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20” [508mm] ASME Full Opening Manhole, Model 8350, 6 Hold Down, 50 psig MAWP
With decades of service and commitment to quality, the Betts’ ASME Full Opening Manhole product line is the proven leader of the chemical transportation and stationary tank markets. This industrial grade 20” [508 mm] manhole is certified to ASME Section VIII, Division 1 and meets the requirements of 49CFR§178.345-5 and §178.347-3 for use as an access port on DOT cargo tanks. The manhole is tagged with an ASME “U” stamp and a certified U2A form is provided.
The 8350-manhole assembly incorporates six (6) threaded 304SS wing‑nut hold‑downs and heavy‑duty 5/8‑inch 17-4 PH stainless steel one-piece fully machined ASME swing-bolts. The hinge is configured to provide 180-degree opening but optional hinge-stops are also available. Manholes are available in multiple material configurations with a range of gasket material options to accommodate specific service applications. Manholes manufactured from 316 stainless steel are fully passivated in accordance with ASTM A380 and are suitable for a wide range of chemical and food‑grade applications.
Internal MAWP: 50 psig (3.4 bar)
External MAWP (Vacuum): FV (-14.7 psig)
Test Pressure **: 75 psig (5.2 bar)
Product Details
| Part Number * | Weld Collar Mat'l | Dome Cover Mat'l | Weight | Collar Height * |
|---|---|---|---|---|
| 8350ASX-10 | Alum. (5454 H32) | Steel (SA414 Gr. C) | 58 lb. (26.4 kg) | 10” (254 mm) |
| 8350ALX-10 | Alum. (5454 H32) | 316L Stainless Steel | 58 lb. (26.4 kg) | 10” (254 mm) |
| 8350SCX-10 | Steel (SA414 Gr. C) | Steel (SA414 Gr. C) | 88 lb. (40 kg) | 10” (254 mm) |
| 8350LCX-10 | 316L Stainless Steel | 316L Stainless Steel | 88 lb. (40 kg) | 10” (254 mm) |
| 8350PLX-10 | 2205 Duplex | 316L Stainless Steel | 88 lb. (40 kg) | 10” (254 mm) |
| * Alternate collar heights are available by designating 4, 6, 8, or 10 as last digits of part number. | ||||
| ** Test pressure established using elastomer gasket. Manhole sealing performance is dependent on gasket selection, condition of sealing surfaces and wing-nut torque. | ||||
| Gasket Code | Material | Temp. Range |
|---|---|---|
| X | No Gasket (Sold Separately) | n/a |
| B | Buna-N (Black) | -40°F to +240°F [-40°C to +116°C] |
| V | FKM Type-A (Brown FDA) | -20°F to +400°F [-29°C to +204°C] |
| C | FKM Type-B (Green) | -20°F to +400°F [-29°C to +204°C] |
| W | Hypalon (White) | -40°F to +275°F [-40°C to +135°C] |
| P | EPDM (Black) | -40°F to +250°F [-40°C to +121°C] |
| T | PTFE Encapsulated Silicone Note: Tef-Sil gasket is difficult to seal. See Bulletin EB-03-99 | -40°F to +400°F [-40°C to +204°C] |
| D | EPDM (White FDA) | -40°F to +250°F [-40°C to +121°C] |
| E | Syntex Fiber (Woven) Note: Braided packing is not leak tight and will seep. | -40°F to +500°F [-40°C to +260°C] |
| F | Buna-N (White FDA) | -40°F to +240°F [-40°C to +116°C] |
| G | Viton™ GF | -35°F to +400°F [-37°C to +204°C] |
| Q | Fluorosilicone | -40°F to +350°F [-40°C to +177°C] |
| H | Viton™ A (White FDA/NSF) | -20°F to +400°F [-29°C to +204°C] |
| - Not all materials are available in every model. | ||
| - Actual performance and temperature values may vary due to service conditions. | ||
Technical Data
Engineering Bulletins
EB3-99: Installation and Care Instructions for Teflon Encapsulated Square Gaskets for Tiona-Betts Full Opening Manholes
EB-07-03: Maintenance and Use of Betts Full Opening Pressure Manhole
Installation and Maintenance Manual
MM-MH001: Full Opening Manhole Installation and Maintenance Manual
Instructional Videos
No video available at this time.
Repair Kits and Accessories
For full a full list of replacement components – see Parts List Page
Prop 65
WARNING: This product can expose you to chemicals including Chromium (hexavalent compounds) which is known to the State of California to cause cancer, birth defects or other reproductive harm. For more information go to: www.P65Warnings.ca.gov. For additional information on Betts products and Proposition 65 list please see: https://www.bettsind.com/prop-65/