Ring joint (RTJ) gasket 8" Class 900 — ASME B16.5 / B16.20
Ring joint (RTJ) gasket 8" Class 900 to ASME B16.5 / B16.20: pitch dia. p 269.88 mm, ring width a 11.13 mm, height oval b 17.5 mm, height octagonal h 16 mm.
Dimensions of Ring joint (RTJ) gasket 8" Class 900
| Symbol | Dimension | Value |
|---|---|---|
| · | Ring no. | R-49 |
| · | Pitch dia. P | 269.88 mm (10.625 in) |
| · | Ring width A | 11.13 mm (0.438 in) |
| · | Height oval B | 17.5 mm (0.689 in) |
| · | Height octagonal H | 16 mm (0.630 in) |
SKU TSH-GASKET-ASME-B16-5-B16-20-CLASS-900-8 · Standard ASME B16.5 / B16.20
Purchase description
RING JOINT (RTJ) GASKET, 8", CLASS 900, SS316 + GRAPHITE, CS RINGS, ASME B16.5 / B16.20
Available materials: SS316 + graphite, CS rings, SS316 + PTFE, CNAF (non-asbestos), Neoprene / EPDM rubber, Soft iron / SS316 (ring joint).
Notes
- There are no Class 900 flanges NPS 1/2–2-1/2 in practice (use Class 1500); ring numbers listed per chart.
- Tolerances: P ±0.18, A ±0.20, B/H +1.3/−0.5 mm.
Same size, other ratings
Other sizes — Ring joint (RTJ) gasket, Class 900
Frequently asked questions
What are the main types of pipe flanges?
Weld neck (WN), slip-on (SO), blind (BL), socket weld (SW), threaded (THD), lap joint (LJ) and plate flanges. Special types include orifice, long weld neck, reducing flanges and spectacle blinds.
When should I use a weld neck flange instead of a slip-on?
Use weld neck flanges for high pressure, high or cycling temperature, and lines with vibration or fatigue loading. The tapered hub and full-penetration butt weld spread stress smoothly. Slip-on flanges are cheaper and easier to align, but their fatigue life is roughly one third of a WN.
What does Class 150, 300 or 600 mean on a flange?
The ASME class is a pressure-rating designation, not a pressure in psi. The allowable pressure depends on the material group and temperature. A Class 150 A105 flange is rated 19.6 bar at 38 °C but 13.8 bar at 200 °C.
Is a 150# flange rated for 150 psi?
No. A Class 150 carbon-steel flange is rated about 285 psi (19.6 bar) at ambient temperature, and about 170 psi (11.7 bar) at 260 °C. The "150" is a class number.