Teshi PipeData
Flanges · Lap Joint

Lap Joint Flange 5" Class 300 — ASME B16.5

Lap Joint Flange 5" Class 300 to ASME B16.5: outside diameter 280 mm, flange thickness, min 33.4 mm, bolt circle (pcd) 235 mm, number of bolt holes 8, bolt hole diameter 22.2 mm; approx. weight 12.3 kg.

BXWOtfYSECTIONn × hFACE VIEW
Lap Joint Flange 5" Class 300 — dimension symbols match the table below. © Teshi Group · www.teshigroup.com

Dimensions of Lap Joint Flange 5" Class 300

SymbolDimensionValue
OOutside diameter280 mm (11.024 in)
tfFlange thickness, min33.4 mm (1.315 in)
WBolt circle (PCD)235 mm (9.252 in)
nNumber of bolt holes8
hBolt hole diameter22.2 mm (0.874 in)
dStud bolt size3/4"
YLength through hub51 mm (2.008 in)
XHub diameter178 mm (7.008 in)
BBore143.8 mm (5.661 in)
mApproximate weight12.3 kg (27.12 lb)

SKU TSH-FLANGE-LJ-B165-300-5 · Standard ASME B16.5 · weight: Calculated from nominal dimensions, carbon steel (ρ 7850 kg/m³)

Purchase description

FLANGE, LAP JOINT, FLAT FACE, 5" (DN 125), CLASS 300, ASTM A105N, ASME B16.5

Available materials: ASTM A105N, ASTM A350 LF2 Cl 1, ASTM A182 F304/304L, ASTM A182 F316/316L, ASTM A182 F11 Cl 2, ASTM A182 F22 Cl 3, ASTM A182 F51 (Duplex), ASTM A182 F53 (Super Duplex), ASTM A694 F52 / F60, IS 2062 E250 (plate).

Bolting and gasket

8 stud bolts 3/4" UNC × 125 mm (5") with 16 heavy hex nuts — ASTM A193 B7 studs + A194 2H heavy hex nuts. Gasket: Spiral wound 5" Class 300, ASME B16.20, SS316 + graphite, CS outer ring.

Additional data

FacingFlat face (lap)

Notes

Same size, other ratings

Other sizes — Lap Joint, Class 300

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.

All piping FAQs →