Standard for thickness of spectacle blind
Standard for thickness of spectacle blind
(OP)
Hi all,
Normally ANSI B31.3 specifies formula for thickness calculation of blind. However,when we specify only pipe size, pressure rating and flange face, mostly all vendors inform the same thickness. For example, thickness of spectacle blind 10" 600# RTJ will be 2.25" (57 mm.)as per information from many vendors.
When I see standard table from many vendors, there is no standard referred for specitacle blind.
Anyone know standard applied for spectacle blind?
Thanks,
Dave
Normally ANSI B31.3 specifies formula for thickness calculation of blind. However,when we specify only pipe size, pressure rating and flange face, mostly all vendors inform the same thickness. For example, thickness of spectacle blind 10" 600# RTJ will be 2.25" (57 mm.)as per information from many vendors.
When I see standard table from many vendors, there is no standard referred for specitacle blind.
Anyone know standard applied for spectacle blind?
Thanks,
Dave





RE: Standard for thickness of spectacle blind
http://www.swecofab.com/spectacle/designspecs.htm
RE: Standard for thickness of spectacle blind
http:/
B16.48 takes the B31.3 formula and does the math for you. The 1997 ed. only covered carbon steel; the 2005 ed. upgraded that to cover more flavors. See the forward.
jt
RE: Standard for thickness of spectacle blind
ANSI 150, 300, & 600 FLANGE SKILLET DESIGN CALCULATIONS
======================================================
DESIGN PRESSURE--- 720 psig
PIPELINE NOMINAL DIAMETER-- 12.0 inches
PIPELINE ACTUAL OUTSIDE DIAMETER.. 12.750 inches
PIPE WALL THICKNESS--- 0.375 inches
PIPE INTERNAL DIAMETER.. 12.000 inches
OUTSIDE DIAMETER OF RAISED FACE.. 15.000 inches
"d" -max SPAN.... 13.500 inches
d = (internal + outside) / 2 = 13.5
"c" - FACTOR----------- 0.020
"S" MAXIMUM ALLOWABE STRESS--- 15,000 psi
MINIMUM REQUIRED THICKNESS SKILLET. 1.301 inches
d*(3/16*Design pressure/S)^0.5+ c = 1.301
RE: Standard for thickness of spectacle blind
- Up to 24", see ASME B16.48.
- For 26" & above, use ASME B31.3 formula.