-47 | R-47 | R-49 | R-50 | R-53 | R-55 |
| 8" | R-54 | R-54 | R-56 | R-57 | R-59 | R-62 |
| 10" | R-61 | R-61 | R-63 | R-64 | R-66 | R-69 |
| 12" | R-66 | R-67 | R-69 | R-70 | R-72 | R-74 |
| 16" | R-75 | R-76 | R-77 | R-78 | R-80 | R-82 |
| 20" | R-82 | R-83 | R-84 | R-86 | R-88 | R-91 |
| 24" | R-90 | R-91 | R-93 | R-95 | R-97 | R-101 |
Ring numbers per ASME B16.20. Always specify the ring number when ordering RTJ gaskets — this defines the exact dimensions for the machined groove in the matching RTJ flange. Contact Naftaar for BX and RX ring numbers for API 6A flanges.
Gaskets & Fasteners — Where & Who We Supply
Naftaar International FZE supplies gaskets and fasteners to a wide range of industries and end-users — from major EPC contractors managing multi-billion-dollar oil & gas projects to maintenance engineers requiring urgent shutdown supply. Our UAE Free Trade Zone location provides competitive export pricing and efficient logistics to all regional and global markets.
Oil & Gas Upstream
Wellhead and production facility flange joint gaskets, manifold bolting kits, separator and test vessel nozzle gaskets, chemical injection flange joints. RTJ rings for high-pressure wellhead connections (API 6A).
SWG CGI · RTJ Inconel 625 · A193 B7M / A194 2HMOil & Gas Midstream
Pipeline station isolation valve flange joints, pig trap bolting kits, meter station orifice flange gasket and bolt sets, compressor station flanged connection gaskets.
SWG (Cl.600–900) · A193 B7 · A320 L7 (cold climate)Refinery & Petrochemical
Process column nozzle gaskets and bolt sets, heat exchanger bonnet gaskets (kammprofile), pump casing flange joints, furnace outlet header RTJ connections.
SWG CGI · Kammprofile · RTJ (Cl.600+) · A193 B7/B16Power Generation
Main steam flange gaskets (graphite-filled SWG or kammprofile), boiler drum nozzle bolting, turbine extraction steam flange joints. High-temperature A193 B16 bolting for P91 flanges.
Graphite SWG · Kammprofile · A193 B16 + A194 Gr7Water & Desalination
Seawater intake flange joints, RO pressure vessel connections, HDPE and GRP flange gaskets (rubber full-face), chemical dosing line gaskets. Duplex/super duplex RTJ for high-chloride RO service.
Rubber FF · PTFE · SWG · Duplex/Inconel RTJOffshore & FPSO
Topside process flange joint packages (gasket + bolt set), riser base connection gaskets, firewater flange bolting, subsea manifold RTJ connections, FPSO turret flange joints.
Inconel 625 RTJ · SWG CGI · A193 B7M + 2HMConstruction & HVAC
Chilled water pump and coil flange gaskets (rubber), heating system valve body gaskets (CAF/CNAF), fire suppression system bolting kits, compressed air pipeline flange joints.
EPDM Rubber · CAF/CNAF · A307 Grade BLNG & Cryogenic
LNG transfer line flange joint gaskets (SWG with SS304 winding, graphite filler), liquid nitrogen and oxygen connections. Low-temperature A320 L7 stud bolts with A194 Grade 7 nuts for -100°C service.
SWG (Cl.150–600) · PTFE · A320 L7 + A194 Gr7Mining & Industrial
Slurry pipeline flange joints, acid leach circuit gaskets (PTFE, PVDF), reagent tank nozzle bolting, process flange joints in corrosive environments.
PTFE / Rubber · A193 B8M (acid) · SWG (general)Regional Supply — Countries We Serve
Standards We Supply To
The primary standard for metallic and semi-metallic gaskets for use with ASME B16.5 and B16.47 pipe flanges. Covers ring type joint (RTJ) gaskets (octagonal and oval) and spiral wound gaskets (SWG), including all dimensional requirements, material requirements, colour coding, testing, and marking. Every gasket supplied by Naftaar is manufactured and supplied in compliance with ASME B16.20.
Covers the dimensional requirements for non-metallic flat gaskets (full-face and ring-type) for use with ASME B16.5 flanges. Specifies inside diameter, outside diameter, and thickness for each NPS and pressure class combination. Applies to compressed fibre (CAF/CNAF), PTFE, rubber, and other sheet gasket materials.
Covers alloy steel and stainless steel bolting materials (studs, bolts, stud bolts) for pressure vessels, valves, flanges, and fittings in high-temperature service. The most important bolting standard for industrial piping — Grade B7 (stud bolts) and B8/B8M (SS stud bolts) are the most widely used globally. Also covers Grade B16 for ultra-high-temperature service.
Covers carbon steel, alloy steel, and stainless steel nuts for high-pressure and/or high-temperature applications. Grade 2H heavy hex nuts (paired with A193 B7 stud bolts) are the industry standard for ASME B16.5 pipe flange bolting. NACE-grade 2HM nuts for sour service. Grade 8/8M for stainless steel systems.
Covers bolting materials (stud bolts, bolts, screws) for pressure vessels, valves, flanges, and fittings for low-temperature service — where materials must be impact-tested to demonstrate adequate toughness at sub-zero temperatures. Grade L7 (Cr-Mo alloy, impact tested at -100°C) is the standard for cryogenic flange bolting.
ASME B18.2.1 covers the dimensional standards for hex head bolts and screws (across flats, head height, thread length). ASME B18.2.2 covers heavy hex nuts, thick hex nuts, and jam nuts. These dimensional standards define the physical dimensions of the fasteners — the ASTM standards (A193, A194) define the material and mechanical properties.
API 601 covers the requirements for metallic gaskets for use in refinery piping flanged joints — particularly for spiral wound and ring type joint gaskets. Supplements ASME B16.20 with additional requirements specifically applicable to refinery and petrochemical plant service conditions, including material qualification and inspection requirements used by major oil companies in their purchasing specifications.
ISO 7005-1 covers steel flanges (including PN-rated metric flanges) and ISO 7005-2 covers cast iron flanges. For European and metric-dimensioned piping systems (PN 10 through PN 400 to EN 1092-1), gasket dimensions are specified per these standards. Naftaar can supply metric-dimensioned gaskets and metric-threaded fasteners (DIN 976 / ISO 4032) for European projects.
Gasket Manufacturer Test Certificate
MTC confirming winding material (with heat or batch number), filler material, inner and outer ring material, and dimensional verification to ASME B16.20. Issued with every gasket supply.
ASTM A193/A194 Fastener MTC
Original mill test certificate for stud bolts and nuts including chemical composition (actual values), tensile test results, hardness test, heat number, and lot traceability. ASME format.
Hardness Test Report (NACE)
For B7M / B7M / 2HM NACE-grade fasteners — hardness survey confirming compliance with NACE MR0175 / ISO 15156 maximum hardness limits (235 HBW for B7M, 22 HRC equivalent) to prevent sulphide stress cracking.
Charpy Impact Test Report
For ASTM A320 low-temperature bolting — Charpy V-notch impact test results at the specified sub-zero test temperature confirming adequate toughness for the intended cryogenic service application.
PMI Test Reports
Positive Material Identification by XRF for critical gasket materials (Inconel 625, Duplex, Monel) and alloy fasteners — confirming actual chemistry and preventing material mix-up in multi-material supply packages.
Export Documents
UAE Certificate of Origin, commercial invoice, packing list, bill of lading, and export customs clearance. SONCAP/COC for West Africa. Full documentation for customs clearance in all supply countries — UAE, Oman, Saudi Arabia, Qatar, India, etc.
Gaskets & Fasteners — Common Questions
Answers to the most common questions our team receives about gasket and fastener procurement. Email sales@naftaar.com or call +971 58 186 5535 for specific technical guidance.
A spiral wound gasket (SWG) is a semi-metallic gasket made of alternating metallic and non-metallic (filler) layers wound in a spiral. It seats between two raised faces (RF flanges) and is compressed by bolt load between the two raised surfaces. The SWG provides an excellent seal for most process applications and is the standard gasket for most ASME B16.5 RF flanges from Class 150 to 2500. It requires a specific minimum gasket seating stress to activate the seal.
A ring type joint (RTJ) gasket is a solid metal ring (octagonal or oval cross-section) that seats in a precision-machined groove in both mating flanges. The ring deforms plastically under bolt load to create a metallic seal. RTJ provides a harder, more reliable seal at high pressures and temperatures compared to SWG — which is why RTJ is standard for Class 600 and above in oil & gas service and for all offshore and API 6A wellhead connections.
Key differences: SWG is for RF (raised face) flanges; RTJ is for RTJ (ring type joint) grooved flanges. SWG can be re-used in some cases; RTJ rings must be replaced every time the joint is opened. RTJ requires matching flange groove machining; RF does not.
The standard bolting combination for carbon steel (ASTM A105N) ASME B16.5 flanges in process service is:
- Stud Bolts: ASTM A193 Grade B7 (Cr-Mo alloy steel) — fully threaded double-end stud bolts to ASME B18.2.1
- Nuts: ASTM A194 Grade 2H heavy hex nuts — two nuts per stud bolt, one at each end
- Gasket: Spiral wound gasket (SWG) with SS304/316 winding and graphite filler, ASME B16.20
Variations for specific service conditions:
- Sour service (H₂S): ASTM A193 B7M (hardness-controlled) stud bolts with A194 2HM nuts per NACE MR0175 / ISO 15156
- Low-temperature (-46°C to -100°C): ASTM A320 Grade L7 (Charpy impact tested) with A194 Grade 7 nuts
- High-temperature above 450°C (P91 flanges): ASTM A193 Grade B16 with A194 Grade 7 nuts
- Stainless steel flanges: ASTM A193 Grade B8M (SS316) with A194 Grade 8M nuts
Yes — Naftaar International FZE regularly supplies gaskets and fasteners to all GCC countries:
- Oman: Supply to Muscat, Sohar Industrial Area, Salalah, and Sur — serving PDO, OQEP, and Oman LNG project contractors and industrial maintenance teams
- Saudi Arabia: Supply to Jubail Industrial City, Yanbu Industrial City, Dammam, and Riyadh — serving Saudi Aramco supply chain contractors, SABIC, Sadara, and independent EPCs
- Qatar: Supply to Doha and Ras Laffan Industrial City — serving QatarEnergy LNG, QCHEM, and major LNG plant maintenance contractors
- Kuwait: Supply to Ahmadi, Shuaiba, and Mina Al-Ahmadi — serving KPC, KNPC, and EQUATE
- Bahrain: Supply to Sitra, Isa Town — serving BAPCO, Alba, and Gulf Petrochemical
Beyond GCC, we supply to India (Mumbai, Chennai, Kolkata), Pakistan (Karachi, Port Qasim), Nigeria, Angola, Egypt, UK, Europe, and the Americas. Contact sales@naftaar.com or +971 58 186 5535 for regional supply enquiries.
The ASME B16.20 colour coding system identifies the winding strip material of a spiral wound gasket through a coloured stripe on the outer guide ring. The most common codes are:
- Yellow inner ring: 304 Stainless Steel winding — standard for most carbon steel piping systems
- Green inner ring: 316 Stainless Steel winding — better corrosion resistance, used for SS flange systems and chemical service
- Orange inner ring: 321 Stainless Steel winding — titanium-stabilised for high-temperature service
- Blue inner ring: 347 Stainless Steel winding — niobium-stabilised for refinery high-temperature service
- Grey inner ring: Inconel 625 winding — for sour gas, seawater, and extreme corrosion environments
The filler material (graphite or PTFE) is identified separately — graphite filler is typically indicated by an olive/green stripe on the winding body, while PTFE is indicated by a white stripe. Colour coding is important because it allows quick visual identification of gasket material during installation and inspection — preventing incorrect gasket material being installed in service. Always verify the colour code against the MTC and the gasket label before installation.
ASTM A193 Grade B7 is the standard Cr-Mo alloy steel stud bolt — hardened and tempered to achieve high tensile strength (minimum 861 MPa UTS). B7 bolts are not hardness-restricted — they may achieve hardness values up to 35 HRC, which is above the NACE MR0175 limit for sour service environments.
ASTM A193 Grade B7M is a modified version of B7 — manufactured from the same alloy steel but with a controlled tempering temperature to limit the maximum hardness to 235 HBW (approximately 22 HRC). This lower hardness prevents Hydrogen Induced Cracking (HIC) and Sulphide Stress Cracking (SSC) in H₂S-containing (sour) environments, making B7M compliant with NACE MR0175 / ISO 15156. The trade-off is reduced tensile strength compared to B7 (minimum 724 MPa UTS for B7M vs 861 MPa for B7).
When to specify B7M / 2HM (NACE) bolting: Whenever the process fluid contains hydrogen sulphide (H₂S) at any partial pressure that would classify the environment as "sour" per NACE MR0175 / ISO 15156. Also required for flanges on pipelines and process equipment handling wet sour gas or crude oil with elevated H₂S content. Your project engineering specification or the operator's materials specification will state whether NACE bolting is required — check this before ordering.
Yes — Naftaar can supply complete flanged joint packages for any ASME B16.5 flange size, pressure class, and material combination. A complete joint package includes:
- Gasket: SWG or RTJ ring (as specified) — sized for the flange NPS and pressure class
- Stud bolts: A193 B7 (or specified grade) in the correct diameter and length for the flange
- Heavy hex nuts: A194 2H (or specified grade) — 2 per stud bolt
We can supply complete bolt kits pre-packed by flange size and class — with gaskets, stud bolts, and 2 nuts per stud all provided in a single labelled kit. This is particularly useful for:
- Shutdown and turnaround maintenance supply — minimises sourcing from multiple vendors
- New project tie-in packages — all components from a single certified source
- Remote or offshore site supply — reduces the risk of missing components on delivery
- Piping spool deliveries — bolt kits can be tagged to specific flange joints in the MTO
Please provide your flange schedule (NPS, pressure class, facing, quantity) and we will provide a complete joint package quotation.
A kammprofile gasket (also called a grooved metal gasket) consists of a solid metal core disc (CS, SS, or alloy) with concentric serrations (grooves) machined into both faces, covered by a layer of flexible facing material (graphite or PTFE). The serrations create a series of high-unit-seating-stress contact zones when the gasket is compressed under bolt load — providing a more reliable seal than a spiral wound gasket, particularly in applications where:
- Bolt load is limited: Heat exchanger bonnet flanges often have a limited number of bolts, so maximum gasket seating efficiency is required — kammprofile achieves a better seal than SWG at the same bolt load
- Large bore flanges: For very large diameter flanges (24″ and above), maintaining uniform gasket seating stress across the full face is difficult — the kammprofile's serrations help compensate for flange deflection and non-uniform bolt load distribution
- High reliability is required: Kammprofile is preferred over SWG in safety-critical connections where any leak would be unacceptable
- Re-use is desired: The kammprofile metal core can sometimes be re-faced and reused (facing material replaced) — SWG cannot be reused reliably
Use a kammprofile when your engineering specification requires it, on heat exchanger bonnet flanges, large-bore critical joints, or where SWG reliability has been demonstrated to be insufficient in the application. The kammprofile requires the same RF flange facing as a SWG — no special groove machining is needed (unlike RTJ).
Complete Piping Solutions
️API 5L · ASTM A106 · A312 · A335 · A790View Pipes →
ASME B16.9 · B16.11 · MSS SP-75 · SP-97View Fittings →
ASME B16.5 · B16.47 — WN, SO, BL, RTJView Flanges →
API 600 · API 6D · BS 1873 — Ball, Gate, GlobeView Valves →