Gulf Union Ozone stocks blind flanges and slip-on flanges in ASTM A105 carbon steel for immediate dispatch from Jeddah. ASME B16.5, Class 150 to 2500, NPS ½ to NPS 24. Raised face (RF) and ring type joint (RTJ) facing. EN 10204 3.1 mill test certificates supplied. SAEP-347 Annex 4 compatible. RFQ response within 4 business hours.
A blind flange (BF) is a solid circular disc without a bore, used to close the open end of a pipe, pressure vessel nozzle, or valve. Blind flanges are the highest-pressure-rated flange type in the ASME B16.5 standard because the full disc cross-section carries the axial load without any bore discontinuity. They are used for permanent isolation, hydrostatic testing, future tie-in points, and temporary shutdown closures across oil and gas, petrochemical, and utility piping systems.
For Saudi Aramco projects, blind flanges in ASTM A105 (carbon steel) are specified under SAEP-347 Annex 4 flange material numbers and must be supplied with EN 10204 3.1 mill test certificates showing heat number, chemical analysis, and mechanical test results. Gulf Union Ozone stocks RF and RTJ blind flanges in the most common Aramco project sizes for same-day dispatch from Jeddah.
A slip-on flange (SO) has a through bore slightly larger than the pipe outside diameter, allowing the pipe to slide inside before being welded. The pipe is sealed with a double fillet weld — one on the inner edge of the flange hub, one at the pipe end face. Slip-on flanges are lower cost than weld neck flanges and easier to fit when pipe length tolerance is large. They are rated for lower fatigue and cyclic service than weld neck flanges and are typically specified in Class 150 and Class 300 for non-critical utility services.
Note for Saudi Aramco projects: SAES-L-108 restricts slip-on flanges to utility and non-hydrocarbon service. For process piping carrying hydrocarbons, corrosives, or sour fluids, weld neck flanges are mandatory on Aramco projects. Verify your service classification with your project piping engineer before substituting slip-on for weld neck flanges on any Aramco-regulated piping system.
The table below shows maximum working pressure (MAWP) for ASTM A105 blind flanges at operating temperatures. Class and temperature together determine the allowable pressure for your application.
| Pressure Class | −29°C to 38°C (bar) | 100°C (bar) | 200°C (bar) | 300°C (bar) | Typical Saudi Aramco Service |
|---|---|---|---|---|---|
| Class 150 | 19.6 | 17.7 | 15.1 | 13.4 | Utility water, low-pressure air |
| Class 300 | 51.1 | 46.6 | 39.8 | 36.4 | Instrument air, steam, cooling water |
| Class 600 | 102.1 | 93.2 | 79.6 | 72.8 | Process hydrocarbon, crude oil, gas |
| Class 900 | 153.2 | 139.8 | 119.4 | 109.2 | High-pressure gas, pipeline isolation |
| Class 1500 | 255.4 | 233.0 | 199.0 | 182.0 | HP hydrocarbon, injection systems |
| Class 2500 | 425.6 | 388.3 | 331.6 | 303.3 | Wellhead, HP gas compression, sour service |
Ratings per ASME B16.5-2017, Material Group 1.1 (ASTM A105). Verify actual design conditions with your pressure engineer.
| Material | Pipe Std | Temperature Range | SAEP-347 | GUO Stock |
|---|---|---|---|---|
| ASTM A105 | ASME B16.5 | −29°C to 538°C | FL-001 ✓ | Ex-stock |
| ASTM A105N (Normalised) | ASME B16.5 | −29°C to 538°C | FL-001 ✓ | Lead 1–2 wks |
| ASTM A182 F11 (1¼Cr½Mo) | ASME B16.5 | −29°C to 593°C | FL-002 ✓ | Lead 2–4 wks |
| ASTM A182 F22 (2¼Cr1Mo) | ASME B16.5 | −29°C to 649°C | FL-003 ✓ | Lead 2–4 wks |
| ASTM A182 F304L | ASME B16.5 | −196°C to 399°C | FL-006 ✓ | Lead 2–4 wks |
| ASTM A182 F316L | ASME B16.5 | −196°C to 399°C | FL-007 ✓ | Lead 2–4 wks |
| Feature | Blind Flange | Spectacle Blind | Slip-On Flange |
|---|---|---|---|
| Function | Close pipe end | Switch open/closed | Connect pipe to pipe |
| Bolts removal required? | Yes — to install | No — rotate plate only | N/A — permanent |
| Pressure rating | Class 150–2500 | Up to Class 900 | Class 150–600 typical |
| Aramco (SAES-L-108) | ✓ All services | ✓ Process piping | ⚠️ Utility only |
| Typical application | Future tie-in, hydro test | Maintenance isolation | Low-pressure utility lines |
Standard documentation supplied with every blind flange order from Gulf Union Ozone:
WhatsApp or email RFQ response: within 4 business hours. Include your required specs and quantity. We confirm stock, lead time, and price by return.
A blind flange is a solid disc bolted to an open pipe end — all bolts are removed to switch between open and closed states. A spectacle blind (figure-8 blind) is a combined blind disc + open ring on a single plate inserted between two flanges — you rotate the plate instead of removing bolts. Blind flanges are simpler and rated to higher pressures (Class 2500). Spectacle blinds are faster to switch and preferred for frequent maintenance isolation in Class 150–900 process lines.
No — Saudi Aramco SAES-L-108 restricts slip-on flanges to non-hydrocarbon utility service (cooling water, instrument air, firewater). Process piping carrying hydrocarbons, corrosives, or Category M fluids requires weld neck flanges per SAES-L-108. Blind flanges, however, are permitted in all service categories including hydrocarbon and high-pressure service. If you are unsure of the service classification, consult your project piping specification or project engineer before ordering.
Sizes above NPS 24 fall under ASME B16.47 (large diameter flanges, NPS 26 to NPS 60) rather than B16.5. These are not ex-stock items — they are typically fabricated to order with lead times of 6–14 weeks depending on size, class, and material. Gulf Union Ozone can source ASME B16.47 Series A and Series B large bore blind flanges to order. Contact us with your size, class, and quantity requirement for a lead time and price indication.
Gulf Union Ozone stocks ASTM A105 blind flanges and slip-on flanges ex Jeddah. Include flange type, NPS, pressure class, facing, material grade, and quantity in your RFQ. EN 10204 3.1 MTCs, CoC, and ISO 9001:2015 documentation supplied with every order. Delivery same-day within Jeddah; 24–48h to Riyadh, Dammam, and Jubail.
Gulf Union Ozone Trading Co. supplies Blind Flange and Slip-On Flanges to industrial customers across Saudi Arabia with delivery from our Jeddah warehouse — all products ship with original Mill Test Certificates and Certificates of Conformance.
Blind Flange and Slip-On Flanges from Gulf Union Ozone serves Saudi Aramco SAEP-347 projects, SABIC, SADARA, SEC utilities, NEOM mega-projects, and industrial facilities across the Kingdom — our inventory covers the most common material grades and pressure ratings.
Gulf Union Ozone stocks a wide range of Blind Flange and Slip-On Flanges including various grades, sizes, and pressure classes — contact us on WhatsApp for immediate availability confirmation and a quotation with full MTC documentation.
For urgent Blind Flange and Slip-On Flanges procurement in Saudi Arabia, WhatsApp +966 55 098 8062 — our procurement team confirms stock availability within the hour and provides competitive quotations with full compliance documentation for Aramco, SABIC, SEC, and government projects.